Benthic survey report 2018/19 , Compliance and Control ...

MF236 Okehampton

BENTHIC SURVEY Report 2018/19

(Compliance and Control sites)

ANNUAL REPORT (VERSION 1.0)

July 2019

Report to:

Tassal Limited

Prepared by:

AQUENAL PTY LTD

A Q U E N A L

www.aquenal.com.au

4

Document Control and Distribution

Date Name Company Document

Type Version Copies

23/7/2019 Deleeze Chetcuti,

Sean Riley Tassal electronic 1.0 1

23/7/2019 Claudia Russman EPA electronic 1.0 1

COPYRIGHT: The concepts and information contained in this document are the property of Aquenal Pty Ltd. Use or copying of this document in whole or in part without the written permission of Aquenal Pty Ltd constitutes an infringement of copyright.

DISCLAIMER: This report has been prepared on behalf of and for the exclusive use of Aquenal Pty Ltd’s client and is subject to and issued in connection with the provisions of the agreement between Aquenal Pty Ltd and its Client. Aquenal Pty Ltd accepts no liability or responsibility whatsoever for or in respect of any use of or reliance upon this report by any third party.

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Table of Contents Operational Summary............................................................................................................................................. 6

1. Introduction ........................................................................................................................................................ 7

2. Methods.............................................................................................................................................................. 8

2.1. Sampling Design and Sampling Events ........................................................................................................ 8

2.2. Visual assessment of sediment cores ....................................................................................................... 10

2.3. Redox potential ......................................................................................................................................... 10

2.4. Sulphide concentration ............................................................................................................................. 10

2.5. Particle Size Analysis ................................................................................................................................. 11

2.6. Stable Isotopes .......................................................................................................................................... 11

2.7. Benthic Infauna ......................................................................................................................................... 11

2.8. Licence conditions ..................................................................................................................................... 12

3. Results and Interpretation ................................................................................................................................ 13

3.1. Visual assessment of sediment cores ....................................................................................................... 13

3.2. Redox Potential ......................................................................................................................................... 20

3.3. Sulphide concentration ............................................................................................................................. 20

3.4. Particle Size Analysis ................................................................................................................................. 23

3.5 Benthic Infauna .......................................................................................................................................... 26

3.5.1. Abundance ........................................................................................................................................ 26

3.5.2. Diversity and important species ........................................................................................................ 27

3.5.3. Compliance and control sites ............................................................................................................ 27

3.5.4. Community structure. ....................................................................................................................... 27

3.6. Performance against licence conditions ................................................................................................... 33

4. Summary of performance against licence conditions ...................................................................................... 41

5. References ........................................................................................................................................................ 43

6. Appendices ....................................................................................................................................................... 44

Appendix 1: Survey coordinates for seabed sampling provided by EPA, based on the Mapping Grid of Australia Zone 55 (Datum GDA94). .................................................................................................................. 44

Appendix 2: Total abundance of benthic infauna by site for sediment surveys conducted in November 2018 (Spring 2018) and April 2019 (Autumn 2019).. ................................................................................................ 45

Appendix 3: Raw data for sediment chemistry. ............................................................................................... 52

Appendix 4: Images of Core Samples ............................................................................................................... 53

Appendix 5: Particle Size Analysis Raw Data .................................................................................................... 59

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Operational Summary

Contractor: AQUENAL PTY LTD

ABN 74 151 011 157

244 Summerleas Road,

Kingston, Tasmania 7050

Phone 03 6229 2334 Fax 03 6229 2335

Client: Tassal Limited

GPO Box 1645

Hobart 7001

Phone: Hobart 03 6244 9099 Huonville 03 6244 8102

Fax: 1300 880 239

Field work: Seabed sampling: Aquenal Pty Ltd

Dates of fieldwork: 30/10/2018, 1/11/2018, 30/4/2019, 1/5/2019

Weather:

Survey: Spring 2018 Autumn 2019

Date: 31/10/2018 1/11/2018 30/4/2019 1/5/2019

Wind: 0-10 kn N 10-15 kn N 15-20 kn N L & V

Sky: Partly cloudy Partly cloudy Clear Cloudy

Rain: Nil Nil Nil Nil

Sea: <0.5 m < 0.5 m 0.5 – 1 m 0.5 – 1 m

Current: Negligible Negligible Negligible Negligible

Positioning for seabed sampling was undertaken using a Garmin GPS in combination with a Novatel Smart Antenna Differential GPS, giving positions accurate to ~2m. The GPS systems were referenced to a State Permanent Mark (SPM) prior to commencement of fieldwork.

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1. Introduction

The Okehampton Bay marine lease MF236 operates under Environmental Licence No. 10172/2. As

part of the conditions of Environmental Licence No. 10172/2, results of benthic infauna and

sediment surveys undertaken at compliance and control sites must be reported as part of the Annual

Environment Report submitted to the EPA Director.

Survey sites and methodologies were consistent with section 3V10 of the environmental licence,

with reporting following guidelines outlined in 3V11. Surveys were conducted biannually: once in

autumn and once in spring. Benthic survey components included benthic biota (infauna and

bacteria/algal mat identification), sediment chemistry (i.e. redox potential and sulphide

concentration), stable isotopes, sediment core descriptions and particle size analysis. Survey sites

included compliance sites 35 m from the lease boundary and control sites >250 m from the lease

boundary.

The first autumn survey was conducted in March 2018 and reported in the inaugural annual reports

for Environmental Licence 10172/2 (Aquenal 2018a). The current report summarises the results of

benthic sampling activities undertaken in November 2018 (spring 2018) and April 2019 (autumn

2018). Results from analagous sediment surveys at compliance and control sites around MF236

conducted as part of the Baseline Environmental Assessment in July 2017 (winter 2017) were used

to contextualise more recent results.

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2. Methods

2.1. Sampling Design and Sampling Events

Environmental Licence No. 10172/2 requires benthic surveys to be conducted at eleven control and

compliance sites in Okehampton Bay in autumn and spring each year. Survey sites 1-8 are

compliance sites located 35 m from the MF236 lease boundary (Figure 1). Sites 9-11 are control sites

located at least 250 m outside the MF236 lease boundary (Figure 1). Sites for monitoring under the

Environmental Licence were co-located with the central location of sites sampled during the Baseline

Environmental Survey in July 2017 (Figure 1). In the 2017 Baseline Survey, single sediment samples

were taken from three locations 20 m apart at each site (e.g. 1.1, 1.2, 1.3; Figure 1; Table 1). For

monitoring under the Environmental Licence, three replicate samples were taken from the central

site from the Baseline Environmental Survey (i.e. 1.2, 2.2……11.2; Figure 1; Table 1).

As part of Environmental Licence monitoring, three benthic surveys have been undertaken to date:

March 2018, November 2018 and April 2019 (Table 1; Figure 1). Results for the March 2018 survey

were reported in the previous annual report (Aquenal 2018a) and results for November 2018 and

April 2019 surveys are presented in this report. To contextualise results for the current reporting

period, information from the July 2017 Baseline Environmental Survey was included. When

presenting data for July 2017, the three locations 20 m apart at each site (i.e. 1.1, 1.2, 1.3) were

considered as replicates.

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Table 1: Details of benthic surveys conducted in Okehampton Bay. Refer to Figure 1 for map of

sites, locations and replicates.

Survey Date Methodology No.

Sites

No.

Locations

No.

Replicates

Winter 2017 05 Jul 2017 Baseline Survey 11 3 1

Autumn 2018 21 Mar 2018 Environmental Licence 11 1 3

Spring 2018 01 Nov 2018 Environmental Licence 11 1 3

Autumn 2019 30 Apr-01 May 2019 Environmental Licence 11 1 3

(a) (b)

Figure 1: Map of sediment sampling sites in Okehampton Bay for surveys conducted for (a) the

Baseline Environmental Survey in July 2017 (winter 2017); and (b) the Environmental Licence

10172/2 monitoring program in March 2018 (autumn 2018), November 2018 (spring 2018) and

April 2019 (Autumn 2019). Sites sampled in 2018 and 2019 were co-located with the central

locations sampled in winter 2017 (i.e. 1.2, 2.2……11.2). Single samples were taken at each location

(e.g. 1.1, 1.2, 1.3) in winter 2017 and three replicates at each site (e.g. 1.2) for monitoring under

the Environmental Licence in 2018 – 2019.

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2.2. Visual assessment of sediment cores

A Craib corer was used to collect 50 mm diameter sediment cores in transparent Perspex tubes.

These were handled carefully and retained in a vertical orientation to minimise disturbance of the

sediment surface. In the laboratory cores were then visually assessed before redox and sulphide

measurements were taken. The cores were described in terms of length, colour (using a Munsell soil

chart), plant and animal life, gas vesicles, and smell. Odour from hydrogen sulphide gas, if present,

was noted after the water was removed from the core tubes.

2.3. Redox potential

Redox potential was measured in millivolts at 30 mm below the sediment surface using a WTW pH

320 meter with a Mettler Toledo Ag/AgCl combination pH/Redox probe. Calibration and

functionality of the meter were checked before each test using a Redox Buffer Solution (248 mV at

10 °C). Measurements were made within 3 hours of the samples being collected. Corrected Redox

potential values were calculated by adding the standard potential of the reference cell to the

measured redox potential and are reported in millivolts (mV).

In all cases the lowest reading observed was recorded as the Redox value. In low permeability,

muddy sediments, the recorded value is determined when the reading is stable or dropping at less

than 1 mV per second. In permeable, sandy sediments, the lowest reading is often observed while

the probe is being worked to the measurement depth. As soon as the probe stops moving in sandy

sediments with low Redox values, the readings normally start to increase when water is drawn down

by the probe diluting the interstitial fluids.

2.4. Sulphide concentration

Sediment sulphide was measured in accordance with the prescribed DPIPWE protocols (Macleod

and Forbes 2004). Measurements were made using a TPS uniPROBE Sulphide ISE and a WTW pH 320

meter. Using a modified syringe, 2 mL of sediment was removed at 30 mm depth from the core and

mixed with 2 mL of reagent (sulphide anti-oxidant buffer, SAOB) in a small beaker. The

sediment/SAOB mixture was carefully stirred with the probe for 15-20 seconds, until the reading

stabilised. The accuracy and functionality of the meter and probe was assessed prior to analysis

commencing, using standards of known concentration. A calibration curve was produced using three

standards of known concentration.

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2.5. Particle Size Analysis

The top 100 mm of each sediment core was homogenised and approximately 70 ml of sediment was

sub-sampled for particle size determination. Each sample was gently wet sieved through a sieve

stack of 4 mm, 2 mm, 1 mm, 500 μm, 250 μm, 125 μm, 63 μm. The <63 μm fraction was allowed to

drain away. The material remaining on each sieve was dried of excess water before being carefully

removed and placed in a graduated cylinder. The volume of sediment from each size fraction was

measured as the displaced volume. The < 63 μm fraction was obtained by subtracting the sum of all

sieve fractions from the initial volume. The data was presented graphed as stacked percentages and

cumulative percentages for each site.

2.6. Stable Isotopes

Stable isotope analysis is required every four years commencing in March 2018 and was not

undertaken in the current reporting period. In accordance with the environmental licence, samples

for stable isotope analysis were taken in spring 2018 and autumn 2019 and retained as an archive

(frozen).

2.7. Benthic Infauna

Benthic infauna were collected using a Van Veen grab which sampled a 0.07 m2 area of seabed.

Triplicate grabs were collected at each monitoring site, with a total of 33 grabs collected. Grab

samples were sieved in the field using 1 mm mesh sieve bags, with animal and sediment material

retained in the mesh bags placed in 5-10% buffered formalin. Fauna were identified to family level

and enumerated in the Aquenal laboratory. In accordance with licence conditions, identification of

some taxa was to species level. These groups currently include the family Capitellidae, family

Turitellidae and all introduced marine species.

Data from triplicate grabs were analysed using multidimensional scaling (MDS) in the PRIMER

software package (Clarke & Gorley 2001). This analysis produces the best graphical depiction of

faunal similarities between samples. For MDS analyses, the data matrix showing total abundance of

species in each sample was fourth root-transformed and then converted to a symmetric matrix of

biotic similarity between pairs of samples using the Bray-Curtis similarity index. These procedures

follow the recommendations of Faith et al. (1987) and Clarke (1993) for data matrices with

numerous zero records. The usefulness of the two-dimensional MDS display of relationships

between samples is indicated by the stress statistic, where <0.1 indicates that the depiction of

relationships is good, and > 0.2 that the depiction is poor (Clarke, 1993).

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2.8. Licence conditions

The licence holder must comply with a range of environmental standards in carrying out operations

on the MF236 marine lease. The licence stipulates that there must be no significant visual, physico-

chemical or biological impacts at or extending beyond 35 m from the boundary of the lease areas

(General conditions; section 1.1.) Licence conditions relevant to the benthic surveys are summarised

in Table 2. The performance of against these conditions is tested and discussed throughout this

document and summarised in Table 5 in section 6 of this document. Note that visual impacts are

based on ROV surveys and are reported elsewhere, in accordance with licence condition 3V9.

Table 2: List of general licence conditions (3E2) relevant to the benthic survey at MF236.

Conditions (3E2) Report

Section

1.1.2: Physico-chemical

1.1.2.1.1. A corrected redox value which differs significantly from the reference site(s) or is less

than 0 mV at a depth of 3 cm within a core sample.

3.2

1.1.2.2.1. A corrected sulphide level which differs significantly from the reference site(s) or is

greater than 250 mV at a depth of 3 cm within a core sample.

3.3

1.1.3. Biological

1.1.2.3.1 A 20 time increase in the total abundance of any individual taxonomic family relative to

reference sites.

3.4

1.1.2.3.2. An increase at any compliance site of greater than 50-times the total Annelid abundance

at reference sites.

3.4

1.1.2.3.3. A reduction in the number of families by 50 percent or more relative to reference sites. 3.4

1.1.2.3.4. a complete absence of fauna 3.4

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3. Results and Interpretation

3.1. Visual assessment of sediment cores

Results from the visual assessment of cores collected in spring 2018 (November 2018) and autumn 2019

(April 2019) are summarised in Table 3 and Table 4. The nature of the sediments was similar across

sampling sites for both sampling events. Sediments were generally dark grey to dark greyish brown in

colour. Sparse to coarse shell grit was observed in most cores. The observed sandy nature of the sediments

indicates that wave and/or swell action influences the seabed sediments and the rate of deposition of finer

sediment fractions is low. At some sites darker colouration and streaks were evident in some cores. The

darker sediment colouration evident at some sites may be indicative of low oxygen levels in the sediment.

In these cases, the dark coloration is likely to arise from well compacted sediments in sandy environments

rather than organic enrichment. This is supported by the lack of gas or smell in any of the cores.

There was evidence of animal and plant life in sediments collected in spring 2018 and autumn 2019.

Caulerpa spp. macroalgae and drift red, brown or green macroalgae was observed on the surface of seven

cores in spring 2018 and five cores in autumn 2019. Animal burrows were observed in many cores and a

range of animals were observed either in the cores or on the sediment surface. Animals observed included

amphipods, bivalves, gastropods, ghost shrimp, New Zealand screw shells, nemerteans, polychaetes and

terebellids.

Sediment core visual characteristics for the spring 2018 and autumn 2019 surveys were broadly similar to

those described in the winter 2017 for the Baseline Environmental Survey (Aquenal 2017) and autumn 2018

for the inaugural monitoring survey for the marine farm licence (Aquenal 2018a). Images of sediment cores

are included in Appendix 4.

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Table 3: Core descriptions for sediments collected in spring 2018 (November 2018). Colour codes were based on the Munsell soil chart.

Core First Layer Second Layer Third Layer Biota Gas or Smell Notes

Site Length (mm)

Colour Sediment Depth (mm)



Plants Animals Gas Smell

1.2 (1) 190 10YR 4/2 Dark greyish

brown Sand with shell grit 190

Nil Ghost shrimp at 80 mm Nil Nil

1.2 (2) 150 10YR 4/2 Dark greyish


Caulerpa sp. on

surface

Polychaetes on surface, whelk on surface

Nil Nil

1.2 (3) 190 10YR 4/2 Dark greyish


Red algae on surface

Nil Nil Nil Dark streaks

at 50 mm

2.2 (1) 130 10YR 4/2 Dark greyish

brown Sand with sparse

shell grit 80

10YR 4/1 Dark grey

Sand with sparse shell

grit 130

Nil Nil Nil Nil

Dark streaks throughout

2.2 (2) 125 10YR 4/2 Dark greyish


shell grit 125

Nil Nil Nil Nil

Dark streaks at 40 mm

2.2 (3) 140 10YR 4/2 Dark greyish


shell grit 140

Nil Nil Nil Nil

3.2 (1) 140 10YR 4/1 Dark grey Sand with shell grit 60 10YR 3/1 Very dark

grey


grit 140

Caulerpa sp. on

surface

Nemertean at 80mm, burrows throughout

Nil Nil

3.2 (2) 120 10YR 4/1 Dark grey Sand with shell grit 70 10YR 3/1 Very dark

grey


grit 120

Nil Polychaete at 50mm Nil Nil

Dark streaks throughout

3.2 (3) 120 10YR 4/1 Dark grey Sand with shell grit 120

Caulerpa sp. on

surface Nil Nil Nil

Dark streaks at 40 mm

4.2 (1) 140 10YR 4/2 Dark greyish

brown Sand with coarse

shell grit 70

10YR 3/1 Very dark

grey

Sand with shell grit

140

Nil Burrows at 50mm Nil Nil

4.2 (2) 100 10YR 4/2 Dark greyish


shell grit 60

10YR 3/1 Very dark

grey


100

Nil Nil Nil Nil

4.2 (3) 100 10YR 4/2 Dark greyish


shell grit 40

10YR 3/1 Very dark

grey


100


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Table 3: Core descriptions for sediments collected in spring 2018 (continued).


Site Length (mm)





5.2 (1) 140 10YR 4/3 brown Sand with coarse

shell grit 40

10YR 2/1 Black


70 10YR 3/1 Very dark

grey

Sand with

sparse shell grit

140 Nil Terebellids on surface, amphipods on surface,

burrows at 0-10mm Nil Nil

5.2 (2) 195 10YR 4/1 Dark grey Sand with shell grit 195

Nil Nil Nil Nil Very dark

streaks throughout

5.2 (3) 90 10YR 4/3 brown Sand with coarse

shell grit 30

10YR 3/1 Very dark

grey


90

Brown algae on surface

Nil Nil Nil Very dark streaks to

30mm

6.2 (1) 140 10YR 4/2 Dark greyish


shell grit 140

Nil

Polychaete at 20mm and 60mm

Nil Nil

6.2 (2) 150 10YR 4/2 Dark greyish


shell grit 150

Nil Bivalve on surface Nil Nil

6.2 (3) 100 10YR 4/2 Dark greyish


shell grit 100

Nil Nil Nil Nil

Dark spots at 20mm

7.2 (1) 110 10YR 4/2 Dark greyish


shell grit 110


Dark streaks at 30-80 mm

7.2 (2) 180 10YR 4/2 Dark greyish


shell grit 180

Nil Nil Nil Nil

Dark streaks at 40-150

mm

7.2 (3) 150 10YR 4/2 Dark greyish


shell grit 150

Nil Nil Nil Nil

Dark streaks at 40-60 mm

8.2 (1) 150 10YR 4/2 Dark greyish


10YR 4/1 Dark grey


grit 150

Nil Nil Nil Nil

Dark streaks at 70mm and

120mm

8.2 (2) 120 10YR 4/2 Dark greyish


10YR 4/1 Dark grey


grit 120

Nil

Polychaete and amphipods on surface, polychaete at 30mm

Nil Nil

8.2 (3) 120 10YR 4/1 Dark grey Sand with sparse

shell grit 120

Nil

Maoricolpus roseus on surface

Nil Nil

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Table 3: Core descriptions for sediments collected in spring 2018 (continued)


Site Length (mm)


Colour (Munsell

score) Sediment

Depth (mm)



9.2 (1) 140 10YR 4/2 Dark greyish


shell grit 140

Nil

Polychaetes on surface

Nil Nil

9.2 (2) 120 10YR 4/2 Dark greyish


shell grit 120

Caulerpa sp. on

surface Burrows at 20mm Nil Nil


shell grit 180

Nil

Polychaetes on surface

Nil Nil

10.3 (1) 110 10YR 4/3 Brown Sand with dense shell

grit 40

10YR 3/1 Very dark

grey

Sand with sparse

shell grit 110

Nil Nil Nil Nil

Dark streaks at

40-110mm


shell grit 180

Nil Nil Nil Nil

Dark streaks

throughout


shell grit 40

10YR 4/3 brown


60

10YR 4/2

Dark greyish brown

Sand with

sparse shell grit

110 Nil Gastropod at 60mm,

burrow at 20mm Nil Nil


shell grit 130

Nil Nil Nil Nil

Dark streaks at

70mm


shell grit 105

Red algae on surface

Amphipods on surface, polychaete

at 40mm Nil Nil


shell grit 125

Nil Nemertean at 40mm Nil Nil

Dark streaks at

40 mm

17

Table 4: Core descriptions for sediments collected in autumn 2019 (April 2019). Colour codes were based on the Munsell soil chart.

Core First Layer Second Layer Biota Gas or Smell Notes

Site Length (mm)




1.2 (1) 140 10YR 4/2 Dark greyish brown

Sand with sparse fine shell grit

140

Nil Burrows, gastropod on

sediment surface Nil Nil Dark streaks 30-80 mm



130

Nil Burrows Nil Nil Dark streak at 50 mm, very fine silt on surface

2 mm thick



110

Nil Ghost shrimp at 80 mm Nil Nil



120

Nil Worm tube on sediment

surface Nil Nil



110

Drift Caulerpa on

sediment surface

Burrows Nil Nil



130

Caulerpa and rhizome on sediment surface

Burrows Nil Nil


Sand with fine shell grit

140

Nil Burrows, ghost shrimp at

100 mm Nil Nil

Layer of fine silt (flocculent) 2 mm thick



140

Nil Burrows, ghost shrimp at

50 mm and 100 mm Nil Nil

Faint dark streak at 100 mm



150

Nil Burrows Nil Nil

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Table 4: Core descriptions for sediments collected in autumn 2019 (continued)

Core First Layer Second Layer Biota Gas or Smell Notes

Site Length (mm)





Sand with shell grit 110

Nil Burrows Nil Nil Layer very fine silt on

surface 2 mm thick, faint dark streaks 50-100 mm


Sand with shell grit 50 10YR 3/1 Very

dark grey Sand with

sparse shell grit 150 Nil Ghost shrimp at 60 mm Nil Nil

Dark streaks 60-140 mm, colour change a gradient

rather than distinct change



dark grey Sand with

sparse shell grit 110 Nil Burrows Nil Nil Dark streaks 80-100 mm



dark grey Sand with

sparse shell grit 120 Nil Burrows, Maoricolpus Nil Nil Dark streaks 40-80 mm



dark grey Sand with




dark grey Sand with





sediment surface Nil Nil



Nil Nil Nil Nil




sediment surface Nil Nil


Sand with sparse shell grit

40 10YR 4/1 Dark

grey Sand with

sparse shell grit 140 Nil Burrows Nil Nil

Faint dark streaks 20-100 mm



30 10YR 4/1 Dark

grey Sand with

sparse shell grit 130 Nil Burrows Nil Nil




30 10YR 4/1 Dark

grey Sand with


19

Table 4: Core descriptions for sediments collected in autumn 2019 (continued)

Core First Layer Second Layer Third Layer Gas or Smell Notes

Site Length (mm)





Sand with shell grit 120 Nil Nil Nil Nil Dark streaks 40-80 mm


Sand with shell grit 110 Drift

Caulerpa and red algae

Gastropods on sediment surface

Nil Nil


Sand with shell grit 120 Nil Burrows Nil Nil Faint dark streak 10-20 mm


shell grit 130 Nil Nil Nil Nil


shell grit 120 Nil Burrows Nil Nil

Layer of fine silt (flocculent) 2mm thick


shell grit 140 Nil

Burrows, polychaete at 30 mm

Nil Nil Dark streak 30-40 mm



140 Nil Burrows Nil Nil Dark streaks 30-90 mm,

layer flocculent 2mm



30 10YR 3/1 Very

dark grey Sand with

sparse shell grit 150

Drift red, green algae on surface

Burrows Nil Nil Dark streaks



40 10YR 3/1 Very

dark grey Sand with

sparse shell grit 120 Nil Burrows Nil Nil Dark streaks



Faint dark streaks 40-130 mm, layer flocculent 2mm






Faint dark streak 90-120 mm

20

3.2. Redox Potential

Mean redox potential for sediment cores collected across eleven sites in Okehampton Bay (Figure 2) was

213 mV in winter 2017 (range 138-319 mV); 300 mV in autumn 2018 (range 230-373 mV); 175 mV in spring

2018 (range 100-335 mV); and 212 mV in April 2019 (range 161-283 mV) (Figure 2). There was no evidence

of a region wide declining trend (i.e. toward degraded sediments; < 0 mV, Macleod and Forbes 2014) in

redox potential across the compliance (sites 1-8) or control sites (sites 9-11) (Figure 2; Figure 4). Across all

surveys, redox potential values in Okehampton Bay were well above the < 0 mV threshold considered

evidence of organic enrichment in south-eastern Tasmania (Macleod and Forbes 2014, see Figure 2, dashed

line).

3.3. Sulphide concentration

Mean sulphide concentrations potential for sediment cores collected across eleven sites in Okehampton

Bay (Figure 3) was 11 µM in winter 2017; 31 µM in autumn 2018; 8 µM in spring 2018; and 8 µM in autumn

2019 (range 3-18 µM). There was no evidence of a consistent increasing trend (i.e. toward degraded

sediments; >100 µM, Macleod and Forbes 2014) in sulphide concentrations across the compliance (sites 1-

8) or control sites (sites 9-11) (Figure 3; Figure 4). Compliance sites were generally more variable than

control sites (Figure 4) and median values between the compliance and control sites were approximately

equivalent through time (Figure 4). Sulphide concentrations in autumn 2018 tended to be higher than other

surveys at some compliance and control sites (e.g. sites 3, 4, 5, 7, 10, 11), a pattern indicative of natural

variation in sulphide concentration. At site 5, one replicate recorded a sulphide concentration of 114 µM in

autumn 2018. A single relatively high sulphide reading is not considered evidence of organic enrichment,

and is occasionally observed in circumstances where sandy, well compacted sediments are present.

In all four surveys, mean sulphide concentrations were well below the 100 µM threshold (Figure 3, dashed

line) used as an indicator of degraded or ‘impacted’ sediments in south-eastern Tasmania (Macleod and

Forbes 2004). Sulphide concentrations were also well below the < 250 µM threshold set by the licence

conditions (Table 2). These results are therefore indicative of sediments that are unimpacted by organic

enrichment over this period.

21

Figure 2: Corrected redox values (mV) at 30 mm depth for sediments collected at eleven sites in

Okehampton Bay as part of the Baseline Environmental Survey (Winter 2017) and monitoring under the

Environmental Licence 10172/2 (Autumn 2018; Spring 2018; Autumn 2019). Crosshairs indicate the mean

and filled circles represent replicate observations at each site. Organic enrichment is typically indicated

by redox values < 0 mV and (Macleod and Forbes 2004) and this is represented by the dashed line.

Figure 3: Sulphide values (µM) for sediments collected at eleven sites in Okehampton Bay as part of the

Baseline Environmental Survey (Winter 2017) and monitoring under the Environmental Licence 10172/2

(Autumn 2018; Spring 2018; Autumn 2019). Crosshairs indicate the mean and filled circles represent

replicate observations at each site. Organic enrichment is typically indicated by sulphide values >100 µM

and (Macleod and Forbes 2004) and this is represented by the dashed line. Licence conditions stipulate a

threshold of >250 µM (Table 2)

22

Figure 4: Boxplots comparing redox (mV) and sulphide (µM) in sediments collected at compliance sites

(Sites 1-8; 35 m from lease boundary) and control sites (Sites 9-11; >250m from lease boundary) during

the Baseline Environmental Survey (Winter 2017) and the monitoring program for Environmental Licence

10172/2 (Autumn 2018; Spring 2018; Autumn 2019). Organic enrichment is typically indicated by redox

values < 0 mV and sulphide values >100 µM and (Macleod and Forbes 2004; threshold of >250 µM in

licence; see Table 2) and this is represented by the dashed line. Boxes represent the range (vertical line),

20th and 80th percentile (box) and the median (horizontal line)

23

3.4. Particle Size Analysis

Particle size results across the four surveys are summarised in Figures 5 and Figure 6. Across all surveys,

sediments throughout the area sampled were generally dominated by sand (0.5-0.25 mm) and fine sand

(0.25-0.125 mm) fractions, with the majority of sediments being in the 0.25-0.125 mm size class (average

45.1 % v/v across all sites and surveys). Overall, sediments showed a relatively low proportion of fine clay

and silt fractions (i.e. < 0.063 mm; average 5.6 % v/v across all site and surveys). Patterns of particle size

distribution have been very similar between sites, although control site 10 has had a slightly higher level of

coarse particle size fractions, while a slightly higher level of finer sand and silt/clay fractions have been

evident at control sites 9 and 11 (Figure 5, Figure 6).

Overall, patterns of particle size distribution have remained stable across surveys. There was a tendency for

a higher proportion of coarser sand fractions in autumn 2019 compared to previous surveys. This change

was apparent at compliance and control sites (i.e. sites 1, 3, 4, 5, 7, 9, 11; see Figure 5). It is possible that

changes in sediment transport (e.g. due to swell events) may have contributed to these patterns, but it is

also plausible that sampling or analytical variation has influenced these patterns. It should be noted that

the wet sieve particle size method provides a general indication of sediment type and is not considered to

be a particularly sensitive response variable for monitoring environmental change.

The observed particle size distributions were indicative of a sedimentary environment with moderate

agitation of seabed sediments and associated low abundance of fine silt and clay fractions. These patterns

are considered typical of sediments in relatively deep (i.e. >20 m) and exposed locations. The similarity in

particle size distribution between most sites implies similar depositional environments.

Raw data from the spring 2018 and autumn 2019 particle size analysis are included in Appendix 5.

24

(a)

(b)

Figure 5: (a) Mean particle size content (%) of gravel (> 2 mm), coarse sand (0.25-2 mm), fine and very

fine sand (0.25-0.063) and mud/silt (< 0.063 mm) at eleven sites in Mercury Passage sampled in winter

2017, autumn 2018, spring 2018 and autumn 2019. (b) Mean particle size for sites classified as

compliance (35m from lease) and control (>250 m from lease). Results represent % contribution of each

broad sediment size category, pooled across three cores per survey at each site.

25

(a)

(b)

Figure 6: (a) Cumulative frequency curves for sediment size collected in winter 2017, autumn 2018, spring

2018 and autumn 2019 at eleven sites in Mercury Passage. (b) Cumulative frequency curves for sediment

size for sites classified as compliance (35 m from lease) and control (>250 m from lease) in Mercury

Passage. (b) Volumetric (V) thresholds are 4 mm (V4), 2 mm (V2), 1 mm (V1), 0.5 mm (V0.5), 0.25 mm,

0.125 mm (V0.125), 0.063 mm (V0.063), <0.063 mm (<0.063).

26

3.5 Benthic Infauna

3.5.1. Abundance

The abundance (583-874 individuals per site) and faunal diversity (44-54 families per site) of benthic

invertebrates (benthic infauna) at compliance and control sites in Okehampton Bay (Table 5; Figure 7) is

broadly equivalent to the abundance and diversity of benthic infauna at broad scale monitoring sites across

Mercury Passage (698-903 individuals and 46-50 families per site; Aquenal 2019). Abundance and diversity

in Mercury Passage are relatively high for benthic environments in south-eastern Tasmania. By comparison,

broad scale monitoring sites in the Huon and D’Entrecasteaux Channel averaged 373 individuals from 33

families in surveys conducted in 2007, 2013 and 2017 (Aquenal 2018a). Broadscale monitoring sites around

the Tasman Peninsula recorded an average of 592 individuals from 48 families in 2018 (Aquenal 2018b).

The abundance of benthic infauna across all sites fluctuated between 6413 individuals in winter 2017 and

9648 individuals in autumn 2018 (Table 5; Figure 7). Faunal communities were dominated by polychaete

families (marine annelid worms) and crustacean families (e.g. crabs, crayfish, shrimps, amphipods etc.).

Crustaceans were the dominant group in the most recent two sampling events and in winter 2017 (Figure

7a). The abundance of crustaceans has increased in the last three surveys (Figure 7b) mostly due to the

increased abundance of amphipods from the family Ampeliscidae (Table 5; Figure 11). Polychaetes were

the dominant group in autumn 2018 making up ~50% of all individuals (Figure 7a). This was driven by an

increased abundance of sabellid polychaetes (feather duster worms, family Sabellidae; Figure 11).

Importantly, relatively high sabellid densities were also recorded at broad scale monitoring sites

throughout Mercury Passage during this period (see Aquenal 2019). Molluscs, echinoderms and other

families made up only a minor proportion of total benthic infauna abundance in Okehampton Bay. A spike

in echinoderm abundance (largely Loveniidae; Figure 11) in autumn 2018 is notable (Figure 7).

27

3.5.2. Diversity and important species

The total number of families observed across all sites was 103 in winter 2017, 134 in autumn 2018, 118 in

spring 2018 and 118 in autumn 2019 (see Figure 11). The number of families per site and the relative

dominance of each taxonomic group has remained relatively stable across the four sampling events (Table

6; Figure 8). Crustaceans were the most dominant taxonomic group (~47% of species), followed by

polychaetes (~26%) and molluscs (~16%) (Table 6; Figure 8).

Some polychaete species within the family Capitellidae are known pollution indicator species and are often

used as indicators of organic enrichment in south-eastern Tasmania (Macleod and Forbes 2004). Three

capitellid taxa were found in the 2018 and 2019 surveys: Notomastus sp., Mediomastus sp. and Barantolla

sp. (Figure 11; Appendix 2). These particular capitellid taxa are not regarded as pollution indicator species

in Tasmania and were present in extremely low numbers (16 individuals across four surveys; Appendix 2).

The introduced New Zealand Screw Shell Maoricolpus roseus was recorded at moderate densities (118-157

individuals across four surveys) (Figure 11; Appendix 2). Other introduced species have been recorded in

very low densities, including the introduced bivalve Varicorbula gibba (17 individuals across all surveys) and

the ‘fire crab’ Pyromaia tuberculata (two individuals across all surveys).

3.5.3. Compliance and control sites

Comparisons of the abundance and diversity of benthic infauna at compliance sites (35 m from the lease

boundary) and control sites (~250 m from the lease boundary) may provide an indication of whether

particulate waste or organic enrichment from marine farm MF236 is influencing nearby habitat. If patterns

of abundance and diversity at compliance and control sites diverge, then it may indicate marine farm

effects on benthic infauna. In Okehampton Bay, compliance and control sites had an equivalent abundance

of benthic infauna in winter 2017, spring 2018 and autumn 2019 (Figure 9). Control sites had a relatively

high abundance of benthic infauna compared to compliance sites in autumn 2018. This disparity was

primarily driven by a periodic increase in polychaete abundance (mainly sabellids) at control sites (largely at

site 9; Figure 9). The numbers of families per site has been relatively stable across the four surveys,

although there were slightly less crustaceans, polychaetes and echinoderms in winter 2017 compared to

the subsequent surveys (Figure 10).

3.5.4. Community structure.

Multidimensional scaling (MDS) analysis graphically depicts the relationship between ecological

communities based on the abundance and diversity of species or family groups. Sites with similar

community structures will be close together in ordination space and those with different community

structure will be distant in ordination space. The four surveys tended to separate along the y-axis in

ordination space (Figure 12a), however, the differences between surveys in the MDS analysis were

28

relatively small and all four surveys remain within a single cluster (50% similarity level; Figure 12a). There

were no strong family-based drivers of this divergence with the possible exception of the Nuculanidae

(bivalve mollusc) and Hexapodidae (crab) families (Figure 12b). It is notable that the separation of site 5 and

site 10 from the main grouping is partly driven by the occurrence of high numbers of the invasive New

Zealand screw shell (Maoricolpus roseus) (Figure 12b).

If organic enrichment was affecting community structure of the surrounding benthic environment (i.e. 35

m) then compliance sites would be expected to diverge from control sites over time (see for example,

Macleod and Forbes 2004). Across all four surveys, compliance sites (triangles) were intermixed with

control sites (circles) and there was no systematic divergence of either site grouping over time (Figure 12a).

Overall, the combined MDS analyses were indicative of consistent benthic community structure over time

and across compliance and control sites.

29

(a) (b)

Figure 7: Total abundance of benthic infauna in five broad taxonomic groups from sediments collected at

eleven sites adjacent to the MF236 marine farm in Okehampton Bay. Plots are arranged to highlight (a)

composition during each survey and (b) trends over time. See Figure 11 for families included in each

taxonomic group.

(a) (b)

Figure 8: Mean number of benthic infauna families per site (i.e. diversity) in five broad taxonomic groups

from sediments collected at eleven sites adjacent to the MF236 marine farm in Okehampton Bay. Plots

are arranged to highlight (a) composition during each survey and (b) trends over time. See Figure 11 for

families included in each taxonomic group.

30

(a) (b)

Figure 9: Mean abundance of benthic infauna in five broad taxonomic groups from sediments collected at

eight compliance and three control sites adjacent to the MF236 marine farm in Okehampton Bay. Plots

are arranged to highlight (a) composition during each survey and (b) trends over time. See Figure 11 for

families included in each taxonomic group.

(a) (b)

Figure 10: Mean number of benthic infauna families (e.g. diversity) in five broad taxonomic groups from

sediments collected at eight compliance and three control sites adjacent to the MF236 marine farm in

Okehampton Bay. Plots are arranged to highlight (a) composition during each survey and (b) trends over

time. See Figure 11 for families included in each taxonomic group.

31

Figure 11: Total abundance of benthic infauna families within each taxonomic group for winter 2017 (red), autumn 2018 (blue), spring 2018 (green) and autumn

2019 (purple). The direction of change in abundance between each consecutive time period at compliance and control sites is represented in Figure 13.

32

(a)

(b)

Figure 12: Results of multidimensional scaling analysis (MDS; 2D stress = 0.19) using benthic infauna data

collected from eight compliance sites (circles) and three control sites (triangles) in Mercury Passage in

winter 2017, autumn 2018, spring 2018 and autumn 2019 (winter/spring = green; autumn = blue). Points

represent the summed abundance of three replicates at each site. The ellipse in (a) indicates community

similarity at a level of 50%, based on cluster analysis. Vectors in (b) indicate key families with a high

correlation (>0.6) with ordination space and represent families driving the separation of sites in two

dimensions.

33

3.6. Performance against licence conditions

The licence conditions (3E2) stipulate that there must be no significant visual, physico-chemical or

biological impacts at or extending beyond 35 m from the boundary of the Lease Area (Table 2). Biological

impact licence conditions comprise measures of benthic infauna1 including changes in (1) the total

abundance of individual taxonomic families; (2) the abundance of annelid (i.e. polychaete) worms; (3) and

the number of families at sites; and (4) the absence of fauna (see Table 2). These measures are contingent

on comparisons of changes in the relative abundance and the relative number of families at control and

compliance sites between survey events. These measures are addressed separately below.

Criteria 1.1.2.3.1: A 20 times increase in the total number of any individual taxonomic family relative to

reference sites1.

The ratio of change (increase, decrease or stable) in the total number of individuals in each taxonomic

family detected at compliance and control sites in Okehampton Bay was calculated for the period between

each sampling event (Figure 13a-d). Of the 134 families found in Okehampton Bay, only two polychaete

families with exceptionally low overall abundance (maximum < 26 animals across eight sites) recorded a 20-

times increase in total abundance at compliance sites for a given period (Figure 13c). The Sigalionidae

increased by > 20 times between winter 2017 and autumn 2018 at compliance sites (0 to 23 animals2) with

control sites showing a 13-fold increase in abundance at control sites during the same period (2 to 26

animals2). The Pectinaridae increased by > 20 times between spring 2018 and autumn 2019 (0 to 21

animals2) with control sites showing a ~4-fold increase in abundance at control sites during the same period

(3 to 11 animals2). One crustacean taxa (family Nannastacidae; cumacean) increased by ~30 fold between

autumn 2018 and spring 2018, with a 3.5 fold increase observed at control sites over the same period

(Figure 13a). This family is not considered a pollution indicator and the magnitude of increase in ratio terms

is partly attributable to its low abundance in the winter 2017 survey. None of the most abundant families

showed signs of dramatic increases in population size at compliance sites (Figure 13a-d); Overall, there was

1 Note that the wording of Criteria 1.1.2.3.1, Criteria 1.1.2.3.2 and Criteria 1.1.2.3.3 is imprecise and open to a range of interpretations, particularly in relation to the spatial and temporal scale(s) of interest. For the purpose of this report the compliance assessment was made by comparing the ratio of increased abundance at compliance sites to control sites. For example, a 4 times increase at control sites would require an 80 times increase (i.e. 4 x 20) at compliance sites to exceed the licence condition. More clarity is required as to how to relate changes at compliance sites to reference (i.e. control) sites. Every effort to interpret these criteria in a practical and informative way has been made for this report. A review of the wording of these criteria is recommended. 2 It is not possible to calculate change in abundance for individuals that are absent in previous surveys. To facilitate calculations observations of 0 individuals were modified to 1 individual. Criteria based on change to between surveys with low taxa is difficult to interpret and a review of this approach is recommended.

34

no evidence of a 20-times increase in the total number of any individual taxonomic family relative to

reference (i.e. control) sites.

Criteria 1.1.2.3.2: An increase at any compliance site of greater than 50-times the total annelid

abundance at reference sites.

The ratio of change (increase, decrease or stable) in the total number of annelid individuals detected at

compliance and control sites in Okehampton Bay was calculated for the period between each sampling

event (Figure 14). For the two periods between the most recent three surveys (i.e. autumn 2018-spring

2018; spring 2018 -autumn 2019), changes in abundance of annelids at control and compliance sites were

of a similar direction and magnitude (Figure 14). Annelid abundance decreased at most sites or increased

slightly (by < 15%) at two sites during these two periods (Figure 14). In contrast, between winter 2017 and

autumn 2018 annelid abundance increased at all sites except site 2 but the magnitude of the increase

differed markedly between sites. At one compliance site (site 8), annelid abundance increased by ~ 7 fold,

but – importantly, an equivalent increase in annelids was recorded at two control sites - Site 9 (~6 fold

increase) and Site 10 (~8 fold increase) (Figure 14). The increase in annelids at these sites was driven by

increased densities of polychaetes from the family Sabellidae in autumn 2018 (Figure 11; see section 3.1.1).

Based on this data, there was no evidence of a 50-times increase at any compliance site of greater than 50-

times the total annelid abundance at reference (i.e. control) sites.

Criteria 1.1.2.3.3: A reduction in the number of families by 50 percent or more relative to reference

sites1.

The percent change in the total number of families observed at compliance and control sites in

Okehampton Bay was calculated for the period between each sampling event (Figure 15). Between winter

2017 and autumn 2018 there was a net increase of family diversity at all sites. Between spring 2018 and

autumn 2019, only two sites exhibited a reduction in the number of families (compliance site 3; control site

9). Between autumn 2018 and spring 2018, four compliance sites recorded a reduction in the number of

families, but a reduction of a similar magnitude was also detected at control site 10 and control site 11.

Based on this data, there was no evidence of a reduction in the number of families by 50 percent or more

relative to reference (i.e. control) sites.

Criteria 1.1.2.3.3: a complete absence of fauna.

The four surveys revealed an abundant and diverse benthic fauna at all surveyed sites with a high number

of individuals and families relative to other benthic ecosystems in south-eastern Tasmania (see section

3.1.1).

35

Figure 13a: Proportional change in abundance of crustacean families at compliance (red circles) and control sites (blue triangles) in

Okehampton Bay for three time periods: (1) winter 2017 to autumn 2018; (2) autumn 2018 to spring 2018; and (3) spring 2018 to

autumn 2019. Increases and decreases in abundance are left and right of the solid vertical line that delineates zero change. Families are

ordered from most abundant to least abundant (see Figure 11). Licence conditions (1.1.2.3.1.) stipulate that significant impacts may be

regarded as an increase of 20 times (i.e. see dashed vertical line) the total abundance of any individual relative to reference sites. Note

that 1 was added to all 0 abundance observations for this analysis to calculate meaningful statistics.

36

Figure 13b: Proportional change in abundance of mollusc families at compliance (red circles) and control sites (blue triangles) in






37

Figure 13c: Proportional change in abundance of polychaete families at compliance (red circles) and control sites (blue triangles) in



ordered from most abundant to least abundant (see Figure 11) Licence conditions (1.1.2.3.1.) stipulate that significant impacts may be



Figure 13c: Proportional change in abundance of “other” families at compliance (red circles) and control sites (blue triangles) in






38

Figure 14: Proportional change in total Annelid abundance at compliance (red circles) and control

sites (blue triangles) adjacent to marine farm MF236 in Okehampton Bay for three time periods:

(1) winter 2017 to autumn 2018; (2) autumn 2018 to spring 2018; and (3) spring 2018 to autumn

2019. Increases and decreases in abundance are above and below the solid horizontal line that

delineates zero change. Licence conditions (1.1.2.3.2.) stipulate that significant impacts may be

regarded as an increase at any compliance site of greater than 50 times the total Annelid

abundance at reference sites.

Figure 15: Percent change in the number of families at compliance (red circles) and control sites

(blue triangles) adjacent to marine farm MF236 in Okehampton Bay for three time periods: (1)

winter 2017 to autumn 2018; (2) autumn 2018 to spring 2018; and (3) spring 2018 to autumn 2019.

Increases and decreases in abundance are above and below the solid horizontal line that

delineates zero change. Licence conditions (1.1.2.3.3.) stipulate that significant impacts may be

regarded as a reduction in the number of families by 50 per cent or more relative to reference

sites.

39

Table 5: Summary table for abundance of benthic infauna at eleven compliance (sites 1-8) and control sites (9-11) in Okehampton Bay. Benthic infauna

families are grouped by five major taxonomic groupings (CRU=Crustaceans; POL=Polychaetes; MOL=Molluscs; ECH=Echinoderms; OTH=Other; see Figure

11). Data is the summed abundance of benthic infauna for three replicates per site.

Winter 2017 Autumn 2018 Spring 2018 Autumn 2019

Class CRU POL MOL ECH OTH CRU POL MOL ECH OTH CRU POL MOL ECH OTH CRU POL MOL ECH OTH

1 537 236 50 7 18 261 318 51 54 8 194 242 51 6 14 501 163 88 14 23

2 514 676 44 4 17 256 611 21 39 14 133 184 28 16 5 155 162 29 8 16

3 384 74 42 13 5 216 268 91 12 5 605 132 28 11 9 821 122 19 3 8

4 118 50 49 3 4 434 167 25 2 5 871 153 35 6 14 784 84 50 5 8

5 120 37 38 1 2 147 67 67 22 4 101 89 81 8 25 167 86 91 7 13

6 382 185 80 2 12 349 288 68 10 4 853 328 31 22 16 865 156 53 5 23

7 451 95 67 5 13 412 176 68 21 5 445 135 44 5 9 711 93 62 5 12

8 269 87 61 9 5 672 703 37 68 12 694 147 42 12 3 905 126 52 3 12

9 396 164 61 3 25 505 1413 32 38 12 755 240 33 14 7 878 115 88 3 9

10 119 20 100 1 1 221 149 84 18 7 173 75 125 17 3 137 55 96 2 10

11 507 187 24 18 21 475 540 21 33 12 365 117 10 14 4 899 105 27 4 7

Total 3797 1811 616 66 123 3948 4700 565 317 88 5189 1842 508 131 109 6823 1267 655 59 141

Mean (site) 345.2 164.6 56.0 6.0 11.2 358.9 427.3 51.4 28.8 8.0 471.7 167.5 46.2 11.9 9.9 620.3 115.2 59.5 5.4 12.8

% 59.2 28.2 9.6 1.0 1.9 41.0 48.9 5.9 3.3 0.9 66.7 23.7 6.5 1.7 1.4 76.3 14.2 7.3 0.7 1.6

40

Table 6: Summary table for the number of families (i.e. diversity) of benthic infauna at eleven compliance (sites 1-8) and control sites (9-11) in

Okehampton Bay. Benthic infauna families are grouped by five major taxonomic groupings (CRU=Crustaceans; POL=Polychaetes; MOL=Molluscs;

ECH=Echinoderms; OTH=Other; see Figure 11). Data is the number of families of benthic infauna across three replicates at each site.

Winter 2017 Autumn 2018 Spring 2018 Autumn 2019

Class CRU POL MOL ECH OTH CRU POL MOL ECH OTH CRU POL MOL ECH OTH CRU POL MOL ECH OTH

1 21 10 10 2 2 23 11 10 2 2 21 13 10 2 3 23 16 11 3 4

2 23 14 6 2 3 25 16 8 3 2 26 14 4 4 2 23 17 4 4 2

3 23 12 8 1 1 28 20 8 3 1 25 12 7 2 4 22 12 5 2 2

4 22 11 12 2 3 29 14 9 2 2 25 11 9 1 5 27 16 11 1 3

5 20 11 7 1 2 26 13 7 3 3 22 16 13 2 6 27 16 11 2 3

6 21 11 7 2 2 25 20 14 2 2 21 16 7 3 3 24 16 7 2 4

7 21 11 7 2 3 22 14 11 3 3 24 16 9 1 3 24 14 11 2 4

8 17 10 11 2 1 21 14 6 2 3 24 14 8 2 2 33 13 9 3 2

9 18 11 9 1 2 30 13 3 3 2 25 11 9 2 4 26 9 8 2 4

10 22 8 13 1 1 34 15 12 2 4 29 17 15 2 2 33 15 17 2 2

11 17 11 8 2 3 22 17 10 2 2 24 9 4 3 3 21 12 6 1 3

Mean (site) 20.5 10.9 8.9 1.6 2.1 25.9 15.2 8.9 2.5 2.4 24.2 13.5 8.6 2.2 3.4 25.7 14.2 9.1 2.2 3

% 46.5 24.8 20.2 3.7 4.8 47.3 27.7 16.3 4.5 4.3 46.6 26.1 16.6 4.2 6.5 47.5 26.2 16.8 4 5.5

41

4. Summary of performance against licence conditions

The licence stipulates that there must be no significant visual, physico-chemical or biological impacts

at or extending beyond 35 m from the boundary of the lease areas (General conditions; section 1.1;

see Table 7). Data from four sediment surveys conducted at approximately six-monthly intervals

between July 2017 and April 2019 in Okehampton Bay have demonstrated compliance against all

nominated physico-chemical and biological impacts (Table 7).

The environmental licence includes identification of algal and bacterial mats as part of the benthic

biota assessment [see section 3F(2)] but there are no licence standards associated with these

observations. Based on observations of sediment cores collected in four surveys to date (e.g. Table

3) there has been no observations of bacterial or algal mats at compliance or control sites. It is worth

noting that core and/or grab samples are not regarded as useful methodologies for assessing

bacteria or algal mats. Other survey methods covered under licence condition 3E2 (i.e. ROV

assessment of lease and compliance site) are more appropriate for monitoring these variables and

have been undertaken as part of visual compliance monitoring activities.

42

Table 7: Performance against licence standards for physico-chemical and biological impacts

stipulated under Environmental Licence No. 10172/2 for MF236 in Okehampton Bay (under 3E2). A

summary of the results is included along with reference to the relevant section and Figures and

Tables presenting available evidence.

Conditions Report

Section

Figures/

Tables

Summary Compliant/

non-compliant

1.1.2: Physico-chemical

1.1.2.1.1. A corrected redox value which

differs significantly from the reference

site(s) or is less than 0 mV at a depth of 3

cm within a core sample.

3.2 Figure 2,4 All sites well above 0 mV. Control and

compliance sites equivalent values.

Compliant

1.1.2.2.1. A corrected sulphide level

which differs significantly from the

reference site(s) or is greater than 250

mV at a depth of 3 cm within a core

sample.

3.3 Figure 3,4 All sites well below 250 mV (and 100

mV). Control and compliance sites

equivalent values.

Compliant

1.1.3. Biological

1.1.2.3.1 A 20 time increase in the total

abundance of any individual taxonomic

family relative to reference sites.

3.4 Figure 13 Two families with low abundance

increased by >20-times at compliance

sites but a concomitant increase in

those families also at control sites.

Compliant

1.1.2.3.2. An increase at any compliance

site of greater than 50-times the total

Annelid abundance at reference sites.

3.4 Figure 14 Observations of increases in Annelid

abundance at compliance sites was

complemented by a concomitant

increase at control sites of a similar

magnitude.

Compliant

1.1.2.3.3. A reduction in the number of

families by 50 percent or more relative to

reference sites.

3.4 Figure 15 Decreases of family diversity at

compliance sites was complemented by

a concomitant decrease at control sites

of a similar magnitude.

Compliant

1.1.2.3.4. A complete absence of fauna 3.4 Figure 8 An abundant and diverse fauna was

present at all sites for all surveys.

Compliant

43

5. References

Aquenal (2017) MF236 Okehampton. Baseline environmental assessment. Final Report (version 1.0),

July 2017 Report to Tassal Limited, 68 pp.

Aquenal (2018a) MF236 Okehampton Annual Broadscale Monitoring Report for Environmental

Licence No. 10172/2 for the period May 2017-April 2018, Report to: Tassal Limited June 2018.

Aquenal (2018b) Annual Broadscale Monitoring Report for the Tasman Peninsula and Norfolk Bay

Marine Farming Development Area for the period June 2017 to May 2018. Report to: Tassal Limited

August 2018.

Aquenal (2019) MF236 Okehampton Annual Broadscale Monitoring Report for Environmental

Licence No. 10172/2 for the period May 2018-April 2019, Report to: Tassal Limited June 2019.

Butler, E., Parslow, J., Volkman, J., Blackburn, S., Morgan, P., Hunter, J., Clementson, L., Parker, N.,

Bailey, R., Berry, K., Bonham, P., Featherstone, A., Griffin, D., Higgins, H., Holdsworth, D., Latham, V.,

Leeming, R., McGhie, T., McKenzie, D., Plaschke, R., Revill, A., Sherlock, M., Trenerry, L., Turnbull, A.,

Watson, R. and Wilkes, L. (2000). Huon Estuary Study – environmental research for integrated

catchment management and aquaculture. Final report to Fisheries Research and Development

Corporation.

Clarke, K.R. (1993) Non-parametric multivariate analyses of changes in community structure.

Australian Journal of Ecology 18: 117-143.

Clarke, K.R. & Gorley, R.N. (2001) PRIMER v5: User Manual/Tutorial PRIMER-E: Plymouth.

Faith, D.P., Minchin, P.R. and Belbin, L. (1987) Compositional dissimilarity as a robust measure of

ecological distance. Vegetatio 69: 57-68.

Macleod, C.K. and Forbes, S. (2004) Guide to the assessment of sediment condition at marine finfish

farms in Tasmania. Tasmanian Aquaculture and Fisheries Institute – University of Tasmania, Hobart,

Australia, 65 pp.

44

6. Appendices

Appendix 1: Survey coordinates for seabed sampling provided by EPA, based on the Mapping Grid of Australia Zone

55 (Datum GDA94).

Site name Easting Northing

1.2 579777 5290715

2.2 580069 5291185

3.2 580384 5291339

4.2 580779 5291094

5.2 580907 5290712

6.2 580644 5290288

7.2 580126 5290100

8.2 579784 5290312

9.2 579367 5290031

10.3 581384 5290526

11.2 580316 5291659

45

Appendix 2: Total abundance of benthic infauna by site for sediment surveys conducted in November 2018 (Spring 2018) and April 2019 (Autumn 2019). Data represent summed

abundance of three replicates per site. Note the different sampling design for replicates in the Baseline survey (illustrated in Figure 1). Data for April 2018 can be found in Aquenal

(2018).

Family Class November 2018 (Spring 2018) April 2019 (Autumn 2019)

1 2 3 4 5 6 7 8 9 10 11 1 2 3 4 5 6 7 8 9 10 11

Ampeliscidae Crustacean 38 18 415 502 6 552 230 292 283 2 178 134 26 608 533 14 502 413 541 493 6 653

Amphilochidae Crustacean 0 0 0 0 0 0 0 0 1 0 0 0 0 0 2 1 0 0 2 5 0 0

Ampithoidae Crustacean 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Anthuridae Crustacean 0 0 0 0 0 0 0 0 3 0 1 0 0 0 1 0 0 1 1 0 0 0

Aoridae Crustacean 8 9 3 9 4 7 5 11 6 7 3 8 10 15 7 5 26 10 20 4 1 2

Apseudidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Astacillidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Atylidae Crustacean 0 1 0 1 0 0 1 1 0 4 0 0 1 0 0 1 0 0 0 0 1 0

Bodotriidae Crustacean 0 0 3 7 0 3 1 1 1 0 0 0 0 0 0 0 0 3 1 1 0 0

Callianassidae Crustacean 0 1 1 0 0 1 1 0 0 0 0 0 5 13 5 0 7 1 1 0 0 2

Caprellidae Crustacean 2 4 1 1 1 0 2 0 0 2 2 0 0 0 0 0 0 0 1 1 2 0

Cirolanidae Crustacean 0 3 8 4 0 1 4 1 1 0 1 1 1 3 6 0 19 3 5 3 0 1

Colomastigidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Corophiidae Crustacean 0 0 0 0 0 0 0 0 0 1 2 0 0 0 0 2 0 0 1 0 5 0

Crangonidae Crustacean 0 2 0 0 0 0 0 1 0 0 0 0 0 1 1 1 0 0 0 1 0 0

Cypridinidae Crustacean 1 0 1 9 3 4 4 10 3 4 2 8 2 4 2 8 3 9 5 14 2 0

Cytheridae Crustacean 1 0 0 0 1 0 0 0 0 1 0 1 0 0 0 0 0 0 1 0 2 0

Dexaminidae Crustacean 2 7 2 8 8 0 5 4 4 4 11 0 0 0 1 2 2 5 2 1 1 4

Diastylidae Crustacean 13 10 23 88 9 54 31 67 64 21 18 67 7 23 57 10 22 11 43 47 4 9

Eusiridae Crustacean 0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 1 0 1 0

Galatheidae Crustacean 0 0 6 0 1 0 0 0 1 4 0 0 0 0 0 21 0 0 0 0 16 0

Gnathiidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Goneplacidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

46

Hexapodidae Crustacean 0 4 2 0 1 3 3 2 0 0 3 10 5 10 0 2 8 5 5 3 1 6

Hippolytidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Hymenosomatidae Crustacean 0 2 1 2 1 0 0 0 0 1 0 5 3 4 0 3 10 1 2 3 3 3

Ischyroceridae Crustacean 0 2 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

Jaeropsidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

Janiridae Crustacean 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Kallyapseudidae Crustacean 2 4 11 24 0 29 18 22 59 8 0 24 7 26 31 5 36 62 44 41 25 10

Leptocheliidae Crustacean 0 0 1 1 2 0 0 0 0 0 0 0 0 0 0 3 0 0 0 0 1 0

Leucosidae Crustacean 0 0 0 0 0 1 1 0 1 0 2 3 0 0 1 0 2 0 5 0 1 0

Leucothoidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

Luciferidae Crustacean 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 1 0 0 0 0

Lyssianassidae Crustacean 1 1 0 3 0 0 0 3 1 0 3 0 1 4 1 3 1 0 2 4 0 1

Majidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Majidae - Pyromaia tuberculata Crustacean 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 1 0 0 0

Melitidae Crustacean 3 1 11 2 1 30 17 36 24 5 6 8 3 11 6 5 41 43 25 5 4 0

Melphidippidae Crustacean 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0 0 0

Metapseudidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Mysidae Crustacean 0 1 1 1 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 0 0

Nannastacidae Crustacean 13 13 34 46 0 4 3 11 14 0 21 49 2 27 37 3 0 1 3 26 0 11

Nannosquillidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Nebaliidae Crustacean 2 6 2 3 1 10 0 10 19 1 1 10 0 2 12 9 3 7 17 23 0 4

Nototanaidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

Oedocerotidae Crustacean 5 3 10 12 1 16 3 32 16 0 10 22 0 14 9 1 5 3 11 13 0 15

Pagurapseudidae Crustacean 0 0 0 0 0 0 0 0 0 13 0 0 0 0 0 1 0 0 0 0 3 0

Paguridae Crustacean 0 1 0 0 8 0 1 1 2 43 1 0 0 0 1 3 1 0 1 0 6 1

Palaemonidae Crustacean 0 0 1 0 0 0 0 0 0 0 1 0 2 0 0 6 0 0 2 2 4 0

Pandalidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 2 0

Paranthuridae Crustacean 0 0 0 4 0 6 4 4 1 1 14 2 1 1 4 0 8 8 9 4 1 26

Philomedidae Crustacean 1 0 2 2 0 3 32 10 5 0 0 3 0 0 4 2 4 35 32 17 2 1

47

Photidae Crustacean 7 9 37 62 11 71 52 118 123 1 34 20 0 27 7 1 33 21 53 68 4 109

Phoxocephalidae Crustacean 38 17 26 71 26 33 24 52 114 20 47 80 36 20 31 51 30 54 60 89 19 35

Pilumnidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0

Pinnotheridae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Platyischnopidae Crustacean 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 1 0 0 0 0

Podoceridae Crustacean 0 0 0 2 5 0 0 0 1 4 0 0 0 0 0 0 0 0 0 0 0 0

Porcellanidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Portunidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0

Processidae Crustacean 1 1 0 0 0 0 1 0 2 2 0 3 4 0 2 0 0 0 0 2 6 2

Serolidae Crustacean 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Sphaeromatidae Crustacean 4 1 0 0 3 0 0 0 0 11 0 0 1 0 0 2 0 0 1 0 1 0

Stegocephalidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Stenothoidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Synopiidae Crustacean 0 0 0 0 0 1 1 0 0 0 0 2 1 1 1 0 1 5 0 0 0 1

Tanaidae Crustacean 0 0 0 0 5 0 0 0 0 3 0 0 0 0 0 0 0 0 0 0 0 0

Tethygeneidae Crustacean 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Urohaustoridae Crustacean 0 0 2 4 1 2 0 3 6 2 2 3 0 2 1 0 2 0 2 7 1 0

Whiteleggiidae Crustacean 50 11 1 3 2 22 0 1 0 2 0 37 33 4 20 2 98 8 5 0 8 3

Amphiuridae Echinoderm 0 4 2 0 3 6 0 0 0 3 1 2 1 2 0 1 3 1 1 1 1 0

Echinometridae Echinoderm 0 1 0 0 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 0

Loveniidae Echinoderm 5 9 9 6 5 15 5 11 6 14 9 7 1 1 5 6 0 0 1 0 1 0

Ophiuridae Echinoderm 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Synaptidae Echinoderm 1 2 0 0 0 1 0 1 8 0 4 5 1 0 0 0 2 4 1 2 0 4

Anabathridae Mollusc 0 0 0 1 0 1 0 0 0 0 0 0 1 0 2 0 2 1 1 1 1 0

Aplysidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Barleeidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Calyptraeidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0

Cardiidae Mollusc 1 1 2 6 0 3 11 1 4 0 1 0 0 0 2 0 5 4 1 0 2 0

Carditidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

48

Chaetodermatidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Chitonidae Mollusc 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0

Columbellidae Mollusc 4 0 0 0 5 0 0 0 0 0 0 1 0 0 0 10 0 0 0 0 3 1

Condylocardiidae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 0 0

Corbulidae – Varicorbula gibba Mollusc 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0

Cuspidariidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cyamiidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Cystiscidae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Doridae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Eatoniellidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Epitonidae Mollusc 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 0 1 0 1 0

Fasciolariidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 2

Gadilidae Mollusc 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 0 0 1 0

Galeomatidae Mollusc 0 0 0 1 3 0 2 1 1 0 0 1 0 0 6 12 0 12 3 1 3 4

Haminoeidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Hiatellidae Mollusc 0 0 1 0 1 0 0 0 0 0 0 1 0 0 0 2 0 1 0 0 5 0

Hipponicidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Limidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0

Lottidae Mollusc 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 0

Lucinidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1 0 0 0 0

Mangeliidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Marginellidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Mitridae Mollusc 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0

Montacutidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Muricidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0

Myochamidae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Mytilidae Mollusc 0 0 2 1 1 1 1 0 1 0 0 0 0 0 1 0 0 0 0 0 0 0

Nassariidae Mollusc 22 16 17 8 0 5 8 33 12 2 3 56 21 13 14 11 22 10 26 31 8 11

Naticidae Mollusc 1 0 1 0 4 0 1 1 1 0 1 0 0 1 0 1 0 0 0 0 0 2

49

Nuculanidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Nuculidae Mollusc 0 0 0 1 2 1 0 1 0 9 0 0 0 0 1 4 0 0 1 0 5 0

Olivellidae Mollusc 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 1 0 2 0 0

Ostreidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Pectinidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Philinidae Mollusc 0 0 0 0 0 0 0 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0

Phylobryidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Psammobiidae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Pteriidae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Pyramidellidae Mollusc 0 0 0 1 2 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Retusidae Mollusc 1 0 0 0 1 0 2 0 0 0 0 0 1 0 0 0 2 0 2 3 0 0

Rissoidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0

Semelidae - Theora lubrica Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Solemyidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Tellinidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0

Thraciidae Mollusc 2 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 2 1 0

Thyasiridae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Triphoridae Mollusc 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Triviidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Trochidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Turridae Mollusc 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

Turritellidae - Gazameda gunnii Mollusc 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

Turritellidae - Maoricolpus roseus Mollusc 4 1 1 7 49 0 0 0 1 94 0 9 0 0 3 43 0 0 1 4 58 0

Veneridae Mollusc 14 10 4 9 10 19 17 2 10 9 5 15 6 3 18 5 20 29 16 44 3 7

Volutidae Mollusc 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Edwardsiidae Other 7 3 1 8 12 0 4 0 0 0 0 3 10 0 3 6 4 0 0 1 0 2

Enchytraeidae Other 0 0 2 0 1 0 0 0 1 1 0 15 0 3 2 2 4 1 0 2 4 4

Nemertean Other 5 2 5 1 9 10 4 1 2 2 1 2 6 5 3 5 7 1 1 3 6 1

Phascolosomatidae Other 2 0 1 2 1 5 1 2 3 0 2 3 0 0 0 0 8 9 11 3 0 0

50

Phoronid Other 0 0 0 2 1 1 0 0 1 0 1 0 0 0 0 0 0 0 0 0 0 0

Platyhelminthes Other 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ptychoderidae Other 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0

Spadellidae Other 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Ampharetidae Polychaete 126 116 47 73 11 62 35 62 104 10 75 62 63 26 23 11 40 22 72 83 10 67

Capitella Polychaete 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0

Capitellidae - ?Barantolla sp. Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Capitellidae - Mediomastus sp. Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 0 0 1 0

Capitellidae - Notomastus sp. Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0

Cirratulidae Polychaete 0 1 2 0 0 1 0 2 0 1 0 0 5 2 1 1 2 0 1 0 2 1

Dorvilleidae Polychaete 0 0 0 1 1 0 1 1 0 5 0 0 0 1 1 2 0 0 0 0 0 0

Eunicidae Polychaete 0 0 0 0 2 0 0 0 0 1 0 0 0 0 0 2 0 0 0 0 2 0

Flabelligeridae Polychaete 0 0 0 1 0 1 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 0

Glyceridae Polychaete 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Goniadidae Polychaete 0 0 0 0 0 1 2 0 1 0 1 0 3 0 1 1 1 0 0 0 0 1

Hesionidae Polychaete 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0

Lumbrineridae Polychaete 6 4 6 0 4 8 5 2 0 1 3 7 14 13 2 4 0 3 0 1 2 5

Maldanidae Polychaete 0 3 1 0 0 0 0 0 0 0 0 2 2 0 0 0 1 1 0 0 0 0

Nephthyidae Polychaete 29 13 23 13 20 23 19 23 9 17 8 40 20 32 15 13 31 6 5 2 12 3

Nerididae Polychaete 0 0 0 0 4 0 0 0 0 0 0 0 1 0 2 0 0 0 0 0 0 0

Oenonidae Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Onuphidae Polychaete 11 7 4 1 1 7 8 14 9 0 0 2 4 3 0 0 4 7 12 8 0 0

Opheliidae Polychaete 1 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0

Orbinidae Polychaete 28 17 26 13 8 66 9 11 12 9 11 14 28 20 7 20 28 16 9 5 7 5

Oweniidae Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 2 0 0 0 0 0

Paraonidae Polychaete 1 1 0 1 2 2 1 0 0 0 0 0 2 0 2 0 0 0 0 0 0 0

Pectinariidae Polychaete 0 0 0 0 0 0 0 0 0 3 0 7 1 1 1 2 3 5 1 5 5 1

Phyllodocidae Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Poecilochaetidae Polychaete 0 0 0 0 3 0 1 0 0 0 0 2 0 0 2 3 2 0 1 0 1 0

51

Polynoidae Polychaete 1 3 1 0 4 1 0 1 1 1 0 0 0 0 0 0 0 0 0 0 3 1

Sabellidae Polychaete 17 3 6 21 2 10 1 10 93 5 10 4 3 4 3 5 4 8 10 7 2 7

Scalibregmatidae Polychaete 0 0 0 0 0 4 1 0 0 0 0 0 1 0 0 0 0 0 0 0 0 0

Serpulidae Polychaete 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

Sigalionidae Polychaete 0 1 1 4 0 0 5 3 3 1 2 2 1 0 1 3 0 1 2 0 1 4

Spionidae Polychaete 5 2 2 6 6 15 6 2 2 10 1 2 3 2 7 0 1 4 1 1 2 1

Syllidae Polychaete 1 0 0 0 2 17 3 3 1 4 0 2 0 1 0 0 5 2 2 0 1 0

Terrebellidae Polychaete 15 12 13 19 18 12 20 9 5 4 6 12 10 17 15 16 23 16 9 3 4 9

Trichobranchidae Polychaete 1 1 0 0 0 98 18 4 0 1 0 2 1 0 0 0 8 0 1 0 0 0

52

Appendix 3: Raw data for sediment chemistry (Redox potential; sulphide concentration) for sediments collected in

November 2018 and April 2019. Data for April 2018 can be found in Aquenal (2018).

Site Redox (mV) Sulphide (µM)

November 2018 April 2019 November 2018 April 2019

Uncorrected Corrected Uncorrected Corrected

1.2(1) -49 185 18 264 4.8 8.1

1.2(2) 138 372 -48 198 3.0 19.5

1.2(3) -70 164 -52 194 4.1 2.5

2.2(1) -83 151 49 295 8.2 0.8

2.2(2) -86 148 -73 173 1.5 7.0

2.2(3) 21 255 -48 198 0.4 6.1

3.2(1) -99 135 -67 179 3.0 1.6

3.2(2) -73 161 74 320 5.2 1.6

3.2(3) -86 148 -31 215 5.2 8.1

4.2(1) 58 292 -98 148 2.4 2.5

4.2(2) -89 145 -58 188 0.8 6.5

4.2(3) -36 198 -61 185 30.2 4.2

5.2(1) -71 163 -42 204 13.0 15.7

5.2(2) -98 136 -79 167 7.6 15.7

5.2(3) -94 140 10 256 47.9 10.1

6.2(1) 2 236 -81 165 1.8 1.6

6.2(2) 133 367 -77 169 2.6 3.2

6.2(3) 167 401 -11 235 0.6 5.7

7.2(1) 65 299 -67 179 17.7 19.5

7.2(2) -70 164 -108 138 13.0 14.6

7.2(3) -55 179 -80 166 4.8 19.5

8.2(1) -130 104 -58 188 3.0 2.7

8.2(2) -86 148 -77 169 2.2 4.9

8.2(3) -136 98 -83 163 4.4 43.6

9.2(1) -59 175 -17 232 0.7 4.4

9.2(2) -130 104 -42 207 1.2 4.4

9.2(3) -139 95 -30 219 5.2 2.6

10.3(1) -170 64 -64 185 9.6 14.4

10.3(2) -159 75 -36 213 7.0 3.3

10.3(3) -73 161 96 345 8.2 6.8

11.2(1) -95 139 -23 226 10.3 3.3

11.2(2) -155 79 -30 219 12.0 5.5

11.2(3) -126 108 155 404 10.3 2.2

53

Appendix 4: Images of Core Samples

Appendix 4a – Images of core samples, spring 2018

1.2 2.2

3.2 4.2

54

5.2 6.2

7.2 8.2

55

9.2 10.2

11.2

56

Appendix 4b – Images of core samples, autumn 2019

1.2 2.2

3.2 4.2

57

5.2 6.2

7.2 8.2

58

9.2 10.2

11.2

59

Appendix 5: Particle Size Analysis Raw Data

Appendix 5a Raw data – particle size analysis, spring 2018.

Sample No

Vi V4 V2 V1 V0.5 V0.25 V0.125 V0.063 Volume of water

ml ml ml ml ml ml ml ml ml

1.2 (1) 66 25 25.5 25.8 28.8 49 82 91 25

1.2 (2) 67 25 25 25.5 28.5 51.25 80.75 92 25

1.2 (3) 66 25 25 25 29 50.75 78.75 91 25

2.2 (1) 70 25 25 26 30 41 75 92.5 25

2.2 (2) 69 25 25 25.5 28 38.75 75.75 94 25

2.2 (3) 66 25.5 25.5 26 47 81.5 89 91 25

3.2 (1) 70 25.6 26 26.4 28.5 41 75.6 91.5 25

3.2 (2) 68 27.2 27.8 28 30 43.6 61.8 80 25

3.2 (3) 68 25 25.5 26 27.5 36 68 88 25

4.2 (1) 70 25 25.5 26 31.2 53 59 94 25

4.2 (2) 69 25 25 25.4 30 51.2 83.8 89 25

4.2 (3) 70 25 25.2 25.5 29 50.2 85.6 91.5 25

5.2 (1) 70 27 27.2 27.8 31 48 84.6 89 25

5.2 (2) 69 25.5 25.8 26.2 29.5 47 84 89 25

5.2 (3) 69 25.2 25.2 25.8 28.6 44 82.4 87.5 25

6.2 (1) 70 25 25 25.5 29 42.6 77 93.2 25

6.2 (2) 69 25 25.2 25.8 29 41.2 69 89.5 25

6.2 (3) 69 25.1 25.8 26 30 47 83 93.5 25

7.2 (1) 67 25.2 25.5 25.8 28.5 48.5 78 89 25

7.2 (2) 68 25 25 25.4 28.4 53.5 80.6 91 25

7.2 (3) 67 25 25.5 26 29 52.75 82.75 92 25

8.2 (1) 69 26 26 26.8 31 50 84 94 25

8.2 (2) 69 25 25.2 25.4 27 54.5 85.88 94 25

8.2 (3) 66 25 25 25.5 31 71.7 87.5 91 25

9.2 (1) 67 25 25 25.2 25.5 31.5 78 90.5 25

9.2 (2) 68 25 25 25 25.5 41 83.5 92.5 25

9.2 (3) 67 25 25.5 25.8 27 37 83.8 92 25

10.3 (1) 66 25 25.5 26.8 32.8 63 90 91 25

10.3 (2) 68 25.5 25.8 27 30.5 53.25 90.75 93 25

10.3 (3) 67 25.5 25.9 27 32 61.75 91.25 92 25

11.2 (1) 66 25 25 25.5 25.7 28.5 71 89 25

11.2 (2) 71 25 25.2 25.5 26.2 29 72 89 25

11.2 (3) 69 25 25 25.3 26 30 71.5 88 25

60

Appendix 1b Raw data – particle size analysis, autumn 2019

Sample No

Vi V4 V2 V1 V0.5 V0.25 V0.125 V0.063 Volume of water

ml ml ml ml ml ml ml ml ml

1.2 (1) 72 25 25 25.1 29.2 56.3 87.5 92.1 25

1.2 (2) 71 25 25 25 32 62.1 84.6 89.9 25

1.2 (3) 71 25 25.1 25.1 31.5 72.3 86.8 90.7 25

2.2 (1) 73 25 25 25.5 30 41.9 82.4 91.6 25

2.2 (2) 73 25.2 25.2 25.5 28.9 47.3 82 93.9 25

2.2 (3) 73 25 25 25.2 28.9 54.5 82.1 92.3 25

3.2 (1) 70 26.1 26.5 26.8 28.5 43.3 74.7 87.2 25

3.2 (2) 73 25 25 25.2 28 60.4 82.1 91.3 25

3.2 (3) 74 25.1 25.1 25.4 28.9 70 82.3 90.7 25

4.2 (1) 70 25 25.1 25.5 30.2 60.6 84.2 89.8 25

4.2 (2) 73 25 25 25.2 65.3 68 86.9 90.3 25

4.2 (3) 72 25 25.4 26.1 31.1 68.6 90.2 94.8 25

5.2 (1) 70 25 25.3 26.8 33.7 59 85.4 89.9 25

5.2 (2) 70 25.1 25.3 25.9 28.4 56.7 84.7 88.4 25

5.2 (3) 69 25.1 25.1 25.4 32.8 60 85.8 87.9 25

6.2 (1) 72 25 25.1 25.5 28.8 62.9 87.1 94.8 25

6.2 (2) 73 25 25 25.2 29.9 63.9 83.4 90.3 25

6.2 (3) 74 25 25.2 25.8 31.1 52.3 84 89.7 25

7.2 (1) 69 25.1 25.1 25.3 30.2 60.7 83.9 92.3 25

7.2 (2) 71 25.2 25.3 25.5 28 71.2 82.1 87 25

7.2 (3) 74 25 25.3 25.6 28.8 70.5 89 93.9 25

8.2 (1) 73 25 25.1 25.4 27.5 44.9 81.2 90.8 25

8.2 (2) 69 25.2 25.3 25.7 28.2 68.3 80 92.7 25

8.2 (3) 70 25.3 25.3 25.3 27.5 65.8 83.1 90.1 25

9.2 (1) 70 25.5 25.5 25.6 27.7 65.7 86.2 92.5 25

9.2 (2) 65 25 25 25.2 26.1 56.4 81 89.6 25

9.2 (3) 69 25.2 25.3 25.6 26.5 71.8 80.7 91.8 25

10.3 (1) 63 25.1 25.1 26 32.3 66.1 85.3 87.4 25

10.3 (2) 67 25 25.2 27.3 35.3 69.9 89.7 91 25

10.3 (3) 64 27.1 27.8 29.6 36 68.5 87.2 88.8 25

11.2 (1) 68 25 25.1 25.2 26.4 39 80.1 87 25

11.2 (2) 71 25 25 25.8 26.4 42.7 82.2 89.9 25

11.2 (3) 66 25 25 25.1 26.3 48.2 75 84.9 25

Benthic survey report 2018/19 , Compliance and Control ...

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