Ecosystem-based fisheries management in the Northwest Atlantic

Ecosystem-based fisheries management in the Northwest

Atlantic

Jason S Link1, Alida Bundy2, William J Overholtz1, Nancy Shackell2, John Manderson3, Daniel Duplisea4, Jon Hare5,

Mariano Koen-Alonso6 & Kevin D Friedland5

1National Marine Fisheries Sciences, Northeast Fisheries Science Center, 166 Water St., Woods Hole, MA 02543, USA;2Department of Fisheries and Oceans, Bedford Institute of Oceanography, PO Box 1006, Dartmouth, NS, Canada B2Y 4A2;3National Marine Fisheries Service, Northeast Fisheries Science Center, 74 Magruder Road, Sandy Hook, Highlands,

NJ 07732, USA; 4Department of Fisheries and Oceans, Institut Maurice-Lamontagne, Mont-Joli, QC, Canada G5H 3Z4;5National Marine Fisheries Service, Northeast Fisheries Science Center, Narragansett, RI 02882, USA; 6Department

of Fisheries and Oceans, Northwest Atlantic Fisheries Centre, 80 East White Hills Road, St. John’s, NL, Canada

A1C 5X1

Introduction 2

Living marine resource management context, history and background 3

The fisheries 3

The ecosystems 4

Implementation of ecosystem-based approaches in living marine resource management 5

Habitat closures and marine protected areas 6

Models to provide tactical and strategic management advice 6

Addressing questions on groundfish carrying capacity 8

Directly examining pairwise species interactions 9

Integrated management of Canada’s oceans and Integrated Ecosystem Assessments 11

Ecosystem status reports and indicator development and usage 11

Abstract

The northwest Atlantic has had a notable history of living marine resource (LMR)

exploitation. There have been calls for evaluating and improving approaches to manage

those resources as stocks have undergone sequential depletion, with some dramatic

instances of stock declines. The need for more holistic ecosystem-based approaches to

manage LMRs has been increasingly recognized as part of these calls, along with the

recognition that there are broader issues to consider when managing a fishery. We

discuss some of the major efforts to this end which are extant among our institutions.

We emphasize current initiatives to implement ecosystem-based fisheries management

in the northwest Atlantic, with a focus on how advice based on the natural sciences

supports an ecosystem-based approach. We present this information as a case study

within a rich historical context of fisheries science and management.

Keywords Cod, EBFM, fisheries, Georges Bank, Gulf of Maine, Gulf of St. Lawrence,

haddock, herring, invertebrates, Labrador-Newfoundland, mackerel, Mid-Atlantic

Bight, Scotian Shelf, Southern New England

Correspondence:

Jason S Link

National Marine Fish-

eries Sciences, North-

east Fisheries Science

Center, 166 Water

St., Woods Hole, MA

02543, USA

Tel.: 1-508-495-

2340

Fax: 1-508-495-2258

E-mail: jason.link@

noaa.gov

Received 11 Dec 2009

Accepted 23 Dec 2010

F I S H and F I S H E R I E S

� 2011 Blackwell Publishing Ltd DOI: 10.1111/j.1467-2979.2011.00411.x 1

Summary and looking forward 12

Acknowledgements 13

References 13

Introduction

There have been numerous prescriptions and

admonitions to implement ecosystem-based fisheries

management (EBFM; Larkin 1996; Link 2002a,b,

Garcia et al. 2003). Although there have been

relatively few instances where such an approach

has been even close to fully implemented (Pitcher

et al. 2009), the number of attempts is growing as

fisheries scientists, managers and stakeholders

grapple with the specific details of how to do EBFM.

As a discipline, and as a practice, we are now

clearly beyond the why’s and what’s of EBFM

(Murawski 2007) and squarely in the middle of the

how’s. That is, we are now well underway in the

transition towards novel, post-totally-single-species

ways of assessing and managing living marine

resources (LMR). This transition has built on

notable shifts in international policy that have

occurred over the past several decades (Rice, this

volume).

We generally note (personal observation; per-

sonal communication with a wide range of global

colleagues; Pitcher et al. 2009), and other manu-

scripts in this volume confirm, that a full imple-

mentation of EBFM is still distant, but steps to that

end are very much extant. Here, we define full

implementation of EBFM as that governance, man-

agement, science and institutional system that takes

into account all of the systemic, environmental,

inter-specific, inter-fleet, and multivariate and-or

cumulative facets beyond a typical single-species

approach, as outlined in the ‘triage’ tables of Link

(2002a). We compile such steps for the northwest

Atlantic. We do not claim that we are yet fully

implementing EBFM in the northwest Atlantic, but

we do assert that, like elsewhere, there have been

concerted efforts that collectively have moved us

towards that implementation.

We provide a unique perspective from two

countries, Canada and the United States (US), that

share contiguous marine ecosystems. We have

attempted to provide an integrated view of com-

monalities found in ecosystems from both countries

rather than a more classical approach of describing

these ecosystems and countries separately.

Although some of the national distinctions will

undoubtedly remain, we emphasize a synthetic

perspective. The seven ecosystems in the northwest

Atlantic (Fig. 1) have a unique blend of common

features, processes and species, coupled with some

major differences, as seen in the range of ecosystems

from the boreal Newfoundland-Labrador shelf sys-

tem to the subtropical Mid-Atlantic Bight.

Significant legislative and political emphasis has

been placed in both countries on ecosystem-based

management of LMRs. Applicable globally, but

specifically intended for the United States, reports

from the US Commission on Ocean Policy (2004)

and the Pew Ocean Commission (2003) noted the

need for current fisheries management to adopt an

ecosystem-based approach to management. The

updated Magnuson-Stevens Fishery Conservation

and Management Act (amended in 2008) called for

an evaluation of ecosystem science as it pertains to

the management of LMRs and their associated

fisheries, and how best to incorporate ecosystem

considerations into management. Additionally, the

2010 executive order to establish a National Ocean

Policy explicitly called for ecosystem-based manage-

ment as one of its core elements. In general, US

fisheries organizations recognize the need to do so

(Murawski 2007). Similarly, Canada became the

first country in the world to adopt comprehensive

legislation for oceans management with the imple-

mentation of Canada’s Ocean Act (1996), which

explicitly calls for an ecosystem approach in the

management of LMRs. Since then, Canada’s Depart-

ment of Fisheries and Oceans (DFO) has imple-

mented the Sustainable Fisheries Framework,1 a

policy that forms the basis for decision-making in

Canadian fisheries and incorporates the precaution-

ary and ecosystem approaches. The Framework

consists of four main components: conservation and

1http://www.dfo-mpo.gc.ca/fm-gp/peches-fisheries/fish-ren-

peche/sff-cpd/overview-cadre-eng.htm. (Last accessed 2

February 2011.)

Ecosystem-based fisheries management J S Link et al.

2 � 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S

sustainable use policies, economic policies, gover-

nance policies and principles, and planning and

monitoring tools. These all build upon, and align

with, several international shifts in policy towards

an EBM (Rice this volume). Thus, there is significant

interest, demand and development of a mandate for

ecosystem-based management of fisheries in both

countries.

There have been several, extensive background

syntheses of data and efforts supporting EBFM in

this region (Fogarty and Murawski 1998; Breeze

2002; Breeze et al. 2002; Link and Brodziak 2002;

Zwanenburg et al. 2006). Our goal is to provide a

more contemporary and synthetic presentation of

the state of EBFM implementation in the northwest

Atlantic. We do so by providing a brief history of

living marine resource exploitation in these ecosys-

tems for context and then present some major steps

towards implementation of EBFM for this region. We

note that the social, political, economic and gover-

nance aspects of EBFM are equally important, but

are not the primary emphasis of this paper. Rather,

the emphasis is on advice produced from the natural

sciences in support of EBFM. Thus, our focus is on

how the fisheries have been prosecuted, how the

effects of these fisheries have influenced the fisheries

system, and how some scientific approaches have

begun to be adopted to better address the broader

range of considerations for EBFM.

Living marine resource management context,

history and background

The fisheries

Europeans have been exploiting Northwest Atlantic

marine ecosystems for cod, whales, and other

groundfish species for several centuries (Gough

1993; Kurlansky 1997). Fishing vessels have oper-

ated over the whole continental shelf, from the Mid-

Atlantic Bight to Newfoundland. The area has

historically attracted, for example, French, Portu-

guese, English and Spanish fleets in addition to

domestic fleets. Although the nationalities partici-

pating in the fisheries have changed over time, they

were effectively unregulated until the establishment

of the International Convention for Northwest

Atlantic Fisheries (ICNAF) in 1950 and the exten-

sion of maritime jurisdiction to 200 miles in the late

1970s. Thus, until relatively recently, the fisheries

of the NW Atlantic were a shared resource inter-

nationally (and largely remain so to this day,

domestically speaking). The pattern of exploitation

can be characterized as one of sequential depletion

of fishery resources with subsequent large-scale

changes in the relative abundance of various

ecosystem components (Gough 1993; Parsons

1993; Fogarty and Murawski 1998). The ecosys-

tems today have been shaped largely by fisheries

50 °W55 °W60 °W65 °W70 °W75 °W80 °W

60 °N

55 °N

50 °N

45 °N

40 °N

35 °N

LAB

NFLDGoSL

SSGoM

GB

SNE

MAB

BoF

Figure 1 Map of the Northwest Atlantic, with the seven major ecosystems denoted, along with major features of interest.

MAB, Mid-Atlantic Bight; SNE, Southern New England; GB, Georges Bank; GoM, Gulf of Maine; BoF, Bay of Fundy; SS,

Scotian Shelf; GoSL, Gulf of St. Lawrence; NFLD, Newfoundland; LAB, Labrador.

Ecosystem-based fisheries management J S Link et al.

� 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S 3

exploitation and are very different from those first

noted in the sixteenth century (Heymans 2003;

Lotze and Milewski 2004; Rosenberg et al. 2005).

The first fisheries management measures of any

consequence were imposed by the ICNAF, whose

initial objective was to use science to maintain

maximum sustainable catch (Halliday and Pinhorn

1996). ICNAF first imposed mesh size regulations in

the trawl fishery in the 1950s and then introduced

catch controls in the 1960s. However, there was a

clear need for direct controls on fishing as distant

water fleets continued operating in the NW

Atlantic, with the resultant depletion of fish stocks.

The establishment of the ‘two-tier’ quota manage-

ment system in 1974 by the ICNAF (Pinhorn and

Halliday 1990; Parsons 1993; Parsons and Lear

1993; Murawski et al. 1997) was intended to

provide the nucleus for recovery of depleted stocks.

This approach included explicit recognition and

allowance for by-catch, discarding practices, and

inter-specific interactions (Brown et al. 1976) and

as such was a notable precursor to an ecosystem

approach. Unfortunately, it was never fully imple-

mented.

The extension of maritime jurisdiction to the

200-mile Exclusive Economic Zone (EEZ) in the late

1970s gave control of fisheries within that area to

its associated nation for stocks within the EEZ. Thus,

since then, the DFO has managed fisheries activities

in Canadian waters from north of Labrador to the

Bay of Fundy, while the U.S. National Marine

Fisheries Service (NMFS) has managed fisheries

activities in US waters from the Gulf of Maine and

Georges Bank to the Mid-Atlantic Bight (and beyond

to the south). The North Atlantic Fisheries Organi-

zation (NAFO), which replaced ICNAF in 1980, is

the international regulatory authority for waters

outside the 200 miles zone in the northwest

Atlantic (Halliday and Pinhorn 1996).

In Canada, quota-based management and lim-

ited-entry licensing have been the two main fisher-

ies management tools, although seasonal and area

closures, and gear restrictions are also used. DFO’s

policy priorities have changed over time and reflect

the context in which they were made. The priority

in the 1970s, following the extension of jurisdiction,

was to establish control over fisheries in Canadian

waters and to expand the capacity of the Atlantic

fishing industry to harvest and process the resources

within the EEZ. The focus during the 1980s was on

limiting the growth of harvesting and processing

capacity following the LMR declines during the late

1970s. Policies were also developed to regulate the

different fleet sectors and their interaction, to

promote the independence of inshore fish harvest-

ers, and to limit the concentration of ownership of

fishing licences. The widespread collapse of ground-

fish during the early 1990s led to fisheries morato-

ria, and the introduction of new policies such as

formalized co-management, individual quotas or

enterprise allocations, and the diversion of effort

into new fisheries for which new policies have been

developed2 (Parsons 1993).

In the United States, quota-based management

was maintained during the early years of extended

jurisdiction, but was replaced by more gear-specific

measures (constraints on mesh size, legal size limits

for fish, and short-term area and seasonal closures)

in 1982. More restrictive measures (including the

use of large-scale year-round closures and limits to

days-at-sea) were implemented in 1994 when the

earlier measures failed to adequately protect fishery

resources, (Murawski et al. 1997; Fogarty and

Murawski 1998). Management measures in the

US have been based on a wide array of the tools

noted above, but have typically centred on some

form of effort controls in subsequent years. Recently

a return to quota-based management has begun to

be reconsidered and implemented.

The ecosystems

The seven ecosystems of the NW Atlantic (Fig. 1)

are highly productive, which is a main reason why

they have supported substantial commercial fisher-

ies for so long (Sissenwine et al. 1984; Rosenberg

et al. 2005; Rose 2007). Although there are

regional differences, overall the response of these

ecosystems to 500 years of exploitation has been

very similar. The component fish stocks have

exhibited the classic cycles of excessive effort, stock

declines and iterations thereof until the point of

sequential stock depletion (Serchuk et al. 1994;

Murawski et al. 1997; Fogarty and Murawski 1998;

Link and Brodziak 2002; Overholtz 2002; Link

2007; Bundy et al. 2009). Fisheries have diversified

to exploit a broader range of invertebrates and non-

traditional species in response to these changes

(Link 2007; Bundy et al. 2009). Interestingly, many

of the fish populations in these ecosystems have

exhibited strikingly coherent trends (Nye et al.

2http://www.dfo-mpo.gc.ca/fm-gp/peches-fisheries/fish-ren-

peche/index-eng.htm. (Last accessed 2 February 2011).

Ecosystem-based fisheries management J S Link et al.

4 � 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S

2010), likely due to both relatively high levels of

exploitation and common oceanographic features.

Other parts of the biota in this ecosystem have also

exhibited notable dynamics. The eastern Canadian

ecosystems all experienced large increases in pinni-

ped populations, concurrently with elevated mortal-

ity on many fish stocks, leading to hypotheses that

this mortality is due, in some areas, to seal predation

(Chouinard et al. 2005; Benoit and Swain 2008;

Swain and Chouinard 2008). Grey seals, Halichoerus

grypus, have been expanding their range south-

wards, causing concern among fish harvesters in the

Gulf of Maine. The expansion of pinniped populations

is likely a response to the cessation or limitation of

exploitation on them (Templeman 1990; Bowen

et al. 2003).

It has become necessary to develop specific

measures to protect marine species at risk owing

to increased mortality from fisheries and other

causes. There have been notable changes to the

abundance of protected, endangered and threatened

species or species at risk, with many species

in more critical condition than 50 years ago

(Waring et al. 2007; SARA, http://www.dfo-mpo.

gc.ca/species-especes/home_e.asp, last accessed 2

February 2011). Canada’s Species at Risk Act

(SARA) was passed in 2002 (building upon prior

IUCN efforts; Rice this volume) to prevent wildlife

species from becoming extinct (http://www.

sararegistry.gc.ca/default_e.cfm, last accessed 2

February 2011). It requires Canada to at least try

for the recovery of species at risk, especially those at

risk due to human activity, and to manage species

of special concern, making sure they do not become

endangered or threatened. Similarly, the Endan-

gered Species Act was established in the United

States in 1973 to protect species from extinction. As

with Canada’s SARA, a plan to mitigate any threats

and extend recovery is required if a species is listed

under the ESA. The U.S. Marine Mammal Protection

Act (MMPA) of 1972 was also enacted to provide

some measure of protection for these apex species.

All marine mammal species in the United States are

monitored and managed under the MMPA to ensure

recovery if stocks are depleted.

Changes in the abundance of non-targeted fauna

such as some benthos and non-targeted fishes have

occurred (Link and Brodziak 2002; Choi et al.

2005), with some species persisting at relatively

stable levels or even increasing (Link and Brodziak

2002; Choi et al. 2005; Link 2007). This has

happened while regional physio-chemical condi-

tions changed; particularly long-term warming

(Taylor and Bascunan 2001; Friedland and Hare

2007), shifts in the North Atlantic Oscillation, NAO

(Drinkwater et al. 2003), and inter-decadal fluctu-

ations in salinity (Mountain 2004).

Thus, we assert that an EBFM is requisite if for no

other reason than to coordinate across such a

plethora of considerations to fully understand the

myriad of trade-offs among this vast array of biota,

processes and fisheries.

Implementation of ecosystem-based

approaches in living marine resource

management

The discussion of the implementation of EBFM in

the United States and Canada starts with how

single-species management approaches have been

adapted for this purpose and then considers multi-

species methods. Integrated ecosystem-level frame-

works that may define the future of EBFM are

subsequently considered.

Neither the United States nor Canada has a fully

implemented EBFM programme. Nevertheless, ef-

forts are well underway which represent important

steps to that end. They encompass a wide range of

activities, from the development of ecosystem indi-

cators to systemic-level and objective-based

approaches, to specific applications of ecosystem

models, to helping in the development of EBFM

policy. We note that some efforts have been given

more attention in one country or the other (e.g.

more focus on groundfish–seal interactions in Can-

ada, more focus on multispecies modelling in the

United States), but we have attempted to at least

note how each country is addressing each of these

major topics.

National legislation is key to establishing ecosys-

tem approaches. Such legislation is extant in

Canada by means of Canada’s Oceans Act (Oceans

Act 1996), the Sustainable Fisheries Framework,

and is continuing to be solidified in the United States

(Magnuson-Stevens Reauthorization Act, 2008;

Murawski 2007). Internationally, Canada played a

leading role in the 2006 United Nations General

Assembly Resolution 61/105 (UNGA 2006) on

Sustainable Fisheries which calls upon Regional

Fisheries Management Organizations to identify

vulnerable marine ecosystems in the high seas.

Work to provide the scientific underpinnings for

these efforts continues as these types of enabling

legislation continue to develop, with management

Ecosystem-based fisheries management J S Link et al.

� 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S 5

institutions becoming increasingly more versed in

ecosystem approaches.

A key element for implementation of EBFM will be

the framework (e.g. Integrated Ecosystem Assess-

ments (IEAs); sensu Levin et al. 2009) by which

ecosystem-based management advice is provided,

evaluated and acted upon. The following examples

represent both work within existing frameworks

and proposals for modifying or altering others to

develop novel frameworks within which such eco-

system-based management advice can be provided.

Habitat closures and marine protected areas

There have been both area closures and copious

research on fish habitat in both countries. In the

United States, characterizing Essential Fish Habitat

(EFH) was mandated by the Magnuson-Stevens

Reauthorization Act of 1996. EFH has been char-

acterized generally for all managed, fishery-targeted

species in northeast US waters, with technical

memoranda for over 35 species, some of which

have been updated in more recent years (see Reid

et al. 1999 for a description of the full series). Based

largely upon the distributions of these stocks from

surveys, the collective ‘essential’ habitat for all

species has been noted as being quite vast, but we

now have a better understanding of the dimensions

of these species habitats and the interaction of

habitats among species.

United States and Canada have both used area

closures as a fisheries management tool, which have

also served as ad hoc large-scale experiments (see

summaries in Fisher and Frank 2002; Frank et al.

2004; Link et al. 2005; Murawski et al. 2005).

Marine protected areas (MPAs) are a spatial means

to conserve and protect the structure and function

of marine ecosystems, with various levels of utility

in a living marine resource management context.

Generally speaking, both the local and international

literature suggests that the success, efficacy or

effectiveness of temperate area closures depends

upon the substrate type that is being closed to

bottom-tending fishing activities and the mobility of

organisms of interest. Thus, for some fish no

difference is readily discernable inside vs. immedi-

ately outside of an area closure (Link et al. 2005).

Similarly, there is minimal difference inside vs.

outside an area for some habitats that are effectively

sand barrens with very fast overlying currents.

However, the differences in abundance and biomass

inside vs. outside are quite striking for species that

are sessile (e.g. sea scallops). Moreover, cobble and

boulder habitats tend to show notable differences in

a wide range of metrics inside vs. outside of area

closures.

Plans are underway in Canada for a network of

MPAs to increase the ecological effectiveness and

connectivity between individual MPAs. There are

currently five MPAs in the Canadian NW Atlantic,

only one of which, the Gully (a deep channel on the

edge of the Scotian Shelf), is offshore. The MPA

project is jointly implemented by Fisheries and

Oceans Canada, Parks Canada and Environment

Canada (http://www.dfo-mpo.gc.ca/oceans-habitat/

oceans/mpa-zpm/fedmpa-zpmfed/index_e.asp, last

accessed 2 February 2011), and one of its objectives

is to link Canada’s MPA networks with those in the

United States. Understanding and linking among

MPAs is going to be a critical issue if species’ ranges

shift with climate change such that some species

may move out of areas established for their protec-

tion (Burns et al. 2003; Cheung et al. 2009). There

are a range of spatial fisheries closures in addition to

no-take MPAs, including Coral Conservation Areas

and closure of nursery areas to fishing (such as the

‘haddock box’ on the Scotian Shelf). As a member of

NAFO, and in response to UNGA resolution 61/105

and FAO Guidelines for high seas fisheries (FAO

2008), Canada has made it a priority to identify

vulnerable marine ecosystems within the NAFO

Regulatory Area,3 and to close and protect vulner-

able areas such as seamounts and coral areas.

It is likely that habitat considerations, area

closures and more broadly ocean zoning or marine

spatial planning will remain important manage-

ment options. However, we assert that these are one

of many management tools and in and of them-

selves do not singularly constitute EBFM. Neverthe-

less, they certainly can contribute to it, and their

scale is also an important determinant of their

success. However, for most mobile, and especially

pelagic fishes, area closures may be less efficacious

than for their tropical, coral reef counterparts.

Models to provide tactical and strategic

management advice

Management advice in Canada and the United

States is often founded upon outputs from models

that assess the status of living marine resources and

3http://www.dfo-mpo.gc.ca/international/media/bk_2009

0720-03-eng.htm. (Last accessed 2 February 2011).

Ecosystem-based fisheries management J S Link et al.

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their associated mortalities. A suite of ‘minimum

realistic’ models (MRMs) have been developed that

include a series of extended stock assessment models

(ESAM) and multispecies models to explore the

relative magnitude of predation mortality compared

to fishing mortality. Such models are relatively

simple conceptually and operationally as they:

(i) use existing data; (ii) are implemented within

a familiar assessment and management context;

(iii) provide familiar (albeit modified) model outputs

that can be used to calculate biological reference

points (BRPs); (iv) improve the biological realism of

assessment models; and (v) help to inform and

improve stock assessments for species that may pose

modelling challenges. MRMs include age- or stage-

structured, bulk biomass or production models.

These MRMs have ranged from providing context

to stock biomass, tuning indices, or sources of other

mortality, to explicit estimates of additional (i.e.

predation or M2) mortality. In the northwest

Atlantic, MRMs have been developed predominately

for forage stocks, including Atlantic herring (Clupea

harengus), Atlantic mackerel (Scomber scombrus),

longfin squid (Loligo pealei), butterfish (Peprilus

triacanthus), and Northern shrimp (Pandalus borealis)

(NEFSC 2007a,b; Overholtz and Link 2007; Link

and Sosebee 2008; Overholtz et al. 2008a; Tyrrell

et al. 2008; Gamble and Link 2009; Link and Idoine

2009; Moustahfid et al. 2009a,b). These approaches

have the potential to be controversial because they

produce more conservative BRPs and explicitly

address the potential for competition between pre-

dators and fleets that target these stocks. However,

these approaches lack the capability to fully address

all of the trade-offs among species and stakeholders.

Another set of ESAMs, ‘ecological footprint’

models, use some of the same information as the

models used to estimate predation mortality to

calculate the amount of food eaten by a stock. The

estimates of energetic requirements (i.e. consump-

tive demands) at a given abundance level are then

compared to estimates of the amount of food known

to be available in the ecosystem from surveys and

mass-balance system models. In many ways, this is

the same calculation as those referred to above for

predatory removals, with the difference being that

instead of summing across all predators of a stock,

here we sum across all prey for a specific stock.

Estimates of consumptive demands have been cal-

culated for a wide range of groundfish, elasmo-

branch, and pelagic fish species, mostly in the US

ecosystems (NEFSC 2007b; Link and Sosebee 2008).

A third type of ESAM involves incorporating

environmental variables into population models.

Although not yet fully operational, these models

allow for changes in carrying capacity, growth

rates, stock–recruitment relationships, or stock

distribution, to be related to environmental condi-

tions (Keyl and Wolff 2008). Brander and Mohn

(2004) incorporated the NAO into stock recruit-

ment models for 13 cod (Gadus morhua) stocks in the

North Atlantic, recommending that medium and

long-term stock assessments should consider likely

future states of the NAO in areas where the NAO

had a strong effect. With environmental terms in

population models, it becomes possible to forecast

the response of a population to climate change,

thereby providing a long-term forecast that can

inform EBFM (Hare et al. 2010). This has been done

or is being done for a wide range of fish and

invertebrate species in the NW Atlantic (Hare,

personal observation) and continues to be an active

area of research.

One multispecies model, MSVPA-X, has been

applied to two-subsystems in the NW Atlantic and is

being developed for a third (Garrison and Link

2004; NEFSC 2006; Tyrrell et al. 2008; Garrison

et al. 2010). An MSVPA-X for the mid-Atlantic

region emphasizes menhaden (Brevoortia tyrannus)

as prey with three main predators and has been

peer-reviewed extensively (NEFSC 2006). Outputs

from that model have informed the single-species

assessments, particularly by providing time-series of

predation mortalities for the assessment of menha-

den. A second MSVPA-X is for the Southern New

England-Georges Bank-Gulf of Maine ecosystem

(Tyrrell et al. 2008), includes 19 species and

emphasizes herring (Clupea harengus) and mackerel

(Scomber scombrus) as the major prey. An alternate

MSVPA model is currently being developed for the

south-western Scotian Shelf/Bay of Fundy area,

with a focus on herring as prey.

It is easy to see the value of MRMs as tools to

assist in the application of EBFM. Yet somewhat

surprisingly, the information from MRMs has only

rarely been utilized in a fisheries management

context specifically directed to stock assessments,

despite the large amount of effort applied (NEFSC

2006, NEFSC 2007a, 2007b). Essentially the infor-

mation is there, the underlying mechanisms are

mostly understood, and the data are mostly no less

certain than other data used in the assessment and

management process. Certainly, there are aspects of

estimation and precision uncertainty that can

Ecosystem-based fisheries management J S Link et al.

� 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S 7

increase by including additional data on predator–

prey interactions, but these are largely outweighed

by the decreases in process, magnitude and accu-

racy uncertainty that are associated with including

this extra information. We suspect that a lack

of familiarity and ‘comfort’ with these novel

approaches has mainly precluded their inclusion

in the stock assessment process. We also suspect

that, particularly for models that include environ-

mental factors, the challenge of predicting future

states has limited their use. However, the skill of

environmental models is improving, and the ability

to couple climate, environmental and population

models is developing rapidly (Hollowed et al. 2009;

Hare et al. 2010). That said, we are encouraged that

such ‘ancillary’ information has been evaluated in

the stock assessment process to provide ‘contextual’

assessments that are reviewed along with the

primary assessment. Certainly, more research is

still required, but what is encouraging is that much

of this work is now at the stage of focusing on

sensitivity analyses or model diagnostics, having

already accomplished proof of concept and under-

standing of basic, underlying mechanisms.

A range of ecosystem models beyond the MRMs

are used in the NW Atlantic, from minimalist

models, such as the MSVPA described briefly above

to the Ecopath with Ecosim modelling tool (EwE), to

Atlantis (Fulton et al. 2004, in press). EwE has been

used widely to quantitatively describe aquatic sys-

tems and to explore the ecosystem impacts of fishing

(Christensen and Pauly 1992; Christensen and

Walters 2004; Coll et al. 2009). It is composed of

a mass-balance model Ecopath (Polovina 1984;

Pauly et al. 2000; Christensen and Walters 2004;

Christensen et al. 2005), from which temporal

(Ecosim) and spatial (Ecospace) dynamic simula-

tions can be developed (Walters et al. 1997). Eco-

path mass-balance models have been developed for

the Newfoundland-Labrador Shelf (Bundy et al.

2000; Heymans 2003), for the northern and

southern Gulf of St. Lawrence (Morissette et al.

2009), the eastern Scotian Shelf (Bundy 2004,

2005a) and for the Gulf of Maine, Georges Bank,

Southern New England and Mid-Atlantic Bight

ecosystems (Link et al. 2006, 2008a,b). Mass-bal-

ance EcoNetwrk models (Link et al. 2006, 2008a,b)

have also been constructed for the latter, US

ecosystems. Ecosim models have been developed

for the Newfoundland-Labrador Shelf (Bundy

2001), and for the eastern Scotian Shelf (Bundy

2005b). These models were all developed under

specific projects in Canada (CDEENA, The Compar-

ative Dynamics of Exploited Ecosystems in the

Northwest Atlantic) and the United States (EMAX,

The Energy Modeling and Analysis eXercise). Fur-

ther models are being developed for the western

Scotian Shelf and the Bay of Fundy under DFO’s

Ecosystem Research Initiative.

A dynamic simulation model of the Gulf of Maine

(GOM) ecosystem has also been constructed, with

the system partitioned into 16 aggregated biomass

nodes spanning the entire trophic scale from

primary production to seabirds and marine mam-

mals (Overholtz and Link 2009). Parameters from

the EMAX Ecopath model of the GOM system were

used to construct the simulation model using

recipient-controlled equations to model the flow of

biomass and the biomass update equation used in

Ecosim to model the annual biomass transition. The

model has been used to evaluate how the GOM

ecosystem responds to large and small-scale

changes to the trophic components and system

drivers, specifically events such as climate change,

various fishing scenarios, and system response to

changes in the biomass of lower and upper trophic

levels.

These models have been used to further our

understanding of ecosystem structure and function-

ing, as central pieces of broader comparative studies

(spatial and temporal), to develop ecosystem indi-

cators, and in various perturbation virtual experi-

ments. The use of these models is an active area of

research. Some results have been used as contextual

information in an LMR management context [such

as for the groundfish carrying capacity issue

described below (NEFSC 2008), and directly exam-

ining pairwise species interactions; see below].

Addressing questions on groundfish carrying

capacity

A fisheries management question that should have

conclusively been addressed in the past is whether it

is possible to optimize yield simultaneously for all

stocks. This issue has repeatedly brought ecosystem

considerations to the fore in the NW Atlantic

region. In other words, in an ecosystem context,

one key question is, ‘can we manage all species that

we have at their single-species BMSY levels at the

same time?’ This question is driven by recent events

in the U.S. Northeast Shelf LME: recent fisheries

management decisions (1994–2005) for fish stocks

have resulted in some resurgence of depleted fish

Ecosystem-based fisheries management J S Link et al.

8 � 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S

populations (NEFSC 2008). This raised a topic of

some concern among stakeholders as to whether

the ecosystem can support these optimal levels of

biomass at (e.g. BMSY) simultaneously for all the

groundfish stocks, and more broadly, the entire fish

community in the region. This question was

explored in a recent US groundfish assessment

review meeting (GARM III; Fogarty et al. 2008;

Link et al. 2008c,d, NEFSC 2008, Overholtz et al.

2008b,c) under the following two terms of refer-

ence: (i) determine the production potential of the

fishery based on food chain processes and estimate

the aggregate yield from the ecosystem; and

(ii) comment on aggregate single stock yield

projections in relation to overall ecosystem produc-

tion, identifying potential inconsistencies between

the two approaches. Beyond the actual answer,

simply asking the question in that forum was a

major step towards EBFM.

The total system biomass and the total biomass

under fishery management targets were computed

for the U.S. Northeast LME and compared to similar

estimates from other systems worldwide. Methods

and analyses used data from either stock assess-

ments or biomass-based approaches (NEFSC 2007c,

2008). Information on the BRPs for groundfish,

other demersal species, and small pelagic compo-

nents of the U.S. Northeast LME were summarized

and compared to historical studies, recent energy

budgets for the region (i.e. EMAX as noted above)

and to similar estimates from comparable worldwide

temperate, marine systems. BRPs were also esti-

mated for important groups of groundfish, pelagic

and elasmobranch stocks on the U.S. Northeast

Shelf LME using a surplus production model, ASPIC

(Prager 1994). The technical basis for estimating

BRPs for groups of species has been well established,

both classically (Garrod 1973; Pope 1975; Fukuda

1976; May 1976) and in more recent modelling

and empirical studies (Mayo et al. 1992; Pauly and

Christensen 1995; Pauly et al. 1998, 2002).

A wide range of modelling approaches were

applied to address the GARM III terms of reference.

Results from EMAX models (Ecopath and EcoN-

etwrk; Link et al. 2006, 2008a,b) were used to

provide scaling of magnitude relative to similar

studies from other marine ecosystems. GARM III

results for pelagic and demersal biomass were

compared to those for nine temperate and boreal

systems, including Canadian, European and west

coast US systems (NEFSC 2008; Table 1). Addition-

ally, MS-PROD (Link 2003; Gamble and Link 2009)

and an aggregated version thereof (Gamble and

Link 2009) were used to contextualize multispecies

yields. A trophic transfer model was used to

estimate production capacity of the system to bound

feasible limits (Fogarty et al. 2008). Finally, the

production model ASPIC, as parameterized for the

aggregate fish community, was used to estimate

MSY and associated reference points for the entire

groundfish and full fish community (NEFSC 2008;

Overholtz et al. 2008c).

Overall, these and other aggregate production

model results (NEFSC 2008) suggest that the

estimated MSY level for all GARM species is lower

than the sum of individual species MSY estimates,

and overall fishing mortality should be lower.

Therefore, all species are unlikely to simultaneously

be at BMSY if interactions among species are

important, a conclusion supported by several lines

of evidence and multiple approaches. How to best

incorporate this into future stock assessments and

related contexts is an active area of research and

contemplation.

Directly examining pairwise species interactions

Ecosystem considerations have commonly been

invoked in the Canadian and US northwest Atlantic

with regard to trade-offs among species, particularly

owing to suspicions of predatory mortality. Thus,

we have increasingly needed to address various

pairwise species interactions. Examples that effec-

tively pit one species vs. another through predation

or competition are common, despite the highly

Table 1 Comparison of NE US demersal and pelagic fish

biomass (B) densities relative to other marine

ecosystems (adapted from Overholtz et al. 2008b).

System Demersal

B (t km)2)

Pelagic

B (t km)2)

Total

B (t km)2)

Gulf of Alaska 26.48 14.83 41.31

Bering Sea 44.85 7.44 52.30

Barents Sea 4.31 9.32 13.64

North Sea 8.87 10.15 19.02

Baltic Sea 2.13 19.07 21.20

Faroes 10.61 27.91 38.51

Newfoundland-Labrador 10.99 21.82 32.81

Gulf of St. Lawrence 21.78 24.08 45.86

Scotian Shelf 6.85 23.29 30.24

Average 15.21 17.56 32.76

Northeast Shelf LME Target 14.62 8.40 24.48

Northeast Shelf LME Current 13.12 16.80 28.64

Ecosystem-based fisheries management J S Link et al.

� 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S 9

complex nature of this food web (Link 2002c). For

instance, there have been calls to cull spiny dogfish

(Squalus acanthias) because of the perception that it

is a ‘voracious’ predator of commercially and

culturally important gadids (Link et al. 2002a).

These calls continue despite the observation that

spiny dogfish largely eat ctenophores and small

pelagic fishes, rarely consuming (on the order of

10 out of 60 000 stomachs) commercially impor-

tant groundfish species such as cod or haddock

(Melanogrammus aeglefinus). Another example has

been the perception of copious cod (Hanson and

Lanteigne 2000) or white hake (Urophycis tenuis)

predation (Davis et al. 2004) on lobster (Homarus

americaus): suspected species interactions that have

not been supported by data. We generally tend to

discourage such pairwise evaluations and rather

explore them at the very least in an ESAM or

multispecies modelling context.

One pairwise species interaction that has received

great focus over the last two decades in the three

Canadian NW Atlantic ecosystems is the interaction

between pinnipeds and fish. There have been large

increases in the populations of three species of

pinnipeds over the last few decades in these ecosys-

tems, with concerns over their concomitant impacts

on fisheries: grey seals on the eastern Scotian Shelf,

grey seals, harp seals (Phoca groenlandica) and

hooded seals (Cystophora cristata) in the Gulf of

St. Lawrence, and harp seals and hooded seals in

Newfoundland-Labrador. These three areas have

experienced stock collapses of some groundfish

species and severe reductions in others. Natural

mortality (M) has doubled since prior to the collapse

and did not drop when fishery harvests were

reduced to levels that should have allowed rapid

increase had M been at levels documented in the

1970s and 1980s. Great concern has been raised by

the fishing industry concerning the increased seal

populations and their impacts on the fishery. Debate

has been waged in the literature concerning the

cause of the collapse of cod stocks and the role of

fishing (e.g. Hutchings and Myers 1994, 1995;

Myers et al. 1996; Bundy 2001), seals (Bundy

2001; Fu et al. 2001; Trzcinski et al. 2007, Chassot

et al. 2009), and the environment (deYoung and

Rose 1993). The evidence tends to suggest that seals

were not the primary cause of groundfish declines,

but have been identified as a potential impediment

to cod recovery (Bundy 2001, 2005a; Fu et al.

2001; Swain and Chouinard 2008; Chassot et al.

2009).

From a fisheries point of view, the concern is over

why Atlantic cod stocks are not recovering. All

Canadian areas imposed groundfish moratoria in

the early 1990s, but only the eastern Scotian Shelf

groundfish moratorium has consistently remained

in place (Bundy et al. 2009). The clear correlation

between the population trends of pinnipeds and the

knowledge that groundfish comprise a portion of

their diet has led to speculation that seals are one of

the reasons for lack of recovery of fish stocks. This

pairwise interaction has been addressed using a

range of modelling approaches, including ESAMs,

but also by embedding the two species in a wider

ecosystem context using multispecies and ecosystem

modelling tools. Simulations for the Newfoundland-

Labrador shelf based on an Ecosim model suggested

that seals were a plausible factor hindering cod

recovery (Bundy 2001). However, an ongoing

exploration using a single-species model for cod

which allows simultaneous bottom–up (capelin

availability) and top–down (fisheries and predation

by seals) forcing suggests that fisheries and capelin

availability are the most likely drivers of northern

(NAFO areas 2J3KL) cod dynamics (Buren et al.

2009). A third model uses a bioeneregetic–allomet-

ric modelling approach (Yodzis and Innes 1992;

Koen-Alonso and Yodzis 2005) to explore the

dynamics of core species of the Eastern Scotian

shelf marine community, including cod and seals

(Koen-Alonso et al. 2008).

There is some evidence from MRM modelling that

harp seal predation is slowing the recovery rate of the

northern Gulf of St. Lawrence (nGSL) cod through

consumption (Chassot et al. 2009). Harp seals tend

to target the smaller sizes of cod which have not yet

recruited to the fishery. One can therefore imagine

that reductions in seal predation would likely lead to

increased populations over the long run by allowing

more of the population to reach spawning size.

However, this MRM excludes most of the other

ecosystem, indirect effects and non-linear interac-

tions.

Grey seals, not harp seals, are the predominant

seals species in the southern GSL. The recent growth

of the population has led to increased consumption

of fish by seals, but it is unclear how this source of

mortality compares with other sources. An accu-

mulating body of evidence over the past decade

suggests that this is an important source of mortal-

ity on all southern GSL groundfish, and in particular

cod (Chouinard et al. 2005; Benoit and Swain

2008; Bowen et al. 2008; Swain and Chouinard

Ecosystem-based fisheries management J S Link et al.

10 � 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S

2008). As one can imagine, collectively the evi-

dence has remained uncertain, and this particular

species pairing, cod-seals, remains an important

topic of research.

Integrated management of Canada’s oceans and

Integrated Ecosystem Assessments

In 1997, Canada became the first country to adopt

comprehensive legislation for oceans management.

Canada’s Oceans Act (Oceans Act 1996) paved the

way for the development of a national oceans strategy

to guide the management of Canada’s aquatic eco-

systems and provide the overall strategic framework

for Canada’s oceans-related programmes and poli-

cies. The central governance mechanism of Canada’s

Oceans Strategy4 is applied via the development and

implementation of Integrated Management (IM)

plans. IM plans include ecosystem-based manage-

ment, sustainable development, the precautionary

approach, conservation, shared responsibility, flexi-

bility and inclusiveness. They directly involve stake-

holders in the planning process, which is intended to

be flexible and transparent. The three objectives of IM

are: (i) to understand and protect the marine envi-

ronment; (ii) to support the sustainable economic

opportunities; and (iii) to support effective oceans

governance. DFO has the overall mandate for inte-

grated ocean management and the responsibilities for

science, fish and fish habitat management. DFO has

identified five large ocean management areas

(LOMAs) with associated pilot integrated manage-

ment initiatives. Three of these are situated in the

Northwest Atlantic. The eastern Scotian Shelf Inte-

grated Management initiative (ESSIM, Rutherford

et al. 2005; http://www.mar.dfo-mpo.gc.ca/oceans/

e/essim/essim-intro-e.html, last accessed 2 February

2011) was the first plan to be announced in 1998.

The Gulf of St. Lawrence Integrated Management

initiative (GoSLIM) and Placentia Bay/Grand Banks

Integrated Management initiative were subsequently

announced.

Many of these IM plans are still being developed,

but the ESSIM strategic-level plan is published and

contains a comprehensive set of goals, objectives

and strategies for collaborative governance and

integrated management, sustainable human use,

and healthy ecosystems (DFO 2007a). It has been

shaped and accepted by ocean stakeholders, sup-

ported and endorsed by government, and is Can-

ada’s first integrated ocean management plan under

the Oceans Act. It uses an objective-based manage-

ment approach and has three overarching objec-

tives: collaborative governance and integrated

management, sustainable human use and healthy

ecosystems (DFO 2007a).

Several initiatives have contributed to the scien-

tific development of IM and to ecosystem-based

management. Ecosystem overview and assessment

reports were produced, summarizing and synthesiz-

ing existing knowledge about the ecosystem as part

of the National IM planning process in each LOMA

(e.g. DFO 2003; Zwanenburg et al. 2006). In

parallel, a set of criteria were developed and used

to identify ecologically and biologically significant

areas (EBSAs; DFO 2004), degraded areas, ecolog-

ically and biologically significant species and

depleted species (DFO 2007b). These are used to

help define ecosystem objectives, indicators and to

contribute to spatial management.

Integrated Ecosystem Assessments are planned

for US ecosystems. IEAs seek to assess the status of

an ecosystem, cognizant of the major drivers or

pressures influencing that system, and its status

relative to pre-established thresholds (Levin et al.

2009). Ecosystem modelling, ecological indicators

and adaptive management simulations [aka man-

agement strategy evaluation (MSE)] are all integral

parts of an IEA. The status reports noted below, as

well as some of the modelling noted in previous

sections, will all contribute to these assessments. As

in Canada, IEAs are meant to be inclusive of the

wide range of factors and processes that influence

large marine ecosystems, but how focused on

fisheries these IEAs will be, compared to a broader

inclusion of other ocean-use sectors, is still being

explored.

Ecosystem status reports and indicator development

and usage

Integrated Management and IEAs include the use of

ecosystem indicators to assess drivers, pressures,

states, impacts and responses of ecosystems; such

indicators are already being widely used to support

ecosystem management (Cury and Christensen

2005; Levin et al. 2009). There are a growing

number of guidelines on how to select (Fulton et al.

2005; Rice and Rochet 2005; Rochet and Rice

2005; Methratta and Link 2006) and use (Rice

2003; Link 2005) indicators. Various frameworks

4http://www.dfo-mpo.gc.ca/oceans/publications/cos-soc/

pdf/cos-soc-eng.pdf. (Last accessed 2 February 2011).

Ecosystem-based fisheries management J S Link et al.

� 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S 11

and formats have been applied, including a traffic

light approach (Halliday et al. 2001), multivariate

analyses (Link et al. 2002b, 2010; Coll et al. 2010)

and decision trees (Rochet et al. 2005; Bundy et al.

2010). Link et al. (2002b) assessed the status of the

northeast US continental shelf ecosystem using a

suite of biotic, abiotic and human indicators and

tracked how the system had changed over time.

That work, and subsequent follow-ups (Link 2005;

Methratta and Link 2006; EcoAP 2009), have

identified those key metrics that should be moni-

tored over time as leading indicators of ecosystem

change. A multivariate assessment of the state of

the eastern Scotian Shelf Ecosystem was conducted

using a series of oceanographic and ecosystem

indicators (DFO 2003; Choi et al. 2005). This type

of information provides broad contextual advice for

management, such as a shift in size and species

distribution of finfish, a shift in oceanographic

conditions, and a shift from a demersal to a pelagic

system.

From this preliminary work, a series of indicators

are being routinely monitored to detect potential

changes from a more community or systemic basis

(e.g. DFO 2003; Link 2005; EcoAP 2009) and

to provide ecosystem advice (http://www.nefsc.

noaa.gov/omes/OMES/, last accessed 2 February

2011) beyond the single stock level (indicators of

which are also routinely monitored and assessed;

http://www.nefsc.noaa.gov/sos/, last accessed 2

February 2011). A joint Canada–U.S. Ecosystem

Overview Report (EOR) is also under development

that describes major features and drivers of ecosys-

tem dynamics that are germane to both countries.

Summary and looking forward

The NW Atlantic Shelf is one of the most studied

portions of the world’s oceans, and yet we still have

many questions concerning its functioning. The

question remains: do we know enough about how

these marine ecosystems function to practise eco-

system-based fisheries management? Let us sequen-

tially explore that question.

First, we concur with Hunt and McKinnell

(2006) that there are multiple processes acting

simultaneously in an ecosystem. The challenge is to

determine the relative importance of those processes

as they influence the dynamics of the system, and

track their associated dynamics over time and

space. We recognize that it is prudent to avoid

posing one hypothesis over another without

accounting for the possibility of a hybrid among

them (i.e. multiple, concurrent component pro-

cesses). Certainly, further ecosystem modelling,

studies and field work to explore these process-

related questions will shed more light on these and

other, related questions. We do not claim to have an

exhaustive and perfect knowledge of all the pro-

cesses in these and related marine ecosystems.

However, from the experience and knowledge

gleaned from the NW Atlantic, we assert that we

do know enough to make a few definitive, general

statements to facilitate EBFM.

Second, we expect that we will elucidate novel

processes and explore unknown factors, but will

also confirm key findings and principles as we

continue to research the ecosystems of the North-

west Atlantic. For example, over-exploitation gen-

erally leads to depleted fish stocks; changes in

primary production can be driven by large-scale

oceanic phenomena; species that migrate from one

area to another have impacts in both areas; and the

interplay between predators and prey remains

dynamic and challenging given the complexities of

marine food webs. The point is that there are a wide

range of patterns, processes and principles that have

either originated or been affirmed from studies in

these ecosystems, and we aim for that to continue.

Third, we hope to elucidate those aspects of the

ecosystems that are understudied or under-deter-

mined. That includes species such as those associ-

ated with the microbial loop, krill, most benthos (on

a synoptic, broad-scale, real-time fashion), mesopel-

agics and gelatinous zooplankton. Clearly, further

work to understand and monitor those species will

be invaluable for further insights into ecosystem

functioning. Further, the vital rates of many species

are known at only a cursory level, but a better

resolution of such rates will lead to enhanced

parameterization and development of the ecosystem

models. In addition, further exploring some of the

socio-economic elements of EBFM, particularly

related to dealing with trade-offs, also merits further

attention.

There are also plans to apply MSE to the fisheries

in some of these ecosystems [e.g. Greenland halibut

in Newfoundland (Miller et al. 2008)]. MSE (Smith

et al. 1999; Sainsbury et al. 2000) takes what we

know now, places that information in an adaptive

framework, simulates a range of management

options or ‘scenarios’ for a wide range of operating

models, and then reports the outcomes of these

‘virtual’ experiments. The goal of doing this is to

Ecosystem-based fisheries management J S Link et al.

12 � 2011 Blackwell Publishing Ltd, F I S H and F I S H E R I E S

identify management options that are robust to

uncertainty and will meet as many of the legislative

mandates as possible while affording managers the

flexibility to adapt to changing conditions. In the

United States, several preliminary discussions have

occurred with the regional fisheries management

councils (in both the Mid-Atlantic and New

England) and their supporting Scientific and Statis-

tical Committees (SSC). The Councils’ SSCs have a

keen interest in ecosystem approaches as doing so

affords the opportunity for enhanced coordination

across all managed species, as well as holding the

prospect for actually simplifying the entire (ecosys-

tem, multispecies and stock) assessment and allo-

cation process, particularly if a more aggregated

production approach is considered. Similarly, in

Canada, the Fisheries Resource Conservation Coun-

cil, which advises the Fisheries Minister on research

and assessment priorities, advocates an ecosystem

approach to fisheries management.

Finally, we assert that one does not need perfect

knowledge of every process to manage living marine

resources from an ecosystem perspective. We noted

the contrast of the top–down and bottom–up

considerations (Hunt and McKinnell 2006) to

demonstrate that even though those processes can

be interpreted in different ways, there is acknowl-

edgement that they are both important and need to

be evaluated. And in that evaluation, a useful

context for understanding fisheries has emerged.

We have also demonstrated in this paper that

although we have not fully implemented EBFM, we

have taken steps to that end. We reiterate that the

knowledge base to do so exists in Canada and the

United States and that doing EBFM is feasible, now,

with information, tools and approaches that are

available and tractable. A recent evaluation of

progress in implementing ecosystem-based manage-

ment of fisheries in 33 countries placed United

States and Canada in the top ranks across a number

of different criteria (Pitcher et al. 2009), indicating

that both countries are doing relatively well in

implementing EBFM. However, as we continue to

move towards ecosystem approaches to fisheries

management in the NW Atlantic, several challenges

remain and we very much recognize them. These

include the following novelty of the concepts and

information, requiring a need for all involved in the

process to develop familiarity with this approach;

the lack of fully reviewed ecosystem model outputs

or familiarity with them; the lack of the full suite of

information that is often demanded; the need to

establish venues to evaluate and choose among

trade-offs; addressing additional sources of uncer-

tainty when considering other processes outside of

classical fisheries assessment data; the need to more

clearly state goals and objectives, as well as fora for

those to be discussed; the need to better elucidate

relationships among drivers and responses; how to

use strategic advice; and many others like them. Yet

we also assert that we are poised to more fully

implement EBFM in this part of the World’s Ocean,

building upon the knowledge base we do have and

the examples of implementation to date.

Acknowledgements

We thank Tim Essington and Andre Punt who

invited us to contribute to this special volume. We

also thank Jake Rice and Beth Fulton for their very

helpful reviews of this manuscript. We also thank

the various institutes (NMFS and DFO) at which we

work for maintaining and collecting some of the

world’s most excellent fisheries data sets, many of

which have formed the basis for the endeavours

described herein.

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