FAQ: Atlantic Bluefin Tuna

Is Atlantic bluefin tuna endangered or threatened with endangerment?

Atlantic bluefin tuna has never been and is not now endangered or threatened with endangerment. Read the Endangered Species Act Status Review on Atlantic bluefin tuna by the National Oceanic and Atmospheric Administration (NOAA). This document establishes that Atlantic bluefin tuna is not endangered or threatened with endangerment. The link to this document is here.

Is Atlantic bluefin tuna fish stock significantly depleted?

No. Neither west Atlantic nor east Atlantic/Mediterranean bluefin tuna stock is "significantly depleted." Read the 2014 stock assessment for both west and east Atlantic bluefin tuna here. Both west and east Atlantic bluefin fisheries were endorsed for quota increases by ICCAT scientists in 2014. This would never have occurred if the stock was “significantly depleted”. With regard to west Atlantic bluefin tuna, the stock is presently measured to be at 55% of stock size when it was first measured in 1970, a healthy state for any commercially exploited fish stock. West Atlantic bluefin tuna biomass has increased by 70% since 1998 (see stock assessment P. 103, 2nd para.).

How is the health of a fish stock determined?

The typical benchmark used by marine scientists is the measurement of the present size of the "fish stock", referred to as "spawning stock biomass" or SSB, and comparing this with the size of the SSB either before the fish stock was first commercially exploited ("virgin" biomass) or by comparing it to the size of SSB in the first year in which there was sufficient data to measure the size of the fish stock. In the case of Atlantic bluefin tuna, the first year was 1970. Scientists also uses two important criteria for determining the status of tuna stocks: Is the stock presently in an overfished condition and is overfishing presently taking place? Here is a brief explanation of these two terms:

When a fish population or spawning stock biomass is found to be lower than a predetermined amount that has been set by scientists during a process referred to as a stock assessment, it is considered to be overfished. Overfishing is said to be occurring when it has been determined that, within a given time frame (usually a year), the amount of fish removed from a spawning stock biomass is found to be greater than the amount that fish population can replace through normal reproduction. This latter determination is also made by scientists during a stock assessment.

Are there other bluefin fish stocks? If so, are they endangered or threatened and what is the health of these stocks?

Yes, there are, in total, three distinct bluefin stocks worldwide. These stocks do not comingle or cross breed yet they are anatomically nearly identical. They are: Atlantic, Pacific and Southern bluefin tuna. (Southern bluefin tuna refers to bluefin that live and spawn in the temperate waters of the Indian Ocean and in the waters south of the South China Sea.) Unfortunately, Pacific and Southern bluefin tuna have not benefitted from the conservation efforts undertaken by U.S. fishermen, ICCAT and NOAA to protect and enhance spawning stock biomass of Atlantic bluefin tuna. Although Pacific and Southern bluefin fish stocks have never been established as endangered or threatened, science tells us that these stocks are today significantly depleted. Present spawning stock biomass of Pacific bluefin tuna is at 2.5% of virgin biomass and Southern bluefin tuna is at 2.8-7% of virgin biomass, whereas west Atlantic bluefin tuna is at 55% of what it was when first measured in 1970. The 2014 Pacific bluefin tuna stock assessment is here. The 2014 Southern bluefin tuna stock assessment is here.

I’ve heard that Atlantic bluefin tuna is heavily overfished in the East Atlantic and Mediterranean Sea. Is this true?

No. East Atlantic/Mediterranean bluefin tuna was heavily over-harvested from the mid 90’s through 2007. Since 2008, improved enforcement and a general adherence to fishing quota has lead to markedly decreased illegal, unreported and unregulated (IUU) landings, which accounted for most of the overfishing. Beginning in 2008, East Atlantic bluefin tuna fishing quota was reduced to very low levels to allow the stock to recuperate. The consequence of the dramatic changes made to this fishery through stronger management controls is that east Atlantic/Mediterranean bluefin tuna biomass has responded strongly and very surprisingly, and today this spawning stock biomass is vastly improved. Read the 2014 stock assessment here.

What percentage of the bluefin tuna sold in the U.S. comes from the Atlantic bluefin tuna fishery?

According to NOAA, 70% of the bluefin tuna sold in the U.S. is Atlantic bluefin tuna. In those regions that are located close to the Atlantic fishery, that percentage is probably much higher due to proximity to where the fish are caught.

How is Atlantic bluefin tuna commercially caught?

It depends upon the fishery: West Atlantic bluefin tuna is caught by the U.S., Canada, Japan and Mexico. In the US and Canada the largest percentage of the catch is caught by the artisanal fleet, using rod and reel, harpoon or greenstick and the balance is caught by pelagic longline and purse seine. Japan has a small quota for the west Atlantic bluefin tuna and fishes using pelagic longline. Mexico has the smallest quota and fishes with pelagic longline.

East Atlantic/Mediterranean bluefin tuna is caught by artisanal, longline and purse seine methods. By far, the industrial fishing methods – purse seine and longline – dominate in that fishery. There are artisanal fisheries in Portugal, Spain, France, Italy and Greece and they catch a much smaller percentage of the total allowed catch each year. Today, a significant percentage of the purse seine catch in the Mediterranean is used to stock fish farms. The main countries that participate in this fishery are the European Union, Turkey, North African nations and Malta.

I’ve heard that bluefin is overfished because fishermen are paid exorbitant amounts of money for this fish. Is this true?

No. This is a myth. The truth is that, according to NOAA, in 2014, the average price paid to a U.S. fisherman for Atlantic bluefin tuna was about $8.50/lb. U.S. scallop fishermen earn more for their catch.

However, each year there is one event that makes headlines worldwide: It is the sale of the first bluefin tuna of the year in Tokyo. In years past, exorbitant prices have been paid for this single fish. It is always a Pacific bluefin and it is always caught by Japanese fishermen who fish between Honshu and Hokkaido Islands, in north Japan. This single fish is usually purchased each year by the same company, owners of a chain of sushi restaurants in Japan. It is purely a publicity stunt and it does not in any way reflect the “normal” price paid throughout the year for bluefin tuna in Japan or elsewhere.

FAQ – Atlantic bigeye, albacore and yellowfin tuna

Is Atlantic bigeye, albacore or yellowfin tuna endangered or threatened?

No scientific authority has ever established that Atlantic bigeye, yellowfin or albacore tuna are threatened with endangerment or endangered.

I heard that bigeye tuna is overfished. Is this correct?

According to the latest stock assessment (2015), Atlantic bigeye tuna is overfished and overfishing is taking place.

I heard that Atlantic yellowfin tuna is overfished. Is this correct?

No. Atlantic yellowfin tuna is not overfished.

What is the present status of Atlantic bigeye, albacore and yellowfin tuna stocks?

ICCAT uses two important criteria for determining the status of tuna stocks: Is the stock presently in an overfished condition and is overfishing presently taking place? Here is a brief explanation of these two terms:

Yellowfin: Atlantic yellowfin tuna is not overfished, meaning that the present size of yellowfin spawning stock biomass (SSB) is sufficient to support harvesting up to a level that has been specified by ICCAT scientists, and this reference level is not presently met or exceeded. In recent years Atlantic yellowfin harvesting levels have been below the level specified by the scientists, so overfishing is not occurring in this fishery.

Bigeye: The 2015 Atlantic bigeye stock assessment performed by ICCAT scientists has found that bigeye is presently overfished and overfishing is taking place. Although the U.S. Atlantic bigeye fishery is managed and fished sustainably, the same would not be true of other, much larger bigeye fisheries elsewhere in the Atlantic. It is important to keep in mind that, when performing a stock assessment, ICCAT scientists are looking at the health of the entire Atlantic stock of bigeye and their analysis incorporates data from all bigeye fishing countries operating in the Atlantic and its adjacent seas. The U.S. is not a major harvester of Atlantic bigeye.

Albacore: North Atlantic albacore tuna is presently not overfished. However, according to the latest ICCAT stock assessment in 2013, North Atlantic albacore tuna spawning stock biomass is still in the process of rebuilding to a specified target level. The most recent stock assessment states that overfishing of North Atlantic albacore tuna is not occurring and U.S. annual catch is well within its ICCAT-mandated fishing quota.

WHAT IS THE PROBLEM WITH ATLANTIC BIGEYE TUNA?

Not much is known by science regarding population dynamics and migratory and foraging patterns of tropical tunas in the Atlantic, and this would include bigeye tuna. However, there are a few important facts that are known and worth keeping in mind: scientists are in general agreement that the region of Gulf of Guinea in West Africa is, by far, the most important spawning grounds in the entire Atlantic basin for bigeye, yellowfin and possibly skipjack. For bigeye, larvae have also been found off the Senegalese Coast and in the Bay of Biscay. In the Gulf of Guinea, when they are young juveniles, bigeye, yellowfin and skipjack will “school” together (this behavior has been observed in the Pacific, as well). When bigeye reach a certain level of maturity, they will cease to school with yellowfin and skipjack and migrate out of the Gulf of Guinea into deeper water in the equatorial Atlantic. From there, the present theory is that bigeye will continue to migrate north, northeast and northwest during warm months to more distant areas such as the east coast of North America and the sub-equatorial Atlantic to the west of Southern Europe/North Africa and to the east coast of South America. Bigeye are known to be trans-Atlantic migrants, and the same is true of yellowfin. Formerly, it was believed that bigeye and yellowfin caught in the U.S. Atlantic originated the Gulf of Mexico/Caribbean, but this is no longer considered likely. (For example, NOAA scientists have found that the yellowfin population in the Gulf of Mexico appears to be a resident population that does not migrate out of the Gulf.)

The European Union has mounted a huge, multi-year tropical tunas research project in 2015, committing Euro 120M to tagging these species throughout their range, on the east side of the Atlantic. The expectation is that the results of this research will significantly advance the science on Atlantic tropical tunas.

There are two main areas in which ICCAT must focus its conservation efforts on bigeye in order to rebuild bigeye stock:

The Gulf of Guinea

Industrial fishing operations are primarily focused within the Gulf of Guinea but can extend as far north as Mauritania and as far south as Angola. At present, there are 34 large purse seine vessels (owned by Spain, France and Ghana) that are permitted by ICCAT to harvest Atlantic skipjack in this region. Since skipjack, yellowfin and bigeye are known to “school” together when they are juveniles, it is impossible for these purse seine vessels to catch skipjack without also catching a significant quantity of yellowfin and bigeye, as bycatch. When caught as bycatch in this fishery, bigeye and yellowfin typically weigh approximately 3-6 lbs. The level of mortality on juvenile bigeye and yellowfin created by these purse seine vessels is significant; it has been recognized for many years by ICCAT scientists as the single most important deterrent to maintaining and increasing bigeye and yellowfin spawning stock biomass in the Atlantic. Further, given the highly migratory behavior of these species, any excessive mortality on juveniles in the Gulf of Guinea will negatively affect abundance of mature bigeye and yellowfin elsewhere in the Atlantic, as far away as the U.S./Canada or the Azores, off Portugal. Finally, the proliferation of the use of Fish Aggregating Devices (FADs) by purse seine in this region since the mid-1990s has facilitated the harvesting of skipjack and therefore also facilitates the unacceptably high levels of juvenile bigeye and yellowfin bycatch/mortality as well.

The Central (equatorial) Atlantic

It is believed, as previously stated, that bigeye (and yellowfin), when they have attained a certain size, migrate out of the Gulf of Guinea into deep water in the central Atlantic to the west of the Gulf of Guinea, around the level of the equator. From there, bigeye will move further north during warm months in the direction of North America and the sub-equatorial region west of Southern Europe/North Africa. There are over 650 distant water longline vessels, all permitted by ICCAT, that focus their harvesting activities on mature bigeye in this equatorial region of the Central South Atlantic. These vessels are using a fishing technique originally developed by the Japanese, referred to as "deep-water longlining", for the specific purpose of catching mature bigeye tuna. These vessels are chiefly owned by Japan, China, Spain, France, Portugal and Chinese Taipei but also include vessels from Ghana, Panama, the Philippines and Korea. Overwhelmingly, harvesting of mature bigeye in the Atlantic is dominated by this fleet. Further, the existence of this fleet in the migratory path of bigeye as they move further north deprives coastal fishing countries such as the U.S., Canada and others of an equitable distribution of this important resource.

Solutions

Any serious attempt by ICCAT to rebuild Atlantic bigeye stock will require a reduction in harvesting levels on mature bigeye by longline in the Central (equatorial) Atlantic and will require a reduction of bigeye bycatch by purse seine in the Gulf of Guinea. Further, any conservation strategy will also require the development of stringent controls on the use of FADs in the purse seine fishery in the Gulf of Guinea.

Are Atlantic bigeye, albacore and yellowfin fish stocks fished sustainably IN THE NORTHWEST ATLANTIC?

Yes. The question of sustainability of North Atlantic albacore tuna is covered above. Atlantic bigeye and yellowfin tuna are sustainably fished by the U.S. and Canada. Most of the catch of these two species is landed as bycatch by pelagic longline vessels, an industrial fishing method, and a smaller quantity is landed by the U.S. artisanal handgear fleet. Atlantic bigeye, yellowfin and albacore tuna are presently fished by the U.S. and Canada in catch amounts that according to the best available science will ensure the sustainability of these fish stocks.

Is bycatch a problem in the US fisheries that fish for Atlantic bigeye, yellowfin and albacore tuna?

The U.S. artisanal handgear fleet that fishes for Atlantic bigeye, albacore and yellowfin tuna will incur only very occasional bycatch, typically shark. However, since the fishing method used by the artisanal fleet results in each fish being caught individually, one at a time, any shark bycatch can be easily released by the fisherman without removing the shark from the water and consequently there is an extremely low probability of post-release mortality of this bycatch.

In the U.S. pelagic longline fishery, bigeye, yellowfin and albacore tuna are valuable bycatch species that longline vessels are legally allowed to retain and sell. Pelagic longline vessels regularly incur bycatch of over 68 different marine species, so bycatch in general is a problem in the longline fishery.