Seafood Watch Seafood Report

Blackfin tuna Thunnus atlanticus

(Image © Diane Rome Peebles)

Western Atlantic Ocean

Final Report September 7, 2010

Lindsey Peavey Consulting Researcher

MBA SeafoodWatch®_Blackfin Tuna Report September 7, 2010

About Seafood Watch® and the Seafood Reports

Monterey Bay Aquarium’s Seafood Watch® program evaluates the ecological sustainability of wild-caught and farmed seafood commonly found in the United States marketplace. Seafood Watch® defines sustainable seafood as originating from sources, whether wild-caught or farmed, which can maintain or increase production in the long-term without jeopardizing the structure or function of affected ecosystems. Seafood Watch® makes its science-based recommendations available to the public in the form of regional pocket guides that can be downloaded from www.seafoodwatch.org. The program’s goals are to raise awareness of important ocean conservation issues and empower seafood consumers and businesses to make choices for healthy oceans.

Each sustainability recommendation on the regional pocket guides is supported by a Seafood Report. Each report synthesizes and analyzes the most current ecological, fisheries and ecosystem science on a species, then evaluates this information against the program’s conservation ethic to arrive at a recommendation of “Best Choices”, “Good Alternatives” or “Avoid”. The detailed evaluation methodology is available upon request. In producing the Seafood Reports, Seafood Watch® seeks out research published in academic, peer-reviewed journals whenever possible. Other sources of information include government technical publications, fishery management plans and supporting documents, and other scientific reviews of ecological sustainability. Seafood Watch® Research Analysts also communicate regularly with ecologists, fisheries and aquaculture scientists, and members of industry and conservation organizations when evaluating fisheries and aquaculture practices. Capture fisheries and aquaculture practices are highly dynamic; as the scientific information on each species changes, Seafood Watch®’s sustainability recommendations and the underlying Seafood Reports will be updated to reflect these changes.

Parties interested in capture fisheries, aquaculture practices and the sustainability of ocean ecosystems are welcome to use Seafood Reports in any way they find useful. For more information about Seafood Watch® and Seafood Reports, please contact the Seafood Watch® program at Monterey Bay Aquarium by calling 1-877-229-9990.

Disclaimer Seafood Watch® strives to have all Seafood Reports reviewed for accuracy and completeness by external scientists with expertise in ecology, fisheries science and aquaculture. Scientific review, however, does not constitute an endorsement of the Seafood Watch® program or its recommendations on the part of the reviewing scientists. Seafood Watch® is solely responsible for the conclusions reached in this report.

Seafood Watch® and Seafood Reports are made possible through a grant from the David and Lucile Packard Foundation.

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Table of Contents

I. Executive Summary 3 II. Introduction 8 III. Analysis of Seafood Watch® Sustainability Criteria for Wild-caught Species Criterion 1: Inherent Vulnerability to Fishing Pressure 15 Criterion 2: Status of Wild Stocks 17 Criterion 3: Nature and Extent of Bycatch 20 Criterion 4: Effect of Fishing Practices on Habitats and Ecosystems 36 Criterion 5: Effectiveness of the Management Regime 38 IV. Overall Evaluation and Seafood Recommendation 42 V. References 44 VI. Appendices Appendix I: Wild Capture Fisheries Evaluation 58

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I. Executive Summary

Blackfin tuna (Thunnus atlanticus) have a limited range and occur only in the western Atlantic Ocean approximately from the Massachusetts coast of the United States south to Rio de Janeiro in Brazil. Blackfin tuna migrate offshore of Florida to spawn from April through November and to deeper waters off the continental shelf in the Gulf of Mexico from June through September. There is limited specific information on blackfin tuna landings because not all countries report species-specific landings. As a result, existing reports likely underestimate total catches of blackfin tuna. Most International organizations and databases (i.e., Food and Agriculture Organization (FAO), The Fisheries Service Foreign Trade, etc.) fail to document blackfin tuna specifically and instead lump them together with “unspecified tuna”, “other tuna” or “small tuna- like” species. Although information is limited, the literature suggests blackfin tuna are heavily exploited, and catches are increasing despite limited information about landings (both US and international) and stock status.

Blackfin tuna exhibit life history characteristics making them inherently resilient to fishing pressure: low age at maturity, short life span and a fast growth rate. The effects of this resilience on maintaining blackfin stocks are unknown due to the lack of stock assessments. Conference proceedings report on blackfin tuna in reference to their biology and toxicology, both specifically and in the context of the larger-scale categories previously mentioned (e.g., “small tuna-like species”). However, demonstrated ecological roles, stock status and management recommendations are not included in these reports. Accordingly, the International Commission for the Conservation of Atlantic Tunas (ICCAT) has recently called for reports on small tuna species landings for all cooperating parties (Ortiz, pers. comm.). Given the current lack of information, however, the status of blackfin tuna stocks is deemed to be a moderate conservation concern according to Seafood Watch®.

In 2008, the primary gears used in the blackfin tuna fisheries were troll, handline, rod and reel, and bait boat, but purse seine and longline gear were also used. Levels of bycatch vary according to gear type. Purse seine sets on unassociated schools are considered to have moderate bycatch, while purse seine sets on floating objects or fish aggregating devices (FADs) are deemed a critical conservation concern because they incur bycatch of species of concern and are a contributing factor in limiting the recovery of these species. Troll, baitboat, handline, and rod and reel gear types typically have low bycatch, and therefore the incidence of bycatch in blackfin-targeted fisheries using these gears is low. Longline gear, a secondary method for catching blackfin tuna that is used less frequently, incurs significant bycatch. Observer records of bycatch are nonexistent for blackfin tuna-targeted fisheries. Given these uncertainties and the dire status of several common bycatch species such as leatherback sea turtles and sharks, international longlining is a critical conservation concern. US longline bycatch rates have been declining since 2005 due to bycatch mitigation measures, and therefore the domestic longline fisheries have improved to a high conservation concern.

Purse seine, pelagic longline, handline, rod and reel, baitboat and troll gear have negligible habitat effects. Handline, rod and reel, baitboat and troll tuna fisheries are able to take tuna from the ecosystem with minimal bycatch of other large predatory species. There is evidence that tuna longline and FAD purse seine fisheries are having negative impacts on tuna species, but there is

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conflicting evidence as to whether those fisheries are negatively impacting the ecosystem as a whole. It is likely that the negative impacts of FAD purse seine and longline fisheries on tuna and sharks may substantially disrupt the food web. Given this information, the effects on habitats and ecosystems from the handline, rod and reel, baitboat, troll and unassociated purse seine blackfin tuna fisheries are a low conservation concern, while the effects from the longline and FAD purse seine blackfin tuna fisheries are a moderate conservation concern.

Due to lack of data on the western Atlantic blackfin tuna stock, it is unclear if management has been successful in maintaining the long-term productivity of the stock. While bycatch is not an issue in the handline, rod and reel, troll, baitboat and unassociated purse seine fisheries, bycatch is a concern in the longline and purse seine fisheries. Currently, no bycatch plan has been implemented for the purse seine fisheries or international longline fisheries. There are no known comprehensive observer programs for any of the international fisheries mentioned in this report. The US has implemented general bycatch reduction measures, but they have not been proven to be effective at reducing bycatch of all non-target species. There is no international enforcement program, as enforcement is the responsibility of individual countries and not the international management agencies. Given this information, management of the handline, rod and reel, baitboat and troll fisheries is ineffective and of high conservation concern, while management of the purse seine and longline fisheries is a critical concern.

The inherent vulnerability of blackfin tuna is low and the stock status is of moderate concern. The amount and severity of bycatch varies by gear type, as do habitat and ecosystem effects, and management effectiveness. These differences determined the following final recommendations: Blackfin tuna caught using handline, rod and reel, baitboat and troll gear are a Good Alternative due to low bycatch, low habitat and ecosystem effects, and ineffective management. All blackfin tuna caught with longlines are ranked as Avoid. Blackfin tuna caught with longlines in the US are ranked as Avoid due to high bycatch rates and critically ineffective management. International longline fleets have bycatch rates of critical conservation concern, moderate impacts to the habitat and ecosystem and critically ineffective management; therefore, blackfin tuna caught in this manner are ranked as Avoid. Blackfin tuna caught with unassociated purse seines are ranked as Avoid due to critically ineffective management. Blackfin tuna caught with FAD purse seines are also ranked as Avoid due to a critical ranking for bycatch and management.

According to the most recent ICCAT data (2008), approximately 60% of blackfin tuna was caught with handline, rod and reel, baitboat and troll gear, 18% was caught with longline and purse seines (proportions of unassociated and FAD are unknown), and 22% was caught with unclassified gear.

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Table of Sustainability Ranks

Conservation Concern Sustainability Criteria Low Moderate High Critical Inherent Vulnerability √ Status of Stock(s) √ √ Handline, √ FAD √Unassociated Nature of Bycatch rod and reel, √ US longline purse seine / baitboat, purse seine international troll longline √ Handline, rod and reel, Habitat & Ecosystem Effects baitboat, √ FAD purse troll, seine; longline unassociated purse seine √ Handline, √ Purse Management Effectiveness rod and reel, seine / baitboat, troll longline

About the Overall Seafood Recommendation: • A seafood product is ranked Best Choice if three or more criteria are of Low Conservation Concern (green) and the remaining criteria are not of High or Critical Conservation Concern. • A seafood product is ranked Good Alternative if the five criteria “average” to yellow (Moderate Conservation Concern) OR if the “Status of Stocks” and “Management Effectiveness” criteria are both of Moderate Conservation Concern. • A seafood product is ranked Avoid if two or more criteria are of High Conservation Concern (red) OR if one or more criteria are of Critical Conservation Concern (black) in the table above.

Overall Seafood Recommendation:

Seafood Watch® Gear Used Recommendation Best Choice Good Alternative Handline, rod and reel, baitboat, troll Avoid Purse seine, longline

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Common Acronyms and Terms

BMSY Biomass that can support maximum sustainable yield CPUE Catch per unit effort CITES Convention on International Trade in Endangered Species EEZ Exclusive Economic Zone ESA Endangered Species Act FAD Fish Aggregating Device FAO Food and Agriculture Organization FFA Forum Fisheries Agency FMP Fishery Management Plan FR Federal Rule HMS Highly Migratory Species IATTC Inter-American Tropical Tuna Commission ICCAT International Commission for the Conservation of Atlantic Tunas IUCN International Union for Conservation of Nature k Body growth coefficient L∞ Asymptotic fish length MMPA Marine Mammal Protection Act MSY Maximum sustainable yield NCE North Central East Atlantic Ocean NMFS National Marine Fisheries Service NSPF Other, not specified r Intrinsic rate of increase SCRS Stranding Committee on Research and Statistics VBGF von Bertalanffy Growth Function WECAFC Western Central Atlantic Fisheries Commission

Gear Type Definitions

Baitboat: ICCAT uses the term “baitboat” for what are known as pole and line vessels by FAO and other organizations (Restrepo 2006). The definition of pole and line is provided below.

Handline: Fisheries using a single fishing line with one or more lures or baited hooks attached.

Longline: Longlines consist of a main horizontal fishing line that can be as much as 50–65 nautical miles long. Smaller vertical lines with baited hooks are spaced intermittently along the main line and can be rigged to fish at various depths depending on the target species and fishing conditions. Longlines used to target tuna are pelagic longlines and are fished in the upper water column.

Pole and line: Fishers use a pole with a fixed length line and a barbless hook with either an artificial lure or live bait. In this way, fish are caught one at a time, and fishers can immediately throw back any unwanted catch. Pole and line caught is another term for baitboat caught. Pole and line can be used in the open ocean or on FADs.

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Purse seine: Purse seining involves encircling a school of tunas with a long net (typically 200 meters deep and 1.6 kilometers long). The net is weighted at the bottom and the top is kept at the top of the water column by a series of floats. One end of the net is pulled out from the main vessel by a skiff, which encircles the school of tuna, and the bottom of the net is then closed by a purse line run through the leadline by a series of rings. The net is then hauled in, and most of the net is broad onboard, leaving a small volume of water in the net and allowing the catch to be brought onboard using a large dip net (NRC 1992). There are several types of purse seine sets, those set on dolphins (dolphin sets), those set on floating objects or FADs (floating object sets) and those set on tuna not associated with either dolphins or a floating object (unassociated sets). Note that blackfin tuna are caught with purse seines set on FADs or unassociated schools only, as they do not typically school with dolphins.

Rod and reel: Rod and reel refers to a fishing rod with a manually or electrically operated reel attached.

Trolling: Trolling consists of towing artificial lures with barbless hooks behind the fishing vessel (Childers 2003). Troll gear is also called jig gear. Trolling can be done in the open ocean or on FADs.

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II. Introduction

Blackfin tuna (Thunnus atlanticus) is one of the only tunas with a limited range and occurs only in the Western Atlantic Ocean approximately from the Massachusetts coast of the United States south to Rio de Janeiro in Brazil (Figure 1). Blackfin tuna is a neritic species native to the following ecosystems: Western Atlantic Ocean, Caribbean Sea, East Brazil Shelf, Gulf of Mexico, North Brazil Shelf, and the Northeast US Continental Shelf (Majkowski 2005; Froese and Pauly 2007). Blackfin tuna are abundant in tropical regions (water temperature 20° C and above) and is known to be a highly migratory species (Collette 2007). Blackfin tuna migrate to higher latitudes to more temperate waters in the summer months and have been noted as far north as Nova Scotia (Mather III 1962). The distribution of this species has been reported to be related to factors such as water color and clarity, steepness of the continental shelf, water temperature, plankton concentrations caused by upwelling and current rips, and runoff from land (de Sylva et al. 1987). The vertical range of blackfin tuna has been reported as 0–250+ meters (m), with a typical depth to bottom of ~300 m (de Sylva et al. 1987). Blackfin tuna are commonly encountered in large mixed schools, most frequently with skipjack tuna (Katsuwonus pelamis) (Gardieff 2008). Blackfin tuna have also been noted to school with little tunny (Euthynnus alletteratus) in the nearshore off Puerto Rico (de Sylva et al. 1987). Historically, blackfin tuna have been documented in mixed schools with large numbers of sharks (Mather III 1962); however, this has not been documented recently, perhaps due to the decline of shark populations in the Western Atlantic. According to various sport-fishing publications, schools of blackfin tuna have been noted to associate with seabirds during feeding frenzies at the surface De Sylva et al. (1987) reported blackfin tuna swimming in schools at subsurface depths undetectable with the naked eye.

Natural predators of adult blackfin tuna include dolphinfish (Coryphaena hippurus), skipjack tuna, white sharks (Charcharadon charcarius) and, most commonly, blue marlin (Makaira nigricans). Various seabirds, little tunny, white marlin (Tetrapturus albidus), yellowfin tuna (Thunnus albacares) and other tuna and tuna-like fishes prey on blackfin tuna during their earlier life cycle stages (de Sylva et al. 1987; Gardieff 2008). Cannibalism has been noted to occur among blackfin as well (Gardieff 2008).

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Figure 1. World distribution map for blackfin tuna (Figure from Gardieff 2008).

In the Western Central Atlantic (FAO Fishing Area No. 31, Figure 2), which encompasses most of the blackfin tuna range except for its northern and southern margins, tunas, tuna-like species and other large pelagic fishes contribute a relatively small proportion of total fishery landings (about 4% from 1986 to 1990) (Mahon 1996). Blackfin tuna is not a primary commercial tuna species; however, it is still an economically viable fishery (including sport-fishing) for several countries such as Trinidad and Tobago, Cuba, Venezuela, Puerto Rico and Barbados (Mahon 1996). It has been noted as an important resource in the Caribbean Sea and adjacent regions (Sturm 1991).

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Figure 2. The approximate Exclusive Economic Zones of Western Central Atlantic Fisheries Commission countries (Figure from Mahon 1996).

Little is known about blackfin tuna stocks. Mahon (1996) reported the average annual landings of blackfin tuna in the Western Central Atlantic to be 3,000 metric tons (mt) between 1989 and 1992 (2,632 mt in the WECAFC region) but indicated that the status of the stock was unknown (Figure 3). The highest landings in the Atlantic reported by the International Commission for the Conservation of Atlantic Tunas (ICCAT) were over 4,500 mt in 2002, which decreased to just under 2,000 mt in 2006 (Figure 4).

Records of landings have been poorly documented and probably underestimated. Publications have similar but varying records of landings (Figures 3 & 4). The ICCAT regularly collects and reports blackfin catch data from participating countries (Figure 4). Inconsistent data reported by only a portion of the countries fishing for blackfin make accurate stock assessments extremely difficult. As blackfin tuna frequently school with skipjack, many catch reports do not separate the two species, and therefore catches of one or the other of these species may be underreported (de Sylva et al. 1987). Males have been noted to dominate catches of adult blackfin tuna (Collette 2007), which was confirmed in 2000 in a study completed by Taquet et al. (2000) who captured blackfin tuna around fish aggregating devices (FADs) in Martinique. Their results showed 80% of the blackfin tuna catch were males ranging from 30–82 cm fork length (FL).

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Figure 3. WECAFC blackfin tuna landings 1970–1992 (Mahon 1996).

Total Blackfin Catches (1950 - 2006)

5000 4500 4000 3500 3000 2500 2000 1500 1000 500 0 2 6 8 6 8 0 2 6 2 4 8 2 4 6 8 2 6 5 5 6 7 7 8 9 9 0 0 1950 19 1954 19 195 1960 1962 1964 19 196 19 197 1974 19 1978 1980 19 198 1986 198 1990 19 199 19 199 2000 20 2004 20 Year

Figure 4. Total Atlantic blackfin tuna catches (in metric tons) from 1950 to 2006 (Data from ICCAT July 2008).1

Intermittent and outdated regional fishing activity summaries have been made available in various reports such as the 2002 FAO Western Central Atlantic Fishery Commission report, summarized in Table 12.

1 See Appendix I for complete data table.

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Table 1. 2001 Summary of high seas pelagic fishing activity for blackfin tuna in the Lesser Antilles (Data from FAO 2002). Antigua Region Barbuda Cuba Grenada Guadeloupe Martinique Trinidad Caught as a Target Species or "Other" Species Other Target Target Other Other Target Sport Commercial Artisanal Commercial Commercial, Type of Fishery trolling trolling trolling trolling artisanal Commercial longlining No. of Active Registered Boats 35 42 215 758 864 8 Trolling around flotsam Trolling around Pelagic longline 300– or flights; flotsam or 1,000 hooks on a main Rods and Pole and Trolling, surface flights; surface line 24 km to 88 km long Fishing Gear reels line hand lines handlines handlines about 30 to 50m depth 4–40 miles east Antigua NW, SW, of Guadeloupe EEZ, E, N, S of Off the N and E coasts of Fishing Area Barbuda NCE3 Grenada EEZ Martinique Trinidad and into the EEZ Activity Time Period Not listed Not listed Not listed Dec–May Dec–June Year-round Peak Times Not listed Not listed Not listed Jan & March Not listed Nov–Apr

Data reported by ICCAT (2009c) show that participating countries mostly listed the gear used to target blackfin as “unclassified” until 2003 when trolling, rod and reel, and purse seining were reported to be the primary fishing gears used to target blackfin (Table 2, Figure 5). Since then, the primary fishing gears used have varied annually. In 2008, countries listed a large portion of gear as “unclassified” once again, but trolls and purse seines were the primary specified gears types used (Table 2, Figure 5) (ICCAT 2009c).

2 Note that not all countries and islands in the Caribbean Sea are reportedly fishing specifically for blackfin tuna; however, the fishing effort may not be reported and documented, or perhaps they are targeting other species and catch blackfin tuna as unreported usable and marketable bycatch. 3 The referenced report does not provide a definition for the fishing area denoted “NCE”. The author of the report died in 2006. His colleague Servando V. Valle believes the acronym stands for “North Central East”, but is not certain.

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Table 2. Gear types used to capture blackfin tuna between 2000 and 2007; catches are reported in metric tons. The dominant gear type is highlighted in yellow for each year (Data from ICCAT 2009c).

Year Unclassified Gillnet Longline Purse Seine Rod and Reel Troll Handline Baitboat 2000 1,393 123472293057117 2001 1,648 4788914240129859 2002 2,801 0 343 324 292 0 23 972 2003 47 1 33 204 374 504 32 108 2004 5022605 641 384 24 245 2005 5 0 23 121 196 470 19 194 2006 246 0 384 165 8 211 42 71 2007 5016742 7 462 20 267 2008 254 0 10 202 6 481 37 171

100%

80% Baitboat Handline 60% Troll Rod and Reel 40% Purse Seine Longline 20% Unclassified Percentage of Total Percentage

0% 2000 2001 2002 2003 2004 2005 2006 2007 2008 Year

Figure 5. Percentage of gear types used to capture blackfin tuna between 2000 and 2007 (Data from ICCAT 2009c).

Scope of the analysis and ensuing recommendation This report evaluates blackfin tuna caught in the Western Central Atlantic with handline, rod and reel, baitboat, troll, purse seine and pelagic longline gear.

Availability of Science Information on the biology of blackfin tuna is fairly abundant and available in resources such as FishBase, scientific journal articles, government documents and books. However, information on the role blackfin tuna plays in the ecosystem (coastal and pelagic) is sparse, and only a limited number of studies have been conducted specifically on blackfin tuna. The same holds true for blackfin tuna stocks and individual fisheries, and to a lesser extent for fisheries management.

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Most fisheries information is provided in government documents, conference and meeting proceedings, scientific journals, mass media articles (newspapers, magazines, public websites, etc.) or gray literature, and the information is often minimal and presented as part of the larger context of ‘small tunas’ or even generalized to all tuna species. No stock assessments are available, and regional landings seem to be reported sparingly. There are no observer data available (perhaps no coverage at all) on bycatch and discards in any of the targeted blackfin fisheries. This report includes all sources mentioned, and as new information becomes available, especially regarding stock assessments and fisheries management, this report will be revisited and revised.

Market Availability Common and market names (in English) Thunnus atlanticus is known in the US as blackfin tuna, Atlantic blackfin tuna or deep-bodied tunny (Collette 2007).

Seasonal availability Blackfin tuna is available year-round.

Product forms Blackfin tuna is sold whole (fresh or on ice) and as fillets (NMFS 2008b).

Import and export sources and statistics The National Marine Fisheries Service (NMFS) landings database provides information on blackfin tuna. North Carolina and Florida land the majority (88%) of the blackfin tuna caught in the US (Figure 6) (NMFS 2008a). Import and export data specifically for blackfin tuna are not available as blackfin tuna is most often grouped together with “small tuna-like species.” The NMFS Foreign Trade database does not have specific data for blackfin tuna, only ”other/not specified tuna species,” encompassing all tuna species other than albacore, bigeye, bluefin, skipjack and yellowfin. Therefore, it is unclear how much blackfin sold in the US market comes from the US and how much is imported.

7% 4% 1% North Carolina 44% Florida Louisiana South Carolina 44% Texas

Figure 6. Sources of blackfin tuna caught in the US, 2008 (data from NMFS 2008a).

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III. Analysis of Seafood Watch® Sustainability Criteria for Wild-caught Species

Criterion 1: Inherent Vulnerability to Fishing Pressure

Blackfin tuna is a member of the Scombridae family (mackerels and tunas) and is thus classified along with “small tunas” (Louisiana SeaGrant 2008). The intrinsic rate of increase (‘r’) has not been published in the literature and is therefore considered unknown in this report. Typical adults weigh 4.5–9 kg and measure slightly over 100 cm (Collette 2007); they have been known to reach over 8 kg (40 lbs) (Gardieff 2008). Blackfin tuna are short-lived and fast growing, with a maximum age of at least five years. Blackfin tuna reach sexual maturity at approximately two years of age (40–50 cm; 4–6 lbs in weight), and their growth rate is reported at 1–1.5 cm per month (with a von Bertalanffy coefficient k = 0.33) resulting in a minimum population doubling time of 1.4–4.4 years (Gardieff 2008; Louisiana SeaGrant 2008).

Spawning occurs April through November off the coast of Florida and June through September in the Gulf of Mexico in deep water off the continental shelf (Gardieff 2008). This is in contrast the regular habitat of blackfin during feeding and schooling. as they are commonly encountered close to shore (less than 200 m in depth) (Mather III 1962). It is estimated that the average annual egg production per female is approximately 249,300 (de Sylva et al. 1987).

Secondary factors Blackfin tuna is one of the only tuna species with a limited range, and they occur only in the Western Atlantic Ocean from approximately the Massachusetts coast of the United States south to Rio de Janeiro in Brazil (Gardieff 2008). There is no evidence that the habitat has been negatively altered by non-fishery impacts.

Blackfin tuna have special behaviors that increase the ease and population consequences of their capture in fisheries. Blackfin tuna feed on stomatopod and fish larvae, adult shrimp,and crabs as well as juvenile and adult epipelagic fish and squid (Louisiana SeaGrant 2008). The literature is unclear about feeding behaviors but suggests that blackfin tuna descend to depths (perhaps the thermocline or pycnocline) to feed during daylight hours and rise to the surface at dusk and dawn to feed on zooplankton and larval fish assemblages, sinking again at twilight (de Sylva et al. 1987). This model corresponds with fishing success observed near moored fish aggregating devices (FADs) in the Lesser Antilles (Doray et al. 2004). In addition, blackfin tuna tend to associate and school with skipjack tuna in coastal waters making them more susceptible to incidental capture (Collette 2007).

Scientists are currently expressing concern about how FAD fishing impacts tuna populations, specifically because capturing large proportions of young fish may threaten the viability of the population (Hallier and Gaertner 2007). Note that all methods used to catch blackfin tuna can be, and are, used on FADs; however, handline, rod and reel and baitboat methods are able to quickly return non-target species or undersized fish to the sea alive. Troll fishing is not as benign since the bycatch of undersized and/or damaged fish can be higher, although still considerably less than longlining and purse seining (Childers 2003). Purse seine bycatch is estimated at 10% of total catch (Bromhead et al. undated; Bailey et al. 1996), and longline bycatch is estimated at 10–22% of total catch (Kelleher 2004; Lewison et al. 2004; Kaplan

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2005). The behavioral tendency of tuna to associate with FADs may have some long-term effects including loss of genetic quality, slowed population growth, and negative interactions between industrial and artisanal fisheries (Hallier and Gaertner 2007). Since FADs are being used to capture blackfin tuna (see “Criterion 2: Status of Wild Stocks” for additional details), especially in the Caribbean Sea, these concerns are important, as it is possible this type of fishing pressure may alter the vulnerability of tuna that associate with FADs.

Table 5. Life history characteristics of blackfin tuna.

Intrinsic Rate of Age at Growth Max Species Special Max Size Fecundity Sources Increase Maturity Rate Age Range Behaviors (r) Mather III 1962; School de Sylva with et al. Estimated Limited: skipjack 1987; VBGF4: average Massachusetts in coastal Doray et 5 5+ ~108 cm, annual coast (US) areas; al. 2004; Unknown 2 years k=0.33 , L∞=72 years 20+ lbs production south to the migrate Collette cm ~249,300 Rio de Janeiro offshore 2007; eggs/female (Brazil) to spawn Gardieff in pelagic 2008; waters Louisiana SeaGrant 2008

Synthesis Blackfin tuna have a low age at maturity, high growth coefficient and a low maximum age. The limited geographic range of blackfin tuna could hinder their success because their location is predictable (especially when FADs are utilized) in coastal areas when feeding in mixed schools. The tendency of blackfin to school with other species, often with skipjack, increases their likelihood of capture. The species vulnerability effects of capturing blackfin tuna associated with FADs are unknown—further research is needed to determine whether and how population dynamics are affected. Based on their low age at sexual maturity and high growth rate, Seafood Watch® considers blackfin tuna to be inherently resilient to fishing pressure.

Inherent Vulnerability Rank

Resilient Moderately Vulnerable Highly Vulnerable

4 von Bertalanffy Growth Function (VBGF) = a commonly used growth function in fisheries science to determine length as a function of age. L∞ is asymptotic length, and k is body growth coefficient. Note that maximum size may be larger than L∞ due to individual variation around L∞. 5 This k value was noted as high due to the author’s method of including very small eggs in the counts. Collette 2007 listed k=0.22.

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Criterion 2: Status of Wild Stocks

In general, tuna stocks in the Atlantic Ocean are heavily exploited (Miyake and Kebe 2005). Principal market tunas (i.e., albacore, bluefin, yellowfin and bigeye) generally have much more comprehensive data available, including extensive stock assessments. Knowledge and data about other species of tuna and tuna-like species, however, is sparse, unreliable or non-existent (Majkowski 2005). Mahon (1996) reported that most of the small tuna species have not been assessed, although they have been widely exploited for decades. Little is known about blackfin tuna stocks. A steady decline in captures in the Cuban blackfin tuna fishery, which was once the largest blackfin tuna fishery (throughout the 1980s), was reported by the ICCAT in 1989 and was possibly due to an increase in pressure from the Venezuelan fishery (Carles and Valle 1989).

No studies have been conducted to identify or assess blackfin tuna stocks, and their classification status is therefore unknown (Table 6). The UN Fish Stocks Agreement6 calls for precaution when information is uncertain, unreliable or inadequate (FAO 1996; Majkowski 2005). Seafood Watch judges uncertainty based on the information available; therefore, the blackfin tuna stock status is considered highly uncertain in this report as there is little to no reliable information available. Due to this lack of reliable information, classification status, population abundance, fishing mortality, trends in abundance, and current age, size and sex distributions are all unknown.

A trend of increasing artisanal and small-scale fishing effort directed at coastal and pelagic tuna species (including blackfin tuna) has been documented (Mahon 1996) and is likely increasing fishing pressure (commercial plus artisanal) on these species with unknown stock status. In 1993, it was reported that landings of large pelagic fishes7 from the Western Central Atlantic region (including blackfin tuna) doubled from about 50,000 mt to about 100,000 mt (Figure 7) from 1970–1993 (Mahon 1996).

6 The 1995 UN Fish Stocks Agreement calls for the implementation of the provisions of the United Nations Convention on the Law of the Sea of 10 December 1982 relating to the conservation and management of straddling fish stocks and highly migratory fish stocks. 7 Note that although blackfin tuna are usually categorized as “small tunas”, Mahon included the species in its analysis of “large pelagics” under ‘Oceanic Tunas’ in the WECAFC area in 1996.

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Figure 7. Fishery landings of large pelagics in the WECAFC area as reported to FAO. Blackfin tuna is included under ‘Oceanic Tunas’ (Figure from Mahon 1996).

In addition to the increase in fishing effort, another concern with regard to the status of blackfin tuna is that they are attracted to fish aggregating devices (FADs), which can negatively impact populations (as described below). As Hallier and Gaertner (2008) stressed, the use of FADs on a particular species should be analyzed in light of the status of the stock, which in the case of blackfin tuna is largely unknown. The use of FADs has increased drastically since the 1980s, and it is now estimated that 50% of the world’s tuna catches come from fish associated with FADs (Fonteneau et al. 2000; Moreno et al. 2007; Doray et al. 2008). Fish aggregating devices allow purse seiners and other fishers to target smaller tuna species such as blackfin and little tunny as opposed to large predatory, pelagic schooling tunas such as yellowfin and bluefin (FAO 2008a). This trend raises concerns for threatened fish stocks because FADs often alter the exploitation of the resource by making juveniles more vulnerable to capture as compared to free- schooling captures (FAO 2008a; Hallier and Gaertner 2008). The assumption is that the disproportionately high fishing pressure on juveniles associated with FADs decreases the yield per recruit and therefore is a threat to the viability of the population (Moreno et al. 2007; Hallier and Gaertner 2008). Catch rates drop off when too many FADs are deployed, and FADs may exacerbate overfishing and expose juvenile fish to exploitation and predators (FAO 2009a). Hallier and Gaertner (2008) found that there are so many FADs currently in use in the tropics that tunas leaving a FAD have a high probability of encountering other FADs, creating an ‘ecological trap’, which is a condition where “the settlement cues normally used by an individual change in intensity, type or number such that the habitat becomes more attractive while habitat suitability remains unchanged (the settlement cues have changed, but not the ultimate factors)” (Robertson and Hutto 2006). Consequently, tunas can be trapped in poor quality habitats by FADs, which may lead to a decrease in their overall health compared to free-schooling tunas (Hallier and Gaertner 2008). However, there is no clear consensus in the literature regarding the

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long-term effects on tuna stocks associated with FADs, of high fishing pressure on FADs, or on overall fish health and ecology of tunas associated with FADs. Hallier and Gaertner (2008) found that individual tunas associated with drifting FADs were less healthy than those in free schools, using plumpness and individual growth rates as indicators. They also suggest that feeding and migration patterns may be altered by FADs, but the long-term effects on schooling behavior, migrations and the life cycle of tunas are still unknown. Furthermore, Doray et al. (2009) suggest that residence time of fish around FADs increase when global abundance is low.

The FAO (2009) reports that most techniques used to assess risks of stock degradation do not take into account the spatial distribution of fishing stocks. They furthermore suggest that fisheries managers should incorporate new models that account for locations of FADs. Most fishing for blackfin tuna using FADs occurs in the Caribbean Sea. Regions reported to specifically target blackfin tuna around FADs include Antigua, Barbuda, Grenada, Guadeloupe, Martinique, Trinidad and Tobago in the Lesser Antilles, as well as Dominica and Cuba (Doray et al. 2002, Fujii 2004).

In one study, moored FADs in Martinique were monitored and blackfin tuna were observed aggregate in two surface layers: small animals (average of 20 cm FL) in the surface layer (0–10 m) and larger animals (mainly 50 cm FL) in a subsurface layer (30–100 m). The subsurface layer accounted for the majority (~over 90%) of the biomass at the monitored moored FADs (Doray et al. 2004; Doray et al. 2009). In Martinique, subsurface animals are nearly completely unexploited by the artisanal fishery using trolling lines (used for surface catches) and vertical drifting longlines (used for large predatory catches in deep water) during the daytime, with greater success at dusk and dawn. Contrary to this known occurrence of maximum fishing success during dusk and dawn, both Doray et al. (2004) and Taquet et al. (2000) report that Martinican fishermen mainly fish during the daytime using surface trolls, a strategy that does not ensure maximum catch per effort and targets the smaller fish that occur in the surface layer.

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Table 6. Stock status of blackfin tuna. Degree of Occurrence Classification Abundance Age/Size/Sex Uncertainty SFW B/B of F/F Sources Status MSY MSY Trends/CPUE Distribution in Stock Rank Overfishing Status Mahon 1996; Majkowski Highly Unknown Unknown Unknown Unknown Unknown Unknown 2005; Ortiz, Uncertain pers.comm.; ICCAT Moderate 2008

Synthesis No studies have been conducted to identify or assess blackfin tuna stocks, and therefore the stock status is highly uncertain. In the future, this status could be qualified following the completion of a stock assessment. According to Seafood Watch criteria, the stock status of blackfin tuna is considered a moderate conservation concern due to the absence of reliable information on the status of wild stocks.

Status of Wild Stocks Rank

Healthy Moderate/Rebuilding/Unknown Poor Critical

Criterion 3: Nature and Extent of Bycatch8

Seafood Watch® defines sustainable wild-caught seafood as marine life captured using fishing techniques that successfully minimize the catch of unwanted and/or unmarketable species (i.e., bycatch). Bycatch is defined as species that are caught but subsequently discarded (injured or dead) for any reason. Bycatch does not include incidental catch (non-targeted catch) if it is utilized, accounted for and managed in some way.

There is no fishing gear that catches any one species of tuna exclusively, and many of the tuna fisheries in the Atlantic are multi-species fisheries targeting more than one tuna species. Additional species that are caught incidentally are taken on as bycatch (Miyake and Kebe 2005). These multi-species fisheries can be complicated, and it is thought that gear interactions are possibly more substantial for stocks that are heavily exploited because they are targeted by different fisheries simultaneously (Miyake and Kebe 2005). There are no specific data reported for blackfin fisheries and there is no observer coverage in blackfin-targeted fisheries. Therefore, since blackfin tuna frequently school with skipjack, extrapolations from the skipjack tuna fishery and tuna fisheries in general have been applied in this analysis. In addition, fishing practices

8 Portions of this section were taken verbatim from the Seafood Watch® Skipjack Tuna Report written by Jesse Marsh, which is available at: http://www.montereybayaquarium.org/cr/cr_seafoodwatch/content/media/MBA_SeafoodWatch_SkipjackTunaRepo rt.pdf.

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(e.g., type of purse seine sets) vary among the different fisheries, and there may also be spatial differences within regions (Solana-Sansores 2001). The estimated bycatch rates and the stock status of the major bycatch species that interact with these gear types are discussed below (as reported in the Seafood Watch® Skipjack Tuna and Yellowfin Tuna Reports).

Handline, Baitboat, Troll, Rod and Reel All methods used to catch blackfin tuna can be used on FADs; however, handline, rod and reel and baitboat methods are able to quickly return non-target species or undersized fish to the sea alive. Troll fishing is not as benign because bycatch of undersized and/or damaged fish can be higher, although it is considerably less than longlining and purse seining (Childers 2003). The average discard rate, or the proportion of total catch that is discarded, for troll fisheries of highly migratory species (HMS) globally is 0.1% (Kelleher 2004). Bycatch is minimal in the handline, rod and reel, and baitboat fisheries globally as well, as fish are caught one at a time, and fishers can immediately throw back any unwanted catch.

Purse Seine The amount of bycatch and the species caught as bycatch depend on the type of purse seine set. There is considerable spatial variation for some of the species caught as bycatch in purse seine fisheries, such as dolphinfish, while there is a more uniform distribution of other bycatch species, such as silky sharks and sailfishes (García and Hall 1997). However, a Spanish observer program during 2001–2004 showed bycatch in Atlantic purse seine tuna fisheries to be in similar proportion to the same species taken in Pacific purse seine tuna fisheries (ISSF 2009), and more data are available from observer programs in Pacific purse seine fisheries than Atlantic fisheries. As such, bycatch data from purse seine fisheries in both the Atlantic and Pacific are included here.

Purse seines set on floating objects such as FADs have a high bycatch of juvenile tuna, other fishes and vulnerable species such as sea turtles and sharks (Hall 1998; IATTC 2004). Bycatch in FAD sets is estimated to be 10% of the total catch per set. These estimates are similar to bycatch rates described in Bailey et al. (1996), who estimated school-set bycatch at 0.35–0.77% of the total catch by weight and log sets higher at 3.0–7.3%. Bromhead et al. (undated, p. 63) cite five reasons why FAD sets are cause for concern:

1) Catch efficiency of purse seiners has increased dramatically with the use of FADs; 2) Species composition of tuna caught under FADs differs from that of free-schooling tuna; 3) Juvenile tuna are significantly more vulnerable to capture using FADs; 4) The advent of FADs means some species are now caught with multiple gears, both as juveniles and adults; and 5) The use of FADs may trap tuna in unproductive regions, with implications for condition growth and biological productivity.

In addition, in fisheries using FADs that target small tunas such as blackfin, there is bycatch of several species of pelagic sharks (many with declining populations), other non-target bony fishes and juvenile tunas (FAO 2008a). Currently, there is minimal to no regulation or enforcement on the FADs used in the Western Atlantic.

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The most common bycatch taken in open ocean purse seine sets are sharks, rays and marlins (Bromhead et al. undated). Bycatch in tropical open ocean purse seine fisheries may be high and depends on the type of purse seine set (Romanov 2002).

Bycatch Rates and Population Impacts: Marine Mammals Marine mammal bycatch is generally low in sets on FADs, although somewhat higher than in unassociated sets (Molony 2005). Thus, there are not thought to be any severe population impacts for marine mammals due to bycatch in these types of purse seine sets.

Bycatch Rates and Population Impacts: Fishes In general, there is less discarding of small tunas in the Atlantic Ocean, where a market for them exists (Romagny et al. 2000 in Fonteneau et al. 2000), than in other ocean basins. The average amount of bycatch in global tuna FAD purse seine fisheries is 10% of the tuna catch, with small tunas accounting for most of the bycatch (Fonteneau et al. 2000).

Tuna discards in the eastern Pacific skipjack FAD purse seine fisheries ranged from 7–29% from 1992 to 1998 (Lennert-Cody and Hall 2000). Although discards of juvenile bigeye and yellowfin may be low in weight, they account for a large number of fish that are discarded due to their low market value (Sharp 2001).

There are a number of fishes caught as bycatch in the non-dolphin tuna purse seine fisheries, especially on FAD associated schools (in the East Pacific) including: juvenile bigeye, yellowfin, and skipjack tunas, small tunas such as bullet (Auxis rochei), frigate (A. thazzard), black skipjack (Euthynnus lineatus) and bonito (Sarda spp.); billfishes such as blue marlin (M. nigricans), sailfish (Istiophrus platypterus) and swordfish (Xiphias gladius); dolphinfish (Coryphaena hippurus and C. equisetis); wahoo (Acanthocybium solandri); rainbow runner (Elagatis bipinnulata); fishes from the Serranidae and Carangidae families; and triggerfish from the Balisitidae family (García and Hall 1997). The proportion of these species relative to the target species was small, although the diversity of species was high. The large-scale removal of juvenile tuna in tuna purse seine fisheries globally is cause for concern (Dickson and Natividad 2000; Fonteneau et al. 2000; Bromhead et al. undated), although there may be regional differences. In particular, the catch of juvenile bigeye has been increasing in floating object fisheries worldwide since the early 1990s, with serious concerns about recruitment overfishing showing its effects on the population structure in the next 3–10 years (Fonteneau et al. 2000). A possible sign of overfishing is the decline in the CPUE index of adult bigeye caught in the Atlantic and Indian Oceans, which showed a steady decline from 1969–1997 (Fonteneau et al. 2000).

There is concern over the stock status of some species (Table 7), and the increased mortality due to bycatch in the purse seine fisheries may have serious population consequences for these species. Although the impact of FAD fisheries on the ecosystem as a whole may be low to moderate, caution may be warranted for local sub-populations that may be vulnerable to overexploitation (Cury and Anneville 1998 in Fonteneau et al. 2000).

Table 7. Stock status of tunas commonly targeted and caught as bycatch in purse seine fisheries (data from Seafood Watch Bigeye, Skipjack, and Yellowfin Tuna reports). Note that the status of these stocks is not necessarily a direct

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result of the purse seine fishery.

Species Stock Status by Ocean Atlantic Ocean Pacific Ocean Indian Ocean Bigeye Not overfished, overfishing Not overfished, overfishing is Not overfished, not occurring occurring overfishing may be occurring Skipjack Unknown, overfishing not Not overfished, overfishing is Unknown occurring occurring Yellowfin Approaching overfished, Eastern pacific: may be Not overfished, overfishing may be occurring overfished, overfishing overfishing unknown occurring Western pacific: not overfished, overfishing likely

In the Atlantic, biomass estimates for blue marlin, white marlin and sailfish are all below BMSY while fishing mortality on these stocks is above FMSY (Peel et al. 2003; Uozumi 2003). The Atlantic blue marlin stock is at 40% of BMSY, current fishing mortality is four times FMSY and overfishing has been occurring for the last 10–15 years (ICCAT 2001a). There may be ecosystem effects as a result of the removal of high quantities of large predators such as billfish (Gaertner et al. 2002). Fisheries using FADs may also be having a strong negative impact on the yield per recruit of many species (Fonteneau et al. 2000). Decreases in spawning stocks could lead to recruitment overfishing for several tropical tuna stocks, something that has not been seen to date (Fonteneau et al. 2000). Extreme caution is warranted given the uncontrolled growth of FAD fisheries (Fonteneau et al. 2000) and their potential to cause serious problems for the conservation of tropical tuna stocks, billfish, sharks and other species caught as bycatch.

Bycatch Rates and Population Impacts: Seabirds Seabird bycatch is not thought to be a concern in the purse seine fisheries for tuna. No serious population impacts on seabird populations are considered due to bycatch in purse seine fisheries.

Bycatch Rates and Population Impacts: Sea Turtles The sea turtle species caught by purse seines include olive ridley, green, leatherback, hawksbill, and loggerhead sea turtles. In the Eastern Pacific Ocean, the majority of purse seine sea turtle bycatch occurs in purse seines set on floating objects, in particular the FAD fisheries (IATTC 2004c; Molony 2005). Although most sea turtles are released alive (IATTC 2004c), some turtles may be injured or killed. Turtles entangled in the purse seine net may drown if they cannot surface to breathe, or may be lifted out of the water when the net is hauled in and either get injured as they fall from the net or pass through the power block (IATTC 2004c). An additional issue is entanglement of sea turtles in the webbing that is often hung from FADs to increase target catch (IATTC 2004c).

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IATTC observer data9 for the tuna purse seine fishery in the Eastern Pacific Ocean show that annual average mortality from 1993–2003 was 140 sea turtles (IATTC 2004c). Sea turtle bycatch in the purse seine fisheries declined over this time period, and the estimate of sea turtle bycatch in 2004 was 17 sea turtles (IATTC 2006). Small numbers of turtle bycatch in the purse seine fisheries in Atlantic have also been reported (Stretta et al. 1998; Romanov 2002).

All seven species of sea turtles are either endangered or threatened, with sea turtle populations facing many threats including incidental take in fisheries, killing of nesting females, egg collection at nesting beaches and habitat loss, as well as pollution and debris. The population impacts of sea turtle bycatch in the purse seine fisheries are unknown but are likely to be less severe than for the pelagic longline fisheries. However, caution is warranted due to globally increasing effort in FAD fisheries. In addition, bycatch in the FAD fisheries is not well documented, compared to pelagic longline fisheries.

Bycatch Rates and Population Impacts: Sharks and Rays10 Sharks and rays caught as bycatch in non-dolphin purse seine sets in the Eastern Pacific purse seine tuna fisheries include hammerhead (Sphyrna spp.), blacktip (Carcharhinus limbatus), whitetip (C. longimanus), silky (C. falciformis), dusky (C. obscurus) and other sharks (Carcharhinus spp.), as well as manta rays (Mobula spp., Manta birostris) and pelagic sting rays (Dasyatis violacea) (García and Hall 1997). Although shark bycatch is high in tuna purse seine fisheries, it is likely higher in tuna pelagic longline fisheries. Pelagic longlines have been considered one of the primary sources of global shark bycatch due to high effort in the fishery (Bonfil 1994). As with most other bycatch species, the diversity of most of the shark species was higher in purse seine sets on floating objects than in sets on unassociated schools (Williams 1997).

Sharks and rays are generally not resilient to fishing pressure (Hoenig and Gruber 1990 in Musick et al. 2000), as they have a low intrinsic rate of increase (Smith et al. 1998), low fecundity, slow growth rates and a late age at maturity (Camhi et al. 1998 in Musick et al. 2000). Of all predatory fishes, sharks are probably the most sensitive to fishing pressure. Generalizations about declines in predatory fish may underestimate declines in shark species. Indeed, the high sensitivity of sharks to fishing pressure means that they may be twice as likely to go extinct as bony fishes at moderate fishing pressures (Myers and Worm 2003). Although the best data for sharks are from the North Atlantic, many shark populations seem to have declined worldwide (Myers and Ottensmeyer 2005). This has led to considerable concern in national and international organizations such as the IUCN, CITES and the FAO (Musick et al. 2000). Indeed, there are more elasmobranch (sharks, skates and rays) species (263) than other marine fishes (210) on the IUCN’s Red List; 199 of these are sharks, while the other 64 species are skates and rays.

Due to high unreported catches of pelagic shark species in many fisheries, there may be severe population impacts on many of these species (Romanov 2002). Throughout the world’s oceans,

9 These observer data are only from IATTC observers on large purse seiners and do not include data from national observer programs or trips from small vessels that do not carry observers. 10 Portions of this section were taken verbatim from the Seafood Watch® Sharks Report.

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sharks are facing an increasing threat from tuna fisheries, as they are frequently caught as bycatch (Fonteneau 2003). Several of the shark and ray species caught as bycatch in tuna purse seine fisheries worldwide are on the IUCN Red List of Threatened Species (Table 8).

Table 8. Shark and ray species caught as bycatch in the purse seine fishery that are also on the IUCN Red List.

Status on the IUCN Species Description Source Red List Blacktip shark (Carcharhinus NW Atlantic: Near NW Atlantic population assessed; highly Shark Specialist Group limbatus) threatened vulnerable to fishing pressure 2000a; IUCN 2010 Annual fishing mortality as bycatch is likely affecting global population; Stevens 2000a; IUCN Blue shark (Prionace glauca) Near threatened inadequate data to assess the scale of 2010 possible decline Crocodile shark Vulnerable as bycatch in pelagic longline Compagno and Musick (Pseudocarcharias Near threatened fisheries; population decline probable but 2000; IUCN 2010 kamoharai) no CPUE records available Data deficient, Least Some declines reported; lack of data on Denham 2000; Kotas Hammerhead sharks (Sphryna concern, Near population trends; probable bycatch in 2000; Mycock 2004; spp.) threatened, Vulnerable, tropical longline fisheries IUCN 2010 Endangered Highly vulnerable life history; bycatch in global fisheries thought to be rare, but Ishihara et al. 2002; Manta ray (Manta birostris) Near threatened declines have been observed in locations IUCN 2010 where targeted Atlantic & Indo West: Wide-ranging; low reproductive capacity; Shortfin mako shark (Isurus Vulnerable; significant targeted catch and bycatch in Stevens 2000b; IUCN oxyrinchus) Eastern North Pacific: some regions 2010 Near threatened Highly vulnerable to depletion due to low Dusky shark (Carcharhinus NW Atlantic and Gulf Shark Specialist Group intrinsic rate of increase; high mortality obscurus) of Mexico: Vulnerable 2000b; IUCN 2010 rate when taken as bycatch Fast growing and fecund, but declines Tiger shark (Galeocerdo Simpfendorfer 2000; Near threatened have been observed in populations that cuvier) IUCN 2010 are heavily fished Common bycatch species in tuna fishery; Oceanic whitetip shark Vulnerable bycatch is inadequately reported or not Smale 2000; IUCN 2010 (Carcharhinus longimanus) recorded; population impacts unknown

Many shark species have exhibited population declines as exhibited by decreasing CPUE rates. Other than the recent work on the decline of Atlantic shark species by Baum et al. (2003), few data are available detailing the international exploitation of sharks. However, the magnitude of the declines found by Baum et al. (2003) has been challenged based on factors such as inadequate data and exclusion of other data sets such as stock assessments (Burgess et al. 2005).

There are clear differences between the types of purse seine sets—unassociated sets and FAD sets—and their bycatch concerns. Bycatch in school sets is characterized primarily by small and large bony fishes and is a moderate conservation concern. Purse seine sets on floating objects such as FADs result in high bycatch of juvenile tuna, other pelagics such as dolphinfish and wahoo, sharks and sea turtles. Juvenile bigeye and yellowfin in particular have been identified as bycatch species of concern in the floating object fishery. Observer data from the Eastern Pacific

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suggests a declining trend in bycatch, but there are no comprehensive international data regarding bycatch in the global FAD fisheries. Bycatch in the purse seine fishery on FADs or other floating objects thus ranks as a critical conservation concern.

Longline Longlining is a secondary method used to catch blackfin tuna, as this species is predominantly caught with a combination of handline, baitboat, troll, rod and reel gear, and purse seines; however, blackfin is caught incidentally in other tuna longline fisheries. We have therefore evaluated the bycatch of those longline fisheries.

When examining the effects of bycatch, both the level of bycatch and the population effects of the bycatch should be considered (Lewison et al. 2004a). Many of the species caught as bycatch in tuna longline fisheries are long lived, late to mature and slow growing. As such, these species are particularly vulnerable to excessive mortality (Musick 1999). In general, catch data may underestimate the total mortality of certain bycatch species, as hooked animals may fall off the hook prior to the line being retrieved (Ward et al. 2004). Note that mortality rates differ for the various types of longlines.

While pelagic longlines are set at different depths and configured to target specific species, non- target species are known to interact with the gear. In longline fisheries, interactions occur with a range of species including endangered and protected sea turtles, seabirds, marine mammals, sharks and other fishes. These non-target animals approach or are attracted to baited longline hooks and become hooked or entangled in the gear causing them to be injured or drown (NMFS 2001). Tuna are caught using both shallow and deep-set longline gear, with bycatch rates for deep sets generally at about 10% of those in shallow sets targeting swordfish (Lewison et al. 2004; Kaplan 2005). However, if there is more effort in the deep-set fishery, the overall impact could be higher. Although comprehensive global bycatch data for longlines are non-existent, there are some data for specific longline fisheries. Longline gear varies according to the size and intensity of the fishery, the actual configuration of the gear, the region in which the gear is used and the country fishing with the gear. Although these differences may result in differing levels of bycatch, Seafood Watch® adopts a precautionary approach in assuming that problematic bycatch levels in one fishery are similar to other fisheries unless there are data to show otherwise. Of all the gears used to catch tuna in the Atlantic, longlines catch the highest diversity of both fish and seabirds (ICCAT 2005b).

In the US, the discard to landings ratio for finfish in the highly migratory species fishery (pelagic longline, bottom longline and drift/set gillnets) is estimated to be 0.52. The discard to landings ratio for the pelagic longline fishery alone is 0.67, with swordfish and sharks comprising most of the discards (Harrington et al. 2005). That is, for every ten fish that are landed in the pelagic longline fishery, 6.7 fishes, sharks or other incidentally caught individuals are discarded.

The Trinidad and Tobago offshore (drifting) surface and pelagic longline fishery targets ocean pelagics including: yellowfin tuna, bigeye tuna, albacore, blackfin tuna, Lutjanus spp. (redfish), Carcharhinus spp. (shark), Isurus spp. (mako shark), Alopias spp. (thresher shark), Caulolatilus intermedius (gulf bar-eyed tilefish) and Lopholatilus chamaeleonticeps (golden tilefish) (Project GloBAL. 2007, unpub.). The most abundant and commercially important bycatch species in this

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fishery are swordfish (Xiphias gladius), Atlantic blue marlin (Makaira nigricans), Atlantic sailfish (Istiophorus albicans), white marlin (Tetrapterus albidus) and longbill spearfish (Tetrapterus pfluegeri) (Project GloBAL 2007, unpubl.).

Bycatch Rates and Population Impacts: fishes Discards of swordfish and tuna in the US Atlantic pelagic longline fishery exhibited a gradual decline from 1995–2004 (NMFS 2006). Discards of these target species may be economic or regulatory discards. The only fish species for which discards were higher than landings were bluefin tuna. In 2004, the most recent year for which data are available, slightly over twice as many bluefin tuna were discarded as kept (NMFS 2006). For highly migratory species, both the number of individuals kept and the number of individuals discarded have declined over this time period, as has fishing effort (Figure 8) (NMFS 2004c). The reason for this decline is unknown.

Figure 8. Decline of marlin, sailfish and spearfish discards in the US Atlantic pelagic longline fishery (Data from NMFS 2004c).

Longline fisheries targeting tuna and swordfish are responsible for the majority of the fishing mortality of blue and white marlin (Goodyear 1999; Peel et al. 2003). In the Atlantic, the commercial sale of billfish was prohibited in 1991, and although the reported catch of billfish dropped greatly after this (Goodyear 1999), it is likely that reported bycatch rates in the logbooks are underestimates of actual bycatch, based on observer data (Cramer 1996). For fisheries where logbook data are available, the catch ratio of billfish to the targeted species is low. Billfish catch is approximately 5% of the total combined catch of albacore, yellowfin, bigeye, bluefin and southern bluefin (Uozumi 2003).

Other pelagic species that are regularly caught in the directed tuna fishery are dolphinfish, oilfish, pomfret and wahoo. While some of these species are kept, managed and accounted for and are thus not deemed bycatch, others such as pomfret are largely discarded in some fisheries. It is important to note that recreational catch-and-release fisheries for these billfish species also contribute to the mortality of these species, although the magnitude of these mortalities is far less

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than for the pelagic longline fishery. For instance, over 99% of all white marlin are released in recreational fisheries (Goodyear and Prince 2003). The survival of released marlin may be affected by the type of hook used. In the western North Atlantic recreational fishery, white marlin survivability is higher when caught on circle hooks (100%) compared to those caught on J hooks (65%) (Horodysky and Graves 2005). In addition, there are few data examining survival rates following stomach eversion (Horodysky and Graves 2005). Although this mortality does affect the stock status of billfish, Seafood Watch® does not incorporate the effects of recreational fisheries when evaluating commercial fisheries. When 16/0 circle hooks were compared to 9/0 J-hooks in the US Atlantic pelagic longline fishery, circle hooks were found to reduce mortality of non-target species and may result in higher survival for undersize swordfish and billfish (Kerstetter and Graves 2006). In addition, the use of 16/0 circle hooks was found to have a minimal impact on the catch of target species (Kerstetter and Graves 2006).

According to the most recently available logbook data for the Atlantic pelagic longline fishery, discards of blue marlin declined from 1995–2002 but have been somewhat stable since 1998, averaging 1,160 individuals discarded annually from 1998–2002 (NMFS 2004c). White marlin discards exhibited a similar pattern with an average of 1,404 individuals discarded annually from 1998–2002 (NMFS 2004c).

The stock status of billfish species varies by ocean basin and species (Table 9). The pelagic longline fisheries targeting yellowfin and bigeye tuna and swordfish cause the highest Atlantic marlin mortality (Peel et al. 2003). In the Atlantic, biomass estimates for blue marlin, white marlin and sailfish are all below BMSY while fishing mortality on these stocks is above FMSY (Peel et al. 2003; Uozumi 2003). The Atlantic blue marlin stock is at 40% of BMSY, current fishing mortality is four times FMSY, and overfishing has been occurring for the last 10–15 years (ICCAT 2001a). The only management measure in place for Atlantic blue marlin is the mandated reduction of pelagic longline and purse seine landings to 50% of 1996 or 1999 levels, whichever is greater (ICCAT 2001a). White marlin occurs only in the Atlantic. The most recent assessment for this species was in 2000 and indicated that biomass throughout the late 1990s was about 15% of BMSY while fishing mortality was more than five times FMSY (ICCAT 2001a). As with blue marlin, the only management measure in place is a limit on longline and purse seine landings to 33% of their 1996 or 1999 levels (ICCAT 2001a). For Atlantic sailfish, MSY is not estimated and there are no management measures in place (ICCAT 2001b).

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Table 9. Stock status of billfish in the Atlantic, Pacific and Indian Oceans (Table from Uozumi 2003).

Observer data from the US pelagic longline fishery in the Atlantic show that the number of bluefin tuna discarded has been higher than the number kept every year from 1995–2002. Both the East and West Atlantic bluefin stocks are overfished and experiencing overfishing, and are considered overexploited and depleted, respectively (NMFS 2004c; Majkowski 2004). Any dead-discarding of bluefin tuna in Atlantic pelagic longline fisheries removes individuals from stocks that are already in critical shape, thus warranting a critical conservation concern for these longline fisheries.

Bycatch Rates and Population Impacts: Sea Turtles All seven species of sea turtle are listed as threatened or endangered under the US Endangered Species Act of 1978, and six of these species are also listed on the IUCN’s Red List (Table 10). Several of these sea turtle species are caught as bycatch in the pelagic longline fisheries targeting tuna and swordfish, particularly green, hawksbill, Kemp’s ridley, leatherback, loggerhead and olive ridley. Sea turtles are commonly caught as bycatch in tropical waters, and more often in shallow-set fisheries (Beverly et al. 2004). As evidenced by the closure of the U.S. longline fishery in the Northeast Distant Waters (NED), sea turtles are also caught as bycatch in other regions. Loggerheads have been shown to spend the majority of their time at depths shallower than 100 m, and the elimination of shallow-set longlines would result in reduced bycatch of loggerheads (Polovina et al. 2003). Even with deep-set longlines, however, there is potential for hooks to be present at shallow depths when the gear is being set and retrieved, or if the line does not sink to the appropriate depth (Polovina et al. 2003). Leatherbacks are attracted to the squid bait used on longlines (Skillman and Balazs 1992) and commonly become entangled in the branch lines even if they don’t bite the hook (NMFS and USFWS 1998). Some turtles are deeply hooked in the esophagus and others are only lightly hooked in the jaw. While there is a significant difference between the survivability for light and deep hooked loggerheads within 90 days of release, there is no difference in survivability after this period of time (Chaloupka et al. 2004a ). Estimates of sea turtle post-release mortality using satellite tracking has been both controversial and problematic (Hays et al. 2003; Chaloupka et al. 2004a; Chaloupka et al. 2004b; Hays et al. 2004) with estimates ranging from 0.08 for lightly hooked turtles to 0.34 for deeply hooked turtles during the first week after release (Chaloupka et al. 2004a). In general,

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take greatly exceeds documented mortality in longline fisheries, although there are few data on post-release mortality. It is important to note that an interaction does not imply mortality.

Table 10. Global conservation status of sea turtles that interact with pelagic longline fisheries.

Species Status under the U.S. ESA Status on the IUCN Red List Green Threatened, Endangered11 Endangered Hawksbill Endangered Critically endangered Kemp's ridley Endangered Critically endangered Leatherback Endangered Critically endangered Loggerhead Threatened Endangered Olive ridley Threatened, Endangered13 Vulnerable

Although more countries are beginning to collect bycatch data, they are generally not available and therefore a thorough analysis of sea turtle bycatch interactions with international vessels is difficult. However, Lewison et al. (2004b) attempted to quantify the incidental take of loggerhead and leatherback sea turtles on a global scale. By integrating catch data from more than 40 nations and bycatch data from 13 international observer programs, they estimated that over 200,000 loggerheads and 50,000 leatherback sea turtles were taken as bycatch in pelagic longline fisheries in the year 2000. Lewison et al. (2004b) suggest that a large number of interactions with protected species continue regularly in the international (non-US) longline fleet and jeopardize the continued survival of these endangered and threatened sea turtle species.

Although the US pelagic longline fishery in the Atlantic interacts with other sea turtle species, loggerheads and leatherbacks are the primary concern due to their high interaction rates (Figure 9). Sea turtle bycatch estimates for the US pelagic longline fishery in the Atlantic in 2002 were 575 loggerhead takes12 (2 mortalities), 962 leatherback takes (33 mortalities) and 50 unidentified turtle takes (NMFS 2004e). However, these numbers may underestimate mortalities as they do not account for post-release mortality, which may be considerable.

11 There are two green turtle populations, with different statuses under the ESA. 12 These take estimates do not include any estimates of post-release mortality.

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Figure 9. Estimated takes in the US Atlantic pelagic longline fishery, 1992–2002. Takes do not imply mortalities (Data from NMFS 2004e).

The number of loggerhead and leatherback turtle takes was variable from 1992–2002, although there was a peak in loggerhead takes in 1995. Total loggerhead takes appear high in the US Atlantic longline fishery, but the estimated mortalities are low. Average annual loggerhead morality from 1992–2002 was seven individuals, and in 2002 only an estimated two loggerheads were taken (NMFS 2004d). The mortality data for leatherbacks is far more variable with an estimated 88 leatherbacks killed in 1992 and then no leatherbacks killed again until 2002, when 33 leatherbacks were estimated killed in this fishery (NMFS 2004d). The estimated zero mortalities may be a reflection of the low level of observer coverage in this fishery rather than low sea turtle bycatch. From 1995–2000, observer coverage was only 2.5–5.2% (NMFS 2004d). Leatherback takes peaked in 2004 at about 1358 interactions and declined to about 351 interactions in 2005. Estimated loggerhead takes declined from about 734 interactions in 2004 to 274 interactions in 2005 (Walsh and Garrison 2006).

For the pelagic longline fishery, the most effective management measures are likely gear modifications rather than area closures, which can potentially result in the displacement of effort to other areas where bycatch may be higher (James et al. 2005), unless effort is reduced. Hook and gear modifications were required in the US Atlantic pelagic longline fishery in mid- 2004, and as noted above, in 2005 the take of both loggerheads and leatherbacks was greatly reduced (Walsh and Garrison 2006). While the decline in loggerhead and leatherback take is partly explained by reduced effort in 2005 as a result of Hurricane Katrina, the bycatch interaction rate (turtle interactions per hook) also declined 68% for leatherbacks and 53% for loggerheads between 2004 and 2005 (Walsh and Garrison 2006). If this declining trend continues, the conservation concern for this fishery will continue to be ranked differently than the international longline fleets.

Estimates from longline fisheries in the South Atlantic have found that the combined CPUE for loggerheads and leatherbacks in these fisheries was 0.37/1000 hooks from 86 sets (Achaval et al. 2000). With over 13 million hooks set in 1999 by Brazilian boats alone in the southwest Atlantic (ICCAT 2001c), the potential for large amounts of sea turtle bycatch is high. In addition, fishery closures in the North Atlantic due to overfished species such as swordfish and tunas may result

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in effort being displaced to the South Atlantic, possibly increasing sea turtle bycatch there (Kotas et al. 2004). Lewison et al. (2004b) estimate that 1.4 billion hooks were set on pelagic longline gear in the year 2000 alone, with 1.2 billion of those hooks targeting tuna. In the eastern Atlantic, olive ridleys and leatherbacks have been observed interacting with longlines targeting swordfish and tunas, with a CPUE of 0.09 per 102,700 hooks for olive ridleys and 0.39 per 102,700 hooks for leatherbacks (Carranza et al. 2006). In the Gulf of Guinea, the CPUE for olive ridleys was 0.38, and the CPUE for leatherbacks was 0.64 (Carranza et al. 2006). Of the 40 leatherbacks caught, 5% were observed mortalities (Carranza et al. 2006). There are no estimates for post- release mortality for either of these species in this study.

All these studies demonstrate that sea turtle bycatch occurs in many fisheries across most ocean basins. Although observer coverage or logbook data are not available for every fishery targeting tuna, the available data suggest that sea turtle bycatch is an issue in many, if not all, of these fisheries.

Sea turtle populations face several threats, including incidental take in fisheries, the killing of nesting females, egg collection at nesting beaches, habitat loss, and pollution and debris. The population impacts of sea turtle bycatch vary according to the sea turtle species and the region. Population data for leatherbacks in the Atlantic are uncertain and conflicting. However, the main nesting beaches in French Guiana and Suriname exhibited a declining trend in the early to mid- 2000s, with nesting declining at about 15% annually (NMFS 2004d). Leatherback bycatch in the Atlantic pelagic longline fishery has more severe population consequences than loggerhead bycatch for several reasons. Approximately half of the leatherbacks taken in the pelagic longline fishery are mature breeders while the other half are sub-adults; because leatherbacks are sexually mature after 5–15 years, the bycatch of leatherback sub-adults has more severe population consequences than for loggerheads, which mature later (NMFS 2004d). Using the estimates of turtle bycatch from Lewison et al. (2004b), post interaction mortality, sex ratio data, and adult to juvenile ratio data, total leatherback mortality for adult females was estimated at 4,100 leatherbacks per year in the international fisheries in the Atlantic and Mediterranean (NMFS 2004d). While the US longline fleet in the Atlantic accounts for 1.2–1.4% of this mortality per year, the annual mortality of adult and sub-adult females in the US fishery is “not discountable” (NMFS 2004d p. 6–8). In addition, there is considerable uncertainty associated with the status and trends of leatherbacks in the Atlantic. It has been shown that a combination of 18/0 circle hooks and mackerel bait reduces loggerhead interaction rates by 90% and leatherback interactions by 65% (Watson et al. 2005). The 2004 Biological Opinion (BiOp) concludes that the proposed management measures in the US Atlantic pelagic longline fishery are likely to jeopardize the continued existence of leatherbacks but not the existence of other turtle species taken as bycatch in this fishery. The jeopardy finding by NMFS was based on estimated annual mortalities in the US fishery of approximately 200 leatherbacks, continuing indefinitely (NMFS 2004d).

Bycatch Rates and Population Impacts: Seabirds Seabirds are particularly vulnerable to population decreases, as they are long-lived, have low reproductive rates and mature at a late age (Tuck et al. 2003). There are an estimated 61 seabird species that are affected by longline fisheries, 25 of which are threatened with extinction as a result of their bycatch in longline fisheries (Brothers et al. 1999). Seabird take in the Atlantic is

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low, likely due to the night setting of pelagic longlines (NMFS 2004e).

Bycatch Rates and Population Impacts: Marine Mammals All marine mammals, regardless of whether or not they are listed under the ESA, are protected under the MMPA. The US longline fishery for large pelagics in the Atlantic Ocean, Gulf of Mexico and Caribbean is also a Category I fishery (defined as frequent incidental mortality or serious injury of marine mammals, amounting to mortality rates of at least 50% of the PBR13 of a marine mammal stock) due to interactions with humpback whales, minke whales, Risso’s dolphins, long-finned pilot whales, short-finned whales, common dolphins, Atlantic spotted dolphins, pantropical spotted dolphins, striped dolphins, bottlenose dolphins, harbor porpoises and pygmy sperm whales (69 FR 153, August 10, 2004). The only two of these species that are listed as endangered under the ESA, and therefore considered strategic under the MMPA, are humpback whales and pygmy sperm whales in the western North Atlantic. Additionally, of all the protected species interactions, pelagic longlines do not generally result in as much marine mammal bycatch as other gear types such as gillnets (Lewison et al. 2004a; Reeves et al. 2005).

Note that these bycatch rates are only for the US components of the pelagic longline fishery, and the international bycatch levels of marine mammals may be greater than these levels.

The contribution of pelagic longline gear to humpback whale mortality is not included in the most recent humpback whale stock assessment; however, the average annual fishery-related mortality exceeds the PBR for this species (NMFS 2005e). There has also been one report of serious injury to a pygmy sperm whale in the pelagic longline fishery off Florida, and the average annual estimated mortality for this stock of marine mammals is six. Because the PBR value is only three, this stock is considered strategic14 (NMFS 2005e).

Bycatch Rates and Population Impacts: Sharks and Rays Despite their known vulnerability to overfishing, sharks have been increasingly exploited in recent decades, both as bycatch from the 1960s onward and as targets in directed fisheries that expanded rapidly beginning in the 1980s (Baum et al. 2003). The most common shark and ray species caught in longline fisheries are blue sharks, silky sharks, pelagic stingrays and oceanic whitetip sharks (Williams 1997). As with other species caught as bycatch in pelagic longline fisheries targeting tunas, the type and quantity of shark bycatch varies with fishing location, gear configuration, etc.

13 The Potential Biological Removal (PBR) is defined as “the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or maintain its optimum sustainable population.” (50 CFR 229.2)

14 A strategic stock is defined by the MMPA as a marine mammal stock: 1) for which the level of direct human- caused mortality exceeds the potential biological removal level; which, based on the best available scientific information, is declining and is likely to be listed as a threatened species under the ESA within the foreseeable future; or which is listed as a threatened or endangered species under the ESA, or is designated as depleted under the MMPA.

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Data from the observer program in the US Atlantic longline fishery targeting swordfish and tunas suggest that 69% of the blue sharks caught were released alive (Diaz and Serafy 2005). Discard mortality was higher in younger blue sharks (Diaz and Serafy 2005). Other than the recent work on the decline of Atlantic shark species by Baum et al. (2003), few data are available detailing the international exploitation of sharks. The magnitude of the declines found by Baum et al. (2003) has been challenged based on factors such as inadequate data and the exclusion of data sets like stock assessments (Burgess et al. 2005). Estimates of annual fishing mortality range from 10 to 20 million blue sharks worldwide (IUCN 2004).

In the US pelagic longline fleet in the Atlantic, discards of pelagic sharks are greater than the retained catch of pelagic sharks; in 2003 the discard/catch ratio for pelagic sharks was 0.88 (NMFS 2005d). Off the South Atlantic coast of the US, pelagic longline vessels targeting swordfish also land tunas. In this fishery, sharks are the most common species caught as bycatch (Anderson 1985 in Beerkircher et al. 2004) and include dusky, night, silky, oceanic whitetip, tiger, blue, shortfin mako and scalloped hammerhead sharks (Anderson 1985 in Beerkircher et al. 2002 in Beerkircher et al. 2004). From 1992 to 2000, swordfish and tuna comprised 53% of the catch in this fishery while sharks were 15% of the total catch (Beerkircher et al. 2004). Over this time period, both oceanic whitetip and shortfin mako sharks exhibited a declining CPUE trend while CPUE trends for other species (e.g., silky, dusky and tiger sharks) were variable (Beerkircher et al. 2004). Overall, dead discards of pelagic sharks in the US Atlantic, Gulf of Mexico and Caribbean declined from 1987 to 2000, with peaks in 1993 and 1996 (Cortés 2002). In 1987, a total of 13,092 pelagic sharks were discarded dead, and in 2000 a total of 7,495 pelagic sharks were discarded dead in the pelagic longline fishery (Cortés 2002). Recent estimates suggest that between 26,000 and 37,000 mt of blue sharks were discarded dead in the Atlantic in 1987 (ICCAT 2005a).

In the Gulf of Mexico, oceanic whitetip sharks have declined by 99% while silky sharks have declined by 90% based on catch rates using pelagic longline data from longline fisheries targeting yellowfin tuna (Baum and Myers 2004). In addition, the mean size for these species is at or below their size at maturity, which may increase the rate of decline (Baum and Myers 2004). Baum and Myers (2004) conclude it is possible that similar declines in oceanic sharks have occurred in other regions. A preliminary ICCAT stock assessment suggests that the biomass of blue sharks is likely above BMSY while the shortfin mako stock may be below BMSY (ICCAT 2005a).

Shark finning in the Atlantic is banned by ICCAT (Gilman et al. 2007). Individual countries may also have shark finning bans in their respective EEZs (e.g., Australia, Italy, South Africa, and the US) while other vessels from other countries may comply with such regulations while fishing in other countries’ EEZs (Gilman et al. 2007). Despite the existence of shark finning regulations, concern remains over the increased demand for shark meat and the lack of catch restrictions for sharks (Gilman et al. 2007; Hareide et al. 2007; Oceana 2007). Although studies have shown circle hooks to be effective for certain species and size classes of sea turtles, there is some evidence suggesting that shark catch increases with the use of circle hooks (Gilman et al. 2007). Thus, the multi-species impacts of these hooks should be considered. Concurrent conservation measures such as the use of circle hooks and catch-and-release of sharks and

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marlins is more likely to increase the abundance of these species (Kaplan et al. 2007).

Blue sharks have been shown to be sensitive to low exploitation rates (Kleiber et al. 2001; Schindler et al. 2002), but in the Atlantic, blue shark biomass appears to be above BMSY (ICCAT 2005a). The status of the Atlantic shortfin mako stock is highly uncertain, and it is possible that current biomass levels are below BMSY, particularly in light of the 50% depletion seen in the CPUE data (ICCAT 2005a). Although blue sharks are not protected under the US Endangered Species Act, the IUCN Red List of Threatened Species categorizes the blue shark as “Lower Risk,” which is close to qualifying for the “Vulnerable” category (IUCN 2004). The IUCN defines “Vulnerable” as facing a high risk of extinction in the wild (IUCN 2004).

As with seabirds and sea turtles, the impacts of longline fisheries on shark populations are not fully understood. The findings of Baum et al. (2003) in the Atlantic Ocean indicate caution is warranted for these highly vulnerable species. For more information on sharks, please see the Seafood Watch® Sharks Report available at: http://www.mbayaq.org/cr/cr_seafoodwatch/content/media/MBA_SeafoodWatch_SharksReport. pdf.

The continued bycatch of sea turtles, seabirds, marine mammals, sharks, billfish and other pelagic fishes remains a critical conservation concern for the majority of international tuna longline fleets. In 2005, leatherback and loggerhead sea turtle interaction rates declined in the US longline fishery, resulting in a ranking of high conservation concern for domestic longline fisheries in the Atlantic.

Synthesis Bycatch observer records are nonexistent for blackfin tuna-targeted fisheries. Some marketed blackfin tuna may be incidentally caught from a fishery targeting another species such as skipjack tuna.

Blackfin tuna caught using handline, baitboat, troll, and rod and reel gear encounter minimal bycatch and are of low conservation concern.

Bycatch in purse seine school sets is characterized primarily by small and large bony fishes and is a moderate conservation concern. Purse seine sets on FADs result in increased bycatch of juvenile tunas, other pelagics such as dolphinfish and wahoo, and sharks at levels that may be contributing to population declines in these species. Bycatch is not decreasing. Bycatch in the purse seine fishery on FADs or other floating objects thus ranks as a critical conservation concern.

Longline gear, a secondary method used to capture blackfin tuna, incurs substantially more bycatch than handlining. Although there are limited data regarding international bycatch levels and trends, the continued bycatch of sea turtles, seabirds, marine mammals, sharks, billfish and other pelagic fishes remains a critical conservation concern for the majority of international tuna longline fleets. In the absence of data demonstrating that bycatch rates are declining, Seafood Watch® must adopt a precautionary approach in considering the severity of the bycatch problem in global longline fisheries.

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In 2005, leatherback and loggerhead sea turtle interaction rates declined in the US longline fishery, resulting in a ranking of high conservation concern for domestic longline fisheries in the Atlantic. Seafood Watch® will continue to monitor this trend. In addition, the continued bycatch of marlin species with a critical stock status remains a concern.

For the purposes of this report, generalizations are used in order to make recommendations to the general public, although Seafood Watch® recognizes that there are differences between the various tuna longline fisheries. Country or fishery-specific data may be used to identify exceptions to these generalizations in the future.

Nature of Bycatch Rank

Handline, baitboat, troll, rod and reel

Low Moderate High Critical

Unassociated purse seine

Low Moderate High Critical

US Atlantic longline

Low Moderate High Critical

FAD purse seine, international longline

Low Moderate High Critical

Criterion 4: Effect of Fishing Practices on Habitats and Ecosystems

Habitat Effects The fishing practices used to target blackfin tuna (i.e., handline, rod and reel, baitboat, troll, purse seine and longline) have minimal direct habitat effects compared to trawling, for example, which is very destructive to the ocean bottom (Doray et al. 2004). These gears are either pelagic or are surface gears that do not contact the seafloor and thus have no detrimental habitat impacts on the benthos (Chuenpagdee et al. 2003).

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Ecosystem Effects15 By the nature of handlining (including rod and reel, baitboat and troll, in this case) fishers can only catch animals down to the depth of their line. Since small animals (average of 20 cm FL) tend to aggregate in the surface layer (0–10 m)(Doray et al. 2004; Doray et al. 2009), the majority of fish captured with handlines are juveniles and small fish (Doray et al. 2002). This results in one phase of the blackfin life cycle receiving more of the fishing pressure. In the absence of any information about the blackfin tuna stock, it is difficult to determine how this life stage-specific fishing pressure affects the population as a whole and what role that effect may play in the ecosystem.

There is evidence that tuna longline and FAD purse seine fisheries are having negative impacts on tuna species, but there is conflicting evidence as to whether those fisheries are negatively impacting the ecosystem as a whole. Due to the expanding and pervasive pelagic longline fishery, it is thought that the global oceans have lost 90% of their large predators such as tuna (Myers and Worm 2003). Based on CPUE data, Myers and Worm (2003) found that while catch in previously unfished areas remained high at first, catch declined after several years of fishing pressure. However, this argument has proven to be controversial, with questions being raised concerning the methodology (Walters 2003) and the magnitude of the declines (Hampton et al. 2005; Sibert et al. 2006). A recent study (Sibert et al. 2006) concluded that the magnitude of the decline in the biomass of large predators varied by stock and region. For instance, exploited bigeye and yellowfin declined in the western Pacific while skipjack increased. The authors acknowledge that more conservative management measures may be needed for ecosystem-based management (Walters et al. 2001 in Sibert et al. 2006). Both climate change and fishing pressure have been linked to ocean-wide declines in large predator diversity, with fishing being the primary driver behind long-term variation (Ward and Myers 2005; Worm et al. 2005). According to Worm et al. (2005), diversity in the world’s oceans has declined by 10–50% over the last 50 years. The removal of large predators such as tunas, sharks, and billfish from the ecosystem may affect the interactions between these species, as well as result in considerable top-down effects (effects on prey species populations and the food chain below these large predators) (Fonteneau 2003). The potential ecosystem effects of removing these predators from the world’s oceans, as well as the bycatch of vulnerable and threatened species, have been identified as two environmental risks associated with tuna fisheries (Fonteneau 2003).

With increasing use of FADs in the purse seine fisheries, the risk of negative impacts such as increased removal of juvenile tuna and bycatch species increases (Sakagawa 2000). The use of FADs may also affect tuna species by enticing them to remain in an area where they would normally pass through, possibly affecting characteristics such as growth population dynamics (Sakagawa 2000). The effects of FADs on the spatial dynamics and biology of tuna are unknown, and it is also unknown how FAD fishing affects fish stocks and pelagic ecosystems (Hallier and Gaertner 2007, Moreno et al. 2007); caution may be warranted (Sakagawa 2000). Fish aggregating devices may serve as ecological traps, artificially shifting the movement patterns of both tuna and other species that associate with FADs (Marsac et al. 2000). In addition, Hallier and

15 Portions of this section were taken verbatim from the Seafood Watch® Skipjack Tuna Report written by Jesse Marsh, which is available at http://www.montereybayaquarium.org/cr/SeafoodWatch/web/sfw_factsheet.aspx?gid=70.

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Gaertner (2007) found that individual tunas associated with drifting FADs were less healthy than those in free schools, using plumpness and growth rates as indicators. They also suggest that feeding migration patterns may be altered by FADs, but long-term effects on the life cycle of tunas are still unknown. There is also concern that the attraction and capture of large numbers of juvenile and undersized target species may be adversely affecting stocks. The attraction and incidental catch of a variety of non-target species is also a concern (Moreno et al. 2007).

Purse seines on FADs and longlines have serious impacts on the populations of top predators including targeted tuna species and bycatch species such as sharks, which may have cascading effects on the food web and the entire ecosystem. As a result, food web impacts of FAD purse seine and longline fisheries are considered a high conservation concern according to Seafood Watch®. The food web impacts of the handline, rod and reel, baitboat, troll and unassociated purse seine fisheries are unknown and therefore considered moderate according to Seafood Watch®. It is unknown whether any fishing methods in the blackfin tuna fishery cause ecosystem state changes; therefore, this is considered a moderate conservation concern according to Seafood Watch®.

The environmental impacts of fishing are not limited to direct impacts on fisheries resources. Other impacts include emissions (e.g., from fossil fuel and anti-fouling paint) from the operation of these industrial fisheries (Hospido and Tyedmers 2005); however, these impacts are not included in the Seafood Watch® criteria.

Synthesis Purse seine (unassociated and FAD), pelagic longline, handline, rod and reel, baitboat and troll gear have negligible habitat effects. Handline, rod and reel, baitboat and troll tuna fisheries are able to harvest tuna from the ecosystem with minimal bycatch of other large predatory species. There is evidence that tuna longline and FAD purse seine fisheries have negative impacts on tuna species, but there is conflicting evidence as to whether those fisheries are negatively impacting the ecosystem as a whole. Given the important ecological role of large predators, including both targeted tuna and bycatch species such as sharks, negative ecosystem impacts from the removal of these species in the FAD purse seine and longline fisheries are likely. Handlining, rod and reel, baitboat, troll and unassociated purse seine fisheries have less severe impacts on tuna and shark populations. Given this information, the effects on habitats and ecosystems from the handline, rod and reel, baitboat, troll and unassociated purse seine blackfin tuna fisheries are a low conservation concern, while the effects from the longline and FAD purse seine blackfin tuna fisheries are a moderate conservation concern.

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Effect of Fishing Practices Rank

Handline, rod and reel, baitboat, troll, unassociated purse seine

Benign Moderate Severe Critical

FAD purse seine, global longline

Benign Moderate Severe Critical

Criterion 5: Effectiveness of the Management Regime16

The International Commission for the Conservation of Atlantic Tunas (ICCAT) is the international management agency responsible for blackfin tuna management in the Atlantic Ocean together with the cooperation of individual countries. Regulations are generally based on recommendations by ICCAT staff or scientific committees and are implemented by member and cooperating countries, although individual countries may have their own management measures for their respective tuna fisheries. The Standing Committee on Research and Statistics (SCRS) is the fishery statistics body of ICCAT that provides advice on issues such as stock status and fishing effort. Within the SCRS, there are several sub-committees including a Sub-Committee on Bycatch that is responsible for research and analysis of bycatch issues.

The Western Central Atlantic Fishery Commission (WECAFC) is a regional fishery management body that has an advisory (not management) mandate over the living marine resources within the area of the Commission. Membership is open to coastal States whose territories are within the Western Central Atlantic area or whose vessels fish within the area. The Commission’s purpose is to facilitate coordination of research, encourage education and training, assist member governments in establishing policies and to promote rational management of resources of interest to two or more countries (NOAA 2006, FAO 2009b). Only eight countries in the Western Central Atlantic Fishery Commission (WECAFC) area are, or have been, members of the International Commission for the Conservation of Atlantic Tunas (ICCAT): Brazil, Cuba (which withdrew in 1992), Venezuela, the US, St. Vincent & The Grenadines, Belize, Barbados and Trinidad & Tobago, (Mahon 1996; ICCAT 2009a).

Management of blackfin tuna fisheries is poorly documented. The ICCAT database provides the most complete information on fishing activity by large-scale commercial fisheries in the Western Central Atlantic (Mahon 1996). However, documented trends in abundance and the current status of large coastal and pelagic fish stocks being exploited in the WECAFC area are only available

16 Portions of this section were taken verbatim from the Seafood Watch® Skipjack Tuna Report written by Jesse Marsh, which is available at http://www.montereybayaquarium.org/cr/SeafoodWatch/web/sfw_factsheet.aspx?gid=70.

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for the major species assessed by ICCAT (Mahon 1996). By default, mainly due to lack of information, the ICCAT treats blackfin tuna in the Atlantic as a single stock unit. Due to the lack of stock data, there are, in general, no management policies in place for blackfin tuna (Ortiz, pers. comm.), and it is unclear whether management has been able to maintain the long-term productivity of this stock.

In 2002, it was reported that Cuba had instituted a minimum size capture of 30 cm FL for blackfin and skipjack tuna (FAO 2002). In the wider Caribbean, marine protected areas (MPAs) are now being used to manage fisheries. The Caribbean Marine Protected Areas Management Network (CaMPAM), administered by the United Nations Environment Programme – Caribbean Environment Programme (UNEP-CEP), exists to enhance communication and strengthen the network of managers, researchers, planners and educators in the Caribbean. It has been reported that of the 300 MPAs in the region, only six percent are rated as effectively managed (FAO 2005).

There is no comprehensive observer program for international fisheries in the Atlantic, nor are there set requirements for logbook reporting. As a result, there are no bycatch reduction plans in place in the Atlantic. Some fleets do have observer programs while others use logbook data to report bycatch (ICCAT 2005b). The US has an observer program, as does Venezuela, where a program has been in place since 1991 (Marcano et al. 2004). Bycatch of sharks has not been addressed, as ICCAT has not implemented any management measures for shark species (ICCAT 2005a). In addition, the current shark statistics reported to ICCAT are not thought to represent actual removals by the reporting fisheries (ICCAT 2005a). Currently, no management plans are in place to reduce bycatch in the international longline or FAD purse seine blackfin tuna fisheries.

The US does not presently have fishery management regulations for blackfin tuna in the Gulf of Mexico or the South Atlantic council jurisdictions for commercial or recreational fisheries (Ortiz, pers. com.). However, other US fisheries operating in the Atlantic land blackfin tuna. These fisheries are managed by the HMS Division of NMFS. The US fishery targeting tuna in the Atlantic is managed under the Fishery Management Plan for Atlantic Tunas, Swordfish and Sharks. There are permitting requirements for the HMS fishery. The bycatch reduction program put into place by NMFS includes gear modifications and time/area closures. These requirements include mandatory circle hook and bait use, as well as mandatory possession and use of sea turtle release equipment (69 FR 128, July 6, 2004). Outside of the Northeast Distant Waters (NED) area, 16/0 (non-offset only) or 18/0 circle hooks may be used with whole finfish or squid bait (69 FR 128, July 6, 2004). Bycatch assessments and corresponding time/area investigations are conducted. The use of live bait in the longline fishery in the Gulf of Mexico is prohibited under “Regulatory” Amendment 1 to the HMS FMP due to concerns over billfish bycatch (NMFS 2004a). To date, the time/area closures established in the Atlantic appear to be successful at reducing discards of most HMS, excluding large coastal sharks (NMFS 2004a). In the Gulf of Mexico, all Mexican longline vessels are required to have an observer on board during all trips. Observer coverage for US vessels in the Gulf of Mexico has ranged from 3–5% (Brown et al. 2004), although the management objective is 8% throughout the Atlantic, including the Gulf of Mexico and Caribbean, versus just 5% in the Gulf of Mexico (NMFS 2004b). In 2002, average

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coverage was 8.9%; though outside of the NED experiment area coverage was 3.7% (NMFS 2004b).

Within the last 7 to 8 years, some fisheries have incorporated FADs into their fishing strategies (Doray et al. 2002, FAO 2008a), which has encouraged offshore fishing. Some management organizations view FADs as a potential way to increase and stabilize the catch of pelagic species on a “sustainable” basis because they know and can track exactly where the fishing effort is (Fujii 2004). There are many benefits of FAD fishing realized by fishers as it saves time and resources by being able to revisit the same FAD(s) over and over again; however, it is a controversial strategy because it has sparked conflict in some regions, such as the Lesser Antilles, presents management obstacles, and the ecological effects of FAD fishing are still poorly understood.

New fishing concerns and conflicts have risen over issues such as FAD maintenance (government vs. fishers), FAD use and maintenance (professional fishers vs. non-professional fishers), ownership issues of the FAD and/or aggregated fish, potential adverse effects on other fisheries, shipping and navigation, and resource utilization and management (Defoe et al. 2004; FAO 2008a). There have been incidents of “intentional degradation” (cutting the anchoring line) reported in Trinidad and Tobago (Fujii 2004). Unless strictly patrolled and regulated, the number of FADs deployed and the number of boats fishing around them is hard to know, raising management concerns (Defoe et al. 2004).

For example, in Dominica, professional and non-professional fishers use FADs to fish (using a single longline or deep drop-line) for target species (yellowfin and blackfin tuna), as well as dolphin fish and wahoo, mainly from July to November. Dominica’s Fisheries Division acquired a vessel in 2004, which is used to more effectively monitor FADs by keeping a record of their initial installation and specific location via a GIS system (Defoe et al. 2004). In an effort to protect juvenile fishes, the Division is promoting a policy of responsible fishing around FADs asking fishers to capture juveniles for bait purposes only. The Division also recommends the implementation of beacons and radar reflectors as navigational aids; however, the specific fishery that deploys the FAD often does not comply so that other fishers find it more difficult to locate and fish using ‘their’ FAD (Defoe et al. 2004). This presents hazards for unsuspecting boats in the open sea, and ships can destroy FADs quite easily by unknowingly passing over them. As a result, FADs have been destroyed in Dominica, but these incidents have not been properly documented and recorded (Defoe et al. 2004). Although there are three main management initiatives outlined here for Dominica, there no enforcement measures have been reported.

In general, international standards and guidelines regarding surface and mid-water FADs are still very minimal, but a number of countries worldwide have set up their own relevant regulations concerning the number of FADs per owner, position, proper marking, issue of a government authorization, amount of fishing gear authorized, regular reporting of activities around FADs, etc. (FAO 2008a). No such regulations were found for countries in the Southern Atlantic or Caribbean Sea that were evaluated in this report, however, with the exception of the US. Enforcement of these regulations is unknown.

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Table 11. Commercial catch management measures for the blackfin tuna fishery.

Total Management Jurisdictions & Gear Trip Area Allowable Size Limit Sources Agencies Restrictions Limit Closures Landings FAO Dominica Fisheries Division; None in US 2002; Ministry of Agriculture, Land Atlantic waters; Adams and Marine Resource, Trinidad 30cm FL in 2004; and Tobago; Fisheries Division Unlimited Cuba; none None None None Defoe et of other Lesser Antilles islands; reported for other al. 2004; National Marine Fisheries parts of the Fujii Service (US) western Atlantic 2004

Synthesis No stock assessment for blackfin tuna in the western Atlantic has been conducted, and no fishery-independent or independent data are collected. As such, it is unclear whether management has been able to maintain the long-term productivity of the stock. While bycatch is not an issue in the handline, rod and reel, troll and baitboat fisheries, bycatch is a concern in the longline and purse seine fisheries. Currently, no bycatch plan has been implemented for these fisheries. There are no comprehensive observer programs for the international fisheries mentioned in this report. The US has implemented bycatch reduction measures, but they have not been proven to be effective at reducing bycatch of all non-target species. There is no international enforcement program, as enforcement is the responsibility of individual countries and not the international management agencies.

Due to the lack of a stock assessment, fishery-dependent and independent data collection, and enforcement measures, Seafood Watch® considers management of the handline, rod and reel, baitboat and troll fisheries to be ineffective and a high conservation concern. Management of the purse seine and international longline fisheries is a critical conservation concern because, in addition to the lack of stock information, data collection and enforcement, bycatch is a concern and no bycatch plans have been implemented. To the contrary, the US longline fishery has bycatch reduction measures in place, but they have not been proven effective at reducing bycatch of all non-target species. As such, management of this fishery is also deemed to be a critical conservation concern.

Effectiveness of Management Rank

Handline, rod and reel, baitboat, and troll

Highly Effective Moderately Effective Ineffective Critical

Longline, purse seine

Highly Effective Moderately Effective Ineffective Critical

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IV. Overall Evaluation and Seafood Recommendation

Although blackfin tuna are fished in a number of different countries and islands in the Western Atlantic, there is very little information about their population dynamics or ecological role. Blackfin tuna have a low age at maturity, a low maximum age and a high growth rate, and are thus considered by Seafood Watch® to be inherently resilient to fishing pressure. There is little to no information in the literature about blackfin tuna stocks. Due to the lack of available information, the status of the wild stock is considered moderate.

There are low amounts of bycatch in the blackfin tuna fisheries using handline, rod and reel, baitboat and troll gear. Bycatch in the unassociated purse seine fishery is a moderate concern due to bycatch of small and large bony fishes. To the contrary, bycatch is a high conservation concern in the US longline blackfin tuna fishery and critical in both the FAD purse seine and international longline blackfin tuna fisheries. Pelagic longlines and purse seine gear (unassociated and FAD) have negligible habitat effects. There is evidence that tuna longline and FAD purse seine fisheries are having negative impacts on tuna species, but there is conflicting evidence as to whether those fisheries are negatively impacting the ecosystem as a whole. However, it is likely that the negative impacts of FAD purse seine and longline fisheries on tuna and sharks may substantially disrupt the food web. Given this information, the effects on habitats and ecosystems from the handline, rod and reel, baitboat, troll and unassociated purse seine blackfin tuna fisheries are a low conservation concern, while the effects from the longline and FAD purse seine blackfin tuna fisheries are a moderate conservation concern.

No stock assessment for blackfin tuna in the western Atlantic has yet been conducted, and no fishery-independent or independent data have been collected. No bycatch plan has been implemented for the purse seine or international longline fisheries. There are no comprehensive observer programs for the international fisheries mentioned in this report. The US has implemented bycatch reduction measures, but they have not been proven effective at reducing bycatch of all non-target species. There is no international enforcement program, as enforcement is the responsibility of individual countries and not the international management agencies.

The inherent vulnerability of blackfin tuna is low, and the status of the stock is of moderate concern. The amount and severity of bycatch varies by gear type, as do the habitat and ecosystem effects, and management effectiveness. These differences determined the following final recommendations: Blackfin tuna caught with handline, rod and reel, baitboat and troll gear are a Good Alternative due to low bycatch, low habitat and ecosystem effects, and ineffective management. Blackfin tuna caught with longlines in the US are ranked as Avoid due to high bycatch rates and critically ineffective management. International longline fleets have bycatch rates of critical conservation concern, moderate impacts to the habitat and ecosystem and critically ineffective management; therefore, blackfin tuna caught in this manner are ranked as Avoid. Blackfin tuna caught with unassociated purse seines are ranked as Avoid due to critically ineffective management. Blackfin tuna caught with FAD purse seines are also ranked as Avoid due to critical rankings for bycatch and management.

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According to the most recent ICCAT data (2008), approximately 60% of blackfin tuna were caught using handline, rod and reel, baitboat and troll gear, 18% were caught using longlines and purse seines (the proportion of unassociated versus FAD is unknown), and 22% were caught with unclassified gear.

Table of Sustainability Ranks

Conservation Concern Sustainability Criteria Low Moderate High Critical Inherent Vulnerability √ Status of Stock(s) √ √ Handline, √ FAD √Unassociated Nature of Bycatch rod and reel, √ US longline purse seine / baitboat, purse seine international troll longline √ Handline, rod and reel, Habitat & Ecosystem Effects baitboat, √ FAD purse troll, seine; longline unassociated purse seine √ Handline, √ Purse Management Effectiveness rod and reel, seine / baitboat, troll longline

Overall Seafood Recommendation

Seafood Watch® Gear Used Recommendation Best Choice Good Alternative Handline, rod and reel, baitboat, troll Avoid Purse seine, longline

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Acknowledgements

Seafood Watch® thanks Dr. Andre Boustany of Duke University and two anonymous reviewers for graciously reviewing this paper for scientific accuracy.

Scientific review does not constitute an endorsement of the Seafood Watch® program, or its seafood recommendations, on the part of the reviewing scientists. Seafood Watch® is solely responsible for the conclusions reached in this report.

Supplemental Information

The Environmental Defense Fund has issued a consumption advisory for blackfin tuna due to elevated levels of mercury contamination. Environmental Defense applies the same risk-based methodology as the U.S. Environmental Protection Agency (EPA) to data from government studies and papers published in scientific journals. More detailed information about the Environmental Defense advisory can be found at www.edf.org/seafoodfhealth.

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VI. Appendices Appendix I. Wild-capture fisheries evaluation

Capture Fisheries Evaluation Species: Blackfin Tuna Region: Western Atlantic

Analyst: Lindsey Peavey Date: September 7, 2010

Seafood Watch™ defines sustainable seafood as originating from sources, whether fished17 or farmed, that can maintain or increase production in the long-term without jeopardizing the structure or function of affected ecosystems.

The following guiding principles illustrate the qualities that capture fisheries must possess to be considered sustainable by the Seafood Watch program. Species from sustainable capture fisheries: • have a low vulnerability to fishing pressure, and hence a low probability of being overfished, because of their inherent life history characteristics; • have stock structure and abundance sufficient to maintain or enhance long-term fishery productivity; • are captured using techniques that minimize the catch of unwanted and/or unmarketable species; • are captured in ways that maintain natural functional relationships among species in the ecosystem, conserves the diversity and productivity of the surrounding ecosystem, and do not result in irreversible ecosystem state changes; and • have a management regime that implements and enforces all local, national and international laws and utilizes a precautionary approach to ensure the long-term productivity of the resource and integrity of the ecosystem.

Seafood Watch has developed a set of five sustainability criteria, corresponding to these guiding principles, to evaluate capture fisheries for the purpose of developing a seafood recommendation for consumers and businesses. These criteria are: 1. Inherent vulnerability to fishing pressure 2. Status of wild stocks 3. Nature and extent of discarded bycatch 4. Effect of fishing practices on habitats and ecosystems 5. Effectiveness of the management regime

Each criterion includes: • Primary factors to evaluate and rank • Secondary factors to evaluate and rank • Evaluation guidelines18 to synthesize these factors • A resulting rank for that criterion

17 “Fish” is used throughout this document to refer to finfish, shellfish and other wild-caught invertebrates. 18 Evaluation Guidelines throughout this document reflect common combinations of primary and secondary factors that result in a given level of conservation concern. Not all possible combinations are shown – other combinations should be matched as closely as possible to the existing guidelines.

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Once a rank has been assigned to each criterion, an overall seafood recommendation for the species in question is developed based on additional evaluation guidelines. The ranks for each criterion, and the resulting overall seafood recommendation, are summarized in a table. Criterion ranks and the overall seafood recommendation are color-coded to correspond to the categories of the Seafood Watch pocket guide:

Best Choices/Green: Consumers are strongly encouraged to purchase seafood in this category. The wild- caught species is sustainable as defined by Seafood Watch.

Good Alternatives/Yellow: Consumers are encouraged to purchase seafood in this category, as they are better choices than seafood in the Avoid category. However there are some concerns with how this species is fished and thus it does not demonstrate all of the qualities of a sustainable fishery as defined by Seafood Watch.

Avoid/Red: Consumers are encouraged to avoid seafood in this category, at least for now. Species in this category do not demonstrate enough qualities to be defined as sustainable by Seafood Watch.

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CRITERION 1: INHERENT VULNERABILITY TO FISHING PRESSURE Guiding Principle: Sustainable wild-caught species have a low vulnerability to fishing pressure, and hence a low probability of being overfished, because of their inherent life history characteristics.

Primary Factors19 to evaluate Intrinsic rate of increase (‘r’) ¾ High (> 0.16) ¾ Medium (0.05 - 0.16) ¾ Low (< 0.05) ¾ Unavailable/Unknown

Age at 1st maturity ¾ Low (< 5 years) (2 years) ¾ Medium (5 - 10 years) ¾ High (> 10 years) ¾ Unavailable/Unknown

Von Bertalanffy growth coefficient (‘k’) ¾ High (> 0.16) ¾ Medium (0.05 - 0.15) ¾ Low (< 0.05) ¾ Unavailable/Unknown

Maximum age ¾ Low (< 11 years) ¾ Medium (11 - 30 years) ¾ High (> 30 years) ¾ Unavailable/Unknown

Reproductive potential (fecundity) ¾ High (> 100 inds./year) ¾ Moderate (10 – 100 inds./year)

19 These primary factors and evaluation guidelines follow the recommendations of Musick et al. (2000). Marine, estuarine, and diadromous fish stocks at risk of extinction in North America (exclusive of Pacific salmonids). Fisheries 25:6-30.

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¾ Low (< 10 inds./year) ¾ Unavailable/Unknown

Secondary Factors to evaluate

Species range ¾ Broad (e.g. species exists in multiple ocean basins, has multiple intermixing stocks or is highly migratory) ¾ Limited (e.g. species exists in one ocean basin) ¾ Narrow (e.g. endemism or numerous evolutionary significant units or restricted to one coastline)

Special Behaviors or Requirements: Existence of special behaviors that increase ease or population consequences of capture (e.g. migratory bottlenecks, spawning aggregations, site fidelity, unusual attraction to gear, sequential hermaphrodites, segregation by sex, etc., OR specific and limited habitat requirements within the species’ range).

¾ No known behaviors or requirements OR behaviors that decrease vulnerability (e.g. widely dispersed during spawning) ¾ Some (i.e. 1 - 2) behaviors or requirements ¾ Many (i.e. > 2) behaviors or requirements

Quality of Habitat: Degradation from non-fishery impacts ¾ Habitat is robust ¾ Habitat has been moderately altered by non-fishery impacts ¾ Habitat has been substantially compromised from non-fishery impacts and thus has reduced capacity to support this species (e.g. from dams, pollution, or coastal development)

Evaluation Guidelines

1) Primary Factors a) If ‘r’ is known, use it as the basis for the rank of the Primary Factors. b) If ‘r’ is unknown, then the rank from the remaining Primary Factors (in order of importance, as listed) is the basis for the rank.

2) Secondary Factors a) If a majority (2 out of 3) of the Secondary Factors rank as Red, reclassify the species into the next lower rank (i.e. Green becomes Yellow, Yellow becomes Red). No other combination of Secondary Factors can modify the rank from the Primary Factors.

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b) No combination of primary and secondary factors can result in a Critical Conservation Concern for this criterion.

Conservation Concern: Inherent Vulnerability

¾ Low (Inherently Resilient) ¾ Moderate (Moderately Vulnerable) ¾ High (Highly Vulnerable)

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CRITERION 2: STATUS OF WILD STOCKS

Guiding Principle: Sustainable wild-caught species have stock structure and abundance sufficient to maintain or enhance long-term fishery productivity.

Primary Factors to evaluate

Management classification status ¾ Underutilized OR close to virgin biomass ¾ Fully fished OR recovering from overfished OR unknown ¾ Recruitment or growth overfished, overexploited, depleted or “threatened”

Current population abundance relative to BMSY ¾ At or above BMSY (> 100%)

¾ Moderately Below BMSY (50 – 100%) OR unknown

¾ Substantially below BMSY (< 50%)

Occurrence of overfishing (current level of fishing mortality relative to overfishing threshold)

¾ Overfishing not occurring (Fcurr/Fmsy < 1.0) ¾ Overfishing is likely/probable OR fishing effort is increasing with poor understanding of stock status OR Unknown

¾ Overfishing occurring (Fcurr/Fmsy > 1.0)

Overall degree of uncertainty in status of stock ¾ Low (i.e. current stock assessment and other fishery-independent data are robust OR reliable long-term fishery-dependent data available) ¾ Medium (i.e. only limited, fishery-dependent data on stock status are available) ¾ High (i.e. little or no current fishery-dependent or independent information on stock status OR models/estimates broadly disputed or otherwise out-of-date)

Long-term trend (relative to species’ generation time) in population abundance as measured by either fishery-independent (stock assessment) or fishery-dependent (standardized CPUE) measures ¾ Trend is up ¾ Trend is flat or variable (among areas, over time or among methods) OR Unknown ¾ Trend is down

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Short-term trend in population abundance as measured by either fishery-independent (stock assessment) or fishery-dependent (standardized CPUE) measures ¾ Trend is up ¾ Trend is flat or variable (among areas, over time or among methods) OR Unknown ¾ Trend is down

Current age, size or sex distribution of the stock relative to natural condition ¾ Distribution(s) is(are) functionally normal ¾ Distribution(s) unknown ¾ Distribution(s) is(are) skewed

Evaluation Guidelines

A “Healthy” Stock: 1) Is underutilized (near virgin biomass) 2) Has a biomass at or above BMSY AND overfishing is not occurring AND distribution parameters are functionally normal AND stock uncertainty is not high

A “Moderate” Stock: 1) Has a biomass at 50-100% of BMSY AND overfishing is not occurring 2) Is recovering from overfishing AND short-term trend in abundance is up AND overfishing not occurring AND stock uncertainty is low 3) Has an Unknown status because the majority of primary factors are unknown.

A “Poor” Stock: 1) Is fully fished AND trend in abundance is down AND distribution parameters are skewed 2) Is overfished, overexploited or depleted AND trends in abundance and CPUE are up. 3) Overfishing is occurring AND stock is not currently overfished.

A stock is considered a Critical Conservation Concern and the species is ranked “Avoid”, regardless of other criteria, if it is: 1) Overfished, overexploited or depleted AND trend in abundance is flat or down 2) Overfished AND overfishing is occurring 3) Listed as a “threatened species” or similar proxy by national or international bodies

Conservation Concern: Status of Stocks

¾ Low (Stock Healthy) ¾ Moderate (Stock Moderate or Unknown) ¾ High (Stock Poor) ¾ Stock Critical

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CRITERION 3: NATURE AND EXTENT OF DISCARDED BYCATCH20

Guiding Principle: A sustainable wild-caught species is captured using techniques that minimize the catch of unwanted and/or unmarketable species.

Primary Factors to evaluate

Quantity of bycatch, including any species of “special concern” (i.e. those identified as “endangered”, “threatened” or “protected” under state, federal or international law)

¾ Quantity of bycatch is low (< 10% of targeted landings on a per number basis) AND does not regularly include species of special concern (handline, rod and reel, baitboat, troll) ¾ Quantity of bycatch is moderate (10 – 100% of targeted landings on a per number basis) AND does not regularly include species of special concern OR Unknown ¾ Quantity of bycatch is high (> 100% of targeted landings on a per number basis) OR bycatch regularly includes threatened, endangered or protected species

(longline; FAD purse seine)

Population consequences of bycatch ¾ Low: Evidence indicates quantity of bycatch has little or no impact on population levels (handline, rod and reel, baitboat, troll) ¾ Moderate: Conflicting evidence of population consequences of bycatch OR Unknown ¾ Severe: Evidence indicates quantity of bycatch is a contributing factor in driving one or more bycatch species toward extinction OR is a contributing factor in limiting the recovery of a species of “special concern” (longline; FAD purse seine)

Trend in bycatch interaction rates (adjusting for changes in abundance of bycatch species) as a result of management measures (including fishing seasons, protected areas and gear innovations): ¾ Trend in bycatch interaction rates is down (U.S. longline) ¾ Trend in bycatch interaction rates is flat OR Unknown (FAD purse seine; international longline) ¾ Trend in bycatch interaction rates is up

20 Bycatch is defined as species that are caught but subsequently discarded because they are of undesirable size, sex or species composition. Unobserved fishing mortality associated with fishing gear (e.g. animals passing through nets, breaking free of hooks or lines, ghost fishing, illegal harvest and under or misreporting) is also considered bycatch. Bycatch does not include incidental catch (non-targeted catch) if it is utilized, is accounted for, and is managed in some way.

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¾ Not applicable because quantity of bycatch is low (handline, rod and reel, baitboat, troll)

Secondary Factor to evaluate

Evidence that the ecosystem has been or likely will be substantially altered (relative to natural variability) in response to the continued discard of the bycatch species ¾ Studies show no evidence of ecosystem impacts ¾ Conflicting evidence of ecosystem impacts OR Unknown (handline, rod and reel, baitboat, troll, unassociated purse seine) ¾ Studies show evidence of substantial ecosystem impacts (longline and FAD: removal of large predators)

Evaluation Guidelines

Bycatch is “Minimal” if: 1) Quantity of bycatch is <10% of targeted landings AND bycatch has little or no impact on population levels.

Bycatch is “Moderate” if: 1) Quantity of bycatch is 10 - 100% of targeted landings 2) Bycatch regularly includes species of “special concern” AND bycatch has little or no impact on the bycatch population levels AND the trend in bycatch interaction rates is not up.

Bycatch is “Severe” if: 1) Quantity of bycatch is > 100% of targeted landings 2) Bycatch regularly includes species of “special concern” AND evidence indicates bycatch rate is a contributing factor toward extinction or limiting recovery AND trend in bycatch is down.

Bycatch is considered a Critical Conservation Concern and the species is ranked “Avoid”, regardless of other criteria, if: 1) Bycatch regularly includes species of special concern AND evidence indicates bycatch rate is a factor contributing to extinction or limiting recovery AND trend in bycatch interaction rates is not down. 2) Quantity of bycatch is high AND studies show evidence of substantial ecosystem impacts.

Conservation Concern: Nature and Extent of Discarded Bycatch ¾ Low (Bycatch Minimal) (handline, rod and reel, baitboat, troll) ¾ Moderate (Bycatch Moderate) ¾ High (Bycatch Severe) (U.S. longline) ¾ Bycatch Critical (international longline; FAD purse seine)

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CRITERION 4: EFFECT OF FISHING PRACTICES ON HABITATS AND ECOSYSTEMS

Guiding Principle: Capture of a sustainable wild-caught species maintains natural functional relationships among species in the ecosystem, conserves the diversity and productivity of the surrounding ecosystem, and does not result in irreversible ecosystem state changes.

Primary Habitat Factors to evaluate

Known (or inferred from other studies) effect of fishing gear on physical and biogenic habitats ¾ Minimal damage (i.e. pelagic longline, midwater gillnet, midwater trawl, purse seine, hook and line, or spear/harpoon) ¾ Moderate damage (i.e. bottom gillnet, bottom longline or some pots/ traps) ¾ Great damage (i.e. bottom trawl or dredge)

For specific fishery being evaluated, resilience of physical and biogenic habitats to disturbance by fishing method ¾ High (e.g. shallow water, sandy habitats) ¾ Moderate (e.g. shallow or deep water mud bottoms, or deep water sandy habitats) ¾ Low (e.g. shallow or deep water corals, shallow or deep water rocky bottoms) ¾ Not applicable because gear damage is minimal

If gear impacts are moderate or great, spatial scale of the impact ¾ Small scale (e.g. small, artisanal fishery or sensitive habitats are strongly protected) ¾ Moderate scale (e.g. modern fishery but of limited geographic scope) ¾ Large scale (e.g. industrialized fishery over large geographic areas) ¾ Not applicable because gear damage is minimal

Primary Ecosystem Factors to evaluate

Evidence that the removal of the targeted species or the removal/deployment of baitfish has or will likely substantially disrupt the food web ¾ The fishery and its ecosystem have been thoroughly studied, and studies show no evidence of substantial ecosystem impacts ¾ Conflicting evidence of ecosystem impacts OR Unknown (handline, rod and reel, baitboat, troll, unassociated purse seine) ¾ Ecosystem impacts of targeted species removal demonstrated (Longline, FAD purse seine)

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Evidence that the fishing method has caused or is likely to cause substantial ecosystem state changes, including alternate stable states ¾ The fishery and its ecosystem have been thoroughly studied, and studies show no evidence of substantial ecosystem impacts ¾ Conflicting evidence of ecosystem impacts OR Unknown (all gear types) ¾ Ecosystem impacts from fishing method demonstrated

Evaluation Guidelines

The effect of fishing practices is “Benign” if: 1) Damage from gear is minimal AND resilience to disturbance is high AND neither Ecosystem Factor is red.

The effect of fishing practices is “Moderate” if: 1) Gear effects are moderate AND resilience to disturbance is moderate or high AND neither Ecosystem Factor is red. 2) Gear results in great damage AND resilience to disturbance is high OR impacts are small scale AND neither Ecosystem Factor is red. 3) Damage from gear is minimal and one Ecosystem factor is red.

The effect of fishing practices is “Severe” if: 1) Gear results in great damage AND the resilience of physical and biogenic habitats to disturbance is moderate or low. 2) Both Ecosystem Factors are red.

Habitat effects are considered a Critical Conservation Concern and a species receives a recommendation of “Avoid”, regardless of other criteria if: ¾ Four or more of the Habitat and Ecosystem factors rank red.

Conservation Concern: Effect of Fishing Practices on Habitats and Ecosystems

¾ Low (Fishing Effects Benign) (handline, rod and reel, baitboat, troll, unassociated) ¾ Moderate (Fishing Effects Moderate) (longline; FAD purse seine) ¾ High (Fishing Effects Severe) ¾ Critical Fishing Effects

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CRITERION 5: EFFECTIVENESS OF THE MANAGEMENT REGIME

Guiding Principle: The management regime of a sustainable wild-caught species implements and enforces all local, national and international laws and utilizes a precautionary approach to ensure the long- term productivity of the resource and integrity of the ecosystem.

Primary Factors to evaluate

Stock Status: Management process utilizes an independent scientific stock assessment that seeks knowledge related to the status of the stock ¾ Stock assessment complete and robust ¾ Stock assessment is planned or underway but is incomplete OR stock assessment complete but out-of-date or otherwise uncertain ¾ No stock assessment available now and none is planned in the near future

Scientific Monitoring: Management process involves regular collection and analysis of data with respect to the short and long-term abundance of the stock ¾ Regular collection and assessment of both fishery-dependent and independent data ¾ Regular collection of fishery-dependent data only ¾ No regular collection or analysis of data

Scientific Advice: Management has a well-known track record of consistently setting or exceeding catch quotas beyond those recommended by its scientific advisors and other external scientists: ¾ No ¾ Yes ¾ Not enough information available to evaluate OR not applicable because little or no scientific information is collected

Bycatch: Management implements an effective bycatch reduction plan ¾ Bycatch plan in place and reaching its conservation goals (deemed effective) ¾ Bycatch plan in place but effectiveness is not yet demonstrated or is under debate ¾ No bycatch plan implemented or bycatch plan implemented but not meeting its conservation goals (deemed ineffective) purse seine, longline ¾ Not applicable because bycatch is “low” Handline, rod and reel, baitboat, troll

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Fishing practices: Management addresses the effect of the fishing method(s) on habitats and ecosystems ¾ Mitigative measures in place and deemed effective ¾ Mitigative measures in place but effectiveness is not yet demonstrated or is under debate ¾ No mitigative measures in place or measures in place but deemed ineffective ¾ Not applicable because fishing method is moderate or benign

Enforcement: Management and appropriate government bodies enforce fishery regulations ¾ Regulations regularly enforced by independent bodies, including logbook reports, observer coverage, dockside monitoring and similar measures ¾ Regulations enforced by fishing industry or by voluntary/honor system ¾ Regulations not regularly and consistently enforced

Management Track Record: Conservation measures enacted by management have resulted in the long-term maintenance of stock abundance and ecosystem integrity ¾ Management has maintained stock productivity over time OR has fully recovered the stock from an overfished condition ¾ Stock productivity has varied and management has responded quickly OR stock has not varied but management has not been in place long enough to evaluate its effectiveness OR Unknown ¾ Measures have not maintained stock productivity OR were implemented only after significant declines and stock has not yet fully recovered

Evaluation Guidelines

Management is deemed to be “Highly Effective” if the majority of management factors are green AND the remaining factors are not red.

Management is deemed to be “Moderately Effective” if: 1) Management factors “average” to yellow 2) Management factors include one or two red factors

Management is deemed to be “Ineffective” if three individual management factors are red, including especially those for Stock Status and Bycatch.

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Management is considered a Critical Conservation Concern and a species receives a recommendation of “Avoid”, regardless of other criteria if: 1) There is no management in place 2) The majority of the management factors rank red.

Conservation Concern: Effectiveness of Management ¾ Low (Management Highly Effective) ¾ Moderate (Management Moderately Effective) ¾ High (Management Ineffective) Handline, rod and reel, baitboat, troll ¾ Critical (Management Critically Ineffective) purse seine; longline

Overall Seafood Recommendation

Overall Guiding Principle: Sustainable wild-caught seafood originates from sources that can maintain or increase production in the long-term without jeopardizing the structure or function of affected ecosystems.

Evaluation Guidelines

A species receives a recommendation of “Best Choice” if: 1) It has three or more green criteria and the remaining criteria are not red.

A species receives a recommendation of “Good Alternative” if: 1) Criteria “average” to yellow 2) There are four green criteria and one red criteria 3) Stock Status and Management criteria are both ranked yellow and remaining criteria are not red.

A species receives a recommendation of “Avoid” if: 1) It has a total of two or more red criteria 2) It has one or more Critical Conservation Concerns.

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Conservation Concern Sustainability Criteria Low Moderate High Critical Inherent Vulnerability √ Status of Stocks √ √ FAD √ Handline, √ Unassociated √ U.S. purse seine / Nature of Bycatch rod and reel, purse seine longline international baitboat, troll longline √ Handline, rod and reel, √ FAD purse Habitat & Ecosystem Effects baitboat, troll, seine; longline unassociated purse seine √ Handline, √ Purse Management Effectiveness rod and reel, seine / baitboat, troll longline

Seafood Watch® Gear Used Recommendation Best Choice Good Alternative Handline, rod and reel, baitboat, troll Avoid Purse seine; Longline

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