Atlantic Bluefin Tuna:
International Management of a Shared Resource
Eugene H. Buck

Senior Analyst in Natural Resources Policy

Environment and Natural Resources Policy Division

March 8, 1995


Atlantic Bluefin Tuna:
International Management of a Shared Resource
Eugene H. Buck

Senior Analyst in Natural Resources Policy

Environment and Natural Resources Policy Division

March 8, 1995


95-367 ENR
SUMMARY
Prior to the 1960s, fishing for north Atlantic bluefin tuna was limited to subsistence fishing, international sport tournaments, and small-scale commercial ventures. During the 1960s, fishing efforts intensified as international markets developed for canned and fresh bluefin. By the late 1970s and early 1980s, large numbers of commercial purse seiners, targeting small schooling bluefin, supplied canneries while harpooners and longliners sought giant bluefin for export to Japan, where consumers treasured fresh fatty bluefin flesh as a delicacy. By the late 1960s, the western north Atlantic bluefin tuna population showed pronounced signs of stress from overfishing, suggesting international management was required to prevent the collapse of the fishery.




In 1966, the International Convention for the Conservation of Atlantic Tunas (ICCAT) was negotiated by concerned fishing countries to coordinate international research and management of highly migratory tunas and billfish in the north Atlantic. As a key instigator of the Convention, the United States joined ICCAT seeking to improve bluefin tuna management through better international cooperation. ICCAT chose to manage eastern and western Atlantic bluefin tuna stocks as separate populations.

Despite the international management and conservation measures undertaken in the 1970s and 1980s, the smaller western Atlantic bluefin population continued to decline. By 1992, ICCAT estimated that the western Atlantic bluefin spawning population had declined to 10 percent of its 1975 level. Between 1990 and 1994, ICCAT and U.S. management regimes were increasingly criticized with science, economics, and politics all being blamed for unsuccessful bluefin management.

In the early 1990s, conservation organizations focused their efforts on conserving north Atlantic bluefin by improving the international management regime. Meanwhile, U.S. commercial fishermen began reporting greater bluefin abundance in the western Atlantic, contrary to scientific assessments. The commercial industry's confidence in resource managers was shaken, and commercial organizations vowed to fight recommendations for still lower harvest quotas unless an independent review of ICCAT's scientific assessments was conducted.

In 1994, the U.S. National Research Council conducted a technical review of western Atlantic bluefin biology and stock assessments and criticized ICCAT's finding that the population had continued to decline. After reassessing Atlantic bluefin stocks with revised data, ICCAT recommended a modest increase in the western Atlantic bluefin harvest quota and took steps to decrease catches in the eastern Atlantic and Mediterranean bluefin fisheries.

CONTENTS

INTRODUCTION
BLUEFIN TUNA BIOLOGY
-- General Biology
-- Distribution, Spawning, and Migration
-- Stock Structure
SPORT AND COMMERCIAL FISHERIES -- HISTORY AND MARKET DEVELOPMENT
-- Sport Fishery
-- Commercial Fishery
MANAGEMENT REGIMES
-- International Management
-- Domestic Management Authority
-- Domestic Management Structure: Fishing Gear and Permit Categories
ICCAT -- MANAGEMENT IN THE 1970s AND 1980s
-- 1975: Regulations and Results
-- 1981-1983: Institution of the Two-Stock Hypothesis
ATLANTIC BLUEFIN IN THE 1990s
-- Fishery Conditions
-- Conservation Movement -- CITES Proposals
-- ICCAT Management in the 1990s
-- Commercial Industry Challenges the Science
NATIONAL RESEARCH COUNCIL REPORT NRC
-- Conclusions and Recommendations
-- -- General Conclusions
-- -- Research Recommendations
-- Interpreting the Report: A Mandate for Change?
-- -- U.S. Fishery Management Assessment
-- -- Commercial Fishermen's View
-- -- Conservationists's View
ICCAT IN 1994 NEW DOMESTIC RESEARCH PROGRAMS
-- Captive Rearing
-- Aerial Survey
-- DNA and Micro-Constituent Analysis
-- Adequacy of Programs

Atlantic Bluefin Tuna: International Management of a Shared Resource (1)
INTRODUCTION
The north Atlantic bluefin tuna, Thunnus thynnus, is regarded as one of the most highly evolved fish species. Bluefin, members of the mackerel family (Scombridae), are noted for their extensive migrations, large size, and impressive speed. These notable qualities have captured the attention of submarine engineers aspiring to imitate the bluefin's efficiency. (2)

Fishing for bluefin dates back thousands of years to fixed trap fisheries in the Mediterranean Sea. Drawn by the bluefin's natural beauty and migratory habits, many early scientists, including Aristotle (384-322 B.C.), studied and wrote about bluefin. The species is currently found in large numbers in the eastern Atlantic, while a relatively smaller bluefin population occupies the western Atlantic. Bluefin fisheries occur in coastal areas throughout the Atlantic Ocean as well as offshore in the Gulf Stream, with some bluefin occasionally crossing the Atlantic.

Management of and scientific research on Atlantic bluefin has been internationally coordinated among major fishing nations since the late 1960s, when international markets stimulated the demand for giant bluefin. Fresh bluefin meat, the fattiest of tuna species, is considered a supreme delicacy by sushi and sashimi connoisseurs. By the early 1970s, giant Atlantic bluefin, commonly weighing more than 180 kilograms (400 pounds), were being caught and immediately shipped to Japan -- the world's largest consumer of fresh bluefin.

In the western Atlantic, choice giant bluefin are caught in cold New England waters in summer and fall. At this time, the lipid content of their flesh is highest, and giant bluefin are avidly pursued. As Japanese importers pay top dollar for select giants, prime quality bluefin are, with rare exception, marketed in Japan. In the United States, commercially caught bluefin is also consumed in restaurants as sushi or sashimi and cooked as steaks. Recreationally caught bluefin are often prepared as steaks for personal consumption.

As international demand remains high for giant bluefin tuna, intensive fishing raises concerns for the long-term sustainability of this resource. Given the large potential profits and many competing users in the bluefin fishery, conservation efforts have sparked heated international debates. It is under these conditions that fishery managers seek to manage north Atlantic bluefin, integrating biology with the demands imposed by global economics and politics.

This report provides background describing the current situation faced by fishery managers and policymakers dealing with domestic and international Atlantic bluefin tuna management. As such, this report provides a basic framework for understanding the concerns of various constituencies for the many factors that affect the health of the industry and the welfare of the resource.

BLUEFIN TUNA BIOLOGY
General Biology

Atlantic bluefin tuna are among the most powerful, as well as largest, fish inhabiting the ocean (figure 1). Preying on mackerel, herring, whiting, and squid, giant bluefin may reach weights of more than 600 kilograms (1,400 pounds), grow as long as 15 feet, and live to 30 years of age. (3) When fresh, their skin is steel blue, with lavender and green reflections. Tuna, originating from the Greek word meaning "to rush," swim at speeds approaching 90 kilometers (55 miles) per hour.

insert figure 1 here

Source: New York Times; September 17, 1991; illustration by Pieter Arend Folkens.

Distribution, Spawning, and Migration

North Atlantic bluefin tuna inhabit the North Atlantic Ocean. (4) on the western side, bluefin are found from Newfoundland to Brazil and, on the eastern side, from Norway to the Mediterranean and Cape Blanc at 20 degrees North Latitude on the West African coast. Bluefin are highly migratory and limited numbers of individuals may cross the Atlantic in as little as 60 days. Bluefin tagged in the Bahamas have been captured in Norway as well as off the coast of Brazil. (5) Bluefin in the South Atlantic belong to a distinct southern population, with known spawning areas south of Java, Indonesia; the southern bluefin population is not discussed in this report, because of its separation from northern populations.

Although Atlantic bluefin are widely distributed and migrate thousands of kilometers, there are two confirmed spawning locations -- the Gulf of Mexico in the western Atlantic and the Mediterranean Sea in the eastern Atlantic. Although many ecological and environmental variables undoubtedly affect both the location and productivity of spawning in these two areas, relatively little is known concerning why bluefin spawn where they do.

Spawning in the Gulf of Mexico occurs between mid-April and mid-June (6) when females, which mature around age 8, release approximately 30,000,000 eggs each. (7) The highest density of bluefin larvae, the primary indicator of spawning, occurs in the northern Gulf of Mexico with lesser larval concentrations appearing off the Texas coast and in the Straits of Florida. (8)

In the eastern Atlantic, spawning occurs exclusively in the Mediterranean and Adriatic Seas from June through August, with the highest larvae concentrations appearing around southern Italy. Although some fishery biologists believe that eastern Atlantic bluefin reach sexual maturity several years earlier than western Atlantic bluefin (possibly as young as ages 4 or 5), (9) this understanding has been criticized. (10)

Seasonal migration patterns of bluefin tuna appear to vary depending on age class and fish size. Movements are presumed to reflect the bluefin's search for optimal conditions relating to food, spawning conditions, and other ecological factors. Bluefin from the Mediterranean spawning grounds migrate into the Atlantic Ocean through the Strait of Gibraltar, and then turn both northward to the Bay of Biscay and southward to the Canary Islands. (11)

After spawning in the Gulf of Mexico, western Atlantic giant bluefin migrate northward along the U.S. coast into Canadian waters, increasing in size and lipid content. While most western Atlantic small bluefin (ages 0 and 1) remain offshore of the mid-Atlantic States, some small bluefin may migrate to the eastern Atlantic. (l2) Considerably less in known regarding medium bluefin migration.

Bluefin tuna distribution has been observed to change markedly through the years. While abundant in the 1950s off Norway and Sweden in northern Europe as well as off Morocco in northwest Africa, they subsequently nearly vanished from these regions. Similarly, bluefin abundance has noticeably declined off Brazil where they were taken in quantities in the early 1960s. It is not known to what degree overharvesting and fluctuating environmental conditions may have contributed to the observed changes in bluefin distribution.

Stock Structure

Several definitions of "fish stock" exist within the scientific community, relying in whole or in part on geography, genetics, and politics. While some define a "fish stock" as all individuals of a given fish species residing in a particular geographic area, (13) a more standard scientific definition identifies a stock as a population wholly or partially reproductively isolated and often displaying unique genetic characteristics. Political boundaries are sometimes used as a means of stock differentiation, but scientific validity may be sacrificed if a migratory stock is defined on the basis of geopolitical boundaries alone. (14) Regardless, a fish stock is a management unit representing a technical choice by scientists -- and sometimes also a political choice. Beginning in 1981, management of north Atlantic bluefin has been based on a two-stock hypothesis assuming limited trans-Atlantic mixing between the two stocks. (15) However, this management assumption has been seriously questioned (see p. 18).

SPORT AND COMMERCIAL FISHERIES -- HISTORY AND MARKET DEVELOPMENT
Sport Fishery

International sport fishing for giant bluefin originated about 100 years ago, becoming popular domestically in the early 1900s. The Sharp Cup in Nova Scotia was a distinguished international bluefin tournament held from the early 1930s through the 1960s, with a peak landing of 1,760 fish in 1949. (16) Many other tournaments existed throughout the northeastern United States until the mid-1960s, when giant bluefin abundance near tournament sites appeared to decline. Although studies have been inconclusive regarding these changes, hypothesized causes include changes in water temperature, oceanic currents. abundance of feed, and a declining population of giant western Atlantic bluefin.

Prior to 1970, sport fishing was exclusively recreational, as giant bluefin tuna had a commercial value of only $.05 per pound. Giant trophy tuna that were not kept for personal display or consumption were sold to cat and dog food producers. With the development of the Japanese specialty market in the early 1970s, giant bluefin tuna suddenly represented big money to traditional sport fishermen. Perspectives on the fishery shifted, and the recreational character of the fishery was altered by economic opportunity. A giant 225-kilogram trophy fish was, by the late 1970s, a highly valued Japanese delicacy. Participation exploded and the giant bluefin fishery capitalized quickly.

Now many "recreational anglers" also obtain commercial permits, so that virtually all giant bluefin tuna currently caught are marketed commercially, except for a small scale catch-and-release sport fishery in the Bahamas. A substantial charter- or party-boat fishery for small bluefin tuna also exists from North Carolina to Massachusetts. Estimated at more than 15,000 recreational anglers annually, this is the only U.S. fishery allowed to catch bluefin smaller than the minimum commercial size (70 inches from the tip of a fish's snout to the fork of its tail); however, no bluefin less than 26 inches (less than 6.4 kilograms in weight) may be retained. Although the small bluefin caught in the charter-boat fishery cannot be sold, this fishery contributes significantly to the economy of many coastal communities.

Commercial Fishery

Commercial fishing for western Atlantic bluefin tuna began in the late 1950s, when purse seine vessels began catching small bluefin for the canned market. By the early 1960s, catches grew rapidly as foreign fleets entered the fishery. While most of the early catch was destined for the canned tuna market, efforts soon turned toward supplying the Japanese sushi and sashimi markets. Japan, which consumes 40 percent of global bluefin landings and relies on imported food for more than half its needs, features fresh fish as a significant part of its culture and diet. By the early 1970s, with the development of air freight, fresh giant Atlantic bluefin could reach Japan's lucrative sushi market overnight.

This market development transformed the fishery as purse seiners, who previously caught small bluefin, began fishing exclusively for giant bluefin. In 1973, prices paid by Japanese importers skyrocketed from $.05 per pound to more than $1.00 per pound. (17) By 1986, Japanese importers were paying $12 per pound, while prices paid by buyers on the 1994 Tokyo market push $80 per pound for the high-prestige delicacy of prime fatty tuna. (18) In 1991, a Japanese importer paid a record price of $68,503 (or about $96.65 per pound) for a single giant bluefin tuna! These prices are the exception, however, since the average reported price (round weight basis) received by fishermen in 1994 was $8.79 per pound, with a reported range of $1.92 to $42.61 per pound. Thus, with bluefin market prices occasionally rivaling that of some illegal drugs and the unique bluefin behavioral traits, such as specific and precise migratory patterns and surface schooling, harvesters continued to locate and profit from catching bluefin tuna at very low population densities. This lucrative economic opportunity underscores the importance of cooperative international management in regulating the commercial exploitation of this highly migratory species.

Intensive fishing was accompanied by a quickly declining population in the western Atlantic. By the early 1970s, catch data warned of a western Atlantic bluefin stock collapse. Total Atlantic catches plummeted and bluefin landings declined from a peak of approximately 35,000 metric tons (MT) (19) in 1964 to about 15,000 MT in 1972. In the western Atlantic, landings peaked at nearly 20,000 MT in 1964, but had sharply declined to less than 5,000 MT by 1968. By the mid-1970s and early 1980s, annual western Atlantic catches averaged 6,100 MT (figure 2), with harvests declining further in response to quotas imposed in the early 1980s.

insert graph on CRS-7 here

MANAGEMENT REGIMES
International Management

Increasing capitalization and declining catch-per-unit-effort (CPUE) (20) trends in the Atlantic during the 1960s drew concern by the international scientific community regarding the abundance, health, and reproductive capacity of bluefin tuna. Recognizing the need for coordinated international management, the International Convention for the Conservation of Atlantic Tunas was negotiated and signed in Rio de Janeiro in 1966. In 1969, member nations established the International Commission for the Conservation of Atlantic Tunas (ICCAT) to recommend conservation and management measures for bluefin tuna and other highly migratory species in the North Atlantic Ocean and Mediterranean Sea.

ICCAT is currently composed of 22 member nations, including the United States, Japan, and most major fishing nations on the North Atlantic rim. ICCAT's primary responsibilities are to provide internationally coordinated research on the overall condition of highly migratory species in the North Atlantic Ocean and Mediterranean Sea and to recommend regulatory and management measures to maintain all highly migratory tunas and billfish at their most productive levels. The Commission conducts annual meetings, usually in November or December, to analyze statistical data and recommend management measures. Although the member nations agreed, in the Convention, to implement ICCAT recommendations domestically within six months, they often may not do so.

The Standing Committee on Research and Statistics (SCRS) provides scientific advise to ICCAT. The SCRS conducts stock assessments of Atlantic tunas and billfish and coordinates multinational research activities related to these species. The stock assessments upon which the Commission bases its decisions thus change from year to year in response to improved methodologies and revised statistics.

ICCAT's primary stated bluefin management objective is to maintain Atlantic bluefin tuna populations at levels that will permit maximum sustainable yield (MSY). MSY is an estimate of the greatest average catch that can be removed from a fish stock year after year without harming its ability to sustain these maximum catches in subsequent years. In an effort to reach this objective, ICCAT recommended a number of management measures for the western Atlantic bluefin fishery, including harvest quotas, per trip catch limits, and minimum size limits (table 1). The effectiveness of implementation and enforcement of these ICCAT recommendations by individual nations has been repeatedly questioned by environmental, fishing industry, and government interests. In addition, environmental groups have faulted ICCAT for weak recommendations that they consider insufficient to assure that ICCAT's MSY objective could be met.

Table 1. Summary of Selected ICCAT Recommendations and Related U.S. Legislation

Year Action
1966 Nations sign the International Convention for the Conservation of Atlantic Tunas on May 14, 1966, at Rio de Janeiro.
1969 Parties to the International Convention establish the International Commission for the Conservation of Atlantic Tunas (ICCAT) to develop conservation and management recommendations.
1974 ICCAT recommends: (a) an Atlantic-wide minimum size limit of 6.4 kilograms (about 14 pounds) with a 15 percent tolerance (see footnote 35), and (b) all fishing nations cap entry into the fishery and limit fishing mortality.
1975 United States enacts the Atlantic Tunas Convention Act (ATCA), 16 U.S.C. §§ 971-971h. This law implements ICCAT for the United States by mandating U.S. representation in ICCAT and authorizing the Department of Commerce (National Marine Fisheries Service) to conduct research and management for Atlantic bluefin tuna.
1976 United States enacts the Fishery Conservation and Management Act (FCMA), 16 U.S.C. §§ 1801-1882. This law created a 200-mile fishery conservation zone, but excluded highly migratory species, including bluefin tuna, from U.S. jurisdiction.
1981 ICCAT: (a) recommends a bluefin catch as near zero as possible for scientific monitoring in the Western Atlantic (quota set at 1,160 MT for 1982); (b) accepts the two-stock management hypothesis with stocks separated at 45 degrees West Longitude; and (c) eliminates directed fishing in the Gulf of Mexico to protect the spawning stock.
1982 ICCAT recommends an increase in the scientific monitoring quota to 2,660 MT for the 1983 western Atlantic bluefin fishery.
1990 United States enacts Fishery Conservation Amendments (Pub.L. 101-627) to amend the FCMA and the ATCA by extending U.S. jurisdiction over highly migratory species including tunas, giving the Secretary of Commerce authority to manage bluefin tuna within waters under U.S. jurisdiction, and mandating development of a comprehensive management plan for highly migratory species under FCMA guidelines.
1991 Sweden proposes listing of western Atlantic bluefin tuna on Convention on International Trade in Endangered Species (CITES) Appendix I (to prohibit harvests) and eastern Atlantic bluefin tuna on CITES Appendix II (to regulate trade); ICCAT recommends biennial quota for 1992-1993 western Atlantic harvests be reduced to 4,788 MT.
1992 ICCAT creates the Bluefin Statistical Document (BSD) to monitor international trade in bluefin tuna; United States implements 1991 ICCAT quota recommendation with 10% reduction of domestic quota for 1992 and 1993 harvests.
1993 ICCAT reduces 1994 quota to 1,995 MT and mandates further 40 percent quota reduction in 1995 (to 1,200 MT) unless the SCRS indicates that this is not necessary.
1994 Kenya proposes, and later withdraws, listing of Atlantic bluefin tuna on CITES Appendix II; National Research Council analysis rejects the two-stock hypothesis in favor of a single-stock with at least two spawning areas and recommends that future stock assessments integrate trans-Atlantic mixing; ICCAT recommends a harvest quota increase to 2,200 MT for western Atlantic bluefin in 1995 as well as a 25 percent catch reduction for eastern Atlantic bluefin by 1998.

Domestic Management Authority

To implement U.S. participation in ICCAT, the United States enacted the Atlantic Tunas Convention Act (ATCA) of 1975. (21) This Act provides for U.S. representation in ICCAT and creates a domestic management structure for the bluefin fishery. Three delegates, appointed by the President, serve as U.S. ICCAT Commissioners. (22) The Commissioners represent various sectors of the domestic industry, and not more than one can be a Federal employee. A national ICCAT advisory committee meets with the Commissioners prior to annual ICCAT meetings to discuss management issues and concerns.

The ATCA authorizes the Secretary of Commerce to promulgate regulations necessary to implement ICCAT recommendations. (23) The Secretary has delegated to the National Oceanic and Atmospheric Administration (NOAA) the authority to regulate and implement ICCAT recommendations. The National Marine Fisheries Service (NMFS), which is responsible for conducting scientific research and data analysis, works under the authority of NOAA to prepare and implement domestic management plans as provided for in the ATCA. NMFS relies on data compiled from commercial and recreational fishermen for scientific and biological characteristics of the western Atlantic bluefin tuna population.

Domestic Management Structure: Fishing Gear and Permit Categories

Fishing gear used in the directed U.S. bluefin fishery includes purse seines and handgear, which includes harpoons, handlines, and rod-and-reel. Purse seining involves paying out a large net off the stern of a fishing vessel, where a bottom weighted (lead) line and a top float line extend the net vertically in the water column. A second smaller vessel (skiff) pulls one end of the net from the purse seiner as both vessels encircle a school of fish from opposite directions until finally reconnecting the skiff end of the net with the purse seine vessel. The purse seiner then draws the bottom lead line closed, creating a "purse" to entrap the school of tuna. Handgear is usually held by the fisherman, and fish caught are retrieved by hand- or power-reeling. Because of the labor-intensive nature of handgear, this method is typically used only for recreation or for high-value species or those destined for specialty markets.

For management and analytical purposes, bluefin are divided into six size classes: (1) young school bluefin weigh less than 6.4 kilograms (less than 14 pounds); (2) school bluefin weigh between 6.4 and 30 kilograms (14 to 66 pounds); (3) large school bluefin weigh between 30 and 62 kilograms (66 to 135 pounds); (4) small medium bluefin weigh between 61 and 107 kilograms (135 to 235 310 pounds); large medium bluefin weigh between 107 and 141 kilograms (235 to 310 pounds); and (4) giant bluefin exceed 141 kilograms (310 pounds).

The U.S. bluefin fishery is managed under five annual quota categories --purse seine, general, harpoon, angling, and incidental -- each requiring a permit. Each quota category is monitored and regulated by NMFS. While a large number of vessels hold bluefin tuna permits, only a small percentage actually land and sell bluefin tuna. In 1992, excluding five purse seine vessels, only 8 percent of the fishing vessels holding the 11,608 permits landed and sold any bluefin tuna, (24) and between 1990 and 1993, only 156 vessels caught at least one bluefin tuna each year. (25)

The purse seine permit category employs the least number of vessels, but is allocated the second largest share of the U.S. quota (25 percent), set at 301 MT in 1994. Five permitted commercial vessels (three owners) have had exclusive right to landing the purse seine quotas since 1982. Before 1970, purse seiners traditionally targeted small and medium schooling bluefin. After 1982, to protect diminished stocks of smaller bluefin, they were restricted to fishing exclusively for giant bluefin, primarily off the New England coast in late summer and fall. Spotter aircraft are employed by seiners to locate schools large enough to warrant commercial fishing.

The general category permit includes large numbers of handgear fishermen, who land the most tonnage of bluefin of any permit category. General category permit holders may land and sell only one giant bluefin per day. This permit category has often served as an "insurance policy" for fishermen who also held recreational angling category permits. They would obtain the general category permit in the event they caught a salable fish. In 1992, only 6 percent of the 10,879 general category permit holders landed fish, the majority of these catching one or two. (26) The 1994 quota for this category was 531 MT, 44 percent of the U.S. total.

The harpoon permit category takes a small percentage of the annual U.S. catch. Harpooners, with a 1994 quota of 53 MT (4 percent of the U.S. total), target giant bluefin. However, harpooners are permitted to land and sell one medium-large (70 to 77 inches fork length (27) or 235 to 310 pounds) bluefin per day. This provision eliminates discards in case a harpooner misjudges bluefin size. Current proposals call for a measurement change from a straight-line 70-inch minimum to a curved-line 73-inch minimum.

Anglers target small, medium, and giant bluefin. The angling category, which was allocated 219 MT (18 percent of the U.S. quota) in 1994, is restricted to recreational fishermen, and catches cannot be sold.

The incidental permit allows commercial longliners (28) fishing for other species to land a limited number of giant bluefin. This permit category, with a 1994 quota of 113 MT (9 percent of the U.S. total), is mainly used by longliners fishing for swordfish or other tunas. In 1992, 521 bluefin tuna were landed by 191 incidental permit holders. Strict permit provisions require a minimum landing of non-bluefin target species to qualify to land a bluefin. (29) However, bluefin tuna discards are currently not counted against the incidental quota.

ICCAT -- MANAGEMENT IN THE 1970s AND l980s
Expanding capitalization of the U.S. bluefin fishing industry and increasing fishing pressure throughout the north Atlantic in the early 1970s resulted in declining catches and, in some specific bluefin fisheries, economic extinction. (30) In the eastern Atlantic, annual bluefin harvests were halved from an average of 10,222 MT in the mid-1960s to 4,987 MT between 1970 and 1973. During this same period, catches by the Moroccan trap fishery, an ancient Mediterranean Sea fishery, dropped from 4,474 MT to only 832 MT. (31) Similar trends appeared in the western Atlantic, where total landings declined from 14,171 MT in 1965 to 3,871 MT in 1973. (32) These indicators led scientists, environmentalists, and managers to pressure ICCAT into developing more stringent management recommendations for Atlantic-wide bluefin fisheries.

1975: Regulations and Results

In 1974, ICCAT members adopted several recommendations for the Atlantic bluefin tuna fishery to be implemented in August 1975. The first was supposed to cap the fishery (33) at current catch levels, and the second was supposed to prohibit the landing of bluefin tuna smaller than 6.4 kilograms (about 14 pounds) with a 15 percent tolerance. (34) Domestically, NMFS set daily bag limits and seasonal quotas for fishermen. These measures were intended to stabilize catches, to protect small bluefin essential for sustaining bluefin spawning populations, and to initiate stock recovery.

Data from the western Atlantic fishery revealed improvements after these two regulations were implemented. In the late 1970s, western Atlantic bluefin catches averaged about 6,100 MT annually, with landings of age 0 and 1 bluefin tuna at only 10 percent of 1974 levels. Between 40,000 and 65,000 age 1 western Atlantic bluefin tuna had been caught annually in the early 1970s, compared to less than 6,000 age 1 bluefin annually after the regulation. (35)

Although advances were made in the western Atlantic to protect small bluefin tuna and decrease fishing mortality, these measures alone didn't assure the western bluefin's recovery. By 1980, annual catches represented an increasingly larger percentage of the total western Atlantic bluefin stock. Some believed that directed longlining for spawning bluefin tuna in the Gulf of Mexico between 1975 and 1981 contributed significantly to the continued decline of the western stock. (36) In 1981, NMFS reported that, while tuna mortality rates in the western Atlantic had stabilized, overall tuna abundance was down and the resource had become alarmingly depleted. (37)

Analysis of the eastern Atlantic and Mediterranean fisheries revealed substantially less compliance with ICCAT recommendations than in the western Atlantic. While total annual landings stabilized, catches of small bluefin declined to only 62 percent of earlier levels. (38) In addition, these data were perceived to greatly overstate the decline in small bluefin catch because non-Contracting parties (nations that are not ICCAT members) did not file reports and some Contracting parties were inconsistent in their statistical reporting.

Given the relative abundance of young bluefin in the eastern stock --roughly 20 times that of the western stock -- concern for the health and sustainability of the eastern Atlantic bluefin was relatively low. A 1981 SCRS report, concluding that the eastern Atlantic bluefin population had stabilized, (39) reinforced perceptions that there was little to be concerned about regarding eastern Atlantic bluefin.

1981-1983: Institution of the Two-Stock Hypothesis

Limited compliance with ICCAT recommendations in the eastern Atlantic fishery and the continued decline of bluefin abundance in the western Atlantic raised more questions, by western fishing nations, over the relationship between eastern and western Atlantic bluefin populations. In 1974, SCRS had deemed it convenient to treat north Atlantic bluefin as a single stock, acknowledging uncertainty about the degree of separation while noting that tag returns confirmed trans-Atlantic migration. (40) Since Atlantic-wide ICCAT conservation measures didn't halt or reverse declining western Atlantic population trends, western managers and industry representatives sought to separate north Atlantic bluefin into eastern and western management units. Separate management assessments and conservation regulations would allow western nations, through ICCAT, to implement strict fishing regulations without the necessity of obtaining eastern Atlantic participation and cooperation.

In 1981, SCRS reiterated uncertainties concerning Atlantic bluefin stock structure. However, conclusions drawn from tagging data and genetic studies supported the concept of two stocks. The existence of two isolated spawning areas, in the Gulf of Mexico and Mediterranean Sea, also helped to assure member nations that the two-stock hypothesis was scientifically valid. Subsequently, based on the assessment that two distinct populations existed, the Commission recommended that bluefin catches in the western Atlantic be reduced to as near zero as possible.

Thus in 1981, ICCAT member nations adopted the two-stock structure and initiated a stock recovery plan for the western Atlantic bluefin population. Contingent upon prohibiting western fleets from transferring fishing effort to the eastern Atlantic, ICCAT recommended a scientific monitoring quota as near zero as possible for the western Atlantic. This first scientific monitoring quota was set at 1,160 MT for the 1982 fishing season in the western Atlantic, keeping intact the minimum size limit throughout the Atlantic and the fishery cap for the eastern Atlantic, as agreed to in 1974. In 1982, the western Atlantic quota was increased to 2,660 MT (41) for 1983. In 1984, SCRS stated that quota reductions instituted for the western Atlantic bluefin fishery were expected to result in a slow stock increase. Despite warnings by the U.S. delegation of continued stock decline, ICCAT retained the annual western quota at 2,660 MT through the 1980s.

ATLANTIC BLUEFIN IN THE 1990s
Fishery Conditions

In the early 1990s, the western Atlantic bluefin stock appeared to resume its decline while some eastern Atlantic fishing nations continued to ignore ICCAT's 1974 recommendations. Conservationists stated that, based on its 1992 stock assessment, the SCRS had concluded that the 2,660 MT western Atlantic quota represented roughly 50 percent of the 1991 western Atlantic breeding adult biomass compared to only 15 percent in 1983, (42) and that the western Atlantic breeding population had decreased to less than 10 percent of 1975 levels. (43)

In 1991, ICCAT reported that eastern Atlantic and Mediterranean fishermen continued targeting undersized bluefin (those weighing less than 6.4 kilograms), catching well in excess of the 15 percent tolerance level. Despite the 1974 ICCAT recommendations, the percent of undersized bluefin caught remained high in the eastern Atlantic and Mediterranean -- 50 percent and 30 percent respectively between 1976 and 1988, and 51 percent and 26 percent respectively in 1989. (44) By 1990, in the eastern Atlantic, the adult bluefin population was estimated to be half its 1970 abundance, (45) decreasing further to only 13 percent of its 1970 abundance by 1993. (46)

Additionally, unreported landings by eastern Atlantic and Mediterranean non-ICCAT-member nations and incomplete catch and size data from eastern Atlantic ICCAT members caused statistics to be incomplete, thereby increasing the uncertainty of stock estimates. In 1992, it was estimated that the bluefin catch by non-ICCAT-member nations, predominately in the eastern Atlantic and Mediterranean, totaled approximately 20 percent of entire north Atlantic landings. (47) Some critics suggested that reflagging of vessels by Contracting Parties (48) may have contributed to the erroneous fishing data and stock assessments. (49)

With this evidence in hand, ICCAT's management -- including the quantity of scientific research, appropriateness of recommendations, and authoritative power -- was called into question by both the fishing industry (50) and conservation organizations. (51) Bearing the economic burden of conservation measures and quota reductions, some U.S. fishing industry organizations viewed ICCAT's management as a failure. Conservation organizations, on the other hand, cited the public economic burden arising from species depletion and perceived management failure by ICCAT. These organizations became increasingly concerned that the original objectives of the Convention were not being met and that eastern Atlantic ICCAT members, who voted to adopt the 1974 conservation measures for the fishery, were not complying with their own recommendations.

Conservation Movement -- CITES Proposals

Concern about the declining western Atlantic bluefin population and criticism of ICCAT's management sparked the interest of and participation by conservation organizations worldwide. Looking to speed the recovery of western bluefin to its pre-1980 abundance and bring eastern Atlantic and Mediterranean fishing nations into ICCAT compliance, conservationists looked for new ways to encourage or force better conservation of Atlantic bluefin tuna. Because of the international nature of bluefin trade, (52) listing of Atlantic bluefin under the international trade regulatory regime of the 122-nation Convention on International Trade in Endangered Species (CITES) was sought. CITES regulates international trade in animals and plants that could be threatened by trade, and a CITES listing of Atlantic bluefin tuna would help accomplish the conservationists' goals. (53)

In 1991, in response to ICCAT and NMFS stock abundance reports, the National Audubon Society promoted a CITES listing for western Atlantic bluefin tuna. The suggested CITES Appendix I listing would have prohibited international trade in western Atlantic bluefin. In addition, NMFS and the U.S. Fish and Wildlife Service expressed interest in a CITES Appendix II listing, a less restrictive status, for the western stock that would enhance monitoring of, but not prohibit, international trade. (54) Due to the strong U.S. commitment to the ICCAT management regime, these agencies selected not to propose either listing. Late in 1991, Japan released an ICCAT statement on CITES, emphasizing that the mandate for conservation and management of Atlantic bluefin tuna lies with ICCAT, and that concerns regarding this highly migratory species should be directed to ICCAT.

Endorsed by global environmental and U.S. sport fishing organizations, Sweden officially announced in late 1991 that it would submit a proposal for listing the western Atlantic bluefin population on CITES Appendix I and the eastern Atlantic population on CITES Appendix II at the 1992 CITES session in Kyoto, Japan. Intense lobbying by Japan, with support from Canada, Morocco, and the United States, created enough pressure for Sweden to withdraw its proposal before a CITES vote. While a CITES Appendix listing did not occur, progress toward bluefin recovery and trade monitoring was accomplished when, during negotiations prior to the CITES meeting, western fishing nations pledged to pursue bluefin quota reductions and institute a trade monitoring program during the 1992 ICCAT session. Subsequently, along with the United States and Canada, Japan supported conservation and trade monitoring recommendations before ICCAT.

While quota reductions and an international trade monitoring program were adopted at the 1992 ICCAT meeting, ICCAT scientists later regarded the quota reduction as being sufficient only to halt further stock declines, but not sufficient to rebuild the stock. In 1994, the international conservation community again insisted on further reducing the ICCAT quota for western Atlantic bluefin, creating a bluefin stock recovery schedule, and bringing Atlantic bluefin tuna trade into a monitoring program under the authority of CITES. In June 1994, Kenya proposed listing all northern and southern Atlantic bluefin tuna on Appendix II of CITES. Within one month, this proposal was again defeated as Japanese pressure caused Kenya to withdraw its proposal. (55)

ICCAT Management in the 1990s

In a 1991 ICCAT resolution, (56) ICCAT addressed issues concerning non-Contracting Parties, including lack of reliable catch statistics and questionable fishing practices, as well as Atlantic-wide issues involving statistical data on bluefin landings and re-flagging of vessels. It was resolved to develop Atlantic-wide management policies designed to improve reporting and ensure ICCAT compliance by standardizing statistical reporting and by establishing an international trade monitoring system. Invitations were extended to all fishing nations to become Contracting Parties and participate in policy formation within the ICCAT forum.

Also in 1991, ICCAT adopted a recommendation to reduce the western Atlantic bluefin harvest by implementing a biennial quota of 4,788 MT. The United States implemented this recommendation by reducing the 1992 and 1993 domestic total harvest quotas by 10 percent. In 1993, ICCAT recommended an additional 15 percent reduction for the 1994 western Atlantic quota to 1,995 MT, with a further 40 percent reduction scheduled for 1995. The 1995 reduction was contingent upon ICCAT approval, to be implemented unless scientific analysis by SCRS concluded otherwise. (57)

A 1992 ICCAT recommendation established policies designed to better monitor trade in bluefin caught by Atlantic-wide bluefin fishermen and to improve statistical data for this fishery. After initially applying only to frozen bluefin, all bluefin imported by a Contracting Party must now be accompanied by an ICCAT Bluefin Statistical Document (BSD). Additionally, the Commission recommended the three Contracting Parties in the western Atlantic increase the minimum size limit by prohibiting the landing of bluefin weighing less than 30 kilograms with an 8 percent tolerance (by weight) or, alternatively, having a fork length less than 115 centimeters (45 inches).

To bring the United States into compliance with ICCAT, in June 1994, NMFS proposed modifications to allow NOAA's Form 370, Fisheries Certificate of Origin (FCO), to serve as a BSD. (58) NMFS also required domestic bluefin tuna dealers to submit daily and bi-weekly reports, instead of weekly reports, to improve both the usefulness of information collected and permit fishery management decisions to be made on a more timely basis. NMFS previously had implemented a mandatory at-sea fishery observer program for purse seine vessels to validate catches, bycatch, and discard data for this segment of the U.S. fishery. (59)

Commercial Industry Challenges the Science

Efforts by the conservation movement in the early 1990s, including two CITES proposals and (in concert with SCRS efforts) subsequent quota reductions for the western Atlantic bluefin fishery, generated opposition from commercial bluefin fishing organizations. Some commercial fishermen perceive that insufficient scientific research, inaccurate fishing statistics, and lax ICCAT conservation adherence in the eastern Atlantic have undermined the effectiveness of conservation measures endured by western Atlantic fishermen. After watching in frustration as eastern Atlantic fishermen continued taking bluefin with little apparent sacrifice for conservation, some U.S. commercial fishermen began lobbying for larger bluefin quotas in the western Atlantic.

The U.S. commercial industry insists that unilateral conservation efforts by western Atlantic fishermen are inadequate to rebuild the western north Atlantic bluefin tuna stock, and that ICCAT conservation measures for bluefin tuna must be shared by all fishing nations. These concerns were echoed in the U.S. Congress. In 1991, both the House and Senate agreed to a sense of Congress resolution, H.Con.Res. 169, on multilateral conservation of Atlantic bluefin tuna, declaring that the United States should not bear a disproportionate share of conservation measures, (60) and that effective management must involve coordinated efforts by all fishing nations. (61)

Throughout the 1980s, the commercial industry questioned the validity of the scientific basis for ICCAT's quota reductions, claiming that ICCAT's research was inadequate to make accurate stock assessments. However, to foster bluefin stock recovery and assure a sustainable future fishery, conservation measures implemented by ICCAT in the early 1980s were accepted.

During the early 1990s, at the same time as conservationists were looking to further reduce bluefin catch, commercial fishermen claimed that they were observing more bluefin in the western Atlantic than scientists reported. After the CITES proposals and ICCAT quota reductions in 1991 and 1992, commercial organizations demanded better stock assessments and a review and reinterpretation of statistical data.

Since the early 1980s, SCRS repeatedly acknowledged that available biological information was inadequate to support conclusions, with any degree of certainty, regarding stock structure. In 1982, SCRS concluded that: (a) separate stock assessments were unreliable if significant interchange occurs between the eastern and western Atlantic, and (b) information on the status of either stock was unreliable if each stock was analyzed as a single stock. (62) By 1990, although data collection in the eastern Atlantic fishery had improved somewhat, the absence of participation and advice from eastern Atlantic scientists with knowledge of the bluefin fisheries limited SCRS's stock assessment capabilities. (63)

Due to the scientific community's limited understanding of trans-oceanic mixing rates for north Atlantic bluefin tuna, undetected variations in the mixing rate could greatly alter bluefin abundance estimates in the western Atlantic. Since 1982, the trans-Atlantic mixing rate was regarded as insignificant by ICCAT, when separately assessing the health of the eastern and western bluefin stocks. However, due to the larger size of the eastern stock, a minor change or increase in the assumed mixing rate could significantly affect the estimated abundance of bluefin in the western Atlantic (64) to account for the increase of bluefin tuna reported by western Atlantic fishermen.

These observations and questions led the commercial industry to believe that, in addition to inadequate science, errors in the interpretation of scientific data could have occurred. Thus, commercial organizations stated they would only support scientifically verified quotas that would rebuild the western Atlantic bluefin stock and only if conservation sacrifices were made by eastern Atlantic fishermen.

U.S. commercial and sport fishermen assisted NMFS by providing catch data and participating in biological research on western Atlantic bluefin tuna. In exchange for their continued cooperation, however, they demanded that the United States make stronger pleas in ICCAT for equality in conservation sacrifices and, because of their observations of increased bluefin abundance in the early 1990s, conduct an independent peer review of the science and biological assumptions that have guided the management of this fishery.

NATIONAL RESEARCH COUNCIL REPORT
After ICCAT recommended a reduction in the western bluefin quota at its 1993 meeting, the U.S. bluefin industry demanded that the United States undertake an independent peer review to verify the scientific basis for Atlantic bluefin tuna management. NOM agreed to the industry request. In an early 1994 attempt to assure that the report was unbiased, NOAA asked the National Research Council (NRC) of the National Academies of Sciences and Engineering to conduct the technical review, which would be presented at the 1994 ICCAT meeting.

NRC's Ocean Science Board formed a Committee to Review Atlantic Bluefin Tuna to address general bluefin management questions and recommend research. The NRC Committee reviewed SCRS's eastern and western Atlantic abundance assessments as well as SCRS's interpretation of the available data, taking into account assumptions regarding uncertainties. The NRC Committee also analyzed the status of Atlantic bluefin tuna relative to ICCAT's goal of managing tuna to achieve MSY and re-analyzed whether available information supports treating bluefin tuna as separate eastern and western management units (i.e., is trans-Atlantic mixing significant?). (65)

NRC Conclusions and Recommendations

General Conclusions

Assumptions made by the NRC Committee differ from those made by fishery scientists over the past 20 years, and were central to the contrasting results regarding Atlantic bluefin abundance and stock structure. The NRC Committee noted that the two populations of north Atlantic bluefin tuna could not be distinguished using current genetic methods and that existing data are consistent with a single stock hypothesis. However, the fish in the eastern and western Atlantic do not mix fully and can be considered separate populations. For management purposes, the Committee recommended that all future stock assessments take into account the observed mixing between the two populations.

In the Committee's view, SCRS abundance assessments do not provide the most defensible interpretation of the available data and, based on 1994 NRC stock assessments, there is no evidence that the western Atlantic stock has changed abundance significantly since 1988. This contrasts with the roughly 50 percent decline in western Atlantic giant bluefin reported by ICCAT between 1988 and 1992 (based on 1993 SCRS stock assessments).

Due to the apparent significance of transatlantic mixing, the Committee declared bluefin tuna in the eastern Atlantic and Mediterranean an important factor in evaluating the status of western Atlantic bluefin tuna. The Committee concluded that the further scheduled reductions of western Atlantic catch quotas recommended by ICCAT in 1992 could not be justified based on the Committee's prior conclusion that the western Atlantic stock had stabilized since 1988. Based on the available data, the Committee was unable to determine the MSY for Atlantic bluefin tuna under a one-stock hypothesis with two spawning grounds.

Research Recommendations

Additional information on the biology of Atlantic bluefin tuna was deemed necessary for assessing stock structure and abundance and to assure proper management of this fishery. As knowledge of the movement of bluefin tuna among fishing grounds has been limited, the Committee recommended a comprehensive tagging program be undertaken, to be coordinated among all nations involved in the Atlantic bluefin tuna fishery. This program would provide additional scientific information on migration patterns and gene flow, both of which are crucial to defining stock structure and refining stock assessments.

Stock assessments can also be refined through the collection of better biological and life history characteristics of north Atlantic bluefin tuna. The NRC Committee recommended that comprehensive studies in these areas be conducted multilaterally. Additionally, the Committee recommended a re-analysis of existing data on distributions of north Atlantic bluefin tuna in relation to spatial and temporal dynamics of major oceanic features. (66)

Interpreting the Report: A Mandate for Change?

U.S. Fishery Management Assessment

The general conclusions and recommendations made by the NRC Committee's technical review were acknowledged by U.S. fishery managers, who agree that trans-Atlantic mixing rates need to be considered when estimating numbers of fish on the fishing grounds. They argue, however, that prior to consideration of future stock assessments and management recommendations, the validity of the NRC Committee's assumptions needs to be evaluated.

The underlying agreement by all fishery managers and analysts is the need for new comprehensive research programs and multilateral participation to broaden the scientific foundation and clarify many uncertainties relating to north Atlantic bluefin biology. The specific research programs recommended by the NRC Committee and the necessity for this biological research concur with NMFS and ICCAT proposals offered since the inception of ICCAT. Due to the domestic and international significance of the north Atlantic bluefin tuna resource, cooperative science and its accurate technical interpretation should provide a sound basis for future management recommendations.

Commercial Fishermen's View

Commercial organizations, which (along with U.S. ICCAT Commissioners) were responsible for bringing about the NRC review, stated that the NRC Committee report proved that faulty science had caused western fishermen to bear an inequitable share in the costs of conservation. The Committee's conclusion -- that giant bluefin in the western Atlantic were 2 to 5 times more abundant than the SCRS estimate and that the western Atlantic stock had been stable since 1988-- contrasted with the roughly 50 percent decline reported by ICCAT in 1993. (67) In the opinion of these fishermen, this conclusion validated their recent claims that bluefin were more abundant than managers acknowledged, as well as their anxiety regarding management of the fishery based on SCRS data.

U.S. commercial organizations insisted that, prior to implementing the 1995 quota reductions, ICCAT needed to reevaluate the Atlantic bluefin fishery under Atlantic-wide enforced compliance with ICCAT regulations. As ICCAT had not previously been able to enforce its regulations, developing standardized trade reporting and other monitoring procedures to document and account for all trade in bluefin, while encouraging ICCAT membership by all fishing nations, would greatly enhance the effectiveness of ICCAT's management regime. Additionally, multilateral compliance (due to trans-Atlantic mixing of stocks) should have significant benefits for western Atlantic bluefin abundance.

Conservationists's View

Conservation organizations focus on the fact that both ICCAT and the NRC Committee report say that the western Atlantic bluefin spawning stock abundance is greatly depleted from the 1970s. While not reduced to 10 percent as ICCAT had estimated, the NRC Committee concluded that western Atlantic bluefin were reduced to 20 percent of 1975 levels. (68) After considering immigration from the eastern Atlantic, the Committee estimated that the present absolute abundance of adult western Atlantic bluefin was roughly 40,000 fish (ICCAT had estimated 20,000), compared to 220,000 in 1975. (69) The NRC report concludes that, while the western stock has not experienced further decline in recent years, neither is there any sign of recovery. Conservation groups were troubled that the NRC Committee mentioned significant declines in bluefin reproduction in the western Atlantic, but ignored the implications of this situation.

While the NRC Committee's re-analysis of available scientific data revealed several statistical errors made by scientists (accounting partially for the revised estimate of stock decline), conservationists believe the Committee's conclusions did not justify termination of quota reductions scheduled for the western Atlantic. In an effort to achieve conservation, stock recovery, and employment simultaneously for the U.S. Atlantic bluefin fishery, environmental groups have offered several alternative management plans. (70) With the western bluefin stock diminished to 20 percent of 1975 levels, conservation groups believe that rebuilding the stock relies on limiting catch and, thus, harvest quotas should remain conservative. Conservation groups continue to cite the need for recovery goals, targets, and timetables, as well as express their concern that ICCAT has failed to manage north Atlantic bluefin tuna for MSY.

ICCAT IN 1994
During the 1994 ICCAT meeting, SCRS continued to express concern regarding bluefin fishing practices in the eastern Atlantic and Mediterranean, including incomplete statistical reporting, landing excessive fish under the minimum size standard, and total landings exceeding 1975 catch levels. (71) In 1993, landings of undersized bluefin comprised about 30 percent of total catches in the Mediterranean and about 15 percent in the east Atlantic.(72) Combined bluefin landings of both eastern Atlantic regions totaled 27,960 MT in 1993 compared to 21,217 MT in 1975. (73)

SCRS concluded that action, in the form of ICCAT regulations, needed to be taken for the eastern Atlantic regarding fishing mortality rates, especially to limit the catch of fish weighing less than 6.4 kilograms, and that every effort should be made to avoid catching age 0 fish (those weighing less than 1.8 kilograms). SCRS also acknowledged that, if the hypothesis that Mediterranean and east Atlantic bluefin migrate west is correct, then it is possible that these SCRS regulatory recommendations would benefit western Atlantic bluefin. (74)

These SCRS recommendations led ICCAT to recommend that eastern Atlantic fishing nations: (a) prevent increases in fishing mortality rates for the years 1995 and beyond; (b) reduce their total catch of bluefin by 26 percent by the end of 1998 (taking initial action in 1996); (c) prohibit the taking and landing of any bluefin weighing less than 6.4 kilograms; (d) prevent catches of age 0 fish; (e) provide sufficient data as requested by the SCRS to improve stock assessments; and (f) report annually to ICCAT on conservation measures taken to implement these regulations. In response to Atlantic-wide regulatory violations, ICCAT adopted a provision that could lead to trade sanctions against non-ICCAT members who refuse to cooperate with the Commission's conservation programs for bluefin tuna. (75)

In 1994, SCRS employed new methodological and data analysis assumptions in its assessment of the western Atlantic bluefin stock. The Committee recommended that, while separate east and west assessments continue to be required for management purposes, they should incorporate the possible effect of trans-Atlantic mixing rates. At the time of the 1994 meeting, SCRS was not able to evaluate fully the effect of bluefin mixing, but accepted the assumption that mixing could be significant. SCRS also proposed that "a recovery program aimed at achieving a 50 percent increase from current levels in the spawning stock biomass by the year 2008" be developed for western Atlantic bluefin.

For the western Atlantic, based on SCRS's conclusion that the 1995 quota reduction from 1,995 MT to 1,200 MT was no longer essential, ICCAT recommended a 205 MT quota increase for 1995 and 1996 to 2,200 MT annually, (76) unless scientific information available to SCRS in 1995 indicates otherwise. ICCAT also recommended that the three Contracting western Atlantic fishing nations continue to prohibit the taking of bluefin weighing less than 30 kilograms or, alternatively, having a fork length less than 155 centimeters, and to tag and release all bluefin less than the minimum size.

NEW DOMESTIC RESEARCH PROGRAMS
Several new research programs and techniques to improve understanding of bluefin biology have been developed by domestic organizations in cooperation with NMFS. The following studies should furnish fishery managers with better information on the biology of bluefin tuna as well as reduce scientific uncertainties. The results should provide a basis for better assumptions about bluefin tuna biology, migration patterns, and spawning behavior.

Captive Rearing

Since 1992, the New England Aquarium has been rearing captive bluefin tuna to better understand population and reproductive biology as well as user group impacts, including catch-and-release mortalities.

Aerial Survey

In 1994, the New England Aquarium, the East Coast Tuna Association, and NMFS conducted bluefin tuna aerial surveys to study bluefin abundance, surfacing behavior, three-dimensional characteristics of schools, local movements based on tagging, size classes of photographed bluefin, and environmental influences, including the effects of weather, food, and temperature on bluefin distribution. This was a coordinated effort to develop additional measures for better assessing population abundance.

DNA and Micro-Constituent Analysis

New NMFS research programs include revised tagging programs to estimate trans-Atlantic mixing rates and stock structure as well as develop new catch-per-unit-effort (CPUE) indices, study spawning biomass, and investigate tuna reproductive biology. NMFS has also been analyzing bluefin DNA to determine stock structure based on gene frequencies from eastern and western Atlantic stocks. In addition, micro-constituent analysis is being used to measure heavy metals, possibly characteristic of individual spawning grounds, in fish hard parts (e.g., bones) as another means to determine the origin of individual bluefin.

Adequacy of Programs

Fishery scientists and managers regard research programs as vital for understanding the complex biology of bluefin, essential to developing effective fishery management plans, and critical to providing for long-term sustainable bluefin fisheries. Comprehensive research programs, coordinated internationally, are a prerequisite to verifying important biological assumptions on the basis of which management regimes can be created to rebuild Atlantic bluefin tuna stocks. Conservationists have expressed concern that adequate funding for NMFS bluefin research, including tuna tagging programs, not be eliminated or reduced, and often have expressed amazement that the decline of bluefin tuna has not resulted in increased priority or spending being given to bluefin tuna research. Individuals representing the U.S. commercial fishing industry have often criticized domestic and international bluefin tuna managers for what they perceive to be insufficient scientific research to accurately portray the status of Atlantic bluefin tuna populations. SCRS emphasized the importance of research in 1994 when it concluded that an international large-scale research program on bluefin tuna, with a dedicated budget and adequate ICCAT staff, was required to be conducted simultaneously on both sides of the Atlantic to answer many fundamental questions of bluefin tuna biology and behavior.

Endnotes

Brian Wagner, Public Policy Intern from the University of Washington's School of Fisheries, researched and wrote the draft of this report under the supervision of Eugene H. Buck, Senior Analyst in Natural Resources Policy.
Marcus, Jon. Fish Design for Submarines Tested. Associated Press Newswire, Nov. 8, 1994.
Cole, John N. "The Vanishing Tuna." Atlantic, v. 239, (Dec. 1976): 50.
In addition other lesser known populations inhabit the North Pacific, and southern bluefin are fished extensive in the Pacific and Indian Oceans.
National Academy of Sciences. National Research Council. An Assessment of Atlantic Bluefin Tuna. Washington DC National Academy Pr