ICES Journal of
Marine Science ICES Journal of Marine Science (2014), 71(2), 183– 194. doi:10.1093/icesjms/fst119
Implementing a science-based system for preventing overfishing and guiding sustainable fisheries in the United States R. D. Methot, Jr1*, G. R. Tromble2, D. M. Lambert 2, and K. E. Greene2 1
NOAA, National Marine Fisheries Service, 2725 Montlake Blvd East, Seattle, WA 98112, USA NOAA, National Marine Fisheries Service, 1315 East-West Highway, Silver Spring, MD 20910, USA
2
*Corresponding author: tel: +1 206 860 3365; fax: +1 206-860-3217; e-mail:
[email protected] Methot, R. D., Tromble, G. R., Lambert, D. M., and Greene, K. E. 2014. Implementing a science-based system for preventing overfishing and guiding sustainable fisheries in the United States. – ICES Journal of Marine Science, 71: 183 – 194. Received 30 January 2013; accepted 20 June 2013; advance access publication 4 September 2013.
Fisheries management in the United States is primarily governed by the Magnuson – Stevens Fishery Conservation and Management Act, first enacted in 1976. Overarching principles are that fishing mortality rates should not jeopardize the capacity of a stock to produce maximum sustainable yield (MSY) and that overfished stocks (i.e. biomass is too low) should be rebuilt to the level that will support MSY. The science-based system for achieving sustainable fisheries is implemented, in part, through setting annual catch limits (ACLs) that cannot exceed the acceptable biological catch that is recommended by Scientific and Statistical Committees using methods that account for scientific uncertainty. Accountability measures (AMs) are management measures to prevent ACLs from being exceeded or correct any overages that occur. Implementation in 2012 of ACLs and AMs in all Federal fisheries was a historical achievement in the United States; one that will help rebuild stocks and ensure sustainable fisheries into the future. Some remaining challenges include: determining appropriate catch levels and management approaches for stocks with incomplete data; assessing more stocks, more frequently; addressing differences between managing stocks as a complex vs. managing individual stocks in a multistock fishery; and incorporating social and economic factors in determining the appropriate response to uncertainty. Keywords: annual catch limits, Magnuson– Stevens Act, National Standard guidelines, rebuilding, US fisheries management.
Introduction The Fishery Conservation and Management Act (FCMA) of 1976 established the framework for domestic fisheries management in the 200-nautical mile exclusive economic zone (EEZ) of the United States. The FCMA established jurisdiction over fisheries in the EEZ because of conservation concerns about foreign fleets fishing off the US coasts and because there was interest in developing a national programme for the conservation and management of fishery resources and a desire to develop fisheries for US fishers. Since its inception, the Act has used the concept of maximum sustainable yield (MSY) to provide a scientific basis for the acceptable level of impact that a fishery may have on fish stocks and, since 1996, as an upper limit on the optimum yield (OY) for each fishery. Implementation of the Act has led the United States to be among the forefront of nations in the prevention of overfishing and the rebuilding of overfished stocks (Worm et al., 2009). The fishery management system established by this legislation includes eight regional Councils, which are responsible for fisheries next to their
constituent states. The FCMA has had two major and some minor amendments. The first major revisions came from the Sustainable Fisheries Act (SFA) in 1996, which among other things, renamed the Act as the Magnuson –Stevens FCMA (MSA). The second major revision came from the Magnuson –Stevens Fishery Conservation and Management Reauthorization Act of 2006 (MSRA). The history of the MSA and associated guidelines has been documented by Darcy and Matlock (1999) and Tromble et al. (2009) and is summarized in Table 1. A list of acronyms that are used throughout this paper is provided in Table 2. The acronym MSA is used to refer to the main legislation that governs fisheries management in the United States. The acronym FCMA is used to refer to the Act as written in 1976, and the acronyms SFA and MSRA are used to refer to changes that were introduced by those amendments. Here, we recap the basis and history of the MSA with regard to provisions to prevent overfishing and attain OY, describe the new requirement for ACLs that prevent overfishing, and present some of the current challenges to the implementation of
Published by Oxford University Press on behalf of the International Council for the Exploration of the Seas 2013. This work is written by US Government employees and is in the public domain in the US.
184
R. D. Methot et al.
Table 1. Timeline for major legislative changes to the Magnuson– Stevens Act and to the NS1 guidelines. Date 1976
Action Fishery Conservation and Management Act (FCMA) signed
1977
NMFS published National Standard (NS1) guidelines NMFS revised the NS1 guidelines NMFS revised the NS1 guidelines
1983 1989 1996
Sustainable Fisheries Act (SFA) signed
1998
NMFS revised the NS1 guidelines
2005
NMFS publishes a proposed rule to revise the NS1 guidelines
2007
Magnuson-Stevens Fishery Conservation and Management Reauthorization Act (MSRA) of 2006 was signed in January 2007 NMFS revised the NS1 guidelines to address new ACL and AM requirements
2009
2007 – 2012 2012
Summary The Act established the eight Regional Fishery Management Councils; jurisdiction over fisheries within the exclusive economic zone; NS1–7; and described the concepts of maximum sustainable yield and OY The NS1 Guidelines were short, less than one page of regulatory text, and provided a definition of overfishing The NS1 guidelines described OY as a target and revised the definition of overfishing The NS1 guidelines recommended the use of measurable definitions of overfishing (in F or biomass) Major amendments to the MSA include: addition of NS8–10; revised the definition of OY; required measurable criteria for determining overfished status; established rebuilding requirements; and required annual reports to Congress on the status of US fisheries The NS1 guidelines distinguish the difference between “overfishing” (i.e. the rate of removals is too high) and “overfished” (i.e. the population is too low) and required SDC to determine overfishing and overfished status of stocks. Extensive section on rebuilding overfished stocks was added to the guidelines The proposed rule focused on potential revisions to rebuilding plan requirements. The rule was never finalized and was withdrawn because NMFS needed to focus on the 2007 revisions to the MSA The revisions introduced new requirements for annual catch limits and accountability measures in Federal fisheries. Councils must set ACLs that do not exceed the fishing level recommendation (i.e. ABC) of their SSC
The NS1 guidelines describe how ACLs should be set and how they relate to other reference points. A major aspect of the guidelines is the requirement to account for scientific and management uncertainty in the ACL framework. The guidelines require ABC control rules to account for scientific uncertainty and describe two types of AMs, in-season AMs and AMs for when catches exceed an ACL All eight Regional Fishery Management Councils have implemented ACLs and AMs through their FMPs NMFS publishes Advance Notice of Proposed Rulemaking to revise NS1 guidelines
NMFS is considering revising the NS1 guidelines and invites the public to submit comments on potential revisions
an even more effective fishery management system in the United States. The Councils develop fishery management plans (FMPs) and regulations that are reviewed by NMFS—acting on behalf of the US Secretary of Commerce (Secretary)—for consistency with all applicable Federal laws and Executive Orders. The Secretary may approve, disapprove, or partially approve the Council’s measures, but may not substantively change measures just because the Secretary might prefer different measures. Thus, the Councils have a primary role in fisheries management. Each Council has between 7 and 21 voting members consisting of representatives from each constituent state and the Regional Administrator of NMFS for the geographic area. Councils also have non-voting members, including a representative from the US Fish and Wildlife Service, US Coast Guard, Department of State, and the Executive Director of the Marine Fisheries Commission for the geographical area concerned. Each Council appoints a Scientific and Statistical Committee (SSC) composed of scientists from academic, Federal and state agencies and elsewhere. These SSCs review scientific information and develop science-based recommendations for their Councils to assure that the Council is acting based on the best scientific information available. The MSA contains ten National Standards for fishery conservation and management (Table 3), and all FMPs, FMP amendments, and regulations that the Councils or the Secretary establish must be consistent with all ten [16 United States Code (USC) § 1851(a)]. The MSA also requires that the Secretary establish advisory guidelines for each National Standard to assist in the development of FMPs
[16 U.S.C. § 1851(b)]. The National Standard guidelines are codified within US Federal regulations. As guidelines, they do not have the “force and effect of law”, but it is expected that management measures will be consistent with the guidelines unless a deviation is justified and supported by analysis. NMFS refers to the guidelines when making decisions on whether to approve, disapprove, or partially approve a Council’s management measures. Additionally, courts will often refer to the guidelines during legal challenges to fishery management decisions to determine if NMFS has followed its own guidance. This paper will focus on National Standard 1 (NS1) regarding the prevention of overfishing and the attainment of OY.
History of NS1 and efforts to prevent overfishing Ending overfishing and rebuilding overfished stocks is a management challenge that NMFS and the Councils have been addressing since the FCMA was enacted in 1976. This mandate is articulated in NS1 of the MSA as: “Conservation and management measures shall prevent overfishing while achieving, on a continuing basis, the optimum yield [OY] from each fishery for the United States fishing industry”. NMFS first developed guidelines for NS1 in 1977 (Federal Register, 1977). The 1977 NS1 guidelines were relatively short (less than one page) and provided the general descriptions of MSY, OY, and overfishing. The term MSY is used, but not defined in the MSA. MSY was defined in the first NS1 guidelines as: “the largest average annual catch or yield in terms of weight of fish caught by both commercial
Implementing a science-based system for preventing overfishing and guiding sustainable fisheries Table 2. List of acronyms used in this paper. Acronym ABC ACL ACT AM Blimit BMSY EC EEZ FABC Flimit FMSY FCMA FMP FSSI M MSA MSRA MSY NMFS NOAA NS1 OFL OY P* SDC SFA SPR SSC Ttarget Tmax Tmin
Definition Acceptable biological catch Annual catch limit Annual catch target Accountability measure Biomass limit Biomass level of a stock that can support maximum sustainable yield Ecosystem component Exclusive economic zone Fishing mortality rate that if applied would produce the acceptable biological catch Fishing mortality limit Fishing mortality rate that if applied over the long term would produce MSY Fishery Conservation and Management Act Fishery management plan Fish stock sustainability index Natural mortality rate Magnuson –Stevens Fishery Conservation and Management Act Magnuson –Stevens Fishery Conservation and Management Reauthorization Act of 2006 Maximum sustainable yield National Marine Fisheries Service National Oceanic and Atmospheric Administration National Standard 1 Overfishing limit in terms of catch Optimum yield Acceptable probability of overfishing Status determination criteria Sustainable Fisheries Act Spawning potential ratio Scientific and Statistical Committee Target time to rebuild a stock Maximum allowable time to rebuild a stock Minimum time to rebuild a stock
and recreational fishermen that can be taken continuously from a stock under existing environmental conditions”. Although this definition has been modified slightly in the NS1 guidelines over time, the current definition is very similar to this original one. In terms of population dynamics, the MSY concept is essentially that there is a rate of fishing mortality, termed FMSY, that if applied consistently from year to year to a fluctuating stock would produce an annual catch that also would fluctuate above and below MSY. The average of this time stream of catches would be the MSY, and the average stock size would be characterized as BMSY and would be typically between a third and a half of the unfished stock size. Actually maintaining the fishing mortality rate at FMSY is not feasible due to scientific uncertainty, time-lags, and other factors, so MSY is a theoretical limit that exceeds the realizable performance of a fishery. It is likely that many members of the fishing public did not appreciate this dynamic nature of stocks when MSY was used in the FCMA. The definition of OY in the FCMA read: “The term ‘optimum’ with respect to yield from a fishery means the amount of fish which – (A) Will provide the greatest overall benefit to the Nation, particularly with respect to food production and recreational opportunities; and (B) is prescribed on the basis of the maximum sustainable yield from the fishery, as modified by [emphasis added] any relevant economic, social, or ecological factor”. Hence, OY was based on MSY as modified by various factors and could, for some
185
Table 3. The ten National Standards from the MSA (from Darcy and Matlock, 1999). 1. Conservation and management measures shall prevent overfishing while achieving, on a continuing basis, the optimum yield from each fishery for the United States fishing industry 2. Conservation and management measures shall be based upon the best scientific information available 3. To the extent practicable, an individual stock of fish shall be managed as a unit throughout its range and interrelated stocks of fish shall be managed as a unit or in close coordination 4. Conservation and management measures shall not discriminate between residents of different States. If it becomes necessary to allocate or assign fishing privileges among various United States fishermen, such allocation shall be (A) fair and equitable to all such fishermen; (B) reasonably calculated to promote conservation; and (C) carried out in such manner that no particular individual, corporation, or other entity acquires an excessive share of such privileges 5. Conservation and management measures shall, where practicable, consider efficiency in the utilization of fishery resources; except that no such measure shall have economic allocation as its sole purpose 6. Conservation and management measures shall take into account and allow for variations among, and contingencies in, fisheries, fishery resources, and catches 7. Conservation and management measures shall, where practicable, minimize costs and avoid unnecessary duplication 8. Conservation and management measures shall, consistent with the conservation requirements of this Act (including the prevention of overfishing and rebuilding of overfished stocks), take into account the importance of fishery resources to fishing communities by utilizing economic and social data that meet the requirements of paragraph (2) [National Standard 2], in order to (A) provide for the sustained participation of such communities, and (B) to the extent practicable, minimize adverse economic impacts on such communities 9. Conservation and management measures shall, to the extent practicable, (A) minimize bycatch and (B) to the extent bycatch cannot be avoided, minimize the mortality of such bycatch 10. Conservation and management measures shall, to the extent practicable, promote the safety of human life at sea
period, be set higher than MSY. However, in the long term, OY can never exceed MSY. The FCMA also determined that fishing by foreign nations in the EEZ was limited to the portion of the OY that would not be harvested by US vessels. Many of the first OY specifications in FMPs were phrased as general statements such as “OY is the amount of catch that results from implementing the fishery management program”. The domestic annual harvest for many stocks was set equal to OY, with the result that there would be nothing left for foreign vessels. The definition of overfishing in the 1977 NS1 guidelines (Federal Register, 1977) was “a level of fishing that results in a reduction in the capacity of a management unit to produce maximum biological yield on a sustained basis for specified habitat and environmental conditions”. NMFS revised the NS1 guidelines in 1983 (Federal Register, 1983) after being petitioned by the Environmental Defense Fund, who asserted that the guidelines failed to ensure that the conservation objectives of the MSA were being implemented. The concept of MSY was revised in the 1983 guidelines as “MSY, a theoretical concept, is the largest average annual catch or yield that can be taken over a period of time from each stock under prevailing ecological and environmental conditions”. The guidelines also noted that MSY could be specified for a related group of species in
186 a mixed-species fishery. The 1983 guidelines also characterized OY as a management target and stated that conservation and management measures should be designed to achieve OY. The 1983 guidelines explained that OY “need not be expressed in terms of numbers or weight of fish”; for example, OY could be expressed in terms of an annual harvest of fish having a minimum weight, length, or other measurement or taken by a specified amount of fishing effort. The definition of “overfishing” was modified in the 1983 guidelines. The revised definition read: “Overfishing is a level of fishing mortality that jeopardizes the capacity of a stock(s) to recover to [emphasis added] a level at which it can produce maximum biological yield or economic value on a long-term basis under prevailing biological and environmental conditions”. What is now referred to as the “mixed-stock exception” was also added into the 1983 guidelines. This provision allowed a limited exception to the prevention of overfishing where it could be demonstrated that it is in the best interest of the Nation to allow limited overfishing of some stocks to attain a better overall OY, as long as it would not cause any stock to require protection under the Endangered Species Act. NMFS revised the NS1 guidelines again in 1989 (Federal Register, 1989), partially due to the recommendations of the NOAA Fishery Management Study (NOAA, 1986). The NOAA Fishery Management Study recommended that NOAA determine the annual biologically acceptable catch, abbreviated to ABC, for each managed fishery. The ABC was described as the “total allowable removals from the resource that would remain a healthy and productive resource into the future” and would represent the maximum allowable quota for the stock (Federal Register, 1989). The ABC concept was added into the 1989 guidelines as a potential tool in deriving OY from MSY, but Councils were not required to use it. The majority of the revisions in the 1989 NS1 guidelines focused on the overfishing concept. Councils were directed to include in their FMPs “objective and measureable definitions” of overfishing for each stock or stock complex covered by that FMP. The definition of overfishing was revised again in the guidelines to read “a level or rate of fishing mortality that jeopardizes the long-term capacity of a stock or stock complex to produce MSY on a continuing basis”, which is very similar to the current definition of overfishing in the MSA. The guidelines stated that the definition of overfishing could be expressed in terms of a minimum level of spawning biomass or a maximum level or rate of fishing mortality. Rosenberg et al. (1994) reviewed over 100 of the overfishing definitions that were established after the 1989 NS1 guidelines and found that, in most FMP’s, this new requirement was met by defining overfishing in terms of a limit on the fishing mortality rate, rather than a minimum biomass level. The most common definitions of overfishing referred to a fishing mortality rate that would reduce spawning biomass per recruit to 20 or 30% of the unfished level (Rosenberg et al., 1994). Although FMP amendments intended to end overfishing were implemented, management measures proved insufficient for many stocks, and some stocks continued to show declines in biomass. The SFA of 1996 made significant amendments to the MSA, including the addition of three new National Standards (NS8 –10; Table 3) and provisions related to preventing overfishing and rebuilding stocks. The SFA modified the definition of OY to read: “The term ‘optimum’, with respect to the yield from a fishery, means the amount of fishing which – (A) will provide the greatest overall benefit to the Nation, particularly with respect to food production and recreational opportunities, and taking into account the
R. D. Methot et al. protection of marine ecosystems; (B) is prescribed as such based on the maximum sustainable yield from the fishery, as reduced by any relevant economic, social, or ecological factor; and (C) in the case of an overfished fishery, provides for rebuilding to a level consistent with producing the maximum sustainable yield in such fishery (16 U.S.C. § 1802(33)).” Thus, the main changes relative to the pre-SFA definition include that OY take into account the protection of marine ecosystems, OY be no greater than MSY, and OY for an overfished fishery allow for rebuilding to the MSY level. Note that both MSY and OY are considered as long-term concepts and that a short-term annual catch recommendation (e.g. ABC) for a stock that is above BMSY could exceed the MSY. The SFA also established the statutory requirement that each FMP specify “objective and measurable criteria” for determining when the fishery to which the plan applies is overfished [16 U.S.C. § 1853(a)(10)]. The SFA defined the terms “overfishing” and “overfished” as “a rate or level of fishing mortality that jeopardizes the capacity of a fishery to produce the MSY on a continuing basis” [16 U.S.C. § 1802(34)]. The SFA also required that the Secretary report annually to the US Congress and the Councils on the status of fisheries [16 U.S.C. § 1854(e)(1)] and established requirement that within 1 year of notification that a stock is overfished, the Council implement a rebuilding plan to end overfishing and rebuild the affected stocks. Rebuilding plans for overfished stocks are required to specify a period for rebuilding that is “as short as possible”, taking into account a number of factors such as the biology of the stock and needs of fishing communities and that shall “not exceed 10 years” (with a few exceptions). Given the significant amendments to the MSA, NMFS revised the NS1 guidelines, as well as many of the guidelines for other National Standards, and added guidelines for NS8– 10 in 1998 (Federal Register, 1998). In response to the SFA requirement for FMPs to specify “objective and measurable criteria” for when a fishery is overfished, the 1998 NS1 guidelines created bivariate status determination criteria (SDC; Figure 1). The bivariate SDC helped clarify the difference between the terms “overfishing” and “overfished”, as the SFA provided one definition for the two terms. One aspect of the status determination relates to the rate of fishing.
Figure 1. Criteria for the determination of overfishing and overfished status of fish stocks are presented in this figure. Overfishing is occurring if the fishing mortality rate exceeds the rate that would produce MSY. A stock is considered overfished if its reproductive potential (shown here as biomass) falls below a specified biomass limit, which is typically set at half of the biomass level that would produce MSY.
Implementing a science-based system for preventing overfishing and guiding sustainable fisheries A stock is determined to be experiencing overfishing if the most recent year’s fishing mortality rate is greater than the fishing mortality limit (Flimit), which typically is set at FMSY (the fishing mortality rate that if applied over the long term would produce MSY), or a suitable proxy for FMSY. The second aspect of the status determination relates to the level of the stock’s reproductive potential (expressed as B). Where feasible, the measure, B, of reproductive potential will be in terms of the stock’s total capacity to produce viable eggs. More commonly, B is measured as the total mature biomass of females and may be referred to as spawning-stock biomass. A stock is considered to be overfished if its reproductive potential falls below a specified limit, the minimum stock size threshold, now termed the Blimit. The NS1 guidelines describe that the Blimit must be expressed in terms of spawning biomass or other measures of reproductive potential. Since stocks fished at or near FMSY are expected to fluctuate in abundance around BMSY, Blimit is set lower than BMSY. Some potential methods for setting Blimit are described in Restrepo et al. (1998). Typical levels are 0.5 × BMSY, (1 2 M ) × BMSY (where M is the rate of natural mortality), and 25% × Bunfished in cases where it is more feasible to estimate unfished biomass than BMSY. The addition of the status determination based on spawning biomass is consistent with the original intent of the Act in 1976, which considered overfishing as jeopardizing the stock’s capacity to produce MSY. The 1998 NS1 guidelines also contained an extensive section on rebuilding overfished stocks. The guidelines reiterated much of the language that was contained in the SFA related to rebuilding and clarified that if a stock is overfished, the purpose of the rebuilding plan is to rebuild the stock or stock complex to the biomass level that would produce MSY (as required by the definition of OY). The 1998 guidelines also defined the starting point in structuring a rebuilding plan as the length of time it would take to rebuild the stock to the biomass level that produces MSY if fishing mortality ceased (referred to as Tmin). If Tmin is 10 years or less, then the maximum time allowable for rebuilding (Tmax) is 10 years. If Tmin is greater than 10 years, then the rebuilding period may be lengthened, but may not exceed the rebuilding period calculated in the absence of fishing mortality, plus one generation time for that stock. The target time to rebuild (e.g. year with 50% chance of being rebuilt, Ttarget) cannot exceed Tmax. The concept of ABC, which was added into the guidelines in 1989, was removed in the 1998 revisions to the guidelines, probably because it was not explicitly defined in the SFA. A similar concept, however, reappears in the MSRA and subsequent NS1 guideline revisions in 2009. During 1998–2007, the concept and usage of ABC remained in many FMPs as an annually varying quantity that was based on the application of a limit or target fishing mortality rate to the annually varying stock abundance. The description of OY as a target was strengthened in the 1998 NS1 guidelines, presumably because of the change in the definition of OY by the SFA. OY was described as a target reference point that should be set safely below limit reference points and that should be risk averse. The description of how OY should be specified was modified slightly, with a preference being placed on specifying OY in terms of numbers or weight of fish. Despite the strengthened provisions in the MSA, overfishing continued for some stocks for the entire period from 1997 through 2006 (Tromble et al., 2009), and many stocks did not rebuild as planned (Rosenberg et al., 2006; Milazzo, 2012). This was one of the major issues Congress addressed in the MSRA.
187
Current state of fisheries management: 2007–present Magnuson–Stevens Reauthorization Act The MSRA was signed by President George W. Bush on 12 January 2007 and made significant amendments to the MSA that impact how US Federal fisheries are managed. The MSRA established new requirements to end and prevent overfishing through the use of ACLs and AMs. The Councils and the Secretary (for Atlantic Highly Migratory Species) were required to establish mechanisms for ACLs and AMs in their FMPs by 2010 for stocks subject to overfishing and by 2011 for all others [16 U.S.C. § 1853(a)(15) and 16 U.S.C. § 1853 note]. Only stocks that have a life cycle of 1 year and stocks subject to international agreements are not required to have ACLs and AMs (16 U.S.C. § 1853 note). Because some FMPs have included large numbers of species, the subsequent revisions to the NS1 guidelines created a mechanism to designate species that are not in the fishery as ecosystem components (ECs) which do not require ACLs and AMs. The MSRA also specified additional requirements for the role of scientific advice in this process, specifically through the Councils’ SSCs. It stated that each SSC “shall provide its Council ongoing scientific advice for fishery management decisions, including recommendations for acceptable biological catch [ABC], preventing overfishing, maximum sustainable yield, and achieving rebuilding targets, and reports on stock status and health, bycatch, habitat status, social and economic impacts of management measures, and sustainability of fishing practices” [16 U.S.C. § 1852(g)(1)(B)]. In addition, the MSRA specifically required that overfishing must be ended immediately when rebuilding plans are implemented [16 U.S.C. § 1854(e)(3)(A)]. Previously, the rebuilding plan could allow overfishing to continue for some years, provided that the biomass rebuilding target was achieved on time. Under the MSRA, Councils are allowed 2 years to prepare and implement a rebuilding plan; and that plan, when implemented, must end overfishing immediately. Because the MSRA established such significant changes in how US fisheries are managed, NMFS revised the NS1 guidelines in 2009 to integrate the new requirements into existing provisions related to ending overfishing, rebuilding overfished stocks, and achieving OY. Additionally, NMFS defined and provided guidance on the terms ACLs, AMs, and ABC that are required but were not defined in MSRA. NMFS revised the guidelines through a rulemaking process, which included two public comment periods, between February 2007 and January 2009. NMFS published final revised NS1 guidelines on 16 January 2009 (Federal Register, 2009).
NS1 guidelines One of the major components of the 2009 NS1 guidelines is the description of the ACL framework and how ACLs relate to other important reference points such as the overfishing limit (OFL), ABC, and annual catch target (ACT; Figure 2). Related to the ACL framework, another major aspect of the guidelines is the concept of incorporating management and scientific uncertainty in the use of ACLs and AMs. The inclusion of provisions to account for uncertainty is a notable feature of the 2009 NS1 guidelines. This stems from the MSRA requirement that the Councils must set “annual catch limits in each fishery at a level such that overfishing does not occur”. Setting the target level of the fishing mortality at its estimated
188
Figure 2. A schematic describing the related roles of the Councils and their SSC in translating scientific information into recommendations for catch limits.
biological limit will entail a 50% chance that the limit will subsequently be found to have been exceeded, potentially to a large degree if uncertainty is high. Previously, the 1998 NS1 Guidelines included a section on precautionary approaches to setting fishery targets below limits (Darcy and Matlock, 1999) in accord with various international agreements including the International Code of Conduct for Responsible Fisheries of the Food and Agriculture Organization (FAO, 1995). Considerations for implementation of this approach are found in Restrepo et al. (1998). Despite this guidance to implement a precautionary approach, some Councils continued to set fishery targets at or beyond the calculated limits for some stocks, and overfishing continued to occur. A seminal court decision in 2000 established that preventing overfishing means that there must be no more than a 50% probability that management measures would result in overfishing (Natural Resources Defense Council, Inc. v. Daley, 209 F.3d 747; D.C.Cir., 2000). The MSRA and the 2009 NS1 guidelines strengthen the requirement that overfishing be prevented through the use of targets that are below limits. The 1998 NS1 guidelines are described by Darcy and Matlock (1999) as expecting that uncertainty be taken into account when the MSY-based limits are calculated. The 2009 guidelines defined this as a two-step process. The first step is calculation of a risk-neutral estimate of MSY and the OFL (described below). The second step is explicit accounting for uncertainty by establishing a scientifically based ABC that is offset from the OFL to account for the degree of uncertainty in the OFL. The calculation of OFL is based on the principle of MSY (Restrepo et al., 1998). If the stock is fished exactly at an OFL control rule such that OFL is approximately equal to FMSY × B, then the annual OFL will vary depending on fluctuations in stock size, and the long-term average of OFLs will define MSY. Commonly, it is necessary to use a proxy for FMSY because there is insufficient contrast in the time-series of assessment data to produce a reliable estimate of FMSY. A typical, but not exclusive, basis for such a proxy is based on life-history characteristics (growth, maturity, and natural mortality) and fishery age-selectivity characteristics. The limit fishing mortality rate is then calculated in terms of the spawning potential ratio (SPR; Goodyear, 1993) that
R. D. Methot et al. is the expected lifetime reproductive output under fishing, relative to the expected lifetime reproductive output with no fishing mortality. The SPR is typically set in the range of 35–50% based on work such as Clark (1993), Mace (1994), and Mace and Sissenwine (1993). The NS1 guidelines describe the ABC as a level of a stock’s annual catch that is adjusted downwards from the OFL according to the degree of scientific uncertainty. This is consistent with the 1983 NS1 guidelines which described MSY as a “theoretical concept”. MSY can be approached but not attained because we lack the perfect scientific knowledge and management control to keep the fishing mortality rate at exactly the level that could produce MSY. To the degree that the control rule for implementing the ABC, i.e. FABC, is less than FMSY, then the long-term average ABC will be less than MSY but not proportionally less in the long-term because the stock, on average, will have an abundance that is greater than BMSY. The degree of buffer between the OFL control rule and the ABC control rule is a trade-off between more confidently preventing overfishing and short-term loss of fishing opportunity. The recommendation for ABC is very important, as the Council’s ACL for a stock may not exceed the ABC recommendation. This empowerment of the SSC to set the biological limit for allowable catch (Crosson, 2012) is in accord with the US Commission on Ocean Policy (United States, 2004) and the Pew Oceans Commission report (Pew Oceans Commission and Panetta, 2003) and was the main recommendation of the 1986 NOAA Fishery Management Study. Technical methods for projecting ABC levels at a specified probability, termed P*, of overfishing have been developed (Shertzer et al., 2008). They use the estimates of scientific uncertainty to calculate future catch levels that would maintain a constant probability of allowing overfishing for each year into a forecast. Forecast models incorporated in fish stock assessments, such as Methot and Wetzel (2013), report forecasts in ratios such as F/Flimit and B/Btarget, and the variance associated with these ratios so that the probability of a stock falling below its target level is directly apparent from the stock assessment. Because comprehensive and consistent estimation of uncertainty is difficult (Patterson et al., 2001), the full application of this method is limited by the degree to which scientific uncertainty can be estimated. Ralston et al. (2011) developed an innovative approach in which they examined the history of assessments for each US West Coast groundfish stock to develop an overall average level of scientific uncertainty for use in calculating ABC for these stocks. However, most FMPs acknowledged the consequences of scientific uncertainty with simpler control rules that set ABC as a constant proportion, often 75%, of OFL. The acceptable probability of overfishing, P*, entails a trade-off by the Councils. Setting P* near 50% means that there will be little buffer between the OFL and the ABC, with little short-term foregone yield. There also will be a nearly 50% chance that subsequent assessments will, in retrospect, find that overfishing had been occurring, either because the revised estimates of historical fishing mortality are higher or because the revised estimates of the fishing mortality limit are lower. Setting the P* lower than 50% creates a buffer between the target and the limit catch. This buffer results in some foregone short-term yield, and greater protection against subsequently finding that overfishing was occurring. The short statutory time frame for the implementation of the OFL/ABC/ACL framework precluded, for the most part, extensive work on management strategy evaluations (Butterworth and Punt, 1999) to investigate the bioeconomic trade-offs involved with the selection of an appropriate level for P*.
Implementing a science-based system for preventing overfishing and guiding sustainable fisheries The ACL is a limit to preventing overfishing on the total annual catch for a stock. The word “limit” means the amount should not be exceeded, and if it is, there are consequences (i.e. accountability measures, AMs). The NS1 guidelines define “catch” as including the mortality of fish that are retained as well as the mortality of fish that are discarded. The NS1 guidelines recommend that ABC (and therefore ACL) should be expressed in terms of catch, but may be expressed in terms of landings as long as estimates of bycatch and any other fishing mortality not accounted for in the landings are incorporated into the determination of ABC. The ACL can be, and often is, set equal to the ABC. The rational for identifying both an ABC and an ACL is based on the language in the MSRA, and the need to establish an explicit distinction between the SSC responsibilities and the Council responsibilities. The relationship between ABC and ACL is essentially the sciencemanagement hand-off (Figure 2). Once on the management (Council) side, additional considerations, such as splitting the ACL into sector ACLs for particular fishery sectors and AMs for each, can be developed. AMs are management controls that include in-season AMs to prevent ACLs from being exceeded and post-season AMs to correct or mitigate overages of the ACL if they occur. Councils should describe in their FMPs both types of AMs that they plan to use. In-season AMs could include monitoring catch in-season and closing a fishery or implementing other management measures to prevent catches from exceeding the ACL, such as changes to trip or possession limits. ACTs that are set below the ACL can be used in situations where it is known that in-season AMs have substantial management uncertainty. Management uncertainty, described by Patrick et al. (2013), refers to the ability of managers to establish measures that are reasonably expected to constrain catch so that the ACL is not exceeded and uncertainty in quantifying the true catch amounts (i.e. estimation error). ACTs are not required, but they are an optional tool that can be used to prevent catches from exceeding the ACL and therefore prevent triggering additional AMs. The NS1 guidelines state that Councils must determine as soon as possible after a fishing year if an ACL has been exceeded. If ACLs are exceeded, AMs are to be implemented to correct the operational issue that caused the overage, such that future overages will not occur, and to mitigate any biological consequences of the overage. These AMs could include modifications of future in-season AMs or overage adjustments on the next fishing season’s ACL. As described above, a Council may, but is not required to, divide an ACL into sector ACLs for distinct user groups (e.g. commercial vs. recreational). If the strategies for managing each sector have different levels of management uncertainty, then the use of sector ACLs may be appropriate so that each sector can be held accountable with sector-specific AMs. The NS1 guidelines require that if sector ACLs are used, then sector AMs should also be used. The 2009 NS1 guidelines identified two methods that Councils can choose to determine if overfishing has occurred. The 1998 NS1 guidelines describe that overfishing is determined if the annual fishing mortality rate is greater than the Flimit, so is based on hindsight from subsequent stock assessments. Where there is substantial scientific uncertainty in the assessment, this method may find that overfishing has occurred even if the catch has been kept at or below the ACL. The 2009 NS1 guidelines describe that an alternative way to determine overfishing status is to compare the annual catch to the OFL (which is based on the Flimit); if the catch exceeds the OFL, then the stock is considered subject to overfishing. This alternative can be implemented more easily in
189
situations where assessments are not updated frequently, but are susceptible to making incorrect overfishing determinations if stock abundance (and hence the correct OFL) has changed since the last assessment. The 2009 guidelines modified the “mixed-stock exception” that was created by the 1983 guidelines. The revised guidance is that limited overfishing could be allowed if it resulted in greater benefits to the nation as long as the stock was not overfished or expected to become overfished as a result of that overfishing. The limited degree of overfishing envisioned with this exception would cause a stock to be persistently below BMSY and thus not able to produce MSY, but not to decline further to the overfished limit. Lastly, another major aspect of the 2009 guidelines was the creation of stock classifications of “stocks in the fishery” and “EC species”. The MSA requires that FMPs contain, among other things, a description of the species of fish involved in the fishery, and therefore, the relevant Council determines which stocks of fish to include in their FMPs. Some FMPs include a relatively small number of species, focusing on the primary targets of the fishery. In other FMPs, a much broader range of species are included, many of which may or may not require conservation and management. The 2009 guidelines stated that as a default, all stocks in a FMP were considered “in the fishery” unless they are designated as “EC species”. For a stock to be classified as an “EC species”, four criteria have to be met, the stock had to: be a nontarget species/stock; not be determined to be subject to overfishing, overfished, or approaching an overfished condition; not be likely to become subject to overfishing or overfished, according to the best available information; and not generally retained for sale or personal use. “EC species” may, but are not required to be, included in an FMP; however, they are not considered to be in the fishery and are not required to have biological reference points or ACLs. “Stocks in the fishery” are required to have ACLs and other biological reference points. The “stocks in the fishery” and “EC species” classifications are meant to both encourage ecosystem approaches to management and acknowledge that management by ACLs may not be appropriate for all stocks. To date, ten stocks or stock complexes have been designated as “EC species”.
Stock status determinations As described above, SSCs review scientific information and develop science-based recommendations for their Councils to assure that the Council is acting based on the best scientific information available. Councils rely substantially on the advice from their SSC when creating SDC regarding overfishing and overfished status, and the SSC then uses these to determine the status of each stock based on the most recent stock assessments. These SDC may be technically updated with new calculations in each assessment, and their basis will be reviewed during the course of some assessments. Of particular importance is whether there is sufficient information to warrant direct calculation of FMSY vs. using a life-history-based proxy for FMSY. If the SSC determines that, based on the best scientific information available, the SDC should be revised, the SSC will make that recommendation to the Council and the Council will develop the new SDC in their FMP and submit it for approval and implementation by NMFS. As with other FMP measures, NMFS must determine that the proposed change is consistent with all the National Standards. The process of evaluating stock status is ongoing. As new or updated assessments are produced, they receive either a full (benchmark) or partial (update) review through processes jointly commissioned by the Council and NMFS and typically involving a
190
Figure 3. Progress of the FSSI for 230 stocks. The FSSI is responsive to ending overfishing, rebuilding stocks, and conducting assessments. The maximum possible score for the FSSI is 920. combination of SSC and external, independent reviewers. The reviewed assessments are passed to the SSC for their use in making recommendations to their Council. NMFS also uses these assessments as the basis for the official determination of stock status. The status of all managed stocks is reported to the public on a quarterly basis on NMFS’s website (http://www.nmfs.noaa .gov/sfa/statusoffisheries/SOSmain.htm) and provided in reports to the US Congress yearly. Notification letters are sent to the Councils for stocks found to be subject to overfishing or overfished. One way that NMFS tracks both the scientific understanding of managed stocks and the effectiveness of management measures is through the fish stock sustainability index (FSSI). The FSSI is a performance measure that tracks the status and progress of 230 important stocks in commercial and recreational fisheries (Figure 3). The FSSI is calculated by assigning a score for each fish stock based on the following criteria: 0.5 points if the overfished status is known; 0.5 points if the overfishing is status is known; 1.0 point if overfishing is not occurring (for stocks with known overfishing status); 1.0 point if the stock biomass is above the overfished level defined for the stock (for stocks with known overfished status); and 1.0 point if the stock biomass is at or above 80% of the biomass that produces MSY (BMSY). Stocks rebuilding from a previously overfished condition are not awarded the fourth point until they reach BMSY. The maximum score each stock can receive is 4 points; the value of the FSSI is the sum of all 230 individual stock scores. Since its inception, annual target scores have been set, based on goals for assessing new stocks, ending overfishing, and rebuilding stocks. All these target scores have been met and the overall score has continued to increase every year, demonstrating continued improvement in the index over time.
Rebuilding overfished stocks The requirements to specify criteria for determining when a stock is overfished and to rebuild overfished stocks to a level that can support MSY (i.e. BMSY) in a period that is as short as possible, not to exceed 10 years (subject to some exceptions) were enacted in the 1996 SFA amendments to the MSA [16 U.S.C. § 1854 (e)(4)]. Revised NS1 guidelines were published in 1998 and Councils subsequently amended their FMPs. As a result, a significant number of rebuilding plans were implemented between 1998 and 2004, and many of these targeted rebuilding in 10 years. Murawski (2010) provides the examples of successes and challenges in rebuilding stocks worldwide.
R. D. Methot et al. There is an expectation of accountability with regard to the rebuilding plans. The MSA requires that the Secretary review rebuilding plans at routine intervals, not to exceed 2 years [16 U.S.C. § 1854(e)(7)]. If the Secretary finds that adequate progress has not been made to end overfishing and rebuild affected fish stocks, the Secretary is expected to notify the appropriate Council and provide recommendations for further conservation and management measures to achieve adequate progress. Understanding and practice until now has been that, if a stock was behind in rebuilding, the fishing mortality rate should be reduced to a level such that the stock would maintain an acceptable chance of rebuilding during its original planned period. This policy has a couple of implications. One is that, if a stock is significantly behind in rebuilding and only a few years remain in the rebuilding period, the required fishing mortality rate that is projected to rebuild the stock on time could be very low, significantly impacting the fishery. In some cases, even a fishing mortality rate of zero would not be projected to rebuild the stock. This could put a Council in the unfavourable position of considering closing the fishery or fishing grounds, whereas at the same time acknowledging that they will not be able to rebuild the stock in the required time. Failure to rebuild on time or as planned can result from several factors, or a combination of them. They include: (i) Communication of probabilities: when a rebuilding plan sets forth an expectation that the stock will have, for example, a 60% chance of rebuilding in the specified period, there is a complementary 40% chance that the stock will not rebuild in the specified period. If the stock is close to, but not quite, rebuilt by TMAX, this is not necessarily a failure of the rebuilding plan. (ii) Scientific uncertainty (i.e. the information used to implement the rebuilding plan could, in retrospect, be revised). For example, a new stock assessment may find that the rebuilding target (BMSY) is significantly different from what it was originally estimated to be. (iii) Failure of management measures to control fishing mortality to the planned level (Rosenberg et al., 2006; Milazzo, 2012). (iv) Environmental conditions that do not support average or better stock growth during the rebuilding period (Milazzo, 2012). To address the fact that a number of rebuilding plans were coming to an end, the 2009 revisions to the NS1 guidelines stated that, if a stock reached the end of its planned rebuilding period (Ttarget) and was not rebuilt, or the status was unknown pending a future stock assessment, then the rebuilding plan fishing mortality rate should not be increased until the stock has been demonstrated to be rebuilt (i.e. stock biomass is at or above BMSY). The guidelines state that if a stock has not rebuilt by TMAX, then the fishing mortality rate should be maintained at the rate in the rebuilding plan, or 75% of the maximum fishing mortality threshold (Flimit), whichever is less. This revision is a rational acknowledgement of the probabilistic nature of rebuilding projections and provides a transition from a rebuilding F to the F associated with the long-term ABC control rule. Despite the management challenges, NMFS and the Councils have been successful at rebuilding a number of stocks. Since 2000, 86 stocks have been determined to be overfished. By the end of 2012, over half of those stocks (45) are no longer overfished, and 32 stocks have been rebuilt to BMSY since 2001. There are still
Implementing a science-based system for preventing overfishing and guiding sustainable fisheries challenges that lie ahead, as there are currently 50 stocks in rebuilding plans. Many of these stocks are increasing in biomass, are no longer overfished (their biomass increased above their Blimit), and on are on track to rebuild. Others are not rebuilding as planned, in some cases, as a result of chronic overfishing. With new mandates to implement ACLs that prevent intentional overfishing, NMFS is optimistic that these stocks will soon begin to respond to reduced fishing pressure.
Data-poor situations One of the challenges of managing fisheries is setting appropriate management measures for stocks lacking enough information to conduct a stock assessment (i.e. they are “data-poor”). In a Frequently Asked Question document (http://www.nmfs.noaa .gov/msa2007/catchlimits.htm), NMFS advised that the ACL for data poor stocks could be set at a level to allow a fishery to maintain its average catch levels, or even set ACLs higher than recent average catch, as long as there is no information indicating that those levels are causing overfishing or stock depletion. Some potential protocols for implementing this approach that rely principally on historical catch levels are described in Berkson et al. (2011). Although this appears to be a simple and practical policy, in data-poor situations there remains a high degree of uncertainty in the appropriate catch level, leading some to believe that ACLs for data poor stocks are overly restrictive, and others to argue that they should be reduced further to limit the chance of overfishing. These data-poor ACLs at least provide a cap on the current fishery level until additional data to potentially justify a larger fishery can be obtained. Since the FCMA was enacted in 1976, the scientific information and stock assessment methods to inform fishery management have continually improved, and we have increased the number of stocks with stock assessments. As a result, a number of formerly data-poor stocks now have assessments. However, the status of many stocks is unknown. Of the 446 stocks and stock complexes reported in the 2012 Status of US Fisheries Report to Congress, 202 stocks and stock complexes have both a known overfishing and overfished status determination; and 149 stocks and stock complexes have neither an overfishing nor overfished status determination (NMFS, 2013). The remaining 95 stocks and stock complexes have either a known overfishing or overfished status determination, but not both. Although data collection and stock assessment is focused on those stocks that are considered to be most important to the fishery and most susceptible to overfishing, at least baseline monitoring should be occurring for all stocks that are included in FMPs. NMFS continually strives to improve its data collection and assessment programmes and expects to be able to assess more stocks in the future. To shed light on the question of whether typical fishery management approaches for data-poor stocks have adequately protected them from overfishing, we examined cases where status determinations were made for the first time (i.e. status was previously unknown). Between 2003 and 2012, 14% (6 of 44) of stocks that had a previous unknown overfishing status were determined to be subject to overfishing; and 21% (9 of 43) of stocks that had a previous unknown overfished status were determined to be overfished. This suggests that, for some stocks, past management strategies that were thought to be sustainable were not. However, these percentages are not much different from those for previously assessed stocks, and the stocks chosen for new assessments tend to be those for which there is some concern that the fishery is having a significant impact on the stock.
191
Data-poor stocks are often grouped into complexes so that management measures can be applied to a group of stocks, rather than individual stocks. The NS1 guidelines advise that stocks in complexes should have similar geographic distribution, life history, and vulnerabilities to the fishery. A methodology for determining the vulnerability of a stock is described in Patrick et al. (2010). The composition of stocks and stock complexes in FMPs is continually changing. For example, the number of stocks and stocks complexes changed from 537 in 2011 to 446 in 2012. This change reflects consolidation of stocks with unknown status into stock complexes. ACLs, and sometimes other biological reference points, are often set for the complex as a whole. Because these stock complexes are data-poor, ACLs for these stocks are often based on historical catch, not stock assessments.
Additional challenges There is a challenge in reconciling the approach to managing individual stocks in a multistock fishery vs. managing stocks as a complex. When managing individual stocks in a multistock fishery, each stock is assessed on an individual basis and has biological reference points associated with it. Management is intended to prevent overfishing of each stock. However, because species are rarely caught in exactly the same proportions as the ratios of their intended fishing mortality rates, it is extremely difficult to attain OY for all stocks in a multistock fishery while also preventing overfishing of each of these stocks (Shertzer and Williams, 2008). This results in the less productive stocks becoming a limiting factor that results in fishery management actions that curtail access to more productive stocks in the multistock fishery. As described previously, the NS1 guidelines allow a limited exception to the prevention of overfishing, however, to date, no management measures developed under this clause have been implemented, presumably due to the difficulty in demonstrating its benefits. Furthermore, the provisions of this clause cannot be invoked for stocks that are under rebuilding plans. The catch of stocks in rebuilding plans in fisheries that target on otherwise more productive stocks is one of the nation’s most challenging management problems. When stock complexes are created, the fishing impacts on individual stocks are generally unknown. The guidelines intend that one or more stocks in the complex be assessed as “indicator stocks” for the status of the entire complex. The impact to the other stocks is assumed to be the same as the fishery impact on the selected “indicator stock(s)”. The NS1 guidelines advise that indicator stocks should either be representative of the typical status of a complex or be chosen to represent the more vulnerable stocks in the complex. However, there is no guarantee that scientists can determine the vulnerability of all stocks or that the indicator stock is the “weakest”, or even a typical stock in the complex (Shertzer and Williams, 2008). Thus, by allowing biological stocks to be managed as a complex, perhaps overfishing of some of the included stocks is occurring at an unknown level. Implementing a larger buffer between the ABC and the OFL for complexes is one way to attempt to account for the greater uncertainty associated with complexes. Otherwise, the use of complexes may implicitly be allowing a “mixed-stock exception” to an unknown degree. The MSRA has given greater authority to the SSCs. An SSC is expected to recommend a biological catch limit (the ABC) that sets an upper limit to the Council’s setting of the ACL (Crosson, 2012). This creates considerable pressure on the SSC in the setting of the ABC and the degree to which scientific uncertainty can be taken into account when setting a buffer between the ABC and the
192 OFL. Although the stock assessment process and the SSC can use a purely biological analysis to calculate the OFL, the SSC must know the degree of risk-aversion, P*, of the Council and the assessment uncertainty to calculate the ABC. On the other hand, the Council cannot rationally select a P* level and codify this into an FMP without knowing the potential consequences of that selection. These potential consequences are generally best evaluated by having the science community conduct a management strategy evaluation to describe the trade-off between the short-term loss in fishing opportunity that results from reductions in P*, and the reduced chance of overfishing that accompanies the lower P*. In bioeconomic terms, Lee G. Anderson (pers. comm., 2011) advocates that Councils “keep increasing the buffer until the marginal benefit in terms of the expected increased discounted value of future production due to the reduced risk of ‘overfishing’ equals the marginal cost of the loss of current output”. With a few exceptions, the mandated timeline for the implementation of ACLs did not allow for such extensive bioeconomic evaluation. Most Councils opted for simpler ABC control rules, such as setting ABC ¼ 0.75 × OFL, or for adopting a tiered approach in which the top tier is a full P* approach, to be striven for when comprehensive assessments and trade-off analyses can be conducted, but simpler approaches are implemented in lower tiers for most stocks. The requirement for ACL not to exceed ABC, which itself is reduced from OFL, would seem to warrant an assertion that the fishery management regime in the United States has ended overfishing. The reality is more nuanced because the determination of overfishing can occur at different stages of the process and on different time frames. (i) Intentional overfishing occurs when the fishery management (catch) target is set at a higher level than the OFL. With the MSRA and the Councils’ implementation of measures consistent with the 2009 NS1 guidelines, the United States has ended this type of overfishing. However, stocks that previously were determined to be experiencing overfishing will retain this status until a new assessment can be conducted to verify that overfishing has ended. (ii) Overfishing due to management shortcoming occurs when fishery management procedures fail to keep the catch below the OFL, even when the target level of catch was set below the OFL. This could be accidental (e.g. in-season management procedures were in place but were implemented too late or failed to slow fishing effort sufficiently), or structural (e.g. no credible AMs were in place to keep catch under control within the fishing season, or lags in the monitoring of landings data could result in managers not knowing till months after the fact that an ACL has been exceeded). In FMPs that define overfishing based on annual catch exceeding the OFL, management shortcomings will be the typical way in which a regulatory finding of overfishing will be made. (iii) Scientific uncertainty can lead to a retrospective finding of overfishing. This occurs when a subsequent assessment update causes an upward revision of historical estimates of fishing mortality rates or downward revision of the fishing mortality limit. Whether this results in an official determination of overfishing will depend on the particular features of the FMP, including whether the overfishing determination is based on the fishing mortality rate exceeding Flimit and how far back in time such revisions are considered. Whether or
R. D. Methot et al. not this results in an official determination of overfishing, the best scientific information available now indicates that fishing has had too large an impact on the stock. This could indicate that a larger buffer between OFL and ABC is needed to guard against this type of overfishing. Although management uncertainty might be somewhat random from year to year, scientific uncertainty can be persistent for many years before new information and assessments result in revised estimates. Ralston et al. (2011) developed an approach to examine this structural uncertainty by looking at the history of assessments for US West Coast groundfish. (iv) The fourth level of overfishing is not yet formally defined, but is essentially ecosystem overfishing. This occurs when the model/paradigm under which the tactical, single-species estimates of OFLs are calculated is wrong, biased, or inadequate. We may not find out about this until decades later. It is important to anticipate this possibility and consider the cumulative impact of fishing on the entire ecosystem (Murawski, 2000). When managing at the system level, research suggests that MSY and other reference points should be more conservative than those based on traditional single-species stock assessments (Mueter and Megrey, 2006; Fogarty et al., 2012).
Conclusion Fisheries management in the United States has seen many changes since 1976. The MSA established what we now refer to as the EEZ, prevented foreign vessels from fishing in US waters, and established joint responsibility for managing domestic fisheries through the eight Regional Fishery Management Councils and NMFS. The MSA, since its inception, has used the concept of MSY to provide a basis for the acceptable level of impact that a fishery might have on a stock. Despite the emphasis on conservation and management of our natural resources, overfishing by US vessels occurred on a number of stocks, and in some cases for decades. The MSA and the NS1 guidelines were revised a number of times to address, among other things, the challenge of ending and preventing overfishing and rebuilding stocks, which resulted in the following major changes: (i) NMFS required, in the 1989 NS1 guidelines, that Councils specify definitions for overfishing (in terms of either fishing mortality rate or biomass). Subsequently, the most common overfishing definitions that were implemented referred to a fishing mortality rate that would reduce spawning biomass per recruit to 20 or 30% of the unfished level (Rosenberg et al., 1994). (ii) The SFA in 1996 established the statutory requirement that each FMP specify “objective and measureable criteria” for determining when a fishery is overfished. Subsequently, in the 1998 NS1 guidelines, NMFS required that bivariate SDC be established for stocks to determine both overfishing and overfished status. (iii) The SFA also established the requirement to rebuild overfished stocks to a level that can support MSY in 10 years or less (with some exceptions). (iv) In 2007, the MSRA required ACLs in each fishery “at a level such that overfishing does not occur”. The 2009 NS1 guidelines describe the ACL framework.
Implementing a science-based system for preventing overfishing and guiding sustainable fisheries One of the major aspects of the 2009 NS1 guidelines is the provision to account for scientific uncertainty. A Council’s SSC takes scientific uncertainty into account when setting the ABC below the OFL for a stock. The SSC recommends the ABC for a stock to their respective Council, and that number is very important because the Council’s ACL for a stock may not exceed the ABC recommendation. Thus, the explicit accounting for scientific uncertainty is a built-in, mandatory step in the fishery management process, and is in accordance with the precautionary approach described in the International Code of Conduct for Responsible Fisheries (FAO, 1995). From 2007 to 2012, the 46 Federal FMPs were amended to implement ACLs and AMs. This was a transformative process, because before the ACL requirement, some US fisheries were managed under a total allowable catch system, particularly in the North Pacific, but the majority were managed through effort controls (e.g. days at sea, closures) or without explicit accountability. The US fisheries management regime has been strengthened by an accountable and adaptable process that is designed to prevent overfishing from occurring (ACLs) and quickly responds if it does occur (AMs). The implementation of ACLs reflects tremendous efforts of fishers, fishing communities, and the Councils to make the difficult decisions and absorb the costs of conservation and investment in long-term economic and biological sustainability of the resource. NMFS and the Councils have seen some success over the years in their efforts to address overfishing and rebuild stocks. Between 2000 and 2012, the FSSI has increased from 357.5 to 616 (out of a possible score of 920; Figure 3). This increase reflects an improvement in our understanding of stock status and progress in ending overfishing and rebuilding stocks over time. Since 2000, 86 stocks have been determined to be overfished (biomass below Blimit), and NMFS and the Councils have rebuilt 32 of them (to BMSY or its proxy). In that same period, 80 stocks have been listed as subject to overfishing; NMFS and the Councils have ended overfishing on 51 of those stocks. With the implementation of ACLs and AMs and with the new mandate to end overfishing immediately upon implementing rebuilding plans, NMFS is optimistic that more stocks will come off the overfishing and overfished lists, and stocks will begin to respond to reduced fishing pressure. Despite these accomplishments, challenges do remain. Some challenges include developing and promoting the understanding of how to determine appropriate catch levels and management approaches for data poor stocks; improving data collection and assessment programmes to be able to assess more stocks; addressing differences between managing stocks as a complex vs. managing individual stocks in a multistock fishery; and incorporating social and economic factors in determining the appropriate response to scientific uncertainty. NMFS is currently considering how to best address these and other issues related to NS1. Whatever approach NMFS decides to take, NMFS will continue to apply the best scientific information available to inform our fisheries policy and management.
Acknowledgements The authors are grateful for comments provided by Grant Thompson, George Darcy, Kyle Shertzer, and three anonymous reviewers on earlier drafts of this paper.
References Berkson, J., Barbieri, L., Cadrin, S., Cass-Calay, S., Crone, P., Dorn, M., Friess, C., et al. 2011. Calculating acceptable biological catch for stocks that have reliable catch data only (Only Reliable Catch
193
Stocks – ORCS). NOAA Technical Memorandum, NMFS-SEFSC616. 56 pp. Butterworth, D. S., and Punt, A. E. 1999. Experiences in the evaluation and implementation of management procedures. ICES Journal of Marine Science, 56: 985– 998. Clark, W. G. 1993. The effect of recruitment variability on the choice of a target level of spawning biomass per recruit. Management of Exploited Fish, Alaska Sea Grant, pp. 233– 246. Crosson, S. 2012. The impact of empowering scientific advisory committees to constrain catch limits in US fisheries. Science and Public Policy, doi:10.1093/scipol/scs104. Darcy, G. H., and Matlock, G. C. 1999. Application of the precautionary approach in the national standard guidelines for conservation and management of fisheries in the United States. ICES Journal of Marine Science, 56: 853– 859. District of Columbia Circuit Court (D.C.Cir.). Court opinions. http://www.cadc.uscourts.gov/internet/home.nsf. FAO. 1995. Code of Conduct for Responsible Fisheries. FAO, Rome. 14 pp. Federal Register. 1977. Volume 42, page 34450, date 5 July 1977. http://heinonline.org. Federal Register. 1983. Volume 48, page 7402, date 18 February 1983. http://heinonline.org. Federal Register. 1989. Volume 54, page 30826, date 24 July 1989. http://heinonline.org. Federal Register. 1998. Volume 63, page 24212, date 1 May 1998. https://www.federalregister.gov/. Federal Register. 2009. Volume 74, page 3178, date 16 January 2009. https://www.federalregister.gov/. Fogarty, M. J., Overholtz, W. J., and Link, J. S. 2012. Aggregate surplus production models for demersal fishery resources of the Gulf of Maine. Marine Ecology Progress Series, 459: 247 – 258. Goodyear, C. P. 1993. Spawning stock biomass per recruit in fisheries management: foundation and current use. In Risk Evaluation and Biological Reference Points for Fisheries Management, pp. 67– 81. Ed. by S. J. Smith, J. J. Hunt, and D. Rivard. Canadian Special Publication of Fisheries and Aquatic Sciences, 120. 442 pp. Mace, P. M. 1994. Relationships between common biological reference points used as thresholds and targets of fisheries management strategies. Canadian Journal of Fisheries and Aquatic Sciences, 51: 110– 122. Mace, P. M., and Sissenwine, M. P. 1993. How much spawning per recruit is enough? In Risk Evaluation and Biological Reference Points for Fisheries Management, pp. 101– 118. Ed. by S. J. Smith, J. J. Hunt, and D. Rivard. Canadian Special Publication of Fisheries and Aquatic Sciences, 120. 442 pp. Methot, R. D., Jr, and Wetzel, C. R. 2013. Stock synthesis: a biological and statistical framework for fish stock assessment and fishery management. Fisheries Research, http://dx.doi.org/10.1016/j.fishres. 2012.10.012. Milazzo, M. J. 2012. Progress and problems in U.S. marine fisheries rebuilding plans. Reviews in Fish Biology and Fisheries, 22: 273 – 296. Mueter, F. J., and Megrey, B. A. 2006. Using multi-species surplus production models to estimate ecosystem-level maximum sustainable yields. Fisheries Research, 81: 189– 201. Murawski, S. A. 2000. Definitions of overfishing from an ecosystem perspective. ICES Journal of Marine Science, 57: 649– 658. doi:10.1006/ jmsc.2000.0738. Murawski, S. A. 2010. Keynote: rebuilding depleted fish stocks: the good, the bad, and, mostly, the ugly. ICES Journal of Marine Science, 67: 1830– 1840. NMFS. 2013. Status of Stocks 2012—Annual Report to Congress on the Status of U.S. Fisheries. U.S. Department of Commerce, NOAA, National Marine Fisheries Service, Silver Spring, MD. http://www. nmfs.noaa.gov/sfa/statusoffisheries/SOSmain.htm.
194 NOAA. 1986. NOAA Fishery Management Study, Department of Commerce. http://www.gpo.gov/fdsys/pkg/CZIC-sh328-n62 – 1986/html/CZIC-sh328-n62-1986.htm. Patrick, W. S., Morrison, W., Nelson, M., and Gonza´lez-Marrero, R. L. 2013. Factors affecting management uncertainty in U.S. fisheries and methodological solutions. Ocean and Coastal Management, 71: 64 – 72. Patrick, W. S., Spencer, P., Link, J., Cope, J., Field, J., Kobayashi, D., Lawson, P., et al. 2010. Using productivity and susceptibility indices to assess the vulnerability of United States fish stocks to overfishing. Fishery Bulletin, 108: 305 – 322. Patterson, K., Cook, R., Darby, C., Gavaris, S., Kell, L., Lewy, P., Mesnil, B., et al. 2001. Estimating uncertainty in fish stock assessment and forecasting. Fish and Fisheries, 2: 125– 157. doi:10.1046/ j.1467-2960.2001.00042.x. Pew Oceans Commission and Panetta, L. 2003. America’s living oceans: charting a course for sea change: a report to the nation: recommendations for a new ocean policy: summary report. Pew Oceans Commission, Arlington, VA. Ralston, S., Punt, A. E., Hamel, O. S., DeVore, J. D., and Conser, R. J. 2011. A meta-analytic approach to quantifying scientific uncertainty in stock assessments. Fishery Bulletin, 109: 217– 231. Restrepo, V. R. (Convener), Thompson, G. G., Mace, P. M., Gabriel, W. L., Low, L. L., MacCall, A. D., Methot, R. D., et al. 1998. Technical guidance on the use of precautionary approaches to implementing national standard 1 of the Magnuson – Stevens Fishery Conservation and Management Act. NOAA Technical Memorandum, NMFS-F/SPO-31. 54 pp.
R. D. Methot et al. Rosenberg, A. A., Mace, P., Thompson, G., Darcy, G., Clark, W., Collie, J., Gabriel, W., et al. 1994. Scientific review of definitions of overfishing in U.S. Fishery Management Plans. U.S. Department of Commerce, NOAA Technical Memorandum, NMFS-F/SPO-17. 205p. Rosenberg, A. A., Swasey, J. H., and Bowman, M. 2006. Rebuilding US fisheries: progress and problems. Frontiers in Ecology and the Environment, 4: 303 – 308. Shertzer, K. W., Prager, M., and Williams, E. H. 2008. A probabilitybased approach to setting annual catch levels. Fishery Bulletin, 106: 225– 232. Shertzer, K. W., and Williams, E. H. 2008. Fish assemblages and indicator species: reef fishes off the southeastern United States. Fishery Bulletin, 106: 257– 269. Tromble, G. R., Lambert, D. M., and Benaka, L. R. 2009. Prelude to sustainability: ending overfishing in U.S. fisheries. In Our Living Oceans, Report on the Status of U.S. Living Marine Resources, 6th edn, pp. 57 – 66. U.S. Department of Commerce, NOAA Technical Memorandum, NMFS-F/SPO-80. http://spo.nmfs.noaa.gov/ olo6th-edition.htm. United States. 2004. An Ocean Blueprint for the 21st Century, Final Report. US Commission on Ocean Policy, Washington, DC. United States Code (U.S.C.). The U.S.C. is the codification of the general and permanent laws of the U.S. http://www.gpo.gov/fdsys/browse/ collectionUScode.action?CollectionCode=USCODE. Worm, B., Hilborn, R., Baum, J. K., Branch, T. A., Collie, J. S., Costello, C., Fogarty, F. J., et al. 2009. Rebuilding Global Fisheries. Science, 325: 578– 585. doi:10.1126/science.1173146.
Handling editor: Sarah Kraak
