The Atlantic Bluefin Tuna Challenge: Sustaining a High Value Migratory Species in a Highly Impacted Ocean

Transcription

1 The Atlantic Bluefin Tuna Challenge: Sustaining a High Value Migratory Species in a Highly Impacted Ocean ENVIRONMENTAL LAW INSTITUTE, WASHINGTON DC NOVEMBER 8, 2010 SEMINAR SUMMARY The Environmental Law Institute (ELI) hosted a panel discussion on the current state of Atlantic bluefin tuna (Thunnus thynnus) and domestic and international management efforts. Panelists addressed the key sources of uncertainty in our scientific understanding of bluefin tuna and put forward a variety of suggestions for management strategies. Speakers Shana Miller, Director, Tag A Giant Foundation Dr. Guillermo Diaz, National Marine Fisheries Service, NOAA Robert Hayes, General Counsel, Coastal Conservation Association Lee Crockett, Director, Federal Fisheries Policy, Pew Environment Group Rich Ruais, Executive Director, American Bluefin Tuna Association and Blue Water Fishermen s Association Moderator Jordan Diamond, Staff Attorney, Environmental Law Institute Ms. Shana Miller opened the panel by summarizing the current state of Atlantic bluefin tuna management. The cornerstone of the management system adopted by the International Commission for the Conservation of Atlantic Tunas (ICCAT) is the two stock hypothesis : the theory that 45 west longitude separates a western stock of Atlantic bluefin that spawns in the Gulf of Mexico, and an eastern stock that spawns in the Mediterranean. Ms. Miller explained, however, that this assumption does not accurately reflect the two populations movements. One of the main research activities of Tag A Giant (TAG) is tagging Atlantic bluefin with microchip based electronic tags, allowing scientists to track their migrations and learn about behavior and habitat

2 requirements. Using electronic tags, genetic data, and otolith data, scientists have observed high levels of mixing as tuna from both populations travel broadly across the Atlantic. The spawning grounds are the only areas where the two stocks are completely separate, which maintains the genetic distinctions between the two populations. The largely overlapping habitat between eastern and western bluefin creates challenges for management because the distinct populations of fish have different characteristics; the eastern bluefin reach sexual maturity earlier, making them more productive and more capable of withstanding higher fishing mortality. Ms. Miller also noted that, based on genetic data, it appears there may be a third distinct population that spawns in the eastern Mediterranean that may spawn at a younger age and display residency to the Mediterranean Sea, further complicating management decisions. Ms. Miller explained that new overlap models may allow future management decisions to account for population mixing. Stock assessment techniques that consider the distribution of Atlantic bluefin by age, stock, and area may more realistically measure current spawning stock and predict how the two populations would rebuild under different management scenarios. Because the eastern stock is larger and more productive, the western stock is expected to rebuild much more slowly. The overlap models also show the effects of eastern fishing on western stocks, and vice versa. Ms. Miller concluded by briefly addressing impacts from the Gulf oil spill, which occurred in a spawning hotspot at the peak of spawning season. TAG scientists have not observed significant behavior modification among spawners, as Atlantic bluefin that were in the contaminated areas have survived and migrated north to Canadian waters. It is unknown, however, what the impacts of the spill and response efforts will be on the bluefin larvae. Dr. Guillermo Diaz discussed the stock assessment process, conducted by the ICCAT Standing Committee on Research and Statistics (SCRS). In 2010, the SCRS employed a new growth curve, based on new data suggesting that fish of a given size were older than previously estimated. This led to a new perception of the status of the stock, with a higher proportion of older fish in the population and lower fishing mortality. Next, Dr. Diaz examined recent trends in the western stock. From , US fishers caught significantly less than the total allowable catch. While some hypothesize that fishermen were unable to catch their full allocation due to reductions in biomass, Dr. Diaz argued that there is strong evidence that the low catch was due to changes in the fish stock s geographical distribution. Scientists have observed a recent, gradual increase in biomass in the western stock that may be due to management efforts that reduced mortality among spawners. Dr. Diaz also explained several biological factors that contribute to scientific uncertainty about the current status of Atlantic bluefin. First, bluefin tuna is a long lived species, so any population response to management changes occurs very slowly. Second, the fish in the eastern population reach sexual maturity at a younger age than those in the western population. Most importantly, ICCAT does not have sufficient data to develop an accurate recruitment model: it lacks information about whether (a) increases in the adult population coincide with continuous increases in bluefin reproduction rates (the high recruitment scenario), or (b) the recruitment rate remains constant once the adult population reaches a certain threshold (the low, or two line, recruitment scenario). The competing recruitment models result in very different maximum sustainable yields (MSY) for the western stock. Under the high recruitment scenario, even a complete closure of the western fishery would not allow the stock to recover by 2019, whereas under the low recruitment scenario, the stock is probably not overfished under current management. There is similarly a great deal of uncertainty in the management of the eastern stock, but the greater size and productivity of the eastern stock will likely allow it to recover by 2019 if current standards are rigorously enforced.

3 Dr. Diaz introduced the following management suggestions for the western stock: ICCAT should consider protecting the 2003 year class until it reaches maturity and contributes to spawning. Current catches (1,800 mt) will allow the biomass to continue to increase under both recruitment scenarios. Catches of 2,500 mt will keep the stock at its current levels under both recruitment scenarios. Catches of 1,100 mt or less will stop overfishing under the high recruitment scenario and initiate rebuilding. Un quantified levels of uncertainty (mixing, maturity, recruitment) therefore a precautionary approach to management is suggested. Mr. Robert Hayes explained the history and role of ICCAT. The International Convention for the Conservation of Atlantic Tunas, drafted in 1966 and ratified by the United States in 1967, mediates a tremendously broad spectrum of interests within the Atlantic and connected bodies of waters (such as the Gulf of Mexico and the Mediterranean). ICCAT s 48 official members represent the interests of an even larger number of nations; for example, the European Community represents 27 countries, many of which also represent the interests of their island colonies. Mr. Hayes noted that ICCAT manages both tuna and tuna like species, including sea turtles and sharks. Almost every ICCAT meeting includes a substantial discussion of bluefin tuna management, as part of a highly participatory process that provides rewarding opportunities for concerned citizens to engage in tuna management. Mr. Hayes described the two major laws governing domestic bluefin tuna management. First, the implementing legislation for ICCAT is the Atlantic Tunas Convention Act (16 U.S.C. 971 et seq.). Originally, the Act was very short and imposed no restrictions on the authority of the Secretary of Commerce to implement measures adopted by ICCAT. Today, however, the Act states that ICCAT sets quotas and the United States cannot increase or decrease them. Therefore, Mr. Hayes stated, domestic managers cannot publish a regulation prohibiting fishermen from catching the full ICCAT quota. But there is an unresolved legal debate over whether domestic regulators can impose other restrictions that effectively prevent fishers from reaching the quota such as prohibiting certain fishing technologies or season or area closures. Mr. Hayes continued to explain that the second key law for domestic management is the Magnuson Stevens Fishery Conversation and Management Act (16 U.S.C et seq.). It requires the identification of overfished fisheries, prevention of overfishing, development of timely rebuilding plans, and application of the precautionary principle in response to scientific uncertainty. The Act exempts highly migratory species from these criteria when the international body responsible for management has a rebuilding plan. Mr. Hayes noted that he believes ICCAT intentionally categorizes their decisions as rebuilding plans in order to provide a huge exemption from domestic laws. Mr. Lee Crockett began by describing the factors contributing to the overfishing of bluefin tuna. First, the popularity of sushi has driven consumer demand and raised the market price. Second, new fishing and spotting technology enables higher catches and new processing technology allows fresh Atlantic bluefin tuna to reach worldwide markets. Third, quotas have been set higher than the scientifically recommended levels. Finally, there is a large amount of illegal, unregulated, or unreported (IUU) fishing of bluefin, especially around the Mediterranean.

4 Next, Mr. Crockett discussed the specific threats to bluefin tuna in the Gulf of Mexico. First, longline fishing for swordfish and yellowfin tuna occurs in the only known spawning grounds for Western bluefin tuna, at the peak of the bluefin spawning season. Bluefin tuna are often caught as bycatch, and suffer high mortality due to oxygen deprivation and fatigue from spawning activities in warm surface waters. Second, Mr. Crockett expressed concern over the effects of the oil spill and dispersants. Fish eggs are primarily made of oil, so dispersants that break up oil may have negative impacts on fish eggs. Further, the oil itself is toxic and may harm both bluefin tuna and their prey species. These effects have been and are being studied in laboratories, and field data on eggs and larvae sampled before and after the spill is forthcoming from Dr. Jim Franks, University of Southern Mississippi. Mr. Crockett proposed several measures for protecting bluefin tuna. On the domestic stage, he recommended a prohibition on surface longlining in the Gulf of Mexico. He stated that commercial fishing can continue by using gear with lower bycatch rates, such as the highly selective buoy gear that is already used to catch swordfish along the east coast of Florida and greensticks that are used to catch yellowfin tuna. Recreational catch and release fishing, Mr. Crockett noted, does not pose a major threat because of the low mortality rates for bluefin. Internationally, Mr. Crockett explained that Pew advocates for a suspension of the Atlantic bluefin fishery until there is strong evidence of recovery and effective management; closing the fishery would make it easier to detect illegal fishing. Pew also seeks greater protections for spawning grounds in the Gulf of Mexico and in the Mediterranean. If ICCAT fails to take sufficient action, Mr. Crockett stated that the organization would actively support efforts to list Atlantic bluefin tuna as an Appendix I species at the 2012 meeting of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Mr. Rich Ruais began his presentation by expressing his approval of the most recent SCRS bluefin tuna assessment and the United States leadership role in ICCAT. He stated that the 2010 assessment and data are the most positive that the SCRS has presented since the 1970s, and that it puts the bluefin tuna on the path to becoming a success story. Mr. Ruais also emphasized the significance of the SCRS report in reversing the concept of a bluefin tuna stock collapse. He rebutted the argument that high prices for Atlantic bluefin tuna contribute to overfishing, noting an average price per pound of approximately $7 no greater than that of other successfully managed species, like Atlantic sea scallops and that price cannot cause overfishing if the management infrastructure is science based. Mr. Ruais also noted that Mr. Crockett's extensive comments on Pelagic Longline fishing, although consistent with Pew s position, were not really relevant to the topic of the seminar given that longline fishing plays such a small role with bluefin tuna and is already prohibited from directed fishing in the Gulf of Mexico. Mr. Ruais cited an SCRS report stating that, under the two line recruitment scenario, levels of western bluefin tuna have exceeded ICCAT objectives since In other words, Mr. Ruais stated, fishing has stayed below MSY, and the fully rebuilt stock seen today could support a catch increase of 30 40%. Mr. Ruais noted that while there is ongoing debate regarding the recruitment model i.e., the high recruitment or two line recruitment scenario described by Dr. Diaz scientists have never demonstrated a relationship between spawning stock size and recruitment. Bluefin recovery has taken place under management based on the two line recruitment scenario, and given the success of the fishery, Mr. Ruais predicted that US fishermen would not comprehend or accept quota reductions based on what would be seen as overly precautious management assumptions. Mr. Ruais also noted that it is premature to change management in response to the oil spill because there is no data regarding negative impacts. In the worst case scenario, the oil spill may cause a missing year class, but anecdotal evidence suggests that at least some young successfully migrated to the Virginia coast.

5 The American Bluefin Tuna Association recommends modestly raising the total allowable catch for western Atlantic bluefin tuna. According to the SCRS report, there is a 78.2% chance that a western catch of 2,500 metric tons would allow bluefin tuna biomass to reach ICCAT s 2019 recovery goals. Given this scientific justification, Mr. Ruais emphasized that the fair thing to do is to reward US fishermen for their years of unilateral sacrifice. He acknowledged the challenges posed by an inadequate understanding of the bluefin life cycle, their spawning ground locations, their changing migration patterns, and how the populations mix. Scientists are making progress in helping managers understand these issues. However, Mr. Ruais stated that uncertainty is a huge factor in all fishery management, and that managers must always make the best decisions they can with the best science available to them. Raising the catch limits would also show eastern fishers that conservation will be rewarded. Mr. Ruais asserted that management of eastern bluefin has long been a complete disaster, although recent efforts to improve it (such as European demand for more data reporting and the placement of observers on vessels) have significantly reduced illegal catch. Mr. Hayes concluded the panel by commenting on the perspective of recreational fishermen. Mr. Hayes stated that most recreational fishermen view the bluefin tuna fishery as a commercial fishery. Charter boats and anglers who sell their catch are part of the commercial sector. Mr. Hayes explained that for recreational fishers, bluefin tuna management is a conservation issue. Regulatory efforts have been largely unavailing in the west, and minimal in the east. Mr. Hayes stated that the solution to rationalizing both western and eastern management without hurting the US fishing industry is to eliminate the international trade in bluefin tuna. Question and Answer Would Mr. Hayes elaborate on his assertion that the Atlantic Tunas Convention Act states that ICCAT sets quotas and the United States does not have the power to deviate from those quotas, given the contrary holding in the 2002 case, Blue Water Fishermen s Association v. National Marine Fisheries Service, 226 F. Supp. 2d 330 (D. Mass. 2002)? Mr. Hayes answered that his assertions were related to the realistic implementation of quotas from ICCAT. In practice, ICCAT sets the quotas, and the National Marine Fisheries Service regulates how quotas are distributed and then allocates the catch. Mr. Hayes also observed that the case has been given little precedential value within the agency. Is there any uncertainty about whether the western stock has declined 83% since the 1950s? Dr. Diaz stated that there is general agreement that the fish stocks were much greater in the 1970s. Any disagreements are over specifics, such as whether stocks declined by 83% or 85%. Mr. Ruais agrees that there has been a decline in the western availability of fish. However, there is no certainty about the level of decline experienced in the western stock since the 1960s and 1970s. Stock assessments are influenced by catch data, which is influenced by availability. In recent decades, the unprecedented and unrestrained increase in eastern catch has affected western stock assessments. More science is needed to determine how much of the decline in availability can be attributed to a decline in biomass and recruitment of natal western stock, as opposed to these other factors. Given the biology of the fish, are there any signs that would provide evidence of recovery other than increased biomass?

6 Dr. Diaz answered that the size and structure of the population can be examined. Ideally, it would show a healthy representation of all age classes, which is not present today. The 2010 Ocean Seminar Series is made possibly by generous support from the Naomi and Nehemiah Cohen Foundation.