Galloper Wind Farm Project - Planning Inspectorate · Galloper Wind Farm Project Environmental Statement – Chapter 13: Natural Fish and Shellfish Resources October 2011 Document

Galloper Wind Farm ProjectEnvironmental Statement – Chapter 13: Natural Fish and

Shellfish ResourcesOctober 2011

Document Reference – 5.2.13

Galloper Wind Farm Limited

Galloper Wind Farm ES 9V3083/R01/303730/Exet

Final Report - i - October 2011

Document title Galloper Wind Farm Project

Environmental Statement – Chapter 13: Natural

Fish and Shellfish Resources

Document short title Galloper Wind Farm ES

Document Reference 5.2.13

Regulation Reference APFP Regulations, 5(2)(a)

Version 7

Status Final Report

Date October 2011

Project name Galloper Wind Farm Project

Client Galloper Wind Farm Limited

Royal Haskoning

Reference

9V3083/R01/303730/Exet

Drafted by Randolph Velterop

Checked by Peter Gaches

Date/initials check PG 28.09.2011

Approved by Martin Budd

Date/initials approval MB 19.10.2011

GWFL Approved by Kate Harvey

Date/initials approval KH 01.11.2011


Final Report - ii - October 2011

CONTENTS Page

13 FISH AND SHELLFISH RESOURCES 1 13.1 Introduction 1 13.2 Guidance and Consultation 1 13.3 Methodology 7 13.4 Existing Environment 13 13.5 Assessment of Impacts – Worst Case Definition 68 13.6 Potential Impacts during the Construction Phase 81 13.7 Potential Impacts during the Operational Phase 111 13.8 Potential Impacts during Decommissioning 118 13.9 Inter-relationships 119 13.10 Cumulative Impacts 121 13.11 Transboundary Effects 133 13.12 Monitoring 133 13.13 Summary 134 13.14 References 137

Technical Appendix 13.A Fish Resource Surveys (2008-2009)

Technical Appendix 13.B Underwater Noise Impact Assessment

Technical Appendix 13.C Supplementary Herring Spawning Information


Final Report Chapter 13 - Page 1 October 2011

13 FISH AND SHELLFISH RESOURCES

13.1 Introduction

13.1.1 This Chapter of the Environmental Statement (ES) describes the existing environment with regard to the natural fish and shellfish resource within the proposed Galloper Wind Farm (GWF) project, as well as the wider area of the Outer Thames Estuary and southern North Sea.

13.1.2 This Chapter serves to provide a description of the distribution and seasonal

abundance of fish and shellfish species known to occur, or which have been recorded within both the study area and across the wider region. This description draws upon data collected through site specific and / or regional surveys, both in the published and grey literature and as a result of original data collection. Subsequent to this, the assessment of potential impacts of the construction, operation and decommissioning phases of the proposed GWF project on the existing environment are presented and detail on the proposed mitigation that will be considered by Galloper Wind Farm Limited (GWFL) are also provided. Finally, approaches to monitoring are presented.

13.1.3 For the purposes of the Infrastructure Planning (Applications: Prescribed Forms and Procedure) Regulations 2009, Figures 13.4 to 13.10 and Figures 13.13 to 13.20 taken together with this Chapter, fulfil the requirements of Regulation 5(2)(l) in relation to the effects of the proposed development on fish and shellfish resources.

13.2 Guidance and Consultation

Legislation, policy and guidance

13.2.1 The assessment of potential impacts upon fish and shellfish resource has been made with specific reference to the relevant National Policy Statements (NPS). These are the principal decision making documents for Nationally Significant Infrastructure Projects (NSIP). Those relevant to GWF are:

Overarching NPS for Energy (EN-1); and

NPS for Renewable Energy Infrastructure (EN-3).

13.2.1 The following paragraphs provide detail from sections of the relevant National

Policy Statements (NPS) (July 2011) EN-1 and EN-3 that are considered of relevance to the assessment of impacts on the fish and shellfish resource.

13.2.2 The specific assessment requirements relating to fish and shellfish resource, as detailed within the NPSs, are repeated in the following paragraphs. Where any part of the NPS guidance has not been followed within this assessment, it is stated after the NPS text and a justification provided. In all other cases the assessment requirements suggested within the NPSs have been applied to this assessment.



13.2.3 Section 5.3 of EN-1 sets out the policy for the IPC in relation to generic biodiversity impacts and paragraphs 2.6.58 to 2.6.71 of EN-3 set out offshore wind-specific biodiversity policy (see Section 5.3.3). In addition, there are specific considerations which apply to the effect of offshore wind energy infrastructure proposals on fish as set out below.

13.2.4 Paragraph 2.6.73 states that:

13.2.5 “There is the potential for the construction and decommissioning phases, including activities occurring both above and below the seabed, to interact with seabed sediments and therefore have the potential to impact fish communities, migration routes, spawning activities and nursery areas of particular species. In addition, there are potential noise impacts, which could affect fish during construction and decommissioning and to a lesser extent during operation.” (Sections 13.6, 13.7 and 13.8).

13.2.6 Paragraph 2.6.74 states that:

13.2.7 “The applicant should identify fish species that are the most likely receptors of impacts with respect to:

feeding areas;

spawning grounds;

nursery grounds; and

migration routes.” (Section 13.4)

13.2.8 In addition, paragraphs 2.6.75, 2.6.76 and 2.6.77 also discuss mitigation measures for reducing electromagnetic field (EMF) effects as well as for reducing the overall impacts of construction on fish communities. (Section 13.7).

13.2.9 The following guidance documents have also been used during the assessment of marine and intertidal ecology impacts:

Guidance on the Assessment of Effects on the Environment and Cultural Heritage from Marine Renewable Developments (Produced by: the Marine Management Organisation (MMO), the Joint Nature Conservation Committee (JNCC), Natural England, Countryside Council for Wales (CCW) and the Centre for Environment Fisheries and Aquaculture Science (Cefas), December 2010); and

Guidelines for data acquisition to support marine environmental assessments of offshore renewable energy projects. Draft for Consultation issued 10th March 2011. Cefas contract report: ME5403 – Module 15.

Offshore wind-farms: guidance notes for EIA in respect of FEPA and CPA requirements. Prepared by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) on behalf of the Marine Consents and Environment Unit (MCEU). Version 2 – June 2004



13.2.10 The implications of the following regulations and legislation have been taken into consideration when writing this ES:

Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007;

Conservation of Habitats and Species Regulations 2010 (“Habitats Regulations”); and

Wildlife and Countryside Act 1981.

Consultation

13.2.11 As part of ongoing consultation, key stakeholders were invited to respond to a scoping document produced as part of the EIA process (GWFL, 2010). Table 13.1 summarises issues that were highlighted by the consultees in the IPC Scoping Opinion (IPC, 2010) and indicates which sections of the assessment address each issue. GWFL undertook early consultation with Cefas on the requirement for, and scope of, site specific surveys to characterise the fish and shellfish baseline environment.

13.2.12 Further consultation was undertaken through formal Section 42 consultation under the Planning Act 2008 (see Chapter 7 Consultation) via the submission of a Preliminary Environmental Report (PER). Community consultation under Section 47 has also been carried out in parallel with the Section 42 statutory consultation. The process for GWFL’s community consultation is set out in the Statement of Community Consultation (SoCC) for GWF (see Chapter 7). Full details of responses received are presented in the IPC Scoping Opinion report (IPC, 2010) and the Consultation Report that accompanies the Development Consent Order (DCO) for this application.

Table 13.1 Summary of consultation and issues

Date Consultee Summary of issue Section where addressed

September

2009

Kent and Essex

Sea Fisheries

Committee

Concerns relating to spawning

species including sole, sandeel,

herring and also egg laying species

such as rays and dogfish which are

thought to lay their eggs in the

deeper water between the Gabbard

and Galloper banks.

Section 13.6

September

2009

Shark Trust and

inshore fishermen

The proposed GWF area is known as

an important local pupping ground for

spurdog. Consideration required of

Section 13.6




spurdog, and other elasmobranchs,

especially egg laying species.

August

2010

IPC & Marine

Management

Organisation

(MMO) & Centre

for Environment,

Fisheries and

Aquaculture

Science (Cefas)

(Scoping Opinion)

Operational noise & vibration on fish

is not scoped out.

Section 13.7

The Commission recommends that

the impacts on protected fish species

is fully assessed and mitigation

provided.

Section 13.6

Noise and vibration levels along the

foreshore potentially affecting fish

should be also be addressed.

Section 13.6

Consideration should be given to

potential impacts on spawning cod.

Pile driving restrictions are likely, with

plaice, herring and sole seen as key

species.

Section 13.6

August

2010

Eastern Sea

Fisheries Joint

Committee

(Scoping Opinion)

Mitigation for effects of suspended

sediment on fish species should be

considered e.g. timing cabling

operations to avoid sensitive periods.

The effects of EMF should be

considered.

Cumulative effects on fish resources

of the proposed works with the

Greater Gabbard OWF and the

proposed East Anglia ONE OWF.

Section 13.6,

13.7 and 13.10

August

2010

Joint Nature

Conservation

Committee

(JNCC) & Natural

England (Scoping

Opinion)

Key consideration for EIA include

suspended sediment impacts on

Spurdog pupping ground.

Section 13.6

August Royal Society for Any impacts on the early life stages Section 13.7




2010 the Protection of

Birds (RSPB)

(Scoping Opinion)

of fish may have lethal effects for bird

life.

July 2011 Suffolk Coast and

Heaths AONB

Unit and Suffolk

County Council

and Suffolk

Coastal District

Council (Section

42)

Consideration should be given to use

of artificial reefs along the cable and

within the wind farm to mitigate

impacts.

Section 13.7.

July 2011

MMO (Section 42)

Clarification on GWF site specific

fisheries survey data analysis,

surveyed area and specification of

survey methodology.

Section 13.3

and Technical

Appendix

13.A

Ideally modelling of noise impacts on

the critically endangered eel would

have been undertaken. This could be

added to the EIA.

Section 13.6

Present data to support the

statement that the main Downs

herring spawning grounds are in the

eastern English Channel and that the

Southern Bight spawning grounds

are of less importance.

Consideration of the impact of noise

on herring eggs.

Section 13.4,

13.6 and

Technical

Appendix

13.C

Use of most recent up-to-date ICES

advice on status of elasmobranch

stocks.

Section 13.4

Piling construction: Potential to install

all monopiles during a 10 week

period thereby avoiding sensitive

periods of herring and sole.

Section 13.4

and 13.6




A condition must be included in the

DCO stating that no piling may occur

from 1st November to 31st May.

Fleeing speeds of fish in relation to

piling.

Section 13.6

Consideration of background noise

levels in EIA.

Section 13.6

Consideration of particle motion

impacts on hearing insensitive

species such as sole.

Section 13.6

Cumulative impacts to sole spawning

should be fully considered in the EIA.

Section 13.10

Consideration of sediment type in

INSPIRE V18 sound propagation

model.

Technical

Appendix

13.B

Use of dBht species metric rather than

the more widely used M-weighted

sound exposure level makes

comparisons and practical

implications difficult.

Section 13.6

Clarification is required on what

parameters are used to derive

regional significance for species

selected for noise modelling.

Section 13.6

and Technical

Appendix

13.B

Insufficient consideration regarding

the cumulative impact of repeated

hammer blows necessary to erect

each foundation and the knock-on

effect that this evokes on impact

range maps.

Section 13.10

and Technical

Appendix

13.B

July 2011

East Anglia

Offshore Wind

Limited (EAOW)

Cumulative impact of underwater

noise with EAOW construction

programme.

Section 13.10




(Section 42)

July 2011

Dutch Fisheries

Organisation

(Section 42)

Effects of underwater sound on fish

and impacts on fish larvae.

Section 13.6

and Technical

Appendix

13.B

July 2011

Aldeburgh local

fishermen,

Aldeburgh

Fishermens Trade

and Guild and

Eastern Inshore

Fisheries and

Conversation

Authority (Section

47)

ES should address construction and

operational noise, EMF, impacts on

local fish stocks, creation of artificial

habitat as mitigation.

Monitoring should consider GWF in

isolation and cumulative needs.

Section 13.6

and 13.7

Section 13.11

July,

August

2011

Eastern Inshore

Fisheries and

Conservation

Authority (EIFCA)

(Section 42)

Suggest monitoring to establish the

effects of EMF. EMF is one of key

reasons that the Authority maintains

a general objection to offshore wind

farm development.

Cumulative EMF impacts associated

with GWF and East Anglia ONE

cable crossing points of export

cables.

Section 13.7,

13.10

13.3 Methodology

Study area

13.3.1 The study location with regard to natural fish and shellfish resources is considered to encompass the proposed GWF, export cable corridor and the wider Outer Thames area, in particular ICES rectangles 32F2, 32F1, 33F2 and 33F1. With regard to fish species and given their highly mobile nature in some cases it is necessary to consider the status of fish stocks in the context of wider regional dynamics across the southern North Sea and also the English Channel. The relation of these ICES rectangles and the Thames Strategic Environmental Assessment (SEA) are shown in Figure 13.1.





Characterisation of the existing environment

13.3.2 Existing data sources that enable a detailed broadscale characterisation of the natural fish and shellfish resource are extensive. Some of these wider data sources and studies encompass the proposed GWF study area (e.g. Marine Aggregate Levy Sustainability Fund (MALSF), 2009) and, therefore, also serve to augment site specific data and knowledge. Those data sources and studies that are considered of relevance to the proposed GWF project include:

Environmental Statements (ES’s) from other offshore wind farm developments and aggregates dredging sites;

MMO fisheries landings data on commercially important fish species;

Department of Environment Food and Rural Affairs (Defra) spawning and nursery maps for mobile species considered to be of conservation importance (Cefas, 2010a);

Fisheries sensitivity maps (Coull et al., 1998);

The Outer Thames Estuary Regional Environmental Characterisation (MALSF, 2009);

Information on species of conservation interest (JNCC);

Cefas Interactive Spatial Explorer and Administrator (iSEA), research publications and broad scale survey data; e.g. North Sea young fish survey (Aug-Sept) / Eastern English Channel survey (Aug-Sept), all of which cover some of the Greater Gabbard Offshore Wind Farm (GGOWF) and proposed GWF areas;

Kent and Essex Sea Fisheries Committee (KESFC) District Research Reports;

Eastern Sea Fisheries Joint Committee (ESFJC) Research Reports; and

International Council for the Exploration of the Sea (ICES) Reports and Research Publications.

13.3.3 Further information on the distribution and abundance of fish and shellfish species within the general area of the development was obtained from:

Monitoring and surveys carried out as part of the GGOWF Food and Environment Protection Act (FEPA) licence (Licence 33097/07/0) including pre and post construction surveys for:

o Annual fisheries surveys

o Noise and Vibration monitoring during piling

13.3.4 Site specific information has been obtained from dedicated beam and otter trawl surveys carried out in the spring and autumn to target adult and juvenile fish within the proposed GWF site, export cable corridor and their immediate environs (Brown & May Marine Ltd. October 2008 and April 2009). The



methodologies associated with this survey are summarised in the following paragraphs with full detailed accounts of survey methodology and findings provided in Technical Appendix 13.A. It is noted that these surveys were commissioned in 2009 prior to the site boundary having undergone modification (see Chapter 6 Site Selection and Alternatives). Therefore, a number of the sample locations that were within the original project boundary now lie outwith of its refined extents.

13.3.5 These sources are considered to be comprehensive in describing the fish and shellfish resource that has the potential to be impacted as a result of the proposed development of GWF. GWF Survey strategy

13.3.6 GWFL commissioned Brown and May Marine Ltd. to undertake site specific fisheries surveys during the autumn (October) of 2008 and spring (April) of 2009 to characterise the species assemblages within the proposed GWF site.

13.3.7 The surveys were conducted using a standard commercial otter trawl, fitted with ‘rock-hopper’ ground line and 100mm mesh cod end. Tows were limited to approximately 25 minutes duration and undertaken during daylight hours. The durations of the tows were timed to accommodate the ground conditions and the catch rates, as agreed with Cefas.

13.3.8 A two-metre scientific beam trawl fitted with a 5mm mesh cod-end liner was used for the juvenile fish / epibenthic sampling. Beam trawls were approximately five minutes in duration.

13.3.9 A complete description of the survey specifications, methods used including boat and gear descriptions, tow speeds, gear deployment locations, dates and haul and shot times are presented in the survey reports presented in Technical Appendix 13.A.

13.3.10 Fish and shellfish samples were identified, measured and recorded and data standardised to catch per unit effort (CPUE) to account for sampling intensity in the three different areas. The survey methodology, including trawl locations, gear types and data analysis was agreed through consultation with Cefas (Section 13.2) prior to commencement.

13.3.11 The locations of the commercial otter trawls and scientific beam trawls in relation to GGOWF and the proposed GWF site are presented in Figure 13.2, which shows the sites surveyed during both the autumn (2008) and spring (2009) surveys and also the locations sampled during the GGOWF surveys. Both otter trawl and beam trawl surveys were carried out for the proposed GWF site at the locations labelled B01-B18 in blue on Figure 13.2.

13.3.12 The locations of the 2m beam trawls, carried out for the 2007 Outer Thames Regional Environmental Characterisation, are presented in Figure 13.3.







Assessment of impacts

13.3.13 The impact assessment has been undertaken in accordance with the methodology set out in Chapter 4 EIA Process. The development envelope provided in Chapter 5 Project Details, have been used to establish a realistic worst case development scenario for the assessment of impacts. The worst case scenario for impacts on fish and shellfish varies depending on the impact source under consideration. Therefore, the worst case scenario is set out in Section 13.5 and assessed within the specific sections of the impact assessment (Section 13.6, 13.7 and 13.8).

13.3.14 The impact assessment has been informed by dedicated studies, such as underwater noise modelling (Subacoustech, 2011 as provided in Technical Appendix 13.B) and herring spawning larval data investigations (Technical Appendix 13.C) as well as industry experience from monitoring studies associated with existing projects (of particular relevance being the knowledge gained from the ongoing monitoring studies at the adjacent GGOWF project (GGOWL, 2009)). These data are further supported by industry wide studies and Collaborative Offshore Wind Research into the Environment (COWRIE) publications including the following:

Effects of offshore wind farm noise (Thomsen et al., 2006);

The effects of pile-driving noise on the behaviour of marine fish (Mueller-Blenkle et al., 2010); and

A review of the effects of EMF on sensitive marine species (Gill & Bartlett, 2010, Gill et al., 2005).

13.3.15 Other Chapters within this ES (such as Chapter 12 Marine and Intertidal

Ecology, Chapter 15 Commercial Fisheries, Chapter 14 Marine Mammals and Chapter 9 Physical Environment) have been used to inform the assessment where inter-relationships are relevant.

13.4 Existing Environment

Seabed habitats

13.4.1 Distribution patterns of fish depend to some degree on the spatial extent of appropriate habitat. Over broad spatial areas, the main abiotic factors that affect the distribution of fishes and fish communities are water temperature, salinity, depth and substrate type. Other features including biotic factors (predator-prey interactions, competition, local-scale habitat features) and anthropogenic activities (e.g. the presence of artificial structures and fisheries) can also be important factors operating on a variety of temporal and spatial scales (ICES, 2010a).

13.4.2 The study area is characterised by shallow water depths principally between 20m and 40m with sediments comprising medium to coarse sand with silt and clay and mixed sediments with areas of patchy cobbles and gravel on the banks to the east. The benthic habitats associated with these mobile substrates were generally of lower taxonomic diversity and dominated by



polychaetes. Epibenthic faunal composition was characterised by echinoderms and crustaceans, with sparse but diverse mollusc assemblages (Chapter 12).

Broadscale fish species descriptions

13.4.3 In order to gain an understanding of the relative importance, presence and abundance of fish and shellfish species at regional and local levels, commercial landings data for ICES rectangles 32F2, 32F1 and 33F1 from 2006 to 2010 were interrogated to establish which species are regularly landed. Although it must be understood that the quantities of species landed are often driven by market forces and quota restrictions, assessing landings data helps provide context for the site specific fisheries surveys carried out.

13.4.4 The top 10 species of fish, crustaceans, molluscs and bivalves commonly targeted commercially in ICES rectangles 32F2 (main GWF site), 33F1 (export cable corridor) and 32F1 by weight are presented in Table 13.2. A full list of recorded species from both commercial landings data and site specific surveys is presented in Table 13.3.

Table 13.2 Species landings data (tonnes) for the top 15 species landed 2006 – 2010 from ICES rectangles 32F1, 32F2 and 33F1

Species Scientific name Landings (tonnes)

32F1 32F2 33F1 Total

Cockle Cerastoderma edule 2867 - - 2867

Horse Mackerel Trachurus trachurus 1015 1054 0 2069

Sole Solea solea 606 89 336 1031

Cod Gadus morhua 375 35 509 920

Skates & Rays Raja spp. 410 14 258 682

Sprat Sprattus sprattus 265 0 107 372

Plaice Pleuronectes platessa - 176 - 176

Bass Dicentrarchus labrax 112 - 33 145

Herring Clupea harengus 28 41 25 93

Lobster Homarus gammarus 57 - 25 82

Flounder Platichyths flesus - 10 29 39

Whelk Buccinum undatum - 38 - 38

Brown Crab Cancer pagurus - - 37 37

Mullet - Other Mugilidae 27 - - 27



Species Scientific name Landings (tonnes)

32F1 32F2 33F1 Total

Smoothhound Mustelus mustelus - - 20 20

Dab Limanda limanda - 12 - 12

Whiting Merlangius merlangus - 11 - 11

Source: MMO, 2011

13.4.5 Landings data indicates that the regional study area is more important for finfish than shellfish, although brown crab Cancer pagurus, lobster Homarus gammarus and whelk Buccinum undatum landings are recorded from all three ICES rectangles (Table 13.2). The following finfish species are particularly important in the area: horse mackerel Trachurus trachurus, sole Solea solea, cod Gadus morhua, skates and rays Rajidae spp., sprat Sprattus sprattus, plaice Pleuronectes platessa and bass Dicentrarchus labrax (Table 13.2).

13.4.6 The English Channel is generally considered to represent a biogeographical boundary between the northerly boreal province, and the more southerly Lusitanean province (Dinter, 2001). Although many boreal species are widespread throughout much of the North Sea (e.g. cod and herring Clupea harengus), several of the Lusitanian species that are largely restricted to the Southern Bight such as lesser weever Echiichthys vipera, greater weever Trachinus draco and striped red mullet Mullus surmuletus.

13.4.7 The key species recorded at the proposed GWF site as identified from landings and site specific surveys are listed in Table 13.3.



Table 13.3 Fish species present within the study area as identified from landings data and site specific surveys

Common Name Scientific Name Common Name Scientific Name

Marine Finfish

Anchovy Engraulis encrasicolus Lumpfish Cyclopterus lumpus

Bass Dicentrarchus labrax Mackerel Scomber scombrus

Black Seabream Spondyliosoma cantharus Megrim Lepidorhombus whiffiagonis

Bib Trisopterus luscus Monks or Anglers Lophius piscatorius

Brill Scophthalmus rhombus Mullet - Other Mugilidae

Blonde Ray Raja brachyura Pilchards Sardina pilchardus

Cod Gadus morhua Plaice Pleuronectes platessa

Conger Eel Conger conger Pollack Pollachius pollachius

Common Dragonet Callionymus lyra Poor Cod Trisopterus minutus

Dab Limanda limanda Red Gurnard Aspitrigla cuculus

Dover Sole Solea solea Red Seabream Pagellus bogaraveo

Dragonet Callionymus lyra Red Mullet Mullus surmuletus

Eelpout Zoarcidae Saithe Pollachius Virens

Eels Anguilla anguilla Sand Smelt Atherina presbyter




Flounder Platichyths flesus Sand Sole Pegusa lascaris

Garfish Belone belone Sprat Sprattus sprattus

Greater Weever Trachinus draco Squid Unidentified

Grey Gurnard Eutrigla gurnardus Streaked Gurnard Chelidonichthys lastoviza

Haddock Melanogrammus aeglefinus Sole Solea solea

Hake Merluccius merluccius Triggerfish Balistes capriscus

Herring Clupea harengus Tub Gurnard Chelidonichthys lucernus

Horse Mackerel Trachurus trachurus Turbot Psetta maxima

John Dory Zeus faber Twaite Shad Alosa fallax

Lemon Sole Microstomus kitt Whiting Merlangius merlangus

Lesser Weever Echiichthys vipera Witch Glyptocephalus cynoglossus

Ling Molva molva Wrasses Labridae

Shellfish

Edible Crab Cancer pagarus Velvet Crab Necora puber

Lobster Homarus gammarus

Elasmobranchs




Blonde Ray Raja brachyura Starry Smoothhound Mustelus asterias

Lesser Spotted Dogfish Scyliorhinus canicula Thresher Shark Alopias vulpinus

Smoothhound Mustelus mustelus Thornback Ray Raja clavata

Spotted Ray Raja montagui Tope Galeorhinus galeus

Spurdog Squalus acanthias

N.B. species in bold text are those recorded during the site specific fisheries surveys



Principal fish species: distribution, spawning and nursery areas

13.4.8 A number of species of commercial importance are known to use the Outer Thames Estuary for spawning and as nursery grounds. Figures 13.4 to 13.17 show commercially important species which have spawning and nursery grounds in the wider Outer Thames Estuary. Table 13.4 identifies the main periods of spawning activity for commercial fish species in the Outer Thames Estuary and southern North Sea. Further species specific information is discussed subsequently for species which are deemed to be of particular relevance to the site.

Table 13.4 Main periods of spawning activity for key fish species in the Outer Thames region (spawning periods are highlighted in yellow, peak spawning periods marked orange) adapted from Coull et al., (1998)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Sole

Lemon Sole

Herring *

Herring **

Sandeel

Plaice

Cod

Whiting

Mackerel

Sprat

Bass

Edible crab

Herring: * refers to the Downs autumn Channel herring, ** refers to the Thames (or Blackwater) spring

spawning herring

13.4.9 Information on the spawning and nursery grounds of commercially important species (Cefas, 2010a, Coull et al., 1998) that overlap or are in close proximity to the study area or are considered to be sensitive to potential wind farm impacts (e.g. elasmobranchs and herring) are discussed by species below.

Individual fish species accounts - finfish

Herring

13.4.10 Herring are a commercially important pelagic fish, common to much of the North Sea. Herring deposit their eggs on a variety of substrates from coarse



sand and gravel to shell fragments and macrophytes; although gravel substrates have been suggested as their preferred spawning habitat. Once spawned, herring eggs take about three weeks to hatch, depending on sea temperature, after which larvae drift in the plankton.

13.4.11 While a proportion of the proposed GWF site overlaps with the herring spawning grounds (Figure 13.4) the benthic grab (97 stations) and drop-down camera surveys (98 stations) concluded that the majority of sediment throughout the GWF survey area were poorly sorted and did not offer ideal conditions for herring to spawn on (CMACS, 2010, see Technical Appendix 12.A).

13.4.12 North Sea herring fall into a number of different ‘races’, each with different spawning grounds, migration routes and nursery areas (Coull et al.,1998). There are three major races of autumn spawners, which mix on the feeding grounds for the majority of the year, but then migrate to specific grounds to spawn. As shown in Figure 13.4 the proposed GWF site is located on the outer edge of a stock known as ‘the Downs herring’, which spawn in the Southern Bight and eastern English Channel from November to January, defined by Coull et al., (1998) and more recently updated in Cefas (2010a). The other two herring races lie off northeast Scotland and north-east England and undergo autumn spawning (taking place from August to September, and August to October respectively). These three races represent the bulk of the North Sea herring stock, although some spawning also occurs in spring (e.g. the Thames Estuary stocks) between mid February to late April. The principal recognised spawning sites for the Thames spring spawning herring are the Eagle Bank, at the mouth of the Blackwater Estuary and Herne Bay (Wood, 1981) with both of these spawning grounds being located approximately 55km from the proposed GWF site.

13.4.13 The use of the Thames Estuary by herring is generally seasonal, with the

inshore migrations of the Blackwater herring starting in early October with fish concentrating within 10 miles of the East Anglian coast in preparation for spawning the following spring (Wood, 1981 as cited in Fox, 2001). Juveniles generally spend two years in coastal areas before moving offshore to join the adult stock (MacKenzie, 1985, cited in ICES, 2010a).

13.4.14 The Southern Bight spawning ground covers an area of approximately

3,300km2 with the two East Channel Downs herring spawning sites (based on the Coull et al., 1998 data) covering areas of 1,300km2 and 1,500km2 respectively. The latter two sites are located approximately 160km and 260km to the southwest of the proposed GWF site respectively.

13.4.15 Herring have a relatively high sensitivity to underwater sound and vibration

due to their physiology and extension of the swim bladder (bulla) that terminates within the inner ear. Herring spawning and nursery areas are, therefore, particularly sensitive and vulnerable to anthropogenic influences, especially given that herring are a benthic spawning species.



13.4.16 In light of the comments raised during consultation (see Table 13.1) it was recognised that better resolution of the spawning grounds currently used by the Downs herring was required in order to establish the extent of potential noise related impacts. Larval data from the International Herring Larvae Survey (IHLS) was acquired for the years 2000 to 2011 (see Appendix 13.C). Herring larval data, especially for newly hatched yolk-sac larvae, is widely used to indicate herring spawning activity and define the spawning grounds currently being used.

13.4.17 It is widely acknowledged that since the 1970’s the main Downs herring spawning grounds have been confined to the Eastern English Channel (Dickey-Collas et al., 2009, Pawson, 1995, ECA and RPS Energy, 2010, Rohlf & Gröger, 2003) and that the herring larvae recorded in the Southern Bight originate from spawning grounds in the Eastern Channel (C Van Damme 2011, pers. comm. 12 August). This is also reflected by the commercial exploitation of the Downs stock where winter spawning aggregations are targeted by fleets in the eastern English Channel (ICES, 2009, ICES, 2007a).

13.4.18 Maps of the larval data indicate that in agreement with previous studies the centres of newly hatched yolk-sac larvae evident in December centre on the eastern English Channel Downs herring spawning grounds with only limited spawning activity occurring on the Southern Bight spawning grounds (see Technical Appendix 13.C and Figure 13.5). IHLS surveys are undertaken in December and January to capture the Downs herring spawning activity. The presence of non yolk-sac larvae in the Southern Bight by the January surveys is as a result of passive transport whereby larvae originating from the eastern English Channel are transported to their nursery grounds in the southern North Sea by the regional hydrodynamic regime and meteorological forcing. This trend is clearly demonstrated by the 2010/2011 data presented in Figure 13.5 which shows that following the December survey the larvae disperse and are subsequently transported into the southern North Sea by the by the time of the mid and end of January surveys. This transport of eggs and larvae is also well documented for a number of other species with spawning grounds in the eastern English Channel (see Erftemeijer et al., 2009, Dickey-Collas et al., 2009, Houghton & Harding, 1976).

13.4.19 The data indicates that while a proportion of the proposed GWF site lies within areas shown by Coull et al.,(1998) to be part of the Downs Southern Bight Downs spawning grounds, these grounds are not currently used as the main spawning grounds which are currently located in the English Channel.

13.4.20 It has been suggested that the importance of spawning grounds for herring in the North Sea is related to the health of the stock (Schmidt et al., 2009) and some historic spawning grounds which currently have no or very little activity can be “re-colonised” over time (e.g. Corten, 1999). Whilst we must acknowledge that the Southern Bight grounds may be re-colonised in the foreseeable future, based on current trends they are at present not used by the main Downs spawning stock.







Cod

13.4.21 Cod Gadus morhua is widely distributed throughout the North Sea. Adult cod (+70cm) densities tend to be highest in the north, between Shetland and Norway, along the edge of the Norwegian Deep, in the Kattegat off the Danish coast, around the Dogger Bank and in the Southern Bight. Sub-adults (<70cm) are more widespread and occur throughout the North Sea, and Kattegat (ICES, 2010a).

13.4.22 Spawning grounds appear to be wide-spread and not restricted to specific areas, with spawning aggregations found offshore all over the North Sea. Spawning itself can take place anywhere in the water column with eggs released in batches over a number of days. The eggs then take 10 to 30 days to hatch, depending on temperature (ICES, 2010a). Peak spawning in the southern North Sea occurs from the last week of January to mid-February (Daan et al., 1980). Results from plankton surveys and the distribution of mature cod in trawl surveys showed hot spots of egg production around the southern and eastern edges of the Dogger Bank, in the German Bight, the Moray Firth and to the east of the Shetlands (Fox et al., 2008).

13.4.23 As shown in Figure 13.6, the proposed GWF site is situated within a low intensity spawning ground according to Cefas (2010) and in close proximity (approximately 8km) to the original spawning grounds highlighted by Coull et al., (1998). GWF is also within a low intensity nursery area although catch rates seem to indicate that the southern areas of the North Sea are less important than the more northern areas (see Figure 13.6).

13.4.24 Cod has an anterior part of the swimbladder that, although not connected to the inner ear, is in close proximity, and hence cod have a relatively high sensitivity to underwater sound, though lower than herring. Cod is known to use low level grunting sounds to locate mates and coordinate spawning (Hawkins & Rasmussen, 1978). Anthropogenic noise sources may be audible for cod over long distances, potentially masking important communication and disturbing spawning behaviour.

13.4.25 Cod represented an important proportion of the fish species caught during the GWF site surveys and were well distributed between the export cable corridor and wind farm site (see Figure 13.6). Chapter 15 also indicates that cod catches by weight are the most important species in ICES rectangle 33F1 which contains the cable corridor.





Whiting

13.4.26 Whiting Merlangius merlangus is widely distributed throughout the North Sea, Skagerrak and Kattegat off the Danish coast. High densities of both small and large whiting may be found almost everywhere, with the exception of the Dogger Bank, which generally shows a marked hole in the distribution (ICES, 2010a).

13.4.27 Spawning takes place from January in the southern North Sea (Svetnovidov, 1986). The pelagic eggs, which take about ten days to hatch, are shed in numerous batches over a period that may last for up to 14 weeks (ICES, 2010a).

13.4.28 During summer, juveniles are particularly abundant in the German Bight and off the Dutch coast to the north-east of the proposed GWF site. Large whiting occur in high densities south of Shetland during the winter, when densities are relatively low in the central North Sea. During summer, the entire southern half of the North Sea is densely populated by adult whiting. Whiting were also one of the most abundant species caught during the site surveys (Plot 13.2, Plot 13.3, Plot 13.4 and Plot 13.5).

13.4.29 As shown in Figure 13.7 the wind farm site falls within the low intensity spawning and nursery areas. Catch rates presented in Figure 13.7 indicate that, while GWF falls within the nursery area, higher numbers of juvenile whiting tend to be caught in the more northerly parts of the North Sea.





Plaice

13.4.30 North Sea plaice Pleuronectes platessa form a stock that consists of a number of sub-units and they are commonly found all around the UK and Irish coasts, with a preference for sandy substrates, although older age groups may be found on coarser sand.

13.4.31 During the spawning season of December to April, individuals from the sub-units can be found in an area of the southern North Sea known as the ‘Southern Bight’. Hunter et al. (2003) demonstrated that, as previous studies have shown, the Southern Bight is a major spawning ground for plaice.

13.4.32 Peak spawning time shifts from early January in the eastern English Channel to mid-February in the German Bight and off Flamborough (Rijnsdorp, 1989). The duration of the pelagic egg and larval stages of plaice (three to four months) is long compared to, for example, sole (about one month) (ICES, 2010a). This results in long exposures to residual currents, and the young plaice may settle in areas far away from the spawning area. While GWF is located within an area identified as a high intensity spawning area (Figure 13.8) the centres of high egg production in the Southern Bight are to the southeast and southwest of GWF. Data indicates that commercial plaice landings from ICES rectangle 33F2 are higher than from the GWF rectangle (32F2) (see Chapter 15), especially during winter (January). This may be a reflection of the higher importance of this rectangle and area of the North Sea to spawning plaice in comparison to the GWF area.

13.4.33 Tagging experiments have shown strong fidelity behaviour, with individual fish returning to the same spawning and feeding areas (Hunter et al., 2003). Part of the North Sea plaice population spawns in the Channel and returns to its feeding grounds in the North Sea afterwards. Juveniles are found in shallow coastal waters and outer estuaries such as the Thames and as they grow older they gradually move into deeper water (“Heinckes Law”) (ICES, 2010a).

13.4.34 Plaice represent an important commercial species landed from rectangle 32F2, in keeping with the well documented importance of the southern North Sea for this species (see Chapter 15). Plaice were also caught at the GWF site during the otter and 2m beam trawl surveys.

13.4.35 Due to the lack of a swimbladder, it is thought that flatfish species such as plaice tend to be less sensitive to noise than roundfish.





Sole

13.4.36 Sole Solea solea tend to occupy shallow, sandy and sandy / muddy habitats and are widespread throughout UK waters. Although such habitats are common across much of the North Sea and spawning occurs along all southern North Sea coasts, five main spawning grounds can be distinguished (see Figure 13.9):

Inner German Bight;

Belgian coast;

Eastern Channel;

Thames Estuary; and

Norfolk Banks.

13.4.37 Data from Cefas (2010a) show the Thames Estuary as a high intensity spawning area (Figure 13.9). In the Thames mature sole move inshore into relatively shallow water often associated with reduced salinity (Burt and Milner, 2008). At this time of year sole are densely aggregated with spawning taking place within the 30m depth contour. Spawning is triggered by sea water temperature, with peak spawning being advanced during a warm spring (ICES, 2010a). Sole also show a preference for sandy and finer grained sediments during both adult and juvenile stages (Kaiser et al., 1999, Rogers, 1992). The stage I sole egg data presented in Figure 13.9 also supports the presence of inshore sole spawning occurring inshore in the Thames.

13.4.38 Eastwood and Meaden (2000) modelled the spawning habitat suitability for sole in the southern North Sea using the distribution of eggs in relation to parameters such as temperature, depth, salinity and sediment type. Clear relationships were found between these parameters with consistently higher densities of eggs associated with sediment with <30% gravel content, shallower inshore waters, reduced salinity and increased temperature.

13.4.39 Grab sampling undertaken at the proposed GWF site found that in general the sediments in all three development areas consisted gravelly sand or sandy gravel (CMACS, 2010) substrates deemed to be less suitable for sole spawning. The plots for sediment class, depth, temperature and salinity parameters presented in Figure 13.11 along with the final habitat suitability maps (Figure 13.12) produced by Eastwood and Meaden (2000) strongly support the presence of a more defined inshore sole spawning ground which corresponds to the grounds defined by Pawson (1995) in Figure 13.13. These grounds are located 25km to the southwest of the proposed GWF site. These findings also correspond to other studies which suggested that the shallower areas around the channels and sandbanks of the Black Deep and Knock Deep more than 20km to the west of the proposed GWF site are important for sole spawning aggregations (Child et al., 1991).



13.4.40 Studies of sole larval distribution in the Eastern Channel and Southern Bight also found sole larvae to be distributed in coastal waters throughout their development (Grioche et al., 2001). The association of sole spawning grounds with suitable inshore habitats may be linked to a strategy of having the youngest larvae in areas of lower currents, which allows their retention in shallow waters with high temperatures and fluorescence (Grioche et al., 2001). This is also supported by their relatively short pelagic egg and larval phase (one month) which generally means offspring never move large distances from spawning grounds. Nursery grounds are generally found in shallow coastal waters at depths between 5 and 10m, and the local abundances of 0-group sole are thought to reflect the spawning success of local spawning aggregations (Rogers & Stock, 2001).

13.4.41 A study in the Thames Estuary found that at different locations and even on different days peak spawning took place in the evening (Child et al., 1991). Studies on captive sole have also documented complex synchronised spawning courtship behaviour (Baynes et al., 1994). Spawning begins in March, peaking in April and continuing sporadically until late June (Burt and Milner, 2008). The analysis of market sampling data presented in Bromley (2003) also indicated that the proportion of males with full testes peaked in April, at the same time as the peak in the hyaline egg phase in females. These studies would suggest that the key sensitive period for sole spawning is April as spawning activity declines rapidly following this peak period.

13.4.42 Sole migrate to the warmer offshore grounds in autumn when temperatures fall. In severe winters, they may form dense aggregations in the deeper and less cold parts in the southern North Sea and the eastern Channel (Rijnsdorp et al., 1992). In March to May they return to inshore waters.

13.4.43 Tagging experiments support the suggestion that the spawners return to the same spawning grounds year after year, but it is not known whether recruits return to the grounds where they were born (Burt and Milner, 2008).

13.4.44 The proposed GWF site is located just outside the sole nursery area (Figure 13.9) although the cable corridor passes through a low intensity nursery ground. The high intensity nursery areas are located to the west of the proposed GWF site (Figure 13.9) and this area represents an important nursery area for sole on a UK wide level.

13.4.45 Sole represent a commercially important target species in the Outer Thames Estuary. By weight and also by value (Chapter 15), sole landings represent an important proportion of the demersal catches from the ICES rectangles associated with the proposed GWF site. Sole were also well represented in the fisheries surveys (Plot 13.2 and Plot 13.4).

13.4.46 As a flatfish species, sole is considered to be relatively insensitive to sound as it does not have a swim bladder; however construction noise such as pile driving creates high levels of sound pressure and acoustic particle motion in the water and seabed which have been shown to induce behavioural reactions in sole (Mueller-Blenkle et al., 2010)..













Lemon Sole

13.4.47 Lemon sole Microstomus kitt is widely distributed off the coasts of the British Isles but is most commonly found in the English Channel and the Irish Sea (Barnes, 2008). Lemon sole were caught in both the spring and autumn otter trawl surveys in the wind farm, outside the wind farm footprint and export cable corridor sites (Plots 13.2 and Plot 13.4). Figure 13.14 indicates that the proposed GWF site lies within both the spawning and nursery areas for lemon sole as defined by Coull et al., (1998). However, the area covered by the wind farm is small in relation to the total areas of the spawning and nursery grounds.

13.4.48 Lemon sole is thought to spawn everywhere it is found (Rogers and Stocks, 2001), with spawning taking place over a long period (from April to September). Eggs and larvae are planktonic, with post-larvae found in the mid water before becoming demersal, when reaching 3cm in length (Wheeler, 1978). Sandeel

13.4.49 Sandeel Ammodytes marinus have a close association with sandy substrates into which they burrow and are largely stationary after settlement. There is a complex of local (sub-) stocks in the North Sea. Sandeel favour coarse sand with fine to medium gravel and low silt content, avoiding sediment containing >4% silt (particle size <0.063 mm). Observations on the availability of A. marinus to fisheries and their occurrence in sediment suggests that this species rarely emerges from the seabed between September and March, except in December and January when it spawns (Fisheries Research Services, 2011).

13.4.50 They spawn a single batch of eggs in December-January, several months after ceasing to feed. The eggs are deposited on the seabed. The larvae hatch after several weeks, usually in February-March, and drift in the currents for one to three months, after which they settle on the sandy seabed. There are indications that the survival of sandeel larvae is linked to the availability of copepod prey in the early spring, especially Calanus finmarchicus supports the survival of sandeel larvae, and that climate-generated shifts in the Calanus species composition lead to a mismatch in timing between food availability and the early life history of lesser sandeel (Wright and Bailey, 1996; van Deurs et al., 2009).

13.4.51 Sandeel are important prey species for many marine predators (such as seabirds and fish).

13.4.52 Figure 13.15 indicates that the proposed GWF site falls within a low intensity sandeel spawning area and nursery ground. Information shows that, while the whole of the North Sea is a low intensity spawning ground, high density areas exist in the central North Sea on Dogger Bank and on the sandbank complexes off the eastern Scottish coast.









Sprat

13.4.53 IBTS survey data indicates that sprat Sprattus sprattus is most abundant south of the Dogger Bank and in the Kattegat, with the distribution extending around the British coast. Secondary concentrations are found in the Firth of Forth and the Moray Firth (ICES, 2010a).

13.4.54 Sprat are multiple batch spawners, with females spawning repeatedly throughout the spawning season (up to 10 times in some areas) (ICES, 2010a). Spawning occurs in both coastal and offshore waters, during spring and late summer, with peak spawning between May and June, depending on water temperature (ICES, 2010a). Spawning generally takes place at night. The eggs (0.8-1.3 mm in diameter) and larvae of sprat are pelagic (ICES, 2010a).

13.4.55 Sprat represents prey for many commercially important predatory fish, such as the larger gadoids, as well as diving seabirds.

13.4.56 Figure 13.16 indicates that the proposed GWF site lies within the sprat spawning grounds. However, these are widespread and extend throughout the majority of UK coastal waters. Individual fish species accounts - elasmobranchs

13.4.57 Elasmobranchs are the group of electrosensitive fish that includes sharks, rays and skates. A number of these species are protected under the Wildlife & Countryside Act 1981 and as species of priority importance under UK and individual country Biodiversity Action Plan (BAP) arrangements (see section on Species of Conservation Importance Table 13.6 see Page 59).

13.4.58 Elasmobranchs are particularly vulnerable to overexploitation and globally have suffered significant reduction in their numbers due to unregulated fishing effort and habitat degradation. Elasmobranch species generally have a small number of offspring and long maturation periods meaning that populations cannot recruit individuals fast enough to replace those lost through fishing or other sources of mortality. Certain species such as angel shark Squatina squatina, common skate Dipturus batis and white skate Raja alba are now considered to be extinct in large parts of their former range. The status of other commercially important species (for example thornback ray, Raja clavata, other large Rajids, and spurdog, Squalus acanthias is of increasing concern for both fisheries and nature conservation.

13.4.59 Spotted ray and blonde ray are of lesser importance, and other skate species, such as undulate ray Raja undulata and small-eyed ray Raja microcellata, are occasional vagrants to this area from the English Channel. Cuckoo ray Leucoraja naevus and starry ray Amblyraja radiata occasionally occur in the southern North Sea, but the main North Sea stocks of these species are further north.

13.4.60 Elasmobranchs can detect the electrical fields emitted by themselves and other organisms. The most widely known use of electric fields is for prey



detection, where the prey item generates an electric field that the predator senses. Electrosensitivity can also be used for orientation. Orientation is possible due to the differences in resistivity of objects which enter the animal’s electric field. Compass-like navigation is accomplished by interpreting the effect of the earth’s electromagnetic currents on the electric field created as the animal swims underwater (similar to echolocation used by dolphins) (MMO et al., 2010).

13.4.61 The most abundant elasmobranch species caught during the GWF site surveys by number were lesser-spotted dogfish, thornback ray, starry smooth-hound and smooth-hound. Other species recorded included spotted ray, blonde ray and tope (Plot 13.2 and Plots 13.4).

13.4.62 Table 13.5 provides a qualitative summary of the general status of the major elasmobranch species relevant to the proposed GWF site based on ICES 2010 advice. The 2011 and 2012 advice on catches for thornback ray, lesser-spotted dogfish, smooth hound and starry smooth hound for the southern North Sea are to maintain status quo catch (ICES, 2010). Table 13.5 Status of demersal elasmobranchs in the North Sea

Species Scientific name Area State of stock

Thornback ray Raja clavata IVc, VIId Stable / increasing

Lesser-spotted dogfish Scyliorhinus canicula IVa,b,c, VIId Increasing

Smooth hound &

Starry smooth hound

Mustelus mustelus &

Mustelus asterias

IVa,b,c, VIId Increasing

Source: ICES Advice (2010)

13.4.63 Based on their commercial importance, further information for thornback ray and spurdog is provided below along with information on tope Galeorhinus galeus as the proposed GWF site lies within an area identified as potential nursery grounds for tope and also lesser-spotted dogfish. Thornback ray

13.4.64 Thornback ray is the most abundant skate (Rajidae) in the south-western North Sea, and the Outer Thames Estuary is considered to be of regional importance for the species. Thornback ray is one of the most commercially important skate species in UK waters and, in the Thames, can account for some 93 – 100% of the skate catch (Ellis et al., 2008).

13.4.65 Wider studies in the southern and central North Sea by Cefas (ICES, 2007b) demonstrate that thornback ray has shown range contraction as the population has declined, and that they are now most abundant in the Outer Thames Estuary and The Wash (Figure 13.17).

13.4.66 Rays are particularly vulnerable to exploitation due to their low fecundity, late age at maturity and large size at maturity. Survey catch trends in Division



IVc have been stable / increasing in recent years. The status of thornback ray in Divisions IVa,b is uncertain (ICES, 2008).

13.4.67 Thornback ray aggregate by sex and size, often showing an uneven sex ratio, with females dominating the larger size classes. It is evident that juvenile thornback ray are widespread in the shallower waters of the Outer Thames Estuary and along the English Channel coast of Southern England (Ellis et al., 2005), although it is not known whether there are specific spawning grounds for thornback ray. Part of the proposed GWF site and the export cable corridor lie within a low intensity nursery ground for this species (see Figure 13.18).

13.4.68 Studies of ray movements in the Thames Estuary showed that 96% of rays tagged were recaptured there (Hunter et al., 2005), suggesting that these rays form distinct sub-populations and exhibit small scale movements. These studies also showed that rays were located in water of 20m to 35m depth during the autumn and winter, and migrated into shallower water (<20m) during the spring (Hunter et al., 2005). Thornback ray occur on a variety of sediment types, including mud, sand and gravel, but is less frequent on coarser grounds (ICES, 2010a).

13.4.69 Figure 13.17 Identifies the distribution of thornback ray in the North Sea during different survey periods and averaged over the entire survey period (1980–2006), as reported during the Q1 IBTS survey (as reported in ICES, 2007b). Density strata are expressed as mean number per tow. Red and brown denotes high density (where ~90% of the abundance occurs), yellow and green very low and grey surveyed areas where no thornback ray were caught. Squares on “All Years” map are grid averaged survey locations.







Spurdog

13.4.70 Spurdog is one of the more common shark species in the North Sea. At the beginning of the 20th Century it was abundant, and often considered a nuisance by commercial herring fishermen, as they caused damage to the nets and catches. Landings increased rapidly during the late 1950’s and early 1960’s, though landings have since declined (ICES, 2010a).

13.4.71 Spurdog was formerly widespread and abundant throughout most of the area, but IBTS survey data indicates it is currently most abundant in the western North Sea and off the Orkney and Shetland (ICES, 2010a). Spurdog are also caught in the Outer Thames and consultation responses from the Shark Trust and inshore fishermen indicate that the GWF area is thought to be an important local pupping ground (Table 13.1). Information from local fishermen have indicated that a spurdog fishery used to exist between February and March to the eastern side of the Outer Gabbard, although in recent years a quota restriction and maximum landing size has seen this fishery halt (Chapter 15). The spurdog fishery in the North Sea has also been closed since 2011 due to the severely depleted nature of the stocks. During the site specific surveys only a single (one) spurdog was recorded in the otter trawl catches.

13.4.72 Tagging experiments have shown that spurdog may migrate all around the British Isles. Thus, the North Sea component is considered to represent part of a much larger stock (ICES, 2010a). Given their complex and widespread seasonal migrations and long gestation periods, parturition grounds are hard to define (Cefas, 2010).

13.4.73 Spurdog is aplacentally viviparous, giving birth to live young, with two to 21 pups born after a gestation period of 22 to 24 months (Holden and Meadows, 1964; Gauld, 1979; Ellis and Keable, 2008). Young are reliant on yolk reserves during embryonic development and fecundity increases with size. The size at birth ranges from 19cm to 30cm, though is typically 26-28cm. The pupping season is from August to December (ICES, 2010a).

13.4.74 Juvenile spurdog are widely distributed in the central and northern North Sea, North West Scotland and Irish and Celtic Sea (see Figure 13.16). The high intensity nursery grounds are situated off west Scotland. The proposed GWF site does not lie within any identified nursery grounds (Figure 13.19). The apparent absence of juveniles from the eastern English Channel and southern North Sea may be an artefact of the sampling and fewer otter trawl surveys in the area (Cefas, 2010a).

13.4.75 A low fecundity, coupled with an extremely low growth rate, makes spurdog vulnerable to commercial overexploitation.





Tope

13.4.76 Tope is widely distributed in the North-Eastern Atlantic, occurring as far north as Norway. In British waters, it is most common in the southern North Sea, English Channel, Bristol Channel and Irish Sea (Ellis et al., 2005). It is considered to be a single stock of tope in the NE Atlantic.

13.4.77 Tope are ovoviviparous producing live young. Gestation is thought to last for about 12 months, and females move inshore to coastal nursery areas in the late summer to give birth. The proposed GWF site is located in an area identified as a low intensity nursery area for tope (see Figure 13.20). A single juvenile female tope was recorded from GWF during the autumn otter trawl survey.

Lesser-spotted dogfish

13.4.78 Dogfish are thought to lay their egg cases in the deeper water between the Gabbard and Galloper banks and concerns were raised during scoping with regards to the disturbance of this egg laying species (Table 13.1).

13.4.79 Dogfish are widespread in the North-east Atlantic and were one of the most abundant elasmobranchs recorded during the site specific surveys (see Plots 13.2 to 13.5). They are oviparous, laying 2 eggs at a time, with females laying as many as 5/7 eggs per week during the breeding season (November to July). The availability of prey and requirement for females to have suitable egg-laying substrates are also thought to influence their distribution with high abundances often associated with the presence of erect, sessile invertebrates (e.g. Flustra spp.) that are important egg-laying substrates (Ellis & Shackley, 1997, Kaiser et al., 1999).





Individual species accounts - shellfish

13.4.80 While the general GWF areas are acknowledged as being more important for finfish than shellfish (MMO, 2010) ICES rectangles 32F1, 32F2 and 33F1 do provide catches of shellfish. Landings data indicates high landings of cockle Cerastoderma edule from area 32F1. These landings come from the inshore Thames cockle fishery which is not within proximity to GWF. Landings of brown crab Cancer pagarus, and lobster Homarus gammarus are recorded from the inshore area of the export cable corridor (ICES rectangle 33F1) and whelk are recorded from the proposed GWF site (ICES rectangle 32F2). The latter three species are therefore considered in further detail below.

Lobster

13.4.81 Static fishing for European lobster and crab has been recorded from localised areas of the inshore export cable route (Chapter 15) and from commercial landings data for the area (Table 13.2). Lobsters are anticipated to be present at GWF and the export cable corridor on areas of reef or other suitable habitat structures such as wrecks.

13.4.82 Lobsters are usually located in holes on rocky substrate at lower than mean low water neaps (sublittoral fringe) to depths of 150m (Holthius, 1991).

13.4.83 Growth is by moult, which decreases in frequency during the juvenile stages until becoming an annual part of the mating, spawning and egg hatching cycle. Females can spawn annually or following a bi-annual pattern. Reproduction takes place during summer and is linked with the moulting cycle (Atema, 1986). After extrusion, the eggs are held on the pleopods for approximately another year until hatching the following summer. The first few post-hatching weeks are characterised by a pelagic phase usually lasting 14 to 20 days depending on the water temperature. Lobsters are sedentary animals with home ranges varying from 2 to 10km (Bannister et al., 1994). Lobsters do not make extensive migrations when berried and hatching takes place in spring and early summer on the same grounds (Pawson, 1995).

Edible crab

13.4.84 Edible crab is a common and widely distributed species in the UK (Pawson, 1995). It occurs from the upper inter-tidal zone down to 100m depth. Small crabs are rarely caught in offshore areas which suggest that crabs only move into deeper water as they grow and approach maturity. They are known to undertake extensive migrations at rates of 2-3km per day during migrations of up to 200 nautical miles (Pawson, 1995). The main North Sea crab fishery is located to the north of the proposed GWF off Flamborough Head and south of Dogger Bank. This corresponds with the centres of larval abundance in this area. Once hatched crab larvae are planktonic for up to approximately 90 days (Pawson, 1995). The principle potting grounds for brown crab are in the area of the export cable landfall and just to the south (Chapter 15). Brown crab were recorded in low numbers across the GGOWF and the edges of the Galloper bank and export cable route during the 2004 and 2005 fisheries surveys (GGOWL, 2005).



Whelk

13.4.85 Whelks are common in the North Sea and are distributed extensively around the UK coastline (Jacklin, 1998). They inhabit mainly muddy gravel or mud mixed with shell. Whelks spawn when they reach maturity at approximately two to three years of age. Fertilisation occurs in late autumn followed by spawning in November (Jacklin, 1998). After four months development, the fully formed juveniles emerge from the egg capsules during February to March (Jacklin, 1998).

13.4.86 Landings data (Table 13.2) and review of commercial fishing activities (Chapter 15) indicate that whelk are present around the proposed GWF site.

Site specific surveys

GWF baseline fish surveys 2008-2009

13.4.87 Autumn (2008 and spring (2009) fish surveys have been carried out at the proposed GWF site. While it should be acknowledged that the boundaries of the proposed GWF site have been modified since the original fisheries surveys were carried out, the modifications do not have a significant effect on the results presented below, which still remain valid for characterising the area. In the subsequent plots, the survey areas outside of the proposed GWF site have been referred to as ‘control’, the areas within GWF as ‘wind farm’ and locations relating to the export cable as ‘cable / cable route’.

13.4.88 A total of 51 separate fish species were identified from both the otter and beam trawls during the spring and autumn survey, of which nine species were elasmobranchs. Approximately 45 separate species were recorded from within the GWF site, 40 from the control and 30 from the export cable corridor. The differences in species diversity between the GWF site, control and export cable are a reflection of survey effort and total combined tow duration for each area (see Plot 13.1).

13.4.89 The most abundant species caught during the surveys were whiting, cod, lesser spotted dogfish, dab, bib, plaice, thornback ray and starry smooth-hound. The results from the spring and autumn otter trawl survey are discussed below with results including catch per unit effort (CPUE) presented in Plot 13.2 and Plot 13.4 and the proportion of species caught at each site presented in Plot 13.3 and Plot 13.5.



Plot 13.1 Increasing trend between species sampled and total combined tow duration

at each of the sample locations.

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45

50

No

. sp

ec

ies

Otter Trawl Total (otter & beam trawl) No species

Spring otter trawl survey summary

13.4.90 A total of 27 fish species were identified from the otter trawls, 24 within the GWF site, 12 along the cable route and 23 at control locations.

13.4.91 Whiting and lesser spotted dogfish were the species caught in greatest numbers, followed by dab, cod and thornback ray to a lesser extent.

13.4.92 Along the cable corridor lesser spotted dogfish, cod and thornback ray were the most abundant species found, accounting for 77% of the catch. The remaining 33% consisted of low numbers of nine other species (Plot 13.3).

13.4.93 Within the GWF site the composition of the catch was dominated by whiting, dab, lesser spotted dogfish and cod which accounted for 78.5% of the individuals caught. Relatively high numbers of thornback ray were also found, this species accounting for 5.6% of the catch. The remaining 18 species were all caught in small numbers (see Technical Appendix 13.A).

13.4.94 Similarly, at control locations whiting, dab, lesser spotted dogfish and cod were the species caught in greatest numbers accounting for 84.2% of the catch.

13.4.95 Cod and whiting were the main species of commercial interest caught during the survey while sole comprised only a small proportion of the catches (see



Plots 13.2 to 13.7). For cod, the majority of fish caught at all sites were above minimum landing sizes (MLS) whilst approximately 50% of the whiting were below their MLS (see Technical Appendix 13.A).

13.4.96 In general terms most of the individuals of dab and plaice caught were female whilst the majority of lesser spotted dogfish were male. The sex ratio for cod, whiting and thornback ray was approximately 50:50.

13.4.97 The percentage distributions of the species caught are given in Plot 13.2 for the export cable corridor, GWF site and control locations respectively.



Plot 13.2 Individuals caught per hour by species and sampling area during the spring otter trawl survey



Plot 13.3 Percentage distribution of species caught along the export cable corridor, wind farm and control sites during the spring otter trawl survey



Autumn Otter Trawl survey summary

13.4.98 A total of 27 species were identified in the otter trawl sampling (21 species within the wind farm area, 19 species along the export cable corridor and 18 species in the control sites). The catch rates, in terms of the number of individuals caught per hour, and the total number of individuals caught overall are illustrated in Plot 13.4. The relative percentage distributions are illustrated and discussed in Plot 13.5.

13.4.99 Whiting, cod and bib were caught in highest abundances during the otter trawl survey with few other species caught in significant numbers (dab, lesser spotted dogfish, plaice, starry smooth-hound and poor cod). Other species were caught in very low numbers (see Technical Appendix 13.A).

13.4.100 Whiting and cod were caught in highest numbers in the samples collected at the GWF and the control sites. Along the cable corridor, lesser spotted dogfish and bib were the most abundant species. However, cod and whiting were also caught in high numbers in this area.

13.4.101 Lesser spotted dogfish, bib, cod and whiting were the most abundant species found along the cable corridor, accounting for 66.5% of the catch. Starry smooth-hound and dab were also caught in significant numbers, these species accounting for 8.9% and 9.8% of the catch respectively. The remaining 13 species were caught in low numbers, accounting for only 18.9% of the catch (see Technical Appendix 13.A).

13.4.102 In the proposed GWF site, whiting, cod and bib were the most abundant species accounting for 69.8% of the catch. Plaice, poor cod, lesser spotted dogfish, dab and tub gurnard were also caught, representing 23% of the catch. The remaining 7.2% of the catch was comprised of low numbers of individuals from 13 other species.

13.4.103 In the control sites, whiting was the most abundant species accounting for 32.0% of the catch. Cod, dab and bib were also abundant in this area, accounting for 43.1%. Plaice, poor cod and tub gurnard were also found, accounting for 18.1% of the catch, whilst the remaining 6.7% was comprised of low numbers of individuals from 11 other species.

13.4.104 As for the spring survey the majority of the cod caught were above their minimum landing size (MLS) with approximately 50% of whiting below MLS. The other commercial species caught were generally present in only low numbers.

13.4.105 In general terms the majority of the dab, whiting and plaice caught were female whilst the sex ratio for cod was approximately 50:50. The majority of lesser spotted dogfish caught were female in the wind farm site and male along the cable corridor.

13.4.106 The only migratory species sampled were three twaite shad Alosa fallax, which were caught at the proposed GWF site.



Plot 13.4 Individuals caught per hour by species and sampling area during the autumn otter trawl survey



Plot 13.5 Percentage distribution of species caught along the cable route, wind farm and control sites during the autumn otter trawl survey



Shellfish summary

13.4.107 The most abundant shellfish species found during the otter trawl surveys were velvet crab Necora puber, squid Loligo spp., European lobster and Edible crab.

13.4.108 The main crustacean species by number encountered during the spring and autumn beam trawl survey were generally shrimp species including C. allmani, Gastrosaccus spinifer, Pandalina brevirostris, and Pandalus montagui. The main mollusc species were the bivalve Nucula nigra, Abra alba and Chlamys opercularis with gastropods such as painted top shell Calliostoma zizyphinum and common whelk also regularly recorded. The latter two species were also found to be broadly distributed across the area during the GGOWF site surveys (GGOWL, 2005).

Spring 2m beam trawl summary

13.4.109 During the spring 2m beam trawl survey a total of 24 fish species were caught, 19 within the wind farm site, 15 at control locations and 12 along the export cable corridor.

13.4.110 The common dragonet was the most abundant species found along the export cable corridor, whilst the lesser sandeel was the most prevalent within the GWF site. At control locations, the lesser sandeel and the sand goby were the two fish species found in greatest numbers (Plot 13.6). Sole were recorded during the survey in low numbers with a total of 7 caught with a length range of approximately 16 to 29cm.

Autumn 2m beam trawl summary

13.4.111 In the analysis of samples obtained from the autumn beam trawl surveys 23 fish species were identified. The results of the beam trawl sampling show that species from the goby family (Gobiidae) were the most abundant fish species found, especially in the GWF site (Plot 13.7).



Plot 13.6 Spring 2m beam trawl catch as percentage of total catch per site

0%

5%

10%

15%

20%

25%

30%

35%

Black

goby

Comm

on dra

gonetDab

Dover s

ole

Great

er s

andee

l

Lesse

r spotte

d dogfis

h

Lesse

r wee

ver

Norther

n rock

ling

Plaic

e

Pogge/ H

ooknose

Poor cod

Pouting/ B

ib

Raitt'

s sa

ndeel /

Lesse

r san

deel

Retic

ulate

d dra

gonetSan

d goby

Sandee

l fam

ilySca

ldfis

h

Smooth

san

deel

Solenet

teSpra

t

Striped

sea

snai

l

Tub gurn

ard

Two-spotte

d clin

gfish

Whiti

ng

Common name

Per

cen

tag

e o

f to

tal

catc

h p

er s

ite

Cable Control Wind Farm



Plot 13.7 Autumn 2m beam trawl catch as percentage of total catch per site

0%

5%

10%

15%

20%

25%

30%

35%

40%

-

Comm

on dra

gonetDove

r sole

Fiveb

eard

rock

ling

Goby fa

mily

Great

er s

andee

l

Herrin

g fam

ily

Lesse

r spotte

d dogfis

h

Lesse

r wee

ver

Norther

n rock

ling

Norway

pout

Painte

d goby

Pogge/ H

ooknose

Poor cod

Pouting/ B

ib

Raitt'

s sa

ndeel /

Lesse

r san

deel

Sand g

obySca

ldfis

hSpra

t

Striped

sea

snai

l

Thickb

ack

sole

Transp

aren

t goby

Whiti

ng

Common name

Per

cen

tag

e o

f to

tal

catc

h p

er s

ite

Cable Control Wind Farm



Comparison to GGOWF findings

13.4.112 Spring and autumn fisheries surveys were carried out in 2004 and 2005 for GGOWF using otter trawl and 2m beam trawl survey gear (GGOWL, 2005). Based on the survey information available from the GGOWF ES, the species of finfish and shellfish recorded were broadly similar to those identified in the more recent surveys outlined above. Twenty-two species of demersal fish were identified from the 2m beam trawl and otter trawls.

13.4.113 The 2m beam trawl surveys were dominated by catches of dragonet, gobies, and sandeel, which also comprised a large proportion of the catches in the GWF surveys (Plot 13.6 and Plot 13.7). Catches in the otter trawl surveys were dominated by flatfish species including sole, plaice, dabs and lemon sole along with gadoids such as whiting and cod and elasmobranchs including lesser spotted dogfish and smoothhound. These species are broadly similar to those recorded in the GWF otter trawl surveys (see Plot 13.2 and Plot 13.4).

Outer Thames Estuary REC 2m beam trawl surveys

13.4.114 The Outer Thames Estuary REC study (MALSF, 2009) undertook 20 beam trawls (Figure 13.3). These surveys recorded a total of 28 fish species, with the principal ones detailed in Plots 13.8 and Plot 13.9. Plot 13.8 Relative contributions of species of fish to overall weight of fish caught in

the 2 m beam trawls (species contributing to >1% are shown).

Source: MALSF, 2009



Plot 13.9 Relative contributions of species of fish to the total number of individuals caught in the 2 m beam trawls (species contributing to >1% are shown).

Source: MALSF, 2009

13.4.115 Juvenile gobies Pomatoschistus spp. were by far the most numerous fish

recorded and accounted for 57% of the total number of individuals. Sole were also relatively numerous, contributing to 7% of the total number of individuals, followed bib (3%). However, in terms of weight, sole was the largest contributor, accounting for 50% of the total weight of fish caught. Thornback ray and lesser spotted dogfish were secondarily important in this respect, accounting for 13% and 11% of the overall weight of fish respectively. Bib and whiting contributed 8% and 5% respectively. These species were also recorded during the GWF surveys.

Species of conservation importance and migratory species

13.4.116 The draft guidance for offshore wind farm developments (MMO et al., 2010), states that the EIA procedure should address the potential impacts of the offshore wind farm construction and operation on fish species of commercial interest as well as on species of conservation interest. A number of species in UK waters are subject to Species Action Plans (SAP) under the UK BAP, including migratory species, such as salmon, and commercially exploited marine fish species (MMO et al., 2010). BAPs are plans that have been drawn up to encourage the recovery of particular species or habitats in the UK. Some of the key species of relevance to GWF which are BAP species include elasmobranchs such as spurdog and tope as well as commercially important finfish species including cod, herring, plaice, sole, whiting and mackerel. Commercially important species such as cod, thornback ray, spurdog along with a host of migratory fish and species such as sturgeon Acipenser sturio are also on the OSPAR list of threatened or declining species. Over 80 different marine species, ranging from seaweeds to commercial fish species, are the subject of SAPs (MMO et al., 2010). Of particular interest are elasmobranchs (and other electrosensitive species), noise sensitive species and a number of migratory species (MMO et al., 2010).



13.4.117 The main migratory species of conservation importance which are considered to be of relevance to the Thames and GWF are outlined in Table 13.6. Table 13.6 Summary of UK protection legislation for migratory fish species relevant

to the Thames Estuary and GWF

Legislation: BAP UK priority species

Habitats Directive

Conservation of Habitats & Species Regs.

OSPAR

Common Name

Scientific Name

Shad (allis /

twaite)

Alosa alosa / A.

fallax*

✓ ✓ ✓ ✓

River lamprey Lampetra

fluviatilis

✓ ✓ ✓

Sea lamprey Petromyzon

marinus

✓ ✓ ✓

Brown / Sea-

trout

Salmo trutta ✓

Atlantic salmon Salmo salar ✓ ✓ ✓ ✓

European eel Anguilla anguilla ✓ ✓

*shad are also protected under the Wildlife & Countryside Act 1981

Source: JNCC (http://www.jncc.gov.uk/page-3408). OSPAR

13.4.118 There are a number of species known to migrate through the Thames Estuary that may be of conservation interest and of relevance to the GWF project. These include diadromous fish such as Atlantic salmon and sea trout, river and sea lampreys and two species protected under the Habitats Regulations – the allis and twaite shads. Other migratory species such as the European eel and smelt are also known to use the Estuary. A general indication of when anadromous fishes undertake their migrations is given in Table 13.7.

Salmon

13.4.119 Salmon Salmo salar are known to migrate through the Thames Estuary and could potentially pass in close proximity to GWF. During migrations in coastal or offshore waters, salmon spend most of their time within 4m of the surface, although frequent diving behaviour may also be observed (Malcolm et al., 2010). Salmon spawn in upper reaches of rivers, where they live for one to three years before migrating to sea as smolts. At sea, salmon grow rapidly and after one to three years return to their natal river to spawn.



13.4.120 It is thought that salmonids use chemoreceptor clues to locate their natal rivers when migrating in coastal waters, although they are also thought to use electromagnetic fields (EMF) during offshore migrations. Salmon may, therefore, be sensitive to the levels EMF generated from wind farm cables during operation. Although salmon do not have a specific connection between the swim bladder and the auditory apparatus, studies have shown that they respond to low frequency sounds (Gill & Bartlett, 2010).

13.4.121 Salmon were not recorded during any of the GWF site specific surveys.

Table 13.7 Timings of migration for anadromous and catadromous fish species (MMO et al., 2010)

Species Timing of upstream migration

Sea lamprey Move from the sea to estuaries in April / May(2), spawning

in May / June(1,2)

Salmon Spawn late October to early January (1,2)

Sea-trout Spawn October / February (1)

Allis shad Move into estuaries in late spring(2), spawning during

April-May (1)

Twaite shad Start upstream migration in April / May(2), spawning in

May / June(1,2)

Common eel Elvers migrate upstream from January to June, with a

peak in May (2)

References: (1) Wheeler (1969); (2) Maitland and Campbell (1992)

N.B. these are generalised times and peak timing of the upstream migration may vary regionally

Sea-trout

13.4.122 Sea-trout Salmo trutta are known to migrate through the Thames Estuary and could potentially pass in close proximity to GWF. Their life cycle is almost identical to that of salmon (Harris & Milner, 2006), but there are two significant differences. In contrast to salmon, the majority of sea-trout survives spawning and will return to their natal spawning river on numerous occasions during their life time. The other significant difference is that they do not appear to undertake the same sea migration but remain in coastal waters, probably close to their natal river.

13.4.123 Due to their physiological similarities sea-trout are likely to have similar sensitivities to EMF and noise as salmon described above.

13.4.124 Sea-trout were not recorded during any of the GWF site specific surveys.



Eels

13.4.125 The European eel Anguilla anguilla has long been associated with the River Thames. Recorded in the Domesday Book, eels continued to be a valuable fishery in London well into the 1800’s (Defra, 2010). Monitoring of eels within the River Thames has indicated that very few one year old eels are present and it has been suggested that most eels may spend their first year in the lower estuary (Defra, 2010).

13.4.126 European eel spawn in the Sargasso Sea and die after spawning. The larvae are transported by the Gulf Stream to North Africa and Europe and the juvenile eel enter coastal areas and freshwater as glass eel (ICES, 2010c). They quickly transform into yellow eel and stay in Europe for five to 15 years or more (ICES, 2010c). Growth and age at maturity are linked to regional temperature (mature later at colder temperatures) (ICES, 2010c). Mature eels (or silver eels, as they are known on their downstream migration) begin the downstream spawning migration usually from late spring to winter and migrate back to the Sargasso Sea. Although no eels were recorded during sampling at GWF, it is possible eels would pass through the site on their seaward migrations and also on their return to the coastline as elvers.

13.4.127 Little specific information relating to the acoustic ability of anguillid eels has been found; as they do not appear to possess a specific link between the swim bladder and the ear (Popper & Fay, 1993 as cited in Gill & Bartlett, 2010), they could be regarded as hearing generalists (Nedwell et al., 2003).

Allis and twaite shad

13.4.128 While historically the main concentrations of allis and the twaite shad Alosa alosa / A. fallax have been in the Severn Estuary they are recorded within the Thames Estuary and have also been recorded at the Sizewell powerstation near the proposed GWF cable landfall. Three twaite shad were recorded during the autumn otter trawl surveys.

13.4.129 Both shad species are members of the herring family. Shad are marine species, entering freshwater to spawn. They occur mainly in shallow coastal waters and estuaries, but during the spawning migration adults penetrate well upstream in some of the larger European rivers. Both allis and twaite shad have declined across Europe and are now absent from many rivers where they once flourished and supported thriving fisheries (Maitland & Hatton-Ellis, 2003). Because of this decline, the allis shad is now given considerable legal protection. It is listed in annexes II and V of the EU Habitats and Species Directive, Appendix III of the Bern Convention, Schedule V of the Wildlife and Countryside Act (1981) and as a Priority Species in the UK Biodiversity Action Plan.

13.4.130 Mature fish that have spent most of their lives in the sea stop feeding and move into the estuaries of large rivers, migrating into fresh water during late spring (April to June), thus giving the shad the name of 'May Fish' in some



areas. Male shad migrate upstream first, followed by females one or two weeks later (Maitland & Hatton-Ellis, 2003).

13.4.131 The requirements of shads at sea are very poorly understood, but they appear to be mainly coastal and pelagic in habit (Maitland & Hatton-Ellis, 2003). A suitable estuarine habitat is likely to be very important for shad, both for passage of adults and as a nursery ground for juveniles (Maitland & Hatton-Ellis, 2003).

Smelt

13.4.132 Smelt Osmerus eperlanus are inshore migratory fish widely distributed in shallow waters of the continental shelf, but most common close to river mouths and in estuaries, especially in the southern North Sea. It is caught very occasionally in coastal waters as part of the Cefas groundfish surveys. The strongest and most permanent stocks seem to be those associated with the larger estuaries (e.g. the Thames), especially where there is a complexity of minor or nearby smaller estuaries (Maitland, 2003). None were recorded during the GWF surveys.

State of the stocks - teleosts

13.4.133 The depletion of fish stocks through overfishing in the North Sea, has been, and continues to be of concern. A summary of the state of North Sea stocks (ICES Sub Area IV) of finfish species relevant to the GWF site is given in Table 13.8. As is apparent, fishing mortality continues to be a significant threat to fish stocks.

Table 13.8 State of the stocks (ICES, 2009)

North Sea Stock Species

Spawning biomass in relation to precautionary limits

Fishing mortality in relation to precautionary limits

Fishing mortality in relation to high long term yield

Fishing mortality in relation to agreed management target

Herring*

Increased risk Harvested

sustainably

Overfished Above target

Sole

Full reproductive

capacity

Harvested

Sustainably

Appropriate Above target

Plaice Full reproductive

capacity

Harvested

sustainably

Overfished Below target

Whiting Undefined Undefined Undefined NA

Cod Reduced

reproductive

Increased risk Overfished Above target



North Sea Stock Species

Spawning biomass in relation to precautionary limits

Fishing mortality in relation to precautionary limits

Fishing mortality in relation to high long term yield

Fishing mortality in relation to agreed management target

capacity

Sandeel Increased risk Undefined Undefined Undefined

*No ICES advice is provided for the spring spawning Thames herring so this advice is based

on that for the North Sea autumn spawners

Overall summary of GWF baseline – key sensitivities/species of concern

13.4.134 The baseline characterisation has identified that the Outer Thames Estuary and GWF are potentially important for a number of commercially important species. The GWF overlaps or is in close proximity to a number of finfish species spawning grounds including; herring, cod, whiting, sprat, sandeel, sole, lemon sole and plaice. The wider Thames estuary also supports populations of elasmobranchs including thornback ray which are of national significance. A number of migratory fish species such as salmon, sea-trout, eel, shad, lamprey and smelt may also pass through the GWF site, although only twaite shad were recorded during the site specific surveys. Consultation responses have indicated that key sensitive species are considered to be herring and sole and in particular disturbance to these species during key spawning periods. Available larval data for the Downs herring stock indicate that the main spawning ground currently used is within the eastern English Channel and that the usage of the Southern Bight spawning grounds with which the proposed GWF site overlaps is minimal. Similarly for sole, while recent data on the spawning grounds presented by Cefas (2010) indicate that the proposed GWF site falls within an area defined as a high intensity spawning ground, data on suitable sediments, depth, temperature, salinity and maps of habitat suitability support the presence of inshore spawning grounds located to the southwest.

13.5 Assessment of Impacts – Worst Case Definition

13.5.1 The assessment of potential impacts are based on the worst case scenarios for each receptor and establish the maximum potential adverse impact as a result. Therefore no impacts of greater adverse significance would arise should any other development scenario (as described in Chapter 5) to that assessed within this Chapter be taken forward in the final scheme design. Full details on the range of options being considered by GWFL are provided throughout Chapter 5. For the purpose of the fish and shellfish resource assessment, the worst case scenario, taking into consideration these options, is detailed in Table 13.9.



13.5.2 All options considered in Chapter 5, where any range exists (such as pile diameter), are considered realistic and therefore, assessing the worst case option is considered most practicable and conservative. It is considered that if residual impacts on the worst case scenario are acceptable then this will apply to all options within the range.

13.5.3 It is noted that only those design parameters detailed under each specific impact have the potential to influence the level of impact experienced by the relevant receptor. Therefore, if the design parameter is not discussed then it is considered not to have a material bearing on the outcome of the assessment.

13.5.4 The worst case scenarios identified below are also applied to the assessment of cumulative impacts. In the event that the worst case scenarios for the project in isolation do not result in the worst case for cumulative impacts, this is addressed within the cumulative assessment section of the Chapter (see Section 13.10).

.



Table 13.9 Realistic worst case scenarios for impacts on fish and shellfish.

Impact Realistic worst case scenario Justification

Construction

Disturbance /damage

through construction

noise

Lethal effect and physical injury

Maximum number of structures (140

WTGs, three met masts, and four

ancillary infrastructures) on 7m

diameter monopiles. The predicted

noise level associated with a hammer

blow (1100kJ) for a 7m pile is 254dB

re 1 µPa @ 1m (see Chapter 5 and

Technical Appendix 13.B)

Up to two piles installed at any one

time (each taking an indicative 4

hours to install). Based on the

assumption of one vessel being able

to install one pile a day (therefore two

vessels would install a total of two

piles per day) 70 days of piling will be

required, taking place intermittently

over a 39 month period

(approximately two per week).

7m piles represent the largest foundation options which require piling and will be

associated with the loudest noise and therefore considered the worst case for lethal

effect and physical injury. Criteria used in this assessment comprise 240dB re 1μPa for

lethality, 220dB re 1μPa for physical injury and the 130dbht metric which represents the

level at which hearing damage may occur. Lethality may extend to 7m, physical injury

out to ranges of 130m and for sensitive species such as herring traumatic hearing

damage may extend out to approximately 1km. Modelled data indicate that during 3m

piling the levels of noise would not be sufficient to cause lethality although injury could

still occur out to a maximum of 16m.

Piling occurring intermittently over 39 months (the longest time period over which piling

can occur – see Chapter 5) is considered the worst case as it represents the greatest

potential for lethal effect and auditory injury to occur as a result of the timescale. This

scenario therefore gives fish that may have left the area as a result of a piling operation

the opportunity to return and be at risk of physical or lethal injury.

Monopiles will only be installed out to a depth of 45m below CD. Modelling undertaken

by Subacoustech (2011) of 3m pin piles (used for space frame foundations) was also

undertaken to investigate if the installation of smaller piles in deeper parts of the site

(over 45m where monopiles would not be used) might produce a greater noise impact

range than 7m monopiles in shallower water (as noise travels further in deeper water).




As detailed in Subacoustech (2011), the worse case scenario for noise associated with

piling is represented by the 7m pile as the noise associated with its installation extends

the furthest even though it's use in the site is more constrained than space frame

options.

Noise from simultaneous piling installation could represent a larger area for lethal effect

and auditory injury for fish species. The worst case would be that two of the piles

located furthest from each other within the development area are installed at the same

time, thus producing the largest area of noise impact.

Although multiple piling remains a possibility, it is unlikely that more than one foundation

will be piled at any one time as a result of engineering constraints. In order to ensure a

thorough assessment, piling of one foundation has been assessed alongside multiple

piling.

The options stated will result in the maximum potential for lethality and physical injury.

Behavioural effects – spawning

species (herring, sole and cod)

Maximum number of structures (140

WTGs, three met masts, and four

ancillary infrastructures) on 7m

diameter monopiles. The predicted

noise level associated with a hammer

Piling is considered to create the greatest potential for noise impacts upon fish species

during construction. In terms of impacting spawning grounds during key spawning

periods 7m piles represent the widest behavioural impact ranges (see Table 13.12

below) with herring for example perceiving levels of underwater noise above 90 dBht out

to the greatest ranges of approximately 30km for the 7m diameter pile and 20km for the

3m diameter pile.

39 months of piling may occur over a 56 month construction window (assuming a Q2 or




blow (1,100 kJ) for a 7m pile is 254dB

re 1 µPa @ 1m (see Chapter 5 and

Technical Appendix 13.B)

140 piles installed at a rate of two

piles a day (based on two piling

vessels onsite) split over two

consecutive spawning periods with

this period of 35 days coinciding with

the key sensitive periods for herring,

sole and cod spawning.

Q3 2015 commencement) with piling being restricted to covering no more than two

spawning periods for the key sensitive species which are considered to be the Downs

herring and sole.

Criteria used in this assessment comprise the 75 dBht and 90 dBht levels which represent

strong and significant behavioural responses by fish species.

Based on the protracted nature of spawning periods the worst case is therefore

considered to be the installation of 70 monopiles at a rate of two a day over a period of

35 days with this period occurring during the peak spawning periods for the relevant

species. As a worst case, assuming two monopiles are installed every day by two

separate piling vessels and operations do not run concurrently, a total of eight hours

piling per day could occur over a 35 day period the spawning season. If piles were

installed at a rate of one a day, while the duration would be longer, the extent would be

less. Furthermore, species such as sole and herring have key spawning periods e.g.

April and November respectively and it is considered that intense piling over this period

would have the greatest potential for impacts.

The impact contours (see Section 13.6) associated with the installation of 3m piles do

not have the same spatial extent and would not impact as much of the spawning

grounds as the 7m foundation option.

The options stated will result in the maximum potential for noise disturbance and fish

species displacement.




Behavioural effects – general fish

assemblages

Maximum number of structures on

space frame foundations (140 WTGs

(4 legs), three met masts (4 legs),

and four ancillary infrastructures (6

legs). Each space frame foundation

leg using a maximum of two pin piles.

The predicted noise level associated

with a hammer blow (470 kJ) for a 3m

pin pile used in space frame

foundations is 239dB re 1 µPa @ 1m

(see Chapter 5 and Technical

Appendix 13.B)

1,192 piles installed over a 39 month

period (assuming one pile is installed

at any one time) which equates to

approximately 1 pile per day

(assuming construction 7 days per

week).

3m piles used for space frame foundations have smaller behavioural impact ranges (see

Figures 13.25 to 13.27) but represent the foundation option which, as a result of the

number required, will result in the maximum piling activity occurring over the longest

period and provides the greatest potential for disturbance and behavioural effects. It is

considered that if the maximum number of piling operations take place throughout the

maximum period during which piling might take place this represents the worst case

scenario due to the continuous noise and subsequent disturbance (see Chapter 5 for

further details on construction timescales).

Criteria used in this assessment comprise the 75 dBht and 90 dBht levels which represent

strong and significant behavioural responses by fish species.

Modeling carried out by Subacoustech (2011) for 3m piles was carried out at seven

locations (see Figure 13.21). The worse case predicted noise impact range (in km’s) for

3m piles (for space frame jacket foundations) for sensitive species such as herring is

approximately 20km depending on piling location.

As a worst case, a total of 1,192 3m piles will be required at the GWF if space frame

foundations are used. This is based on 1,120 3m piles for 140 WTG foundations (based

on 4 legs and 2 piles per leg), 48 3m piles for ancillary structures (based on 6 legs and 2

piles per leg) and 24 3m piles for met masts (based on 4 legs and 2 piles per leg).




Structures located across all three

Development Areas.

Physical disturbance

of intertidal and

subtidal habitats

Intertidal

Trenching across the intertidal area to

below MHWS where there will be up

to three rig sites for directional

drilling, totalling 75m2. Vehicular

disturbance from vehicles associated

with the preparation of reception pits.

Provides for the maximum amount (spatial extent) of habitat disturbance.

Subtidal

Export cable installation via plough

throughout export cable route (5m x

190km = 0.95km2)

Cable installation via plough for inter

and intra-array cables (300km x 5m =

1.5km2)

Anchored construction vessels – up

to 6 anchors per vessel (up to 4m2

per movement)*

The worst case scenario is established by defining the maximum amount (spatial extent)

of habitat disturbance.

For foundation structures this is represented by the maximum number of structures (140

WTGs, three met masts and four ancillary structures) which will in tern result in the

maximum level of disturbance from construction vessel support structures (anchors and

jack-up legs)

For export and inter/intra-array cabling the maximum footprint is established through

assumption maximum extent of cabling using the installation technique with the largest

footprint). This is represented by the plough, which when considering it’s supporting feet

has an approximate footprint width of 5m.

Any other development scenario or installation technique considered within Chapter 5




Jack-up vessel - 6 legs of

approximately 10m2 per leg.

Therefore, 60m2 in total per

movement with a representative

maximum number of movements of

six per foundation and met mast and

eight for ancillary structures.

Therefore, the total footprint based on

a maximum number of 147 structures

is 0.054km2

The total quantifiable construction

disturbance is therefore is 2.5km2

would result in less of a disturbance footprint.

Loss of subtidal

habitat and benthic

prey resource

101 * 45m Gravity base structure

(GBS) foundations with scour

protection applied to 100% of all

foundations (160,590m2 + 174,730m2

= 335,320m2 (0.335km2))

Three met mast foundations on 45m

GBS foundations including 100%

scour protection (4,770m2 + 5,190m2

The loss of subtidal habitat will result from the placement of built structures (and

associated scour protection material) on the seabed. The worst case scenario is

therefore, represented by the largest footprint from the foundation structures (and

associated scour protection) under consideration.

The GBS foundations have a larger footprint than any of the foundations under

consideration. Of the GBS options for the WTGs, there could be up to 101 45m base

diameter structures or 140 35m base diameter structures. Scour protection for 45m

base diameter structures is 10m in radius around all structures and 9m around all




= 9,960m2 (0.01km2))

Up to four ancillary structures (this

may comprise a combination of

offshore substation platforms (OSPs),

collection platforms and / or

accommodation platforms) on space

frame (self-jacking suction can)

foundations (four leg jackets)

assuming 100% scour protection =

18,748m2 (0.019km2))

Rock placement for cable protection

at a total of 9 export cable crossings

(3,240m2)

Total area = 0.335 + 0.01 + 0.019 + 0.003 = 0.37km2

structures for the 35m base diameter option. Therefore, the total footprint for the 45m

base diameter option is 335,320m2, whilst for the 35m option it is 308,856m2. The 101

45m base diameter option therefore, has the largest overall footprint.

For the met masts GBS options are considered and therefore, the 45m base diameter

option presents the worst case.

For the ancillary structures, only space frame (piled, suction can and self-jacking) and

monopile foundations are considered.

The area for a single self-jacking (suction can) space frame foundation (based on up to

four legs) with 100% scour protection is 4,687m2. For the four foundations this equates

to a total area of 18,748m2.

The area for a single (piled) space frame foundation (based on up to six legs (3m

diameter) each with up to two (3m diameter) pin piles) is 85m2. The piled space frame

requires 100% scour protection (with an additional 5m radius around each structure) the

area of scour protection for four space frame structures is therefore 9,388m2.

A 7m monopile has a footprint of 38.5m2 with a scour protection footprint of 1,700m2 and

therefore an overall footprint of 1,739m2 (total area of 6,956 m2 for four foundations).

All other foundation types considered (Chapter 5) would result in a smaller loss of

habitat.

Indirect impacts due to loss of fish as a

As for noise disturbance associated

with behavioural effects for general

3m piles used for space frame foundations have smaller behavioural impact ranges but

represent the foundation option which, as a result of the number required, will result in




prey source fish assemblages discussed above. the maximum piling activity occurring over the longest period and provides the greatest

potential for disturbance, behavioural effects and displacement of fish species.

Increased

suspended

sediments and

mobilisation of

contaminants

101 (45m base diameter) GBS

foundations for WTG structures, three

(45m base diameter) GBS

foundations for met masts, four 7m

monopile foundations for ancillary

infrastructure (totalling 500,800m3).

Seabed preparation for GBS

comprises mechanical levelling of the

seabed to a depth of approximately

2m.

Turbine installation - two GBS

foundations installed simultaneously

over a three day period.

Cable installation in the marine

environment by jetting methods to

install up to three export cables to a

representative average of 1.5m

depth, 0.5m width and a total of 190

export cable kilometres in length.

The ‘worst case’ scenario is represented by that which could result in the maximum

volume of arisings (and therefore, maximum volume of material that could brought into

suspension).

For the WTG foundations 101 (45m) GBS foundations represent worst case volume

(484,800m3). Other options result in less volume released: 140 35m GBS foundation

resulting in 445,340m3, 140 7m monopiles 224,000m3, 140 space frame foundations

182,000m3, 140 4-legged space frames founded with suction cans 43,960 m3 and 140

monopod buckets 70,000m3. For the met masts where all foundation types are

available, again the 45m GBS foundations represent worst case. For the four ancillary

structures, where GBS are not an option, the worst case is represented by the 7m

monopile as this structure results in higher levels of spoil material (1,600m3 per

foundation).

Ploughing, trenching and jetting were assessed by ABPmer (2011b), see Chapter 9 and

Technical Appendix 9.Aiii, with jetting considered to represent the worst case scenario,

the assumption being that all sediment disturbed would be fluidised and therefore, made

available for re-suspension.




Inter and intra-array cabling will be a

total length of 300 cable kilometres

and have similar burial characteristics

to the export cables.

Operation

Disturbance /

damage through

Electromagnetic

Fields (EMF)

Cabling with 300km of 66kV inter /

intra-array cabling and up to 190

cable kilometres of 132kV export

cable. Representative average

minimum burial depth for inter / intra-

array, and export cables will be 0.6m.

EMF impacts are governed by depth of (cable) burial and not the number of turbines or

their layout or location within the GWF area. Therefore, the worst case scenario is

represented by the shallowest burial depth for all cables. Because the burial depth

achieved varies greatly an average minimum burial depth is applied.

Disturbance /

damage through

operational noise

Monopile or GBS foundations for 140

WTGs

Provides maximum extent of operational noise based on number of turbines and greater

radiation efficiency compared to smaller piles associated with jackets. Studies (ÅF-

Ingemansson, 2007 as cited in Hammar, 2010) have indicated that GBS and monopile

foundations radiate sound in the same magnitude, with the difference that gravity

foundations radiate sound in a lower range of frequency than a monopile.

Aggregation effects Space frame jacket foundations for

140 WTGs with scour protection and

rock placement for cable protection at

a total of 9 export cable crossings

totalling 3,240m2.

Provides the maximum potential for change from baseline conditions by providing the

most complex habitat for fish aggregation. Other structures such as monopiles, GBS or

suction buckets would provide for the least complex fish habitat structure.




Indirect impact of

loss of prey resource

and habitat from

changes in current

regime

104 GBS foundations for WTG

structures (see Section 9.5), three

(45m base diameter) GBS

foundations for met masts, four (7m)

monopile foundations for ancillary

infrastructure. Total volume of

released material from scour of

446,864m3.

No scour protection measures.

The indirect impacts on fish species as a result of the loss of benthic prey resource are

driven by scour events (from changes to current regime) around foundation structures

and the subsequent release of sediments.

GBS results in increased scour as a consequence of the larger surface area and hence

interaction with hydrodynamic flows.

104 x 45m diameter GBS foundations result in the release in 432,952m3 of sediment

while 143 x 35m diameter GBS foundations result in 65,231m3 of sediment release.

Individual foundations sediment release rates via scour:

45m GBS = 4,163m3; 35m GBS = 1,517m3; 7m Monopile = 3,478m3; space frame

(jacket) = 1,097 m3 (see Technical Appendix 9.Aiii)

Therefore, 104 conical 45m diameter GBS foundations (WTGs and met masts) and four

monopile foundations (ancillary structures, which can only use monopiles or space frame

foundations) represent the ‘worst case’ scenario

This scenario results in the release of 446,864m3 of materials with maximum suspension

of fine sediment during operation due to scour effects at the turbine structures.

Decommissioning




Loss of habitat Removal of all cabling and build

structures (based on worst case

assumptions detailed under

construction).

The precise nature of decommissioning will be established prior to construction and a full

Decommissioning Plan for the project will be drawn up and agreed with DECC.

The worst possible potential impacts will be associated by the removal of all structures,

under which circumstance, impacts will be in line with those specified above for the

construction phase with the exception of noise impacts, as piling will not take place.

Loss of prey

resource

Removal of all cabling and build

structures (based on worst case

assumptions detailed under

construction).



13.6 Potential Impacts during the Construction Phase

13.6.1 This section provides an assessment of the impacts from the construction phase of the GWF project on the fish and shellfish receptors. Potential construction impacts identified during the Scoping process are associated with:

Disturbance / damage from construction noise;

Loss of habitat;

Loss of fish as a prey source; and

Disturbance from increased suspended sediments and contaminants.

Impacts due to construction noise

13.6.2 The main activities relating to the construction of offshore wind farms that would be likely to cause noise and vibration disturbance are considered to be impact pile driving which could create underwater noise levels significantly higher than present background levels. These activities are discussed in Chapter 5.

13.6.3 Pile driving noise during construction is of particular concern as the very high sound pressure levels could potentially prevent fish from reaching breeding or spawning sites, finding food, and acoustically locating mates (Mueller-Blenkle et al., 2010) as well as causing physical injury and mortality or disturbing normal behaviour. Consultation responses received from the MMO and Cefas (Table 13.1) have indicated concerns related to percussive piling noise and its effect on cod, plaice, herring and sole and the potential for seasonal piling restrictions relating to the latter two species covering the period 1st November to 30th May. Following the PER submissions two further meetings have been held with Cefas (in July and September 2011) to discuss these potential spawning restrictions in context of additional data provided by GWFL on the Downs herring spawning grounds have been analysed (see Technical Appendix 13.C).

13.6.4 In UK coastal waters general background levels of sea noise of approximately 130 dB re 1 μPa are not uncommon in (Nedwell et al., 2003, Nedwell et al., 2007a). Background underwater noise measurements were undertaken in the area prior to the installation of GGOWF. These measurements indicated that in general the background noise levels range from 110 to 150 dB re 1 μPa, equating to 50 dBht for herring (GGOWL, 2005). In 2009 broadly similar overall levels were observed although unsurprisingly levels were slightly higher as a result of increased shipping traffic due to GGOWF construction activity (Gardline, 2010). Increased shipping results in an increase in noise at lower frequencies (<100 Hz) while also introducing high frequency (kHz) sounds from equipment such as echosounders and sonar (Gardline, 2010).



13.6.5 The worst case scenario outlined in Table 13.9 is based on piling activities occurring over a 39 month period within a 56 month construction window (Chapter 5) with piling being restricted to covering no more than two spawning periods for the key sensitive species which are considered to be the Downs herring and sole. The behavioural disturbance to spawning grounds assumes a maximum intensity of pile installation at a rate of two concurrent 7m monopiles per day with 140 piles being installed over two consecutive spawning seasons (i.e. 70 piles per spawning season). In order to assess the worst case for sensitive periods it has been assumed this 35 day period could occur at any point throughout the 56 month construction programme with the maximum impact considered to result from the disturbance of two consecutive spawning seasons. The worst case assumes a maximum of four hours per monopile installations.

13.6.6 While the worst case for GWF is based on a four hour piling duration, the piling of a 6.3m monopile at GGOWF in a water depth of 31.2m took approximately 1.25hrs and required approximately 2,000 hammer blows, during which the hammer force reached a maximum of 1,072 kJ (Gardline, 2010)

13.6.7 In order to establish the levels of underwater noise from impact piling operations for maximum 7m diameter monopiles and 3m pin piles (proposed for space frame foundations), site specific modelling was carried out at seven representative locations (sites A to G) using a three dimensional underwater sound propagation model (INSPIRE v18) (Subacoustech, 2011). The INSPIRE model enables the level of noise at various ranges from the piling operation to be estimated for varying tidal conditions, water depths and piling locations. Although a number of underwater noise propagation models take into account the sediment type in the region around the piling operation the INSPIRE modelling has indicated that sediment type is not an important factor for estimating propagation of impact piling noise (Subacoustech, 2011). The model is validated against a large existing database of measurements of piling noise (Subacoustech, 2011).

13.6.8 There are two assessment criteria that have been developed for the assessment of underwater noise on fish and marine species. The dBht

(species) metric (Nedwell et al., 2007b) has been developed as a means for quantifying the potential for a behavioural impact on a species in the underwater environment. As any given sound will be perceived differently by different species (since they have differing hearing abilities) the species name must be appended when specifying a level. The other assessment criteria is based on the M-weighted Sound Exposure Level metric (Southall et al., 2007) which has been adopted by the Joint Nature Conservation Committee (JNCC) for addressing impacts on marine mammals. To date all of the Thames OWF projects have used the dBht metric, including monitoring studies during the construction of GGOWF. The monitoring studies for GGOWF suggest that the predictions made by the INSPIRE model are reasonably accurate and provide a precautionary level of effect. The dBht metric method has therefore been used throughout this assessment.



13.6.9 Based on their physiology, fish species can be separated into different categories based on their sensitivity to sound:

Hearing generalists are species with either no swim bladder (e.g. elasmobranchs), a poorly developed swim bladder or well developed swim bladder that is not connected to the ear; and

Hearing specialists, which tend to have their swim bladder directly connected to the ear increasing their hearing sensitivity (e.g. clupeids such as herring).

13.6.10 Hearing specialists i.e. those fish with specialist structures (e.g. Prootic

auditory bullae – a gas containing sphere evolved from the bones of the ear capsule) have been classified as 'high' sensitivity (e.g. herring), non-specialists with a swimbladder or hearing generalists are 'medium' sensitivity (e.g. cod) and non-specialists with no swimbladders are termed 'low' sensitivity (e.g. sole and dab) (Nedwell et al., 2004).

13.6.11 A summary of selected fish species and their sensitivity to sound is provided in Table 13.10 below.

Table 13.10 Example of hearing specialisation of selected fish species

Common name Swim bladder connection Sensitivity

Herring Prootic auditory bullae High

Sprat Prootic auditory bullae High

European eel None Medium

Cod None Medium

Plaice No swim-bladder Low

Thornback ray No swim-bladder Low

Dab (sole surrogate) No swim-bladder Low

13.6.12 The species upon which the dBht analysis has been conducted to inform this assessment have been selected based upon the availability of a good quality peer reviewed audiogram, their regional relevance in terms of the proximity of species spawning sites and concerns raised during consultation.

13.6.13 Where data for a particular species of commercial or environmental significance is not available, a surrogate species may be included in the analysis to indicate the likely response of the type of species to underwater sound. For example, sole is of commercial significance in UK waters and the Thames is known as a spawning ground for this species (Figure 13.10). At present, however, there is no audiogram data available for sole. Another flatfish, dab, has therefore been included as a surrogate. It should be noted



that the assumption that similar species have comparable hearing sensitivity is not always correct. In this case, the use of dab as a surrogate for sole (and also plaice) is considered to be conservative enough to provide an acceptable precautionary assessment.

13.6.14 The fish species considered in this modelling assessment are:

Herring, a fish hearing specialist that, based on current peer reviewed audiogram data is the most sensitive marine fish to underwater sound;

Cod (and other gadoids), a fish hearing generalist that is sensitive to underwater sound;

Dab, a flatfish species with generalist hearing capability, but that based on current peer reviewed audiogram data is the most sensitive flatfish to underwater sound – providing a precautionary surrogate for sole (and also other flatfish species); and

Elasmobranch species, considered to have a low sensitivity to sound (Nedwell et al., 2004).

13.6.15 These species along with a justification of their sensitivities in relation to

GWF are presented in Table 13.11.

13.6.16 The MMO raised the comment (Table 13.1) as to whether specific modelling on European eel should be undertaken. The assessment has focused on those species that are known to be present in the area on a regular basis, and particularly those having important spawning grounds in the region (as informed by the data used to characterise the existing environment and further justified in Table 13.11). Whilst the European eel may pass in close proximity to the proposed GWF site during certain life stages (e.g. adult migration and returning elvers) its passage would be transient and there are no key habitats within the vicinity of GWF which are required as part of the eels lifecycle. Furthermore, eels are not thought to have a high sensitivity to noise and are considered hearing generalists (Nedwell et al., 2003). The modelling is therefore, considered to be commensurate to the sensitivity of the species recorded at the site. Qualitative consideration of impacts on the European eel is given in the assessment of impacts, detailed below.

13.6.17 The effects of noise on fish can be divided into the following categories (Nedwell et al., 2007a):

Lethal injury;

Physical injury;

Traumatic auditory injury (temporary or permanent loss in hearing sensitivity); and

Behavioural responses and masking of biologically relevant sound.



13.6.18 For the purposes of the assessment the lethal, physical and traumatic effects are discussed together, followed by consideration of the behavioural responses.



Table 13.11 Sensitivity and importance of the species spawning grounds potentially affected by noise and vibration

Common name

Value / sensitivity

Justification Occurrence at the site

Herring High

High sensitivity to noise, spawning is restricted by extent

of available and suitable substrate.

North Sea herring consist of different discrete spawning

stocks. GWF overlaps with the Downs herring spawning

ground and the Thames also contains discrete

populations of spring spawning (‘Blackwater’ of ‘Thames’)

herring which do not spawn elsewhere in the North Sea.

The potential noise impacts could disturb herring during

spawning; were they subsequently to fail to spawn in large

numbers, this could affect future recruitment to the herring

sub-populations.

The proposed GWF site just overlaps or lies adjacent to

an area indicated by Coull et al as being part of the

wider Downs herring spawning grounds (November to

January). However, International Herring Larval Survey

(IHLS) data indicates that in fact the main spawning

(based on distribution of yolk-sac larvae) is located in

the Eastern Channel (from Côte d'Opale near

Dunkerque to Cap d’Antifer near Le Havre on the French

coast) and that spawning intensity on the Southern Bight

grounds which overlap with GWF are much less intense;

long time series data confirm this has been the case

since the 1970’s (see -Collas et al., 2009 and Pawson,

1995). The 2000 to 2011 IHLS data presented in

Technical Appendix 13.C also reflect these trends.

Two discrete spawning grounds for the ‘Thames’ spring

spawning herring (mid February to late April) are also

located to the west of the site near the Blackwater

Estuary and to the southwest at Herne Bay (Figure

13.4) both of which are approximately 55km away.



Common name

Value / sensitivity


Cod Medium

Considered a hearing generalist, although are considered

sensitive to noise and are known to use low level grunting

sounds during spawning activities. Most energy emitted

from pile driving activities arises at low frequencies (125

Hz and 250 Hz, as per Thomsen et al., 2006). GWF is

located in a low intensity spawning ground and close to

grounds defined by Coull et al., 1998. Spawning occurs in

the water column and spawning grounds appear

widespread and are not restricted to specific areas,

occurring throughout the North Sea.

Cod represented an important component of catches

during the site specific surveys and also in the

commercial catches (Chapter 15). Cod are wide spread

throughout the North Sea. Peak spawning in the

southern North Sea occurs from the last week of

January to mid-February.

Sole Medium

Based on their surrogate dab, sole are considered to have

a low sensitivity to noise due to the lack of a swimbladder

although they are known to be sensitive to particle motion

(Mueller-Blenkle et al., 2010). The GWF site lies within a

large area indicated as a high intensity sole spawning

area. The Thames estuary is highlighted as one of the 5

main spawning grounds in the UK. Important spawning

areas in the Thames are considered to be the Black Deep

and Knock which are located more than 20km to the west

of the site. Data on the occurrence of recently spawned

eggs supports the presence of inshore spawning grounds

Sole represent a commercially important target species

in the Outer Thames Estuary. By weight and also by

value (see Chapter 16) sole landings represent an

important proportion of the landings from GWF site area.

While sole were not caught in high numbers during the

GWF surveys they were present in surveys carried out

for GGOWF and as part of the Outer Thames Estuary

REC study (MALSF, 2009). The areas of high intensity

spawning are thought to be associated with the

shallower inshore waters in the Thames and areas such

as the Knock and Black Deeps are thought to be of



Common name

Value / sensitivity


(ICES, 2010a). particular importance. These lie to the east of GWF and

it is worth noting that the bathymetry shallows between

these areas and GWF which would result in a higher

attenuation of construction noise in these areas.

Elasmobranch

species (e.g.

thornback ray

and spurdog)

Medium

Elasmobranchs are generally considered to have a low

sensitivity to sound due to the lack of a swim bladder.

Due to the depleted status of species such as spurdog

and the regional importance of species such as thornback

ray, elasmobranchs have been given an overall sensitivity

and importance of medium.

The Thames Estuary is considered to be of national

importance for thornback ray which were also recorded

in the GWF surveys.

While only a single spurdog was recorded during the

GWF surveys, consultation responses indicate that the

area of the GWF is thought to be an important pupping

ground.



Lethal, physical and traumatic auditory injury effects

13.6.19 Currently available information suggests that lethality to fish may occur where peak to peak levels exceed 240dB referenced to 1 microPascal (dB re. 1μPa), and physical injury may occur where peak to peak levels exceed 220dB re 1μPa (Subacoustech, 2011). Nedwell et al., (2007b) has suggested that the use of a 130dBht level provides a suitable criterion for predicting the onset of traumatic hearing damage, which recognises the varying hearing sensitivity of differing species. As discussed in Chapter 5, it is predicted that noise levels of up to approximately 254dB re 1 µPa @ 1m for a 7m diameter monopile could be expected for the proposed GWF project.

13.6.20 Predictions based on the assumption that, at the onset of pile driving, a high blow force would be used indicate that direct impacts such as death, or severe injury leading to death, in fish may occur very close to the source of peak pressure levels. Work undertaken by Yelverton (1973, 1975) highlighted that, for a given pressure wave, the severity of the injury is related to the duration of the pressure wave. The Yelverton model also indicated that smaller fish were generally more vulnerable than larger ones. While specific studies relating to the impacts of piling operations on fish species are limited a study performed on behalf of Caltrans (2004) presents the only direct evidence of the effect of impact piling on caged fish, and showed that there was no damage to steelhead and shiner surfperch at levels of exposure up to 182dB re 1μPa (Subacoustech, 2011).

13.6.21 For the 7m diameter monopile at the proposed GWF site, the modelled data indicate that lethality could occur out to ranges up to 7m from the monopile and physical injury out to ranges of up to 130m (Subacoustech, 2011). By way of comparison the predicted lethal and physical effects ranges for the installation of a smaller 6.3m monopile in a water depth of 31.2m at the GGOWF were 2m and 40m respectively (Gardline, 2010). The extent of traumatic hearing damage effects at GWF varies depending on the species considered. The maximum ranges are 0.97km for herring, 0.36km for cod and 0.05km for dab (Subacoustech, 2011). The traumatic hearing damage range for herring for the installation of a 6.3m diameter monopile at GGOWF was estimated at 0.44km (Gardline, 2010).

13.6.22 Comments received in response to the Section 42 consultation on the GWF project raised concerns about the potential impact of piling on fish eggs and larvae and in particular those of the Downs herring spawning ground population (see Table 13.1) and also species spawning within the region such as sole. Unlike adult species fish eggs and larvae are less able to actively swim away from sources of underwater noise.

13.6.23 Further data covering spawning activity over the past ten years has been acquired from IMARES. These data are presented in detail in Technical Appendix 13.C, and indicate that the majority of the spawning activity within this extensive spawning ground takes place in the eastern English Channel (160km and 260km to the southwest of the proposed GWF site). As such the



noise generated from impact piling will not have a spatial overlap with the majority of the benthic Downs herring eggs which are located in the East English Channel (see Figure 13.22).

13.6.24 There is large uncertainty about the vulnerability of fish eggs and larvae to piling noise and the spatial scale at which mortality or injury will occur (Popper & Hastings 2009). Criteria identified by the US Fisheries Hydro Working Group (Oestman, 2009 as cited in Bolle et al., 2011) for injury to fish from pile driving identified a maximum peak sound pressure levels of 206 dB re 1 mPa2 and maximum cumulative SEL of 187 dB re 1 mPa2s for all listed fish except those that weigh less than 2 gram. For small fish (<2 gram), the threshold for the cumulative SEL is 183 dB re 1 mPa2s.

13.6.25 Common sole larvae have a swim bladder during a limited period of their larval life which may make them sensitive to sound pressure. However, a recent study by Bolle et al., (2011) used cumulative SEL levels (206 dB) which were much higher than the proposed threshold criteria and found no significant effect on the survival of sole larvae. The highest sound exposure used in this study represented 100 strikes at a distance of 100m (and also 2,500 strikes at a distance of 1,000m) from a ‘typical’ North Sea piling site (Bolle et al., 2011). This study showed that the threshold for lethal effects ≥14% in common sole larvae is at a distance of less than 400m from a ‘typical’ North Sea piling site. An estimation of the radius in which a small effect (<14%) may occur cannot be supported statistically, but the absence of effects in the second series of experiments indicated that mortality of common sole larvae at a large distance from the piling site is highly unlikely (Bolle et al., 2011). These levels are not high compared to natural mortality. In most marine fish species, natural mortality rates are much higher during the egg and larval stages than in the juvenile and adult stages. Instantaneous mortality rates of common sole eggs in the field were estimated at 0.4 to 0.6 d-1 (i.e. 94-99% mortality after 7 days) by van der Land (1991 as cited in Bolle et al., 2011).

13.6.26 Studies of the effects of seismic airguns on both eggs and larvae of cod, saithe Pollachius virens and herring found mortality only occurred within about 5m of the noise source and the most substantial effects occurred to fish within 1.4m of the source (Booman et al., 1996).

13.6.27 The evidence suggests that any mortality and physical injury effects associated with piling activities (based on either peak to peak or SEL levels) would be much localised. Furthermore, given the intermittent nature of piling only a very small proportion of planktonic eggs and larvae would be affected.

13.6.28 The localised impact of death and physical injury is anticipated to occur for the duration of the pile driving associated with the installation of up to 140 monopile foundations within an estimated 130m radius. While the impact is considered to be permanent and non reversible, due to the localised nature the magnitude of the effect is considered to be low. While fish, larvae and fish eggs would have a high sensitivity to such impacts, only a small number of individuals would be affected and there would not be any wider population



effects. The impact on the Downs herring population and other fish species arising from death or physical injury due to piling noise is therefore assessed as being of minor adverse significance.

13.6.29 Aside from mortality and physical injury effects traumatic hearing damage may also occur. For this assessment the perceived level of 130dBht has been identified as the level of noise at which traumatic hearing damage (i.e. permanent hearing impairment as a result of a single transient event) may occur. While temporary hearing loss is an injury that is recoverable over a period of time, permanent hearing loss results in the death of sensory hair cells of the ear and is non-reversible. The conclusion of a review of data on auditory injury in fish concluded, in the context of marine fish exposed to underwater noise, it is very unlikely that fish would experience auditory injury unless constrained in a very high level continuous sound field for prolonged periods (Subacoustech, 2011, see Technical Appendix 13.B). Based on behavioural reactions to noise it is anticipated that fish species would swim away from the piling source and therefore are unlikely to be exposed to these high noise levels for any length of time.

13.6.30 The modelling results for pile driving at high blow forces indicate that traumatic hearing damage effects may occur over a range of distances depending on the hearing sensitivities of a given species. The data indicate that herring could suffer hearing impairment within a range of about 0.97km from pile driving operations for the worst case 7m diameter monopile, while the ranges for other species are lower.

13.6.31 The extent of these impacts would be relatively localised (and barely visible on Figures 13.22 to 13.24) and restricted to the duration of pile driving activities. While the sensitivity of herring is considered to be high, given their sensitivity to noise, however the main Downs spawning grounds are located in the English Channel approximately 160km to the southwest of the proposed GWF site. The number of individuals affected within the 0.97km radius by hearing impairments would not be anticipated to have any wider population or recruitment impacts for the species. Based on the intermittent nature of the piling operations and highly localised nature of the impact, the magnitude is considered to be low. Soft start piling would also further reduce the magnitude of this impact. The impact on sensitive receptors such as herring is assessed as being of minor adverse significance. Based on the lower sensitivities and extent ranges for cod and dab (sole surrogate) the impacts on these species are assessed as being of negligible significance.

13.6.32 An analysis was also carried out to determine how close two concurrent piling operation would need to be so that the cumulative impact of two monopiles being installed at the same time would cause a noise dose greater than 90dBht LEP,D for each species and cause auditory injury. These data indicate that, for dab, the piles would have to be 50m apart before the cumulative dose reaches 90dBht LEP,D. This is clearly unrealistic for wind farm construction (with the minimum separation distance being 856m * 642m), so it can be concluded that impact piling at two locations within GWF simultaneously would not increase the risk of auditory injury to dab. For



herring the critical range where noise dose increases above 90dBht LEP,D is calculated at 7km. Therefore, if two monopiles are being installed at locations closer than 7km, herring may not be able to swim out of the auditory injury zone before receiving a noise dose that is likely to cause hearing impairment. As for the assessment of traumatic hearing damage for herring above for a single piling event the impact for concurrent piling on herring is assessed as being of minor adverse significance. While the spatial extent of the impact is anticipated to be larger than that for a single piling event the intermittent and temporary nature of the impact would only increase to magnitude to low.

Mitigation and residual impact

13.6.33 The modelled ranges and discussion presented above are based on the assumption of piling at full blow force, which was carried out in order to assess the worst case scenario. ‘Soft start’ piling is generally considered industry best practice and would be applied at the GWF site; it involves gradually ramping up the blow force on the hammer. When a soft start procedure is used at the onset of piling, the levels of underwater noise from the piling work are lower than during piling at maximum blow force, but above the 90dBht strong behavioural avoidance perceived level for many marine species at close range (Subacoustech, 2011, see Technical Appendix 13.B). Any fish species around the piles are, therefore, likely to flee the region around the piling operation. For fleeing rates, speeds of 1m.s-1 have generally been used during modelling, although in reality herring are generally able to swim at much faster rates (Subacoustech, 2011, see Technical Appendix 13.B).

13.6.34 Provided the fish have sufficient time during the soft start procedure to flee to a safe distance it is considered unlikely that individuals would experience lethal or physical injury, apart from fish larvae and eggs which would be unable to swim away form the impact. As a result for adult fish species soft start would reduce the magnitude of the impact from low to negligible. While based on the impact assessment table (see Table 4.4 in Chapter 4 EIA Process) the impact would remain minor negligible it is considered that the actual residual impact would be of negligible significance given the reduced likelihood of lethal or physical injury. The impact on fish larvae and eggs would be very localised and is considered to remain minor adverse.

13.6.35 Measurements of soft start procedures indicate that the perceived levels of noise for herring at the start of the soft start procedure may be reduced by up to 18dB for pile driving a 7m monopile at high blow forces (Subacoustech, 2011). Re-modelling of the data taking into account these lower levels indicate that herring could suffer hearing impairment out to a range of up to about 220m during installation of a 7m diameter monopile during the early stages of the soft start procedure (as compared to 970m at full force) (Subacoustech, 2011, see Technical Appendix 13.B).

13.6.36 Provided the soft start procedure gradually increases the blow force over time, fish beyond these ranges should have a sufficient opportunity to flee the



area out to a safe distance to avoid traumatic hearing impairment. The modelling data (Subacoustech, 2011 see Technical Appendix 13.B) indicate that the use of the soft start procedure would be likely to provide a suitable method of mitigating the possibility of traumatic hearing damage in marine fish species (Subacoustech, 2011). Soft starts are standard practice in the offshore wind industry and would be applied at the GWF project. Combined with the intermittent nature of monopile installation and the fact that monopile installation very rarely requires pile driving at full blow force, soft start procedures are considered to provide an effective form of mitigation for impacts on fish species. With this mitigation in place, the residual impact associated with traumatic injury would be considered to be of negligible significance.

Behavioural responses

13.6.37 Based on a large body of measurements of fish avoidance of noise, a level of 90dBht(species) has been proposed as the level at which a strong likelihood of disturbance to the majority of individuals of a species would be expected (Subacoustech, 2011). A lower level of 75dBht(species) has also been used to indicate that a significant behavioural impact in approximately 85% of individuals is likely to occur, although the response from a species will be probabilistic in nature and one individual from a species may react, whereas another individual may not. Furthermore, the effect at this level will probably be limited by habituation (Subacoustech, 2011).

13.6.38 The modelling data have indicated that, of the fish species considered, herring are likely to perceive levels of underwater noise above 90dBht out to the greatest ranges. The ranges to which the noise would be expected to remain above 90dBht for this species is 20 to 34km for 7m diameter piling operations. By way of comparison, based on the underwater noise measurements for the smaller 6.3m diameter monopile installation at GGOWF the disturbance range for herring was estimated at 22km (+ 3.3km) (Gardline, 2010).

13.6.39 There may be significant variation in avoidance ranges presented based on the location of piling operations and bathymetry. Table 13.12 presents an overview of the range of avoidance impact ranges for the three indicator species that have been modelled and at the different locations modelled in the GWF site.

Table 13.12 Estimated minimum and maximum impact ranges for a 7m diameter monopile at GWF

90 dBht strong avoidance range (m) Range (km)

Herring 20 - 34

Cod 15 - 26

Dab 6 - 9



90 dBht strong avoidance range (m) Range (km)

75 dBht significant avoidance range (m) Range (km)

Herring 29 - 62

Cod 29 - 51

Dab 16 - 28

Source: adapted from Subacoustech, 2011

13.6.40 Noise modelling for herring, cod and dab were carried out at various locations (sites A to G) within the proposed GWF site in order to demonstrate the extent of impact ranges (see Figure 13.18). Modelling plots for two of the locations are presented and discussed below.

13.6.41 The modelling results presented in Figures 13.22 to 13.24 indicate that the noise generated by pile driving of a 7m monopile could lead to behavioural responses by fish in areas that are indicated by Coull et al.,(1998) as being spawning and/or nursery grounds for the species discussed in Section 13.4. These areas for herring, cod and sole, taken from Coull et al.,(1998), Cefas (2010) and Pawson (1995) have been overlain with the noise contours taken from the noise modelling results in order to show the extent of potential overlaps with these areas. As indicated for species such as herring the worst case is based on concurrent piling at opposite extents of the proposed GWF site (See Figure 13.22) which would result in the greatest spatial overlap with the spawning grounds as presented by Coull et al., 1998.

















13.6.42 Several commercially important species have been identified as having potential spawning and nursery areas covering the Outer Thames Estuary and some of which overlap with the GWF site.

13.6.43 The proposed GWF site partially overlaps with or lies adjacent to an area indicated as forming part of the Downs herring spawning grounds and where spawning is indicated as taking place between November and January. Herring are demersal spawners and their spawning activities are limited by the availability of suitable habitat. The other discrete Thames spring spawning herring grounds lie at the mouth of the Blackwater Estuary and in Herne Bay and both are approximately 55km to the southwest of GWF; the noise modelling indicates these sites would not be impacted by subsea noise from the piling operations at GWF (see Figure 13.22).

13.6.44 Based on the construction window and piling programme, piling activities would impact no more than two spawning periods for any species. Whilst it is anticipated that much of the offshore construction would, by preference (in terms of avoiding inclement winter weather), be completed during the period March to November (see Chapter 5) and would therefore fall outside of the herring spawning season, as a worst case it remains possible that piling activities could occur throughout the year including during the herring spawning season. As a worst case, assuming two monopiles are installed every day by two separate piling vessels split over two consecutive spawning periods a total of 70 piles would be installed over a 35 day period in each spawning period, which if operations do not run concurrently would result in a total of eight hours piling per day during a key 35 day period over two herring spawning seasons.

13.6.45 Figure 13.22 illustrates the extents to which strong (90dBht) and significant (75dBht) behavioural impacts could occur. It also shows that while the piling activities at GWF could impact the areas in the Southern Bight indicated by the Coull et al.,(1998) maps as possible spawning grounds, the main eastern English Channel site where spawning is actually recorded by the IHLS surveys would not be disturbed. It is worth noting that while the 75dBht contour covers a large area of the area indicated by Coull et al.,(1998) as a possible spawning site, this level of underwater noise would only generate a behavioural response from some individuals. Furthermore, habituation to underwater noise is possible (Subacoustech, 2011) and research shows that herring may respond differently to noise depending on the season and their physiological state. While not directly related to piling noise disturbance Missund (1997) observed higher levels of avoidance to noise from vessels when herring were over-wintering than during seasons when they were feeding. Furthermore, Skaret et al., (2005), suggest that in relation to vessel noise during actual spawning, herring will give priority to reproduction, with spawning overruling noise avoidance responses.

13.6.46 While piling at GWF has the potential to impact on a proportion of the Downs herring spawning grounds as identified by Coull et al., (1998), IHLS data and the abundance of yolk-sac larvae indicates that the main Downs herring spawning grounds are in the East English Channel (see Figure 13.22 and in



more detail in Technical Appendix 13.C). It is widely acknowledged that since the 1970’s these have been the main Downs herring spawning grounds (Dickey-Collas et al., 2009, Pawson, 1995, ECA and RPS Energy, 2010, Rohlf & Gröger, 2003) and that the herring larvae recorded in the southern North Sea originate from spawning grounds in the Eastern Channel (Damme pers. Comm., 2011). This is shown by the abundance and distribution of yolk-sac larvae for the years 2000 to 2011 (see Technical Appendix 13.C) which supports the conclusion that there is currently, and this has been the case since at least 2000, no high intensity spawning by the Downs herring stock at the Southern Bight spawning grounds and that the proposed piling activities at GWF would therefore not significantly impact the main Downs herring spawning stock or herring eggs. These trends are also reflected by the commercial exploitation of the Downs stock where winter spawning aggregations are targeted by fleets in the eastern English Channel at the end of the year (ICES, 2009, ICES, 2007a) (see Figure 1.1 in Technical Appendix 13.C).

13.6.47 Based on their high sensitivity to noise and the restricted nature of their spawning habitat the Downs spawning herring are considered to have a high sensitivity to potential noise impacts. The magnitude of the piling impact on the Downs herring is however considered to be negligible. This is based on the fact that piling would not impact the main Downs herring spawning population which currently utilise the spawning grounds in the East English Channel and have done so since the 1970’s. The overall impact is therefore considered to be of minor adverse significance.

13.6.48 It is worth noting that, while the above considers the worst case, the reality is likely to be a more intermittent piling programme during the winter months where weather windows are restrictive and piles are installed more intermittently.

13.6.49 Concerns were raised during scoping with regard to noise impacts potentially masking cod spawning communications and disturbing spawning behaviour as they are known to use low level grunting sounds. Peak spawning in the southern North Sea is known to occur from January to mid-February.

13.6.50 Although cod are considered hearing generalists, because they are known to use sound during spawning activities, their sensitivity is considered to be medium. As discussed for herring above, the worst case assumes that some piling would occur during the winter period and, therefore, would overlap with spawning activities. Modelling indicates that the impact extents would overlap with the spawning grounds indicated by Coull et al.,(1998) (Figure 13.23). The impact magnitude is considered to be negligible as, as cod spawning grounds are distributed widely throughout the North Sea (see Figure 13.6) and the piling disturbance would only affect a small proportion of the cod spawning grounds in the Southern Bight. Furthermore, the duration of the impact would only cover a maximum of two spawning seasons. The overall impact is therefore assessed as being of negligible adverse significance. This impact assessment would be similar for other gadoids species such as whiting, which also have a small proportion of a



spawning ground overlapping with GWF (see Figure 13.7). Furthermore, many marine fish species, including gadoids are generally pelagic broadcast spawners and are not limited to specific substrate types as is the case for species such as herring. The spawning areas also cover larger areas of the North Sea and, as such, localised noise impacts would not be anticipated to have a significant effect on the wider stock, given the wider availability of spawning habitat.

13.6.51 The impacts of piling on spawning sole were also raised as a concern during consultation (Table 13.1). Sole spawning in the Thames Estuary occurs from March to June and based on the construction window (Chapter 5) piling works would overlap with this period as piling could occur at any time of year.

13.6.52 Sole are known to spawn inshore, within the 30m depth contour. Important spawning areas in the Thames are considered to be the Black Deep and Knock which are located more than 20km to the west of the site. Data on the occurrence of recently spawned eggs and also the further data discussed in Section 13.4 supports the presence of inshore spawning grounds (ICES, 2010a) which corresponds to these initially identified by Pawson (1995) with spawning in the wider area including in the vicinity of the GWF being at a markedly lower intensity.

13.6.53 The modelling results indicate that the extent of a strong avoidance reaction (90 dBht) in the majority of individuals is only anticipated to extend to a maximum of 9.5km (mean of 8.7km) from pile driving operations at position D. The lower level behavioural impacts at the 75dBht level will potentially extend to a maximum of 28km. These figures are a worst case and the extents are anticipated to be much lower for the sites closer to the key inshore sole spawning areas due to underwater noise attenuating at a faster rate in shallower water (e.g. a mean of 8km at site F). The extent of a strong avoidance reaction in sole of 9.5km is comparable to the distance of 6.6km estimated for sole during the noise measurements for the installation of the smaller 6.3m diameter monopile at GGOWF.

13.6.54 Sole are considered to be relatively insensitive to noise due to the lack of a swim bladder although studies have indicated that a range of particle motion levels will trigger behavioural responses in sole and cod (Mueller-Blenkle et al., 2010). The levels of particle motion generated during pile-driving and the distance at which it can be detectable are not known at present (Mueller-Blenkle et al., 2010). However, based on the importance of the Thames Estuary as a high intensity spawning ground, and their potentially complex spawning courtship behaviour their sensitivity to spawning disturbance has been assessed as medium. The extent of the noise impacts associated with piling operations as obtained from the modelling are presented in Figure 13.24 where dab has been used as a surrogate for sole.

13.6.55 The magnitude of piling impacts on spawning sole has been assessed as low. This is because, although some lower intensity spawning activity might be disturbed around the GWF site during piling operations, there would be no substantial overlap with the most important areas of high intensity spawning



which are considered to take place in the shallower coastal waters within the Thames estuary and which are protected from the highest noise levels by the shallow Thames bank systems which will lead to rapid noise attenuation as can be seen in the results of the noise modelling. Furthermore, the piling operations would only impact on two sole spawning seasons. The overall impact of the piling activities on sole spawning behaviour is therefore assessed as being of minor adverse significance.

13.6.56 The extent of behavioural impact associated with the piling operations could potentially affect the distribution of commercially important fish species within the vicinity of the piling operations. The worst case is considered to be the use of 3m piles (see Table 13.9) as while the behavioural extents are less than that for 7m piles (see Figures 13.22 to 13.27) due to the numbers required this foundation option would result in the maximum piling activity occurring over the longest period thereby providing the greatest potential for disturbance and behavioural effects.

13.6.57 A number of studies have noted that changes in fish behaviour may arise following exposure to relatively low level sounds. Engås and Løkkeborg (2002) observed a reduction in the catch of haddock and cod that lasted for several days after they had been exposed to seismic airgun emissions and Slotte et al., (2004) found broadly similar results for blue whiting and herring. Skalski et al., (1992) found that the catch of rockfish reduced by 52% following exposure to a single emission of an airgun at 186-191dB re 1 μPa (mean peak level). In the case of the GWF piling, the magnitude of this impact is considered to be low, based on the short-term and localised nature of the displacement that is expected to occur. The sensitivity of fish to such short term behavioural displacement is also considered to be low due to the wide availability of other suitable foraging and feeding habitat for the displaced species and the temporary and reversible nature of the effect. The impact is therefore assessed as being of negligible adverse significance.

13.6.58 The potential impacts of GWF on spurdog pupping grounds were raised during consultation (Table 13.1). The information available to date suggests that spurdog undertake migrations all round the UK coastline and are considered and managed as a single stock. The information available suggests that the areas off the west coast of Scotland are one of the most important areas for spurdog juveniles. The impact magnitude is considered to be low, based on the short-term nature of the impact, which would only occur for the duration of the piling operations. While juveniles have been recorded from surveys within the vicinity of the GWF site (Figure 13.19) and elasmobranch species have a low sensitivity to noise due to lack of a swimbladder (see Table 13.10) their overall sensitivity has been assessed as medium based on their depleted status (Table 13.11). It is anticipated that the impacts of pile driving on spurdog, as well as other elasmobranch species, including egg laying rays, would be minimal and localised and, as such, the impacts would be considered to be of minor adverse significance.

13.6.59 The site specific surveys carried out at the proposed GWF site, combined with commercial fisheries landings data indicate that shellfish species such



as crab are present at the site, and in particular, close inshore along the cable route. These species may be of value as a commercial species and support targeted fisheries (Chapter 15) or as important prey for other marine species.

13.6.60 The first published investigation of invertebrate mortality associated with underwater noise was carried out in 1907 and, although studies have been carried out since, there is insufficient research on the effects of noise on shellfish species. Some studies (e.g. Knight, 1907, Tollefson & Marriage, 1949, Andriguetto-Filhoa et al., 2005) seem to indicate that shellfish are relatively insensitive to noise including from underwater blasting and seismic prospecting at close range. The magnitude of the piling impact is considered to be low based on the short-term duration of the piling. Based on the available information to date, the impact on shellfish species of commercial or prey value present at the site is, therefore, anticipated to be of negligible adverse significance.

13.6.61 During consultation concerns were raised in relation to the potential impacts of foreshore noise on fish (Table 13.1). Construction related activity using construction plant is anticipated to occur on the foreshore in relation to the cable landfall (Chapter 5). The works associated with the cable landfall include the use of directional drilling to connect the cables from the high water mark to the onshore transition bay (see Chapter 5). Construction activities on the foreshore would create air borne noise. Due to the acoustic impedance effects of the amount of acoustic energy transferred from one substance to another (for air and water this difference is large) airborne noise would not contribute significantly to levels of underwater sound. The main pathway for construction plant or drilling activities impacting fish populations would be through low frequency vibration impacts. These vibration impacts are only anticipated to be localised due to the dampening effects of the sand / soil substrate. Any construction related activities would be associated with the installation of up to three export cables and would therefore be of short-term duration. The magnitude is therefore considered to be negligible. The sensitivity of fish species to the low levels of noise or vibration during any onshore works are considered to be low. Overall the impact significance is therefore assessed as negligible adverse.


13.6.62 Consultation responses received from the MMO indicated the potential for a piling restriction from 1st November to 31st May to cover the sensitive spawning periods for the Downs herring stocks and sole (Table 13.1). The data presented on piling noise effects and the distribution of the Downs herring spawning grounds discussed above show that there is no risk of likely significant effect on the main Downs herring spawning population in the English Channel. Similarly for sole, the data for the Thames Estuary on sole spawning habitat suitability, association with reduced salinity, shallower inshore water and increase temperature reflect the sole spawning areas identified by Pawson (1995). Piling noise during construction is not anticipated to cause a significant behavioural overlap with these grounds.



This combined with their relative insensitivity to underwater noise suggests that there is no risk of likely significant effect on the main spawning populations. As such it is felt that for the Downs herring and also sole, given the lack of significant risk, such mitigation is not justified.

13.6.63 Further discussions are ongoing with the regulators to establish the actions that are required in order to bring any necessary restrictions in line with the anticipated impacts associated with the proposed GWF development.

13.6.64 As discussed previously mitigation in the form of soft start piling will be incorporated into construction procedures. However, while such measures would reduce the impacts associated with lethal and physical injury, once piling reaches full blow force the behavioural impact ranges would remain unchanged compared to the pre soft start predictions. Despite the lack of significant impact predicted on herring or sole spawning grounds, further precautionary mitigation is applied through the commitment to restrict piling activity to a maximum overlap of two spawning seasons for each of the two (herring and sole) species over the 56 month construction window. This effectively imposes a piling restriction for two of the four potential seasons that occur within such a window (assuming a Q2 or Q3 2015 commencement).

13.6.65 Given the above it is considered that the residual impact on key receptors such as the Downs herring and sole spawning grounds and elasmobranchs would remain minor adverse. The impact to other receptors discussed is anticipated to remain of negligible adverse significance.

13.6.66 Physical disturbance of intertidal and subtidal habitats

13.6.67 The physical disturbances to the intertidal and subtidal habitats are discussed in Chapter 12, Section 12.6. It is anticipated that there will be some degree of disturbance to benthic communities as a result of the cable and WTG installation. It is anticipated that some scavenging fish, crustacean and invertebrate species may be attracted to the recently disturbed seabed to feed on the recently exposed and damaged benthic animals. These disturbance impacts are however anticipated to be temporary and reversible and are not anticipated to result in any long term changes in fish or shellfish communities. The magnitude of the impact is considered to be negligible based on the limited extent of the disturbance and short term duration. While species may be attracted to such disturbance events their sensitivity is considered to be low based on the localised effects and limited extent of any behavioural changes. The overall impact is therefore assessed as being of negligible significance.

Indirect impacts due to loss of fish as a prey source

13.6.68 Fish species represent important prey for other species including birds, marine mammals and other fish. Concerns have been raised (by the Royal Society for the Protection of Birds see Table 13.1) regarding the impact of GWF on prey and food availability for other species. The impacts of GWF on benthic invertebrates, a fish prey resource, is discussed in detail in Chapter



12 with the conclusion that there would be no significant impacts or changes in community structure. Similarly, the relationship between certain bird species, prey availability and the association of bird distributions with commercial fishing activities are discussed in Chapter 11 Offshore Ornithology. Fish, including sandeel and juvenile life stages of species such as herring, and sprat also form an important prey source for other larger fish species. The main construction related impacts on fish species are discussed in the relevant sections above and below. The main activities with the potential to have a significant impact on fish are associated with the installation of 7m diameter monopiles via pile driving.

13.6.69 As discussed above, the potential impacts to fish species include mortality at close range. However, the localised nature of these impacts would not be anticipated to have any significant wider ranging effects. Furthermore, it could be possible to reduce the extent of mortality associated with pile driving operations through the use of mitigation measures such as soft starts. While it is anticipated that significant mortality impacts can be reduced through the use of appropriate mitigation, the underwater noise generated from impact piling operations could result in hearing sensitive fish such as herring and sprat temporarily moving away from the construction area for the duration of piling operations. Piling operations are intermittent, with pile driving rarely occurring for more than four hours. Any displacement of prey species would therefore only occur for a short duration, a response that may be mirrored by their predators. It is anticipated that the overall effects on fish as a result in the loss of other fish as prey resources, would be negligible.

13.6.70 The implications of the loss of fish prey resource in relation to marine mammals and birds is discussed in Chapter 14 and Chapter 11 respectively.

Impacts due to increased suspended sediment concentrations

13.6.71 Increased suspended sediment load has the potential to impact on fish and crustacean species as well as affecting larvae and egg stages. The impact of increased suspended sediment concentrations (SSC) and volumes likely to be produced are assessed in Chapter 9 and Technical Appendix 9.Aiii. The impacts on water quality are assessed in Chapter 10. These assessments concluded that the levels of SSC associated with foundation installation will be elevated, above natural background levels, by no more than 1.4 mg/l (fine sands). The export cable installation could potentially elevate SSC temporarily in the immediate vicinity of the cable installation activity, however these are anticipated to remain below 0.5 mg/l. The potential increases in SSC for both cable and foundation installation are likely to be of negligible significance in terms of change to existing conditions (see Chapter 9).

13.6.72 Key concerns raised during consultation on GWF relate to the effects of suspended sediment impacts on spurdog pupping grounds and other egg laying elasmobranch species (Table 13.1). Given their large size at birth (26-28cm) it is anticipated that, similarly to other mobile fish species, spurdog would be able to detect the elevated levels of suspended sediments and



move away from the affected area. As such spurdog sensitivity to such impacts is considered to be low. Research carried out on herring and cod (Westerberg et al., 1996) indicates that these species have definite suspended sediment thresholds (approx 3mg/l) and are, therefore, likely to avoid the areas closest to the foundation installation.

13.6.73 Larval species and eggs, especially for herring, could also be affected by increased levels of suspended sediment. Research on the embryonic development of herring eggs (Kiorboe et al., 1981) at levels similar to those anticipated to be released as a result of the cable installation (5 – 300mg/l) found no effects after prolonged exposure (10 days). The sensitivity of larvae and eggs to the levels of suspended sediments anticipated to occur during the construction activities are therefore considered to be low. Furthermore, the levels of SSC predicted as a result of the construction activities are considerably lower than the levels larvae and eggs would be exposed to naturally as a result of regional maximum SSC concentrations especially winter concentration which may range from 64 to >250 mg/l for shallower inshore waters (see Chapters 9 and 10).

13.6.74 Skate and ray species along with other oviparous elasmobranch species are known to lay egg cases. Suspended sediment can cause mortality of embryos through blocking of the respiratory fissures or horns (Richards et al., 1963 as cited in Leonard et al., 1999). There is currently little known about the habitat requirement for skate and ray egg laying and it is unclear whether they have discrete egg laying beds. The 2m beam trawl surveys carried out for GWF site characterisation (as detailed in Section 13.3) did not identify any high densities of egg cases in the vicinity of GWF. While it is possible that egg cases could be affected by the localised sedimentation, it is not anticipated significantly large numbers would be impacted. The overall sensitivity of the receptor is, therefore, considered to be low.

13.6.75 The magnitude of the impact is assessed as low, based on the localised intermittent nature of the impact. In view of the above, the effects of the impacts associated with the turbine and cable installation on fish, larval and egg receptors would be considered to be of negligible significance.

Indirect impacts through re-mobilisation of contaminated sediments

13.6.76 The re-suspension of seabed sediments could also lead to the release of contaminants present within them, which may have direct and indirect impacts on fish and shellfish resources within proximity of the GWF site. The impacts of contaminants on water quality are discussed in Chapter 10, Section 10.6 and in relation to benthic ecology in Chapter 12, Section 12.6. The data presented in Chapter 10, Section 10.4 shows that the levels of contaminants in the sediments are below guideline and action levels. Sampling at GWF was seen to establish similar contaminant levels within its sediments to those present at GGOWF with only elevated levels of arsenic detected. Arsenic is well known to occur at elevated levels in the region of the Outer Thames Estuary and has been attributed to both historic and geological inputs (see Chapter 10, Section 10.4). The fish fauna of the



Outer Thames Estuary inhabit an area of very mobile sediments, and must, therefore, be frequently exposed to generally raised levels of arsenic in the sediments and their sensitivity to the levels which are anticipated to occur are considered to be low. Based on the localised and intermittent nature of any sediment re-suspension the magnitude is considered to be low.

13.6.77 It is anticipated that the impact of re-mobilised contaminants on the fish and shellfish resources would be of negligible significance.

Impacts due to loss of habitat and benthic prey resource

13.6.78 During the construction phase there will be permanent loss of habitat for fish and crustacean species in the direct footprint of the foundations. The potential habitat loss is only likely to have significant effects if the habitat is not widely distributed elsewhere or if the habitat is an essential piece of spawning ground for demersal spawners such as herring for example.

13.6.79 The installation of WTG, foundation structures and supporting infrastructure will result in long term loss of seabed and associated habitats and fauna within the footprint of the structures for the life of the scheme (circa 25 years).

13.6.80 Using the worst case build scenario detailed in Table 12.3 (Chapter 12) the maximum loss of seabed is anticipated to be 0.37km2 (from WTG footprint, scour protection, ancillary structures and cable protection materials at cable crossings (see Table 12.3 (Chapter 12) for detail). The total area affected will constitute 0.17% of the total consent area (222km2). The majority of seabed lost will be as a result of the WTG foundations and associated scour protection.

13.6.81 The loss of benthic communities is assessed in detail in Chapter 12 with the main communities affected being the polychaete-rich deep Venus community which is widespread at a regional level.

13.6.82 While shellfish species have been recorded at GWF, the area does not represent part of any significant shellfish beds in the Outer Thames Estuary. Similarly, only a small proportion of Area B overlaps with areas indicated by Coull et al., as forming part of the Downs herring spawning grounds. The drop-down and benthic grab surveys concluded that the majority of sediment throughout the GWF survey area were poorly sorted and did not offer ideal conditions for herring to spawn on (CMACS, 2010, see Technical Appendix 12.A). There would therefore be no impact due to the loss of herring spawning ground. Furthermore, since the 1970’s the main Downs herring spawning grounds used have been those in the eastern Channel.

13.6.83 Monitoring studies at other wind farm sites such as Kentish Flats have generally indicated that there has not been a significant effect on the fish species present, suggesting that the presence of the wind farm, including the direct loss of habitat, had not had a significant effect (Cefas, 2010b). This suggests that fish species are relatively insensitive to such small changes or loss of seabed habitat and their sensitivity to these impacts is therefore considered to be low. Given the localised nature of the habitat loss the



magnitude is considered to be low. The impacts of habitat loss on fish species would be of negligible significance.

13.6.84 It is noted that some consultees have raised the question over the potential for artificial reefs to be included in the design to help mitigate impacts on fish resource. No additional material or structures to that accounted for within the project envelope (see Chapter 5) will be provided. It is noted that the addition of any new material would further impact on the existing environment and not necessarily have a positive impact. The effect of the new structures and associated material that would be introduced into the environment as a result of the construction of the proposed wind farm is discussed below under operational impacts.

13.7 Potential Impacts during the Operational Phase

13.7.1 This section provides an assessment of the impacts from the operation phase of the GWF project on the fish and shellfish receptors. Aspects associated with the operation phase (as identified during the Scoping process and subsequent consultation) include:

Disturbance due to operational noise;

Disturbance from EMF;

Aggregation effects; and

Loss of prey resource and habitat from changes in current regime.

Disturbance through noise and vibration

13.7.2 When a wind farm is operational, the main source of underwater noise will be mechanically generated vibration from the WTGs, transmitted into the sea through the tower structure and foundation (Nedwell et al., 2003). The underwater noise generated during the operational phase of a wind farm is much lower than the levels created during construction piling. However, unlike the temporary pile driving noise, operational noise will span the lifetime of the wind farm (Nedwell et al., 2007a).

13.7.3 Measurements of operational noise at a series of wind farm sites indicated that the level of noise during the operational phase was found to be very low (Nedwell et al., 2007a). The study calculated the operational noise levels that would be encountered by various species using dBht units. When the results were averaged across all of the fish species considered, the noise levels within the wind farms were found to be just over 2dB higher than background noise levels in the immediate environs (Nedwell et al., 2007a). The variations in level are well within the spatial and temporal variations that are typically encountered in background noise, and hence it was concluded that, while there might be a small net contribution to noise in the immediate vicinity of the wind farm, this is no more than is routinely encountered by marine animals during their normal activity (Nedwell et al., 2007a). Furthermore, dive surveys of operational wind farms have indicated that the



total fish abundances in the vicinity of turbines are often higher than surrounding areas (Wilhelmsson et al., 2006).

13.7.4 Studies of operational wind farm noise in at Lillgrund in Sweden indicate that species like eel and salmon which have a poor sensitivity to sound pressure will only detect operational wind farm noise (during maximum production, wind speeds of 14 to12 m/s) at a distance less than 1km (Andersson, 2011). Fish with higher sensitivity of sound pressure, e.g. herring and cod, might detect the wind farm at a distance greater than 16km although at this distance, the ambient noise will mask out the wind farm noise (Andersson, 2011). These results are in line with other estimations such as the figures calculated by Thomsen et al., (2006) for species such as eel although the zone of audibility for herring and cod was smaller and in the region of 4-5km from the source. Fish lacking a swim bladder (e.g. gobies and flatfish) will only sense the measured particle acceleration at distance of about 10m from the foundation and at greater distances most species are limited by either their hearing threshold or the ambient sound masking the wind farm noise (Andersson, 2011).

13.7.5 The sensitivity of fish species to such small levels of noise are considered to be low. The magnitude of the impact is also considered to be low given the localised extent of the impact. As such, the impact to fish species from underwater noise and vibration during operation would be of negligible significance.

Disturbance through presence of electromagnetic field (EMF)

13.7.6 EMF will be generated by the GWF export, inter and intra-array cables. The worst case scenario set out in Table 13.9 establishes that there will be up to 300km of 66kV AC for the inter and intra array cables, and up to three AC 132kV export cables with a combined length of 190km, all buried to a representative average minimum depth of 0.6m.

13.7.7 It is important to note that 0.6m is not a ‘target’ depth, but a worst case recognition that it may not be possible to bury the cable to a desired depth (around 1.5m) across the whole cable extents. Such instances may arise where ground conditions to not permit a target depth burial depth to be achieved or when the cable rises to join with offshore substation platforms (OSP), or when crossing other cables) the cables may have to be installed on the surface and covered with concrete mattresses. For the purpose of this ES the indicative cable arrangements are presented in Chapter 5.

13.7.8 The EMF and their constituent fields; electric (E field), magnetic (B field) and associated induced electric fields (iE), produced by the inter-array and export cables could affect the behaviours of certain electrosensitive species.

13.7.9 A simplified overview of how induced electrical fields are produced by AC power cables is presented in Plot 13.10.



Plot 13.10 Simplified overview of how induced electrical fields are produced by AC power cables

Source: Gill et al., (2009)

13.7.10 The electrolytic properties of sea water mean that a small current is induced in the water, with this being in the order of 0.1 mA/m² (CMACS, 2003) (for the example of one cable buried 1m in the seabed) and which induces an E-field of around 25 μV/m (conductivity of 4 Siemens/m). An alternative example given in the COWRIE report (CMACS, 2003) reports an E-field of 91μV/m for a 132kV XLPE three-phase submarine cable designed by Pirelli with an AC current of 350 amps buried at a depth of 1m. Table 13.13 indicates that in both these cases it is likely that the EMF from these cables would be detected by electro-sensitive elasmobranch species.

Table 13.13 Elasmobranch sensitivity to electrical fields

Sensitivity E-Field range

Elasmobranch sensitivity: 0.5 – 1000 µV/m

Potential range of attraction: 0.5 – 100 µV/m

Potential range of repulsion: > 100 µV/m

Source: CMACS, 2003

13.7.11 All of the cables will, where ground conditions allow, be buried to a nominal

target depth of 1.5m with the aim to bury all cables at least 0.6m (except for transitional lengths to surface structures). Based on the information discussed above and presented in Table 13.13 where cable burial depths are less than 1.5m it is expected that the E-fields are likely to be of a level expected to attract elasmobranchs.



13.7.12 While most fish species are able to sense EMFs, elasmobranchs and migratory species are considered the key sensitive receptors to any effects that may manifest. The majority of the elasmobranch species occurring in the UK are benthic species inhabiting shallow sandy areas. Concern over potential interactions between wind farm cables and elasmobranchs has been raised (Gill, 2005; Gill et al., 2005; Sutherland et al., 2008).

13.7.13 Migratory species, such as salmonids or anguillid eels, are also known to be sensitive to EMF, especially at specific stages of their life cycle, principally during migration. Some fish species that are regarded as EMF sensitive do not possess specialised receptors, but apparently are able to detect induced voltage gradients associated with water movement or geomagnetic emissions (Gill & Bartlett, 2010) (see Table 13.14). The physiology of these sensory mechanisms for the detection of EMF is poorly understood, and is likely to vary on a species by species basis (Pals et al., 1982 as cited in Gill & Bartlett, 2010). It is likely that the species listed in Table 13.14 will respond to EMF that are associated with peak tidal movements, which can create fields in the range of 8-25 μv m-1 (Barber & Longuet-Higgins, 1948; Pals et al., 1982 as cited in Gill & Bartlett, 2010).

13.7.14 The effects of B and iE fields on fish species depends on their physiology. Many species are sensitive to bioelectric fields or use magnetic fields to aid migration.

13.7.15 Migratory species, which are known to undertake long distance migrations, such as the European eel and some salmonids, are known to have magnetic material in various part of their body which is of the right properties to facilitate magnetic detection. Telemetry studies of migratory patterns of European eel in the vicinity of a WTG in the Southern Baltic by Westerberg (as cited in Öhman et al., 2007) did not show any altered migratory behaviour, at least not 500m beyond the WTG. Catch statistics at eel pound nets in the area did, however, indicate an effect of whether the WTG was on or off. If this should be attributed to the effect of acoustic or electromagnetic disturbances was unclear. An unpublished study on migrating silver eels across a 130kV AC cable in Sweden by Westerberg and Lagenfelt (as cited in Öhman et al., 2007) found swimming speeds to be significantly lower in proximity to the cable with, on average, a 30 minute delay in migration.

13.7.16 Potential prey species such as brown shrimp Crangon crangon have also been recorded as being attracted to the B fields of the magnitude expected around wind farms (ICES 2003).

13.7.17 Elasmobranchs have been shown to respond equally to natural and artificial E field upon first encounter, raising concerns that predators such as elasmobranchs may waste time and energy “hunting” E fields associated with cabling whilst searching for bioelectric fields associated with their prey (Kimber, 2008). Such effects could ultimately reduce reproductive success and have wider population effects (Kimber, 2008). Elasmobranchs are known to respond to magnetic fields (25-100 μTesla; Meyer et al., 2004) and are thought to use the Earth’s magnetic field (approximately 50 μTesla) for



migration. They also respond behaviourally to electric fields emitted by prey species and conspecifics. Further studies of ray egg cases have also demonstrated that embryonic thornback rays cease body movement that facilitates critical ventilatory movement of water upon sensing artificial E fields. This suggested the rays were employing detection minimisation behaviour as the E fields were similar to those of predatory animals (small, adult elasmobranchs and teleosts (Ball, 2007).

Table 13.14 Evidence based list of electromagnetic sensitive teleost fish species and their conservation status (according to the IUCN Red list) in UK coastal waters. Superscript numbers show reference sources. E field = Electric Field; B field = Magnetic field

Species Conservation status

Frequency in UK Waters

Evidence of response to E fields

Evidence of response to B fields

European eel

Anguilla anguilla

Critically

Endangered

Common ✓1,2x ✓3,4

Atlantic salmon

Salmo salar

Least

Concern

Common ✓5,6x ✓5,6

Sea trout

Salmo trutta

Least

Concern

Occasional ✓7

European plaice

Pleuronectes platessa

Vulnerable Common ✓8, ✓8

Yellowfin tuna

Thunnus albacares

Least

Concern

Occasional ✓9-12

European river lamprey

Lampetra fluviatilis

Near

Threatened

Common ✓13,14

Sea lamprey

Petromyzon marinus

Least

Concern

Occasional ✓5-17

1 Berge (1979); 2 Vriens & Bretschneider (1979); 3 Enger et al. (1976); 4 Westerberg (1999); 5 Moore et al. (1990); 6 Rommel & McCleave (1973); 7 Formicki et al. (2004) – juvenile fish; 8 Metcalfe et al. (1993); 9 Kobayashi & Kirschvink (1995); 10 Walker et al. (1984); 11 Walker (1984); 12 Yano et al. (1997); 13 Gill et al. (2005); 14 Akeov & Muraveiko (1984); 14 Bodznick & Northcutt (1981); 15 Bodznick & Preston (1983); 16 Bowen et al. (2003); 17 Chung-Davidson et al. (2004)

Source: Gill & Bartlett, 2010

13.7.18 EMF modelling of cables at a series of wind farms (Gill et al., 2005) also demonstrated that there was a linear relationship between current load and resultant B and iE fields, with both fields directly proportional to current load



such that halving the current halved the resultant fields i.e. when the wind farm is operating below maximum capacity (i.e. at average wind speeds) the resultant B and iE fields will be less. Electromagnetic fields are proportional to current and, as a result, high cable operating voltages will reduce the potential impact. Increasing the voltage from 33kV to 132kV consequently reduces the induced E-fields by a factor of four (CMACS, 2003).

13.7.19 The conclusions from the most recent COWRIE mesocosm studies into EMF effects provided evidence of responses to the presence of EMF of the type and intensity associated with subsea cables. However, the responses observed were not predictable and appeared to be species specific and perhaps individual specific and, as such, there was no evidence to suggest any positive or negative effect on elasmobranchs of the EMF encountered (Gill et al., 2009).

13.7.20 Based on the information available, it is clear that fish species may respond to EMF. However, the magnitude and extent of the B and iE fields are anticipated be localised. Furthermore, while the duration of the effect would occur for the lifetime of the project, the intensity of EMF varies depending on the operating capacity of the wind farm. The overall magnitude is therefore considered to be low. Sensitive species would, therefore, not always be exposed to the highest levels of EMF as these may fluctuate depending on wind conditions. However, given the sensitivity of elasmobranchs and migratory species to detecting EMF and the uncertainty associated with the behavioural response to EMF the precautionary assessment of receptor sensitivity is high.

13.7.21 Given the low magnitude of the effect combined with the high sensitivity of the receptor the overall impact of EMF on sensitive species would be of minor adverse significance.


13.7.22 In order to reduce the likelihood for cable burial not being sufficient a dedicated cable burial protection plan will be developed once the final route has been established and site (geophysical and geotechnical) surveys undertaken (this will not prevent suboptimal burial but can aid in establishing further options if a scenario of insufficient burial presents itself). This cable burial protection plan will be informed by a Burial Protection Index (BPI), which will assess the risks (physical, human and environmental) along the route and set out target burial depths in accordance with the associated risks. Whilst this mitigation will serve to lower the potential for extensive areas of shallow buried cable, it will not remove the potential for some limited extents to remain below desired depths (1.5m in line with EN-3 recommendations). Consequently, magnitude remains low and the impact of minor adverse significance.

Aggregation effects

13.7.23 The concrete and steel wind farm structures are likely to become colonised by a range of benthic invertebrate species (see Chapter 12) and this



increase in the overall diversity and productivity of the local seabed communities as well as providing shelter against strong currents and predators which in turn could lead to an aggregation of fish species. This will increase the number of mobile fauna concentration, such as fish, near the artificial reefs (Hammar et al., 2010).

13.7.24 In a perspective of preservation of the natural existing environment, fouling and reef-effects may be considered as negative environmental impacts in areas without the presence of, or proximity to natural hard bottom (because of the risk of introduction of alien species which can change the ecological conditions) (Hammar et al., 2010). The worst case is considered to be the scenario which would result in the maximum potential for change.

13.7.25 Regarding the reef-effect, the complex structure of a jacket space frame foundation is expected to generate habitats for more species (e.g. fish) than a more homogenous model of foundation like monopile (Hammar et al., 2010). Space frame WTGS are therefore considered as the worst case. Abundant reef-effects have been observed on oil platforms around the world and the structures of these are similar to jacket foundations. Furthermore, more deep living species might exploit the food availability and the various habitats of the artificial reef of jacket foundation since they are planned to be placed at greater depths (Hammar et al., 2010).

13.7.26 Investigations of fish abundance at wind farms using underwater visual census techniques, carried out by Wilhelmsson et al., (2006) found that while total fish abundance was greater next to foundations for some species there were no increases in species richness. Results from this study suggest that offshore wind farms may function as combined artificial reefs and fish aggregation devices for small demersal fish.

13.7.27 As discussed in Chapter 12, in relation to changes in benthos there is clearly potential to increase habitat complexity and improve productivity and studies such as those by Wilhelmsson et al., (2006) have shown changes in fish assemblages. However, given the localised nature of these changes and given the distances between the GWF structures, these potential aggregating effects are not anticipated to result in notable wide scale changes in fish communities or abundances. Given that fish and crustacean species will be protected from activities such as fishing as a result of safety zones around WTGs (which will be applied for post consent) the overall impact is considered to be of negligible beneficial significance.

Indirect impact of loss of prey resource and habitat from changes in current regime

13.7.28 The effects of the operational phase of the proposed GWF on the hydrodynamic and consequently sediment regime are assessed in Chapter 9 and in more detail in Technical Appendix 9.Aiii. The subsequent indirect impacts on subtidal ecology are assessed in Chapter 12 which are limited to sediment scour within close proximity to a small percentage of the foundations. This scouring could have a direct and localised impact on the



fauna within the footprint of the scour which may have indirect implication on fish and crustacean as a result of loss of benthic prey resource.

13.7.29 The assessment on subtidal ecology concluded that the potential effects upon suspended sediment concentrations and benthic ecology would be minimal given the small area affected and anticipated that as a worst case the impact would be of negligible. Based on this assessment it is also anticipated that the indirect impacts on fish as a result of this loss of prey resource would be of negligible adverse significance.

13.8 Potential Impacts during Decommissioning

13.8.1 As stated in Table 13.9, the final decommissioning proposals will be established prior to construction in agreement with the MMO and relevant SNCAs and stakeholders. Options at the end of the operational lifetime of GWF include removal of all infrastructure, leaving cables in situ but removal of all foundation structures and scour protection (or repowering which would be considered under a separate consenting process). As a precautionary worst case scenario for the purposes of this assessment it is assumed that all GWF infrastructure will be removed as this would lead to the highest number of boat movements, duration of activity, noise and disturbance to the seabed.

Loss of habitat

13.8.2 It has been assumed that decommissioning will include the removal of all offshore structures, GBS foundations will be fully removed and piled foundations will be cut off at or just below the seabed. The removal of this infrastructure will necessitate the use of a heavy lift vessel. It is expected that burial depth will be an important factor in helping to determine the appropriate course of action for removal of cables and will therefore be closely monitored throughout the project life-cycle. A typical cable removal programme will include the following

Identify the location where cable removal is required;

Removal of cables, feasible methods include:

o Pulling the cable out of seabed using a grapnel;

o Pulling an under-runner using a steel cable to push the electrical cable from the seabed; or

o Jetting the seabed material.

Transport cables to an onshore site where they will be processed for reuse/recycling/disposal.

13.8.3 Impacts will be similar to those described for the construction phase (physical

disturbance, smothering and re-mobilisation of contaminants), although these are likely to be lower in magnitude. The main impact associated with piling during the construction would not occur during the decommissioning phase.



13.8.4 As discussed for operation the presence of WTGs will increase habitat heterogeneity and has the potential to aggregate fish species by providing shelter and food (see below). The removal of these structures during decommissioning would result in loss of habitat for certain fish and crustacean species. The disturbance impact associated with the decommissioning are assessed as being of negligible significance based on the low sensitivity of the species and magnitude of the impact.

13.8.5 Over time the original habitats lost in the footprint of the infrastructure will redevelop. Overall, the long term effect of this would be to return the area to its former state in terms of fish community assemblages and the impact would be neutral with no impact on the long term.

Loss of prey resource

13.8.6 As discussed in Chapter 12, during operation the WTGs would become colonised by a wide range of benthic species which in turn would provide a food resource for other species. While there would be a loss of prey resource (and habitat) over the short term this impact would be neutral with no impact over the long term as the fish and crustacean community composition would return to their former state.

13.9 Inter-relationships

13.9.1 The inter-relationships between the fish and shellfish resource and other physical, environmental and human parameters are inherently considered throughout the assessment of impacts (Sections 13.6 and 13.7) as a result of the receptor lead approach to the assessment. For example, the availability of fish and shellfish resources has the potential to be influenced by changes in water quality, suspended sediments and benthic communities as a result of the effects of the proposed development. The potential impacts as a result of this indirect effect have been discussed within this chapter based on the findings of the assessments made in Chapter 10 Marine Water and Sediment Quality and Chapter 12 Marine and Intertidal Ecology.

13.9.2 Similarly any impact on fish and shellfish resources from the proposed development has the potential to impact on a number of other receptors, such as commercial fisheries, marine mammals and ornithology. The information provided in this Chapter is used in turn by these relevant receptor lead Chapters to establish the potential for and significance of inter-related impacts.

13.9.3 Table 13.15 summarises those inter-relationships that are considered of relevance to natural fish and shellfish resources and, identifies where within the ES these relationships have been considered.



Table 13.15 Fish and shellfish resource inter-relationships

Inter-relationship Section where addressed Linked Chapter

Construction

Indirect impacts due to the

loss of habitat and benthic

prey resource during

construction

Section 13.6 Influencing parameter:

Chapter 12 Marine and

Intertidal Ecology

Indirect impacts to fish and

crustacean from physical

disturbance to intertidal and

subtidal habitats



Intertidal Ecology

Indirect impacts from loss of

fish as a prey resource

Section 13.6 Affected parameter: Chapter

11 Offshore Ornithology,

Chapter 14 Marine Mammals

and Chapter 15 Commercial

Fisheries

Impact on fish resource from

changes in water quality


Chapter 10 Marine Water

and Sediment Quality and

Chapter 9 Physical

Environment

Operation

Influence of increased

habitat complexity and

benthos on fish aggregation

during operation and

protection from fishing effort

due to 50m exclusion zones

around structures



Intertidal Ecology and

Chapter 15 Commercial

Fisheries

Indirect impact of loss of

prey resource resulting from

changes in current regime

and indirect effects on

subtidal ecology during the

operational phase


Chapter 9 Physical

Environment and Chapter

12 Marine and Intertidal

Ecology



13.9.4 Chapter 29 Assessment of Inter-relationships provides a holistic overview of all of the inter-related impacts associated with the project.

13.10 Cumulative Impacts

13.10.1 A cumulative impact can only occur where a project aspect is identified as having an impact on a receptor in isolation.

13.10.2 The main impacts identified during the construction (Section 13.6) operation (Section 13.7) and decommissioning phases (Section 13.8) of the GWF project which have the potential to result in cumulative effects are considered to be the impacts associated with construction noise and in particular piling activities and also habitat loss which are discussed in Chapter 12.

13.10.3 Cumulative impacts associated with the GWF project could occur on a number of levels:

Interactions between different aspects of the GWF project with other wind farms; and

Interactions with other activities occurring in the region.

13.10.4 The following paragraphs provide an assessment of the potential for cumulative impact over these varying levels. The cumulative impact assessment is based on the impacts identified above and therefore the worst case scenarios for the GWF project outlined in Table 13.9. The cumulative modelling with London Array has been carried out on the worst case assumption of 7m monopile foundations.

GWF and other wind farms

13.10.5 The existing and planned wind farms in the Outer Thames Estuary area which could contribute to cumulative effects when considered alongside the GWF are shown in Figure 13.25. Distances presented in Table 13.15 are for the nearest (minimum) distances and relate to boundary limits rather than specific features or structures within each site. Table 13.16 also presents the predicted construction timetables for the sites within the Thames area.

Table 13.16 Distances (km) of Outer Thames wind farm sites from GWF

Project Details Status Distance From Galloper Site (km)

Predicted Construction Period

Galloper EIA Stage N/A Total maximum

piling duration of

39 months,

notionally

assuming an

earliest Q2 or Q3



Project Details Status Distance From Galloper Site (km)

Predicted Construction Period

2015

commencement

within the 56

month offshore

construction

window

Greater Gabbard In construction 0 2009 - 2012

East Anglia ONE Offshore

Wind Farm

Zonal Assessment

and Scoping for

Project ONE

25.2 Project ONE to

commence at

earliest in 2015

London Array I In construction 24.3 2011 - 2012

London Array II Consented 15.1 2014 - 2015

Thanet Operational 37 Operational

Gunfleet Sands I Operational 42.6 Operational

Gunfleet Sands II Operational 40 Operational

Gunfleet Sands Extension In planning 46.4 2011 - 2012

Kentish Flats Operational 61.6 Operational

Kentish Flats Extension EIA Stage 61.5 2013 -2014

Source: Construction times supplied via www.4coffshore.com





Noise impacts

13.10.6 Evidence (Chapter 5 and Sections 13.6 and 13.7) would suggest that the only possible noise source from offshore wind farms that has the potential to extend sufficient geographical distance as to overlap with that of another wind farm project would occur during foundation pile driving activity associated with the construction phase.

13.10.7 Potential for cumulative underwater noise impacts to affect fish, especially in relation to spawning activities or spawning grounds, is therefore, dependent on two or more projects undertaking pile driving simultaneously and/or two or more projects undertaking pile driving activities over consecutive spawning periods thereby causing longer term disruption.

13.10.8 While several offshore wind farms are planned for future construction in the region (Table 13.16), following a review of the anticipated construction schedules for these projects, only four projects were identified as potentially coinciding with the GWF project. These are East Anglia ONE (although there is a significant degree of uncertainty associated with the project timescale), the Kentish Flats Extension, London Array II (also subject to some uncertainty) and the Gunfleet Sands Extension. Phase II of the London Array project is currently thought to have the greatest potential to coincide with the GWF construction and also have a direct overlap with East Anglia ONE (although to a lesser extent given the uncertainty regarding construction programme for the latter). It is worth noting the uncertainty associated with the construction of London Array Phase II since this can only proceed if conditions relating to the significant barrier effects on red-throated divers can be resolved (see Chapter 11).

13.10.9 Two main areas of potential impact have been identified as:

Those relating to the cumulative noise dose and increased spatial impact extent of concurrent piling operations at different wind farm locations; and

The impact of different projects piling over consecutive years and causing continued disruption to spawning fish species over consecutive spawning periods.

13.10.10 The assessment of the cumulative impact of concurrent piling has been

carried out in two ways to give a broader picture of the impacts that may occur; a behavioural impact assessment for piling at two locations, analysing where the 90dBht contours overlap, and an assessment based on perceived noise dose criteria.

13.10.11 Concerns were raised during consultation (see Table 13.1) regarding the potential cumulative underwater noise impacts associated with the proposed GWF and East Anglia ONE. At the time of writing no specific project information was available for East Anglia ONE in terms of foundation types, pile diameter etc., with which to undertake cumulative noise modelling.



However, in recognition of potential overlap of construction activity a discussion of potential impacts has been undertaken. In terms of assessing the worst case cumulative piling noise impacts, it is worth noting that in the absence of further information on the construction of the East Anglia ONE project a broad assumption of similar foundation types (to that considered for GWF) has been made in order to allow for a qualitative assessment to be made albeit with inherent uncertainties acknowledged.

13.10.12 The cumulative contour plots for herring, cod and dab are shown in Figure 13.29 to 13.31.









13.10.13 The data for Phase II of the London Array project and proposed GWF project indicate that for all the species considered, with the exception of dab (sole), there could be a degree of overlap and, therefore, pile driving at these two locations could be considered to have a net cumulative impact in terms of the total area in which animals may be exposed to aversive levels of underwater noise.

13.10.14 In summary, under some circumstances the areas around two simultaneous pile driving operations at different sites may converge. In this case, the excluded area may increase over that for one pile driving operation, and its ability to block movement may increase accordingly (Subacoustech, 2011).

13.10.15 While the worst case scenario for piling driving at GWF is four hours per monopile, it should be noted, however, that pile driving is intermittent and based on monitoring at GGOWF is more likely to take between one to two hours to install. As such the possibility of a temporal overlap occurring between piling at the two sites is likely to be small.

13.10.16 The cumulative noise assessment (Subacoustech, 2011) has also included received Noise Dose and SEL methodologies (these methodologies are outlined in more detail within Chapter 5) to assess the auditory injury zone in the vicinity of an impact piling operation. This study used the approach that the degree of hearing damage depends upon both the received level of noise, and the time of exposure to it.

13.10.17 The results indicated that, for herring, the critical range between monopiles at which point the cumulative noise dose increases above 90dBht LEP,D is 7km and, in the case of dab, it is 50m. In the case of these species, therefore, the data indicate that if two monopiles were being installed at locations closer than the above ranges, individuals may not be able to swim out of the auditory injury zone before receiving a noise dose that is likely to cause hearing impairment. The closest locations for two piles at the London Array site and the proposed GWF site are approximately 14km apart. Similarly, the distance to East Anglia ONE is over 25km.

13.10.18 The predicted impact ranges for the assessment were similar to those predicted for the 130dBht perceived level at which traumatic hearing damage from a single pile driving event would be expected, therefore, indicating that any possibility of hearing damage would most likely be as a result of underwater noise from the nearest pile to the animal rather than a cumulative effect. These data therefore suggest that the cumulative noise dose from impact pile driving operations at the London Array, and GWF is unlikely to increase the likelihood of auditory injury. This would also indicate that based on similar foundation types and given the distance to East Anglia ONE location (>25km) cumulative noise dose impacts increasing auditory injury are unlikely to occur.

13.10.19 If the pile driving activities were carried out at two wind farm sites concurrently, the overall area of impact and extent of behavioural effects and potential temporary displacement of fish species would be increased.



Depending on the spatial coverage of the impact this could increase the magnitude of any impact. As discussed previously, areas indicated as spawning grounds by Coull et al., and Pawson for species such as herring and sole are in close proximity to the proposed GWF. However, since the noise effects ranges/footprints are only marginally greater than for GWF in isolation and more importantly spatially separate from the main herring grounds (and to some extent the highest intensity sole grounds), the effects would be no more significant than for GWF alone. Furthermore, London Array also has a piling restriction in place which would preclude the potential for cumulative impacts on the sole spawning grounds. As such the impact is assessed as minor adverse.

13.10.20 While pile driving operations disrupting a single species spawning season may not necessarily have potential long term or wider scale population effects, if consecutive wind farm projects continually disrupt spawning behaviour for key spawning sites over consecutive years reduced spawning success and subsequent population recruitment could occur.

13.10.21 The current level of information and certainty on construction timescales and in particular piling programmes for other wind farm projects is limited at present and only indicative timescale are known at this time (see Table 13.16). These current timescales suggest that piling activities could occur during 2011 and 2012 for the Gunfleet Sands Extension and London Array Phase I, 2013 and 2014 for the Kentish Flats Extension and London Array Phase II, 2015 to 2019 for GWF and from 2015 onwards for East Anglia ONE. To put these into perspective it is worth noting that the Gunfleet Sands Extension consists of only 2 WTGs, the Kentish Flats Extension between 10 and 17 WTGs and the London Array construction are subject to a sole spawning restriction. The Kentish Flats and Gunfleet Sands Extensions would not overlap spatially with the Downs herring spawning grounds and in terms of sole given the small number of turbines the actual piling duration would be very short and in order to have any significant impact on sole and would need to coincide with their spawning periods.

13.10.22 The London Array II project, GWF and East Anglia ONE could potentially have consecutive impacts on the Downs herring spawning stocks from 2014 to 2016. As discussed previously, the main Downs herring spawning grounds are those located in the eastern English Channel. These would not be impacted by the consecutive piling events. The sensitivity of spawning herring to noise impacts is considered to be high. As for the arguments discussed in Section 13.6 above, the magnitude would remain negligible as this is based on the impact not extending to the Downs spawning grounds in the eastern English Channel. While the duration of the impact would extend from one year to potentially three, this increase in duration is not significant enough to warrant increasing the overall magnitude. Furthermore, the likelihood of consecutive piling disruption over the Downs herring spawning season (November to January) is considered to be low based on the potential restrictions cause by weather windows, variations in construction programs etc. The overall impact significance of consecutive piling is therefore minor adverse.



13.10.23 Based on the discussion above relating to the small number of piles and restrictions associated with the London Array it is considered that potential consecutive impacts to the inshore Thames sole spawning grounds over the period 2011 to 2016 would not occur. Greater Gabbard OWF also undertook piling in 2009/2010; however, this project was subject to spawning restrictions which avoided the sole spawning period.

13.10.24 Sole are considered to be relatively insensitive to noise and while their overall sensitivity has been assessed as medium (see Section 13.6) the actual extent of behavioural impacts are generally localised (see Figure 13.31). The potential for the different wind farm projects to continually disrupt the same spawning areas is therefore unlikely, especially given the size of the sole spawning area available in the Thames Estuary and license conditions associated with some of the other inshore developments precluding piling during the sole spawning season. While the duration would extend slightly from that discussed in Section 13.6 it is considered that the magnitude of the impact would remain low based on the limited spatial overlap. The significance of the impact is therefore assessed as minor adverse.


13.10.25 Based on the piling noise and cumulative piling noise discussions above it is considered that there is no significant risk of likely cumulative effect on the herring or sole spawning grounds as a result of the proposed GWF project.

13.10.26 Further discussions are ongoing with the regulators to establish the actions that are required in order to bring any necessary restrictions in line with the anticipated impacts associated with the proposed GWF development.

13.10.27 As discussed previously mitigation in the form of soft start piling will be incorporated into construction procedures. However, while such measures would reduce the impacts associated with lethal and physical injury, once piling reaches full blow force the behavioural impact ranges would remain unchanged compared to the pre soft start predictions. Despite the lack of significant impact predicted on herring or sole spawning grounds, further precautionary mitigation is applied through the commitment to restrict piling activity to a maximum overlap of two spawning seasons for each of the two (herring and sole) species over the 56 month construction window. This effectively imposes a piling restriction for two of the four potential seasons that occur within such a window (based on a total maximum piling duration of 39 months, notionally assuming an earliest Q2 or Q3 2015 commencement within the 56 month offshore construction window).

13.10.28 Given the above mitigation it is considered that likelihood for significant potential cumulative impact is low and consequently the impact assessed of negligible significance.

13.10.29 It is anticipated that should the construction programme slip beyond 2019 the same spawning overlap principles discussed above would apply with no



piling occurring during key spawning periods assuming that two overlaps had already occurred.

EMF impacts

13.10.30 During consultation the EIFCA raised concerns about the potential cumulative EMF effects associated with the crossing point of the GWF and East Anglia ONE export cables (See Figure 30.1). Given that the extent of any EMF effects will be very localised it is not anticipated that a single crossing point will have any significantly wider cumulative impacts and would not impact wider species populations. Given the effects would be associated with a single crossing point and therefore localised the impact magnitude is assessed as negligible. As for EMF effects discussed above the receptor sensitivity is considered to be high and the overall impact significance is assessed as minor adverse.

GWF and other activities

13.10.31 There are limited additional human activities occurring within the vicinity of the GWF project site, with the exception of aggregate extraction, which is discussed in more detail in Chapter 18 Other Human Activity and commercial fishing activities (Chapter 15).

13.10.32 As in Section 13.6, the construction related impacts at GWF have the potential to affect the Downs herring spawning grounds. The Downs herring spawning grounds extend into the East English Channel; an area subject to extensive aggregate dredging operations. A series of assessments on the effects of aggregates dredging on the East Channel spawning grounds have been undertaken behalf of the East Channel Association (RPS, 2011).

13.10.33 The study concluded that the proportion of the total herring spawning habitat within the East English Channel potentially impacted by aggregate extraction was extremely small, with less than one third of a percent of the potential herring spawning habitat in the East English Channel impacted, either directly or indirectly (RPS, 2011). The data also indicated that the spawning activity within the area has not been noticeably reduced since the commencement of dredging. In addition the direct impacts to herring spawning are limited at some licensed areas by restrictions to dredging during the herring spawning season of November to February. Furthermore, the areas of very high spawning potential are located to the south of the aggregates extraction sites which are not anticipated to be impacted either directly or indirectly by aggregates extraction activities (RPS, 2011). Given the present level of information available on the impacts associated with GWF there is not anticipated to be any significant cumulative impact to the Downs herring spawning grounds.

13.10.34 Sizewell nuclear facility has a number of existing marine components (namely the intake and outlet cooling water pipes). Intake structures of power stations are known to entrain and kill fish species (Turnpenny & Taylor, 2000). Although the Sizewell project is listed with the IPC, there has been no scoping exercise undertaken and no details of the construction



programme are available. A formal application to the IPC is not expected until 2012 at the earliest, with construction unlikely to be possible until 2015. It is anticipated that similar marine intake structures would be constructed to replace the existing intakes. It is anticipated that, as for other new build power station projects, the regulators would require stringent screening and fish impingement and entrainment mitigation devices to be employed including the use of acoustic deterrents and fish return systems in accordance with the best available techniques. This would ensure that the new intakes would entrain significantly less fish species and have higher survival rates than the current existing structures. Based on the localised and inshore nature of any impacts and mitigation associated with these structures, there is not anticipated to be any significant cumulative interaction with the GWF activities.

13.11 Transboundary Effects

13.11.1 This Chapter has considered the potential for transboundary effects to occur on marine water and sediment quality as a result of the construction, operation or decommissioning of the proposed GWF project. In all cases it is concluded that the potential impacts arising, by virtue of the predicted spatial and temporal magnitude of the effects, would not give rise to significant transboundary effects on the environment of another European Economic Area (EEA) member state. A summary of the likely transboundary effects of the proposed GWF are summarised in Chapter 31 Transboundary Effects.

13.12 Monitoring

13.12.1 NPS EN-3 states that ecological monitoring may be appropriate in order to identify the actual impacts so that where appropriate adverse effects can be mitigated. GWFL propose to undertake underwater noise monitoring during the installation of the largest four WTGs in order to verify the noise modelling carried out by Subacoustech (see Technical appendix 13.B). While the present evidence clearly shows that the mains Downs spawning ground is currently located in the East English Chanel, GWFL recognise that, while it is considered unlikely based on the trends since the 1970’s the recolonisation of the Southern Bight spawning grounds could occur prior to piling works commencing. Prior to, and during the period of construction GWFL will undertake (subject to agreement with the regulators) a yearly analysis of the IHLS herring larval data in order to assess the state of spawning on the Downs herring spawning grounds. If evidence of recolonisation was found (within the relevant timeframe), GWFL would consult with the regulators in order to ensure appropriate mitigation measures were put in place, this might include piling restrictions if deemed necessary.

13.12.2 During Section 42 consultation the Eastern Inshore Fisheries and Conservation Authority (EIFCA) suggested that monitoring should be carried out to establish the impact of EMF (Table 13.1). Based on the current knowledge no specific monitoring programme is proposed for GWF. However, the FEPA licence condition for GGOWF relating to EMF states that the Licence Holder must provide information on the attenuation of field



strengths associated with cables, shielding and burial depth and relate these to the outputs from COWRIE sponsored studies. If this shows the field strengths are sufficient to have potentially detrimental effect further biological monitoring and mitigation may be required to further investigate the effect. Given the adjacent location of the proposed GWF export cable corridor and analogous cable specifications (between the two projects), the results from the GGOWF will be directly applicable to GWF, providing further information on EMF to help inform the industry and also establish if further monitoring is required for GWF.

13.12.3 The requirement for, and detail of, any further pre and post construction monitoring at GWF will be established through consultation with the MMO and Cefas at least four months prior to any (pre-construction) works commencing.

13.13 Summary

13.13.1 This Chapter of the ES has provided a characterisation of the existing fish and shellfish resource based on both existing and site specific survey data, which has established that communities present are indicative of the region and occur over broad extents throughout the Outer Thames Estuary and southern North Sea.

13.13.2 Table 13.17 provides a summary of the predicted impact on marine and intertidal ecology. The impacts represent the maximum potential adverse impact as a result of having assessed the worst case (development) scenario for each receptor. Therefore, the predictions made would not be worse (more adverse) should any other development scenario (in line with those provided in Chapter 5), to that assessed within this Chapter, be taken forward in the final scheme design.

Table 13.17 Summary of impacts

Description of Impact

Impact significance

Mitigation Measures Residual Impact

Construction Phase

Noise and

vibrations - Lethal,

physical and

traumatic auditory

injury effects

Minor

adverse -

negligible

Soft start piling

Minor adverse -

negligible

Noise and

vibrations –

behavioural

responses

Minor

adverse -

negligible

Piling activity will be restricted to

a maximum overlap of two

spawning seasons for herring

and sole species over the 56

month construction window.

N/A




Impact significance


Physical

disturbance of

intertidal and

subtidal habitats

Negligible N/A N/A

Indirect loss of fish

as a prey resource Negligible N/A N/A

Suspended

sediment

concentrations

Negligible N/A N/A

Re-mobilisation of

contaminated

sediments

Negligible N/A N/A

Impacts due to loss

of habitat and

benthic prey

resource

Negligible N/A N/A

Operation Phase

Operational noise

and vibration

Negligible N/A N/A

EMF Minor

adverse

Best practice measures

including burial to a

representative average

minimum burial depth of 0.6m.

Minor adverse

Aggregation effects Negligible

beneficial

N/A N/A

Indirect impact of

loss of prey

resource and

habitat from

changes in current

regime

Negligible N/A N/A

Decommissioning

Loss of habitat Negligible – N/A N/A




Impact significance


no impact

Loss of prey

resource

No impact N/A N/A

13.13.3 Concurrent and consecutive pile driving between GWF and other wind farm are not anticipated to have any cumulative noise impacts on sole and the Downs herring spawning grounds as there is limited scope for continued disturbance over consecutive years given the sole spawning restrictions already in place for London Array and GGOWF and the limited impacts associated with the installation of the Gunfleet Sands and Kentish Flats Extension projects. Consequently no significant cumulative impacts are predicted.



13.14 References

Andersson, M. H. (2011). Offshore wind farms – ecological effects of noise and habitat alteration on fish. Doctoral dissertation 2011. Department of Zoology, Stockholm University. Andriguetto-Filhoa, J.M., Ostrenskya, A., Pieb, M.R., Silvac, U.A. & Boegerb, W.A. (2005). Evaluating the impact of seismic prospecting on artisanal shrimp fisheries. Continental Shelf Research. 25: 1720–1727 Atema, J. (1986). Review of sexual selection and chemical communication in the lobster Homarus americanus. Canadian Journal of Fisheries and Aquatic Science, 43: 2283-2390. Ball, R.E. (2007). Electroreception in embryos of the thornback ray, Raja clavata. Unpublished MSc thesis. Department of Natural Resources, Integrated Earth System Sciences Institute, Cranfield University. Barnes M. (2008). Microstomus kitt. Lemon sole. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 10/02/2011]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3810> Bannister, R.C.A., Addison, J.T., and Lovewell, S.R.J. (1994). Growth, movement, recapture rate and survival of hatchery-reared lobsters (Homarus gammarus Linnaeus, 1758) released into the wild on the English East Coast. Crustaceana, 67: 156-172. Baynes, S.M.; Howell, B.R.; Beard, T.W.; Hallam, J.D. (1994). A description of spawning behaviour of captive Dover sole, Solea solea (L.) Neth. J. Sea Res. 32(3-4): 271-275 Bromley P.J., (2003). The use of market sampling to generate maturity ogives and to investigate growth, sexual dimorphism and reproductive strategy in central and south-western North Sea sole (Solea solea L.). ICES Journal of Marine Science, 60: 52–65. 2003 doi:10.1006/jmsc.2002.1318. Bolle LJ, de Jong CAF, Biermans S, de Haan D, Huijer, T, Kaptein D, Lohman M, Tribuhl S, van Beek P, van Damme CJG, van den Berg FHA, van der Heul J, van Keeken O, Wessels P, Winter E (2011). Shortlist Masterplan Wind. Effect of piling noise on the survival of fish larvae (pilot study).IMARES report. Booman, C., Dalen, H., Heivestad, H., Levsen, A., van der Meeren, T. & Toklum, K. (1996). Effekter av luftkanonskyting pa egg, larver og ynell. Undersekelser ved Hauforskningstituttet ogtoclgisk Laboratorium, Universitet; Bergen. Fisken og Havet, 3.



Burt, G.J. and Milner, R.S. (2008). Movements of sole in the southern North Sea and eastern English Channel from tagging studies (1995 - 2004). Sci. Ser. Tech. Rep., Cefas Lowestoft, 144: 44pp. Cefas (2004) Offshore wind-farms: guidance notes for EIA in respect of FEPA and CPA requirements. Prepared by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) on behalf of the Marine Consents and Environment Unit (MCEU). Version 2 – June 2004 Cefas (2010a). Mapping spawning and nursery areas of species to be considered in Marine Protected Areas (Marine Conservation Zones) Project Code: MB5301. August 2010. Cefas (2010b). Strategic Review of Offshore Wind Farm Monitoring Data Associated with FEPA Licence Conditions. Project ME1117 Centre for Marine and Coastal Studies (CMACS) (2010). Galloper Offshore Wind Farm. Benthic Survey Technical Report 2010. Prepared for OSIRIS PROJECTS (NRL and SSER). Included within Appendix 12.A. Child A. R., Howell B. R., and Houghton R. G. (1991). Daily periodicity and timing of the spawning of sole, Solea solea (L.), in the Thames estuary. ICES J. Mar. Sci. (1991) 48(3): 317-323 doi:10.1093/icesjms/48.3.317. CMACS (2003) A baseline assessment of electromagnetic fields generated by offshore wind farm cables. COWRIE Report EMF - 01-2002 66. Corten, A. 2001. The role of "conservatism" in herring migrations. Reviews in Fish Biology and Fisheries, 11(4): 339 361. Coull, K.A., Johnstone, R., and S.I. Rogers. 1998. Fisheries Sensitivity Maps in British Waters. Published and distributed by UKOOA Ltd. Daan, N., Hislop, J.R.G., Lahn-Johannessen, J., Parnell, W.G., Scott, J.S., and parre, P. 1980. Results of the International O-group Gadoid Survey in the North Sea, 1980. ICES CM, G:5. Defra (2010). Eel Management plans for the United Kingdom Thames River Basin District. Date published: March 2010. Department for Business Enterprise and Regulatory Reform BERR (2008). Review of cabling techniques and environmental effects applicable to the offshore wind farm industry. Technical Report Dickey-Collas, M., L. J. Bolle, et al. (2009). Variability in transport of fish eggs and larvae. II. Effects of hydrodynamics on the transport of Downs herring larvae. Marine Ecology-Progress Series 390: 183-194.



Dinter, W.P. (2001). Biogeography of the OSPAR Maritime area, A synopsis and synthesis of biogeographical distribution patterns described for the North-East Atlantic. Bundesamt für Naturschutz (BfN), 167 pp. Eastwood, P.D.; Meaden, G.J. (2000). Spatial modelling of spawning habitat suitability for the sole (Solea solea L.) in the eastern English Channel and southern North Sea. C.M. - International Council for the Exploration of the Sea, CM 2000(N:05). ICES[S.l.]. 18 pp ECA and RPS Energy. 2010. East English Channel Herring Spawning Potential Assessment. Volume 1, Issue 1 (Rev 1). Ellis J.R., Burt G.J., Cox L. P. N., Kulka D.W., and Payne. A.I.L (2008). The status and management of thornback ray Raja clavata in the south-western North Sea Theme Session K. Small scale and recreational fisheries surveys, assessment, and management ICES CM 2008/K:13, 45 pp. Ellis, J.R., Cruz-Martinez, A., Rackham, B.D. and Rogers, S.I. (2005). The distribution of chondrichthyan fishes around the British Isles and implications for conservation. Journal of Northwest Atlantic Fishery Science, 35: 195–213. Ellis, J. R. and Keable, J. (2008). The fecundity of Northeast Atlantic spurdog (Squalus acanthias L., 1758). ICES Journal of Marine Science, 65: 979–981. Ellis, J. R. & Shackley, S.E. (1997). The reproductive biology of Scyliorhinus canicula in the Bristol Channel, U.K. Journal of Fish Biology, 51:361–372. Erftemeijer PLA, van Beek JKL, Bolle LJ, Dickey-Collas M, Los HFJ (2009) Variability in transport of fish eggs and larvae. I. Modelling the effects of coastal reclamation. Mar Ecol Prog Ser 390:167-181 Engås A and Løkkeborg S. (2002), Effects of seismic shooting and vessel-generated noise on fish behaviour and catch rates, Bioacoustics 12, 313-315 Fisheries Research Services (2011). http://www.scotland.gov.uk/Topics/marine/marine-environment/species/fish/sandeels Accessed on 26/03/2011 Fox, C. J. 2001. Recent trends in stock-recruitment of Blackwater herring (Clupea harengus L.) in relation to larval production. – ICES Journal of Marine Science, 58: 750–762. Fox, CJ, Taylor, M. I. et al. (2008) Mapping the spawning grounds North Sea cod (Gadus morhua) by direct and indirect means. Proceedings Royal Society B. 275: 1543-1548 Gardline (2010) Greater Gabbard Offshore Wind Farm Underwater Noise Monitoring During Marine Piling, Flour Ltd. Project Ref. 8503 September 2010



Gauld, J. 1979. Reproduction and fecundity of the Scottish-Norwegian stock of spurdogs, Squalus acanthias (L.). ICES CM 1979/H:54. 9 pp. Gill, A.B. & Bartlett, M. (2010). Literature review on the potential effects of electromagnetic fields and subsea noise from marine renewable energy developments on Atlantic salmon, sea trout and European eel. Scottish Natural Heritage Commissioned Report No.401. Gill, A. B., Gloyne-Phillips, I., Neal, K. J. & Kimber, J. A. 2005. The potential effects of electromagnetic fields generated by sub-sea power cables associated with offshore wind farm developments on electrically and magnetically sensitive marine organisms - a review. In: Report to Collaborative Offshore Wind Research into the Environment (COWRIE) group, Crown Estates (unpublished report). Gill, A.B., Huang, Y., Gloyne-Philips, I., Metcalfe, J., Quayle, V., Spencer, J. & Wearmouth, V. (2009). COWRIE 2.0 Electromagnetic Fields (EMF) Phase 2: EMF-sensitive fish response to EM emissions from sub-sea electricity cables of the type used by the offshore renewable energy industry. Commissioned by COWRIE Ltd (project reference COWRIE-EMF-1-06). Greater Gabbard Offshore Wind Limited (GGOWL) (2009). Underwater Noise Monitoring During Marine Piling. July 2009. Greater Gabbard Offshore Wind Limited (GGOWL) (2005) Greater Gabbard Offshore Wind Farm Environmental Statement, October 2005 Hammar, L., Andersson, S., and Rosenberg, R. (2010). Adapting offshore wind power foundations to local environment. Published by the Swedish Environmental Protection Agency. Harris G.S. and Milner N.J. (2006) Sea Trout: Biology, Conservation and Management. Proceedings of First International Sea Trout Symposium, Cardiff, July 2004. Blackwell Scientific Publications, Oxford, 499pp. Hawkins, A. D., and Rasmussen, K. J. 1978. The calls of gadoid fish. Journal of the Marine Biological Association, UK, 58: 891–911. Holden, M. J. and Meadows, P. S. 1964. The fecundity of the spurdog (Squalus acanthias L.). Journal du Conseil International pour l'Exploration de la Mer, 28: 418–424. Holthius, L.B. (1991). FAO Species Catalogue. Marine lobsters of the World. An annotated and illustrated catalogue of species of interest to fisheries known to date. FAO Fisheries Synopsis, 125: 13. Houghton, R.G., and Harding, D. 1976. The plaice of the English Channel: spawning and migration. Journal du Conseil International pour



l'Exploration de la Mer 36: 229-239. Hunter, E., Metcalfe, J.D. and Reynolds, J.D. 2003. Migration route and spawning area fidelity by North Sea plaice. Proc. R. Soc. Lond. B 270: 2097-2103. Hunter, E., Buckley, A.A., Stewart, C. and Metcalfe, J.D. (2005) Migratory behaviour of the thornback ray, Raja clavata, in the southern North Sea. Journal of the Marine Biological Association of the United Kingdom, 85: 1095–1105. ICES (2003) http://www.ices.dk/products/CMdocs/2003/E/E0903.PDF ICES (2010a). ICES-FishMap – accessed online November 2010. ICES (2010b). Advice October 2010 - Demersal elasmobranchs in the North Sea, Skagerrak, and Eastern Channel. Pp8 ICES (2010c). Advice November, Revised December 2010. Widely Distributed and Migratory Stocks. European eel. ICES Marine Environmental Quality Commitee, CM 1996/E:26. ICES. 2008. Report of the ICES Advisory Committee 2008. ICES Advice, 2008. Book 6, 326 pp. ICES. 2009. Report of the Herring Assessment Working Group for the Area South of 62 N, 17-25 March 2009, ICES Headquarters, Copenhagen. Diane Lindemann. 648 pp. ICES (2007a) Report of the herring assessment working group for the area south of 62°N. ICES CM 615 2007/ACFM:11, ICES, Copenhagen ICES (2007b). Report of the Working Group on Elasmobranch Fishes (WGEF), 22–28 June 2007, Galway, Ireland. ICES CM 2007/ACFM:27, 318 pp. Jacklin, (1998). Exploratory fishing trials for Buccinum undatumn around the Islands of Barra and South Uist in the Western Isles. Consultancy Report No. CR144 June 1998. Sea Fish Industry Authority Technology Division (SeaFish). Kaiser, M. J., Rogers, S. I. & Ellis, J. R. (1999). Importance of benthic habitat complexity for demersal fish assemblages. American Fisheries Society Symposium, 22: Pp 212–223. Kioerboe T, Frantsen E, Jensen C & Nohr, O (1981). Effects of suspended-sediment on development and hatching of herring (Clupea harengus) eggs. Estuarine, Coastal and Shelf Science, vol. 13, 107-111.



Kimber J. A. (2008). Elasmobranch Electroreceptive Foraging Behaviour: Male-Female Interactions, Choice And Cognitive Ability. School Of Applied Sciences. Phd Thesis Cranfield University Academic Years 2005-2008. Knight A.P. (1907). The effects of dynamite explosions on fish life. A preliminary report. Further contributions to Canadian Biology Being Studies from the Marine Biological Station of Canada 1902-1905. 39th Annual Report of the Department of Marine and Fisheries, Fisheries Branch. Sessional Paper No. 22a, pp. 21-30 Leonard J.B.K., Summers A.P., and Koob T.J (1999). Metabolic Rate of Embryonic Little Skate, Raja erinacea (Chondrichthyes: Batoidea): The Cost of Active Pumping. Journal of Experimental Zoology 283:13-18 (1999). Malcolm. I.A., Godfrey. J, and Youngson. A.F. 2010. Review of migratory routes and behaviour of Atlantic salmon, sea trout and European eel in Scotland’s coastal environment: implications for the development of marine renewables.. Scottish Marine and Freshwater Science Vol 1 No 14. Maitland PS & Hatton-Ellis TW (2003). Ecology of the Allis and Twaite Shad. Conserving Natura 2000 Rivers Ecology Series No. 3. English Nature, Peterborough. Maitland P. (2003). The Status of smelt Osmerus eperlanus in England. English Nature Research Reports, Report Number 516. ISSN 0967-876X. Marine Management Organisation (MMO) (2011). Commercial Fisheries landings data 2006 to 2010 for ICES rectangles 32F1, 32F2 and 33F1. Marine Management Organisation (MMO), JNCC, Natural England, Countryside Council for Wales and Cefas (2010). Draft Guidance on the Assessment of Effects on the Environment and Cultural Heritage from Marine Renewable Developments. December 2010. Marine Aggregate Levy Sustainability Fund (MALSF) (2009) Outer Thames Estuary Regional Environmental Characterisation Meyer, C.G., Holland, K.N & Papastamatiou, Y.P. (2004) Sharks can detect changes in the geomagnetic field, Journal of the Royal Society Interface, (DOI: 10.1098/rsif.2004.0021 First Cite):2pp Uhlmann 1975 Misund O. A., Aglen A., Hamre J., Ona E., Røttingen I., Skagen D., Valdemarsen J. W.Improved mapping of schooling fish near surface: comparison of abundance estimates obtained by sonar and echo integration. ICES Journal of Marine Science 1996;53:383-388. Mueller-Blenkle, C., McGregor, P.K., Gill, A.B., Andersson, M.H., Metcalfe, J., Bendall, V.,Sigray, P., Wood, D.T. & Thomsen, F. (2010) Effects of Pile-



driving Noise on the Behaviour of Marine Fish. COWRIE Ref: Fish 06-08, Technical Report 31st March 2010. Nedwell J R, Langworthy J and Howell D (2003). Assessment of sub-sea acoustic noise and vibration from offshore wind turbines and its impact on marine wildlife; initial measurements of underwater noise during construction of offshore windfarms, and comparison with background noise. Subacoustech Report ref: 544R0423, published by COWRIE, May 2003 Nedwell J R , Parvin S J, Edwards B, Workman R , Brooker A G and Kynoch J E (2007a).Measurement and interpretation of underwater noise during construction and operation of offshore windfarms in UK waters. Subacoustech Report No. 544R0738 to COWRIE Ltd. ISBN: 978-0-9554279-5-4. Nedwell J R, Turnpenny A W H, Lovell J, Parvin S J, Workman R, Spinks J A L, Howell D (2007b). A validation of the dBht as a measure of the behavioural and auditory effects of underwater noise. Subacoustech Report Reference: 534R1231, Published by Department for Business, Enterprise and Regulatory Reform. Nedwell, J. R, Edwards, B, Turnpenny, A.W.H, & Gordon, J. (2004). Fish and Marine Mammal Audiograms: A summary of available information. Subacoustech Report ref: 534R0214. Norro, A., Haelters, J., Rumes, B., Degraer, S. (undated). Chapter 4. Underwater noise produced by the piling activities during the construction of the Belwind offshore wind farm (Bligh Bank, Belgian marine waters). Thomsen F, Lüdemann K, Kafemann R, Piper W (2006) Effects of offshore wind farm noise on marine mammals and fish, biola, Hamburg, Germany on behalf of COWRIE Ltd, Newbury, UK. Tollefson R, and Marriage L D. (1949). Observations on the effects of the intertidal blasting on clams, oysters and other shore inhabitants. Oregon Fish Comm. Res. Briefs 2(1): 19-23 Turnpenny, A.W.H., Taylor, C.J.L., 2000. An assessment of the effect of the Sizewell power stations on fish populations. Hydroe´cologie applique´e 12, 87e134. Rijnsdorp, A.D. 1989. Maturation of male and female North Sea plaice Pleuronectes platessa L.). Journal du Conseil International pour l'Exploration de la Mer 46: 35-51. Rijnsdorp, A.D., Beek, F.A. van, Flatman, S., Millner, R.M., Giret, M. and Clerck, R. de. (1992) Recruitment of sole stocks, Solea solea (L.), in the northeast Atlantic. Neth. J. Sea Res. 29: 173-192.



Rogers, S. I. (1992). Environmental factors affecting the distribution of sole (Solea solea L.) within a nursery area. Netherlands Journal of Sea Research, 29, 153-161. Rogers S, Stocks R (2001) North Sea fish and fisheries. Department of Trade and Industry. Strategic Environmental Assessment—SEA2 Technical Report 003—Fish and Fisheries CEFAS. Rohlf, N. and Groger, J. (2002) Report of the Herring Larvae Surveys in the North Sea in 2002/2003. International Council for the Exploration of the Sea, CM 2001/ACFM:12, 10pp Schmidt J.O., van Damme C.J.G., Röckmann C., and Dickey-Collas M (2009). Recolonisation of spawning grounds in a recovering fish stock: recent changes in North Sea herring. SCI. MAR., 73S1, October 2009, 153-157. Skaret G., Axelsen B. E., Nøttestad L., Fernö A., Johannessen A.The behaviour of spawning herring in relation to a survey vessel. ICES Journal of Marine Science 2005;62:1061-1064. Skalski J R, Pearson W H, and Malme C I. (1992). Effects of sounds from a geophysical survey device on catch-per-unit-effort in a hook-and-line fishery for rockfish (Sebastes ssp.). Can. J. Fish. Aquat. Sci. 49, 1357-1365. Slotte A, Kansen K, Dalen J, and Ona E. (2004). Acoustic mapping of pelagic fish distribution and abundance in relation to a seismic shooting area off the Norwegian west coast. Fish. Res. 67, 143-150 Southall, B. L., Bowles, A. E., Ellison, W. T., Finneran, J. J., Gentry, R. L., Greene, C. R. Kastak, D., Ketten, D. R., Miller, J. H., Nachtigall, P. E., Richardson, W. J. Thomas, J. A., Tyack, P. L, (2007). Marine Mammal Noise Exposure Criteria Aquatic Mammals, Vol 33 (4). Subacoustech (2011). Galloper Offshore Wind Farm Project: Underwater Noise Impact Assessment. Subacoustech Environmental Report No. E218R0120. Svetnovidov, A.N. 1986. Gadidae. In: Whitehead, P.J.P., Bauchot, M.L., Hureau, J.C., Nielsen, J., and Tortonese, E. (eds.). Fishes of the North-eastern Atlantic and the Mediterranean. UNESCO, United Kingdom. 1473 pp. Öhman M. C., Sigray P., and Westerberg H. (2007). Offshore Windmills and the Effects of Electromagnetic Fields on Fish Ambio Vol. 36, No. 8, December 2007. Pawson, M.G.(1995). Biogeographical identification of English Channel fish and shellfish stocks. Fisheries Research Technical Report, Directorate of Fisheries Research, Lowestoft, 99:1–72.



van Deurs, M., van Hal, R., Tomczak, M.T., Jónasdóttir, S.H. & Dolmer, P. 2009. Recruitment of lesser sandeel Ammodytes marinus in relation to density dependence and zooplankton composition. Mar. Ecol. Progr. Ser. 381: 249–258. Yelverton, J. T., Richmond, D. R., Hicks, W., Saunders, K. and Fletcher, E. R. (1975). The Relationship Between Fish Size and Their Response to Underwater Blast. Report DNA 3677T, Director, Defence Nuclear Agency, Washington, DC. Westerberg H, Rönnbäck P & Frimansson H (1996). Effects of suspended sediment on cod egg and larvae and the behaviour of adult herring and cod. Wheeler, A. 1978. Key to the fishes of northern Europe. London, Frederick Warne, 380. Wilhelmsson, D., Malm, T., and O¨ hman, M. C. 2006. The influence of offshore windpower on demersal fish ICES Journal of Marine Science, 63: 775e784. Wright PJ, Bailey MC (1996) Timing of hatching in Ammodytes marinus from Shetland waters and its significance to early growth and survivorship. Marine Biology 126:143-152 Wood, R. J. (1981). The Thames Estuary herring stock. Fisheries Research Technical Report No.64, Lowestoft, ISSN 0308-5589.

Galloper Wind Farm Project - Planning Inspectorate · Galloper Wind Farm Project Environmental Statement – Chapter 13: Natural Fish and Shellfish Resources October 2011 Document

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