Atlantic Yellowfin Tuna (Thunnus albacares)

• The Atlantic yellowfin tuna stock is believed to be near target levels, and overfishing is not occurring.
• Atlantic yellowfin tuna are managed both domestically (by NMFS Highly Migratory Species Management Division) and internationally (by the International Commission for the Conservation of Atlantic Tunas and other organizations).
• Yellowfin is low in saturated fat and sodium and is a very good source of protein, thiamin, selenium, and vitamin B6. For more on nutrition, see Nutrition Facts. (USDA)
• The United States accounted for about 7% of the total Atlantic yellowfin tuna landings in 2006.

Sustainability Status

Biomass: The Atlantic yellowfin tuna stock biomass level is estimated to be between 72 and 122% of the level needed to support maximum sustainable yield (near the target level recommended by ICCAT).
Overfishing: No
Overfished: No
Fishing and habitat: Atlantic yellowfin are caught primarily with longline, handline, and rod and reel gear. Habitat damage by fishing gear used to capture highly migratory species, other than bottom longlines, is minor because it rarely comes in contact with the ocean floor.
Bycatch: Pelagic longline gear sometimes catches non-target finfish with little or no commercial value, as well as species that cannot be retained by commercial fishermen due to regulations, such as billfish. Pelagic longlines may also interact with protected species such as marine mammals, sea turtles, and seabirds. Area closures are used to minimize bycatch by closing ocean areas that historically have the highest rates of bycatch, and Vessel Monitoring Systems are required on U.S. Atlantic pelagic longline vessels to enforce closures and monitor the fishery. Circle hooks are also required to increase post-release survival of animals that are inadvertently caught. Additionally, U.S. Atlantic pelagic longline fishermen must attend workshops to learn how to properly handle and release these animals. The Atlantic, Caribbean, and Gulf of Mexico pelagic longline fishery is designated as a Category I fishery according to the List of Fisheries published annually by NMFS as required under the Marine Mammal Protection Act. This means that annual mortality and serious injury of certain marine mammal stocks in this fishery is greater than or equal to 50% of the Potential Biological Removal level (the maximum number of animals, not including natural mortalities, that may be removed from a marine mammal stock while allowing it to be at sustainable levels). NMFS is addressing this challenge through the Pelagic Longline Take Reduction Team, which works to reduce serious injuries and mortalities of short-finned pilot whales, long-finned pilot whales, and Risso's dolphins in the Mid-Atlantic portion of the Atlantic pelagic longline fishery. Troll-caught yellowfin tuna has very little bycatch.
Aquaculture: There is currently no commercial aquaculture of yellowfin tuna in the United States.

Science and Management

The U.S. fishery for yellowfin tuna in the Atlantic is managed by NMFS Highly Migratory Species Management Division through the 2006 Consolidated Atlantic Highly Migratory Species Fishery Management Plan. Because yellowfin is highly migratory and fished by many nations, the fishery is also managed internationally by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Several management measures have been implemented in the United States, consistent with ICCAT advice to limit fishing effort and to prevent overfishing. In 1999, NMFS implemented limited access in the pelagic longline fishery for Atlantic tunas, as well as a recreational retention limit for yellowfin tuna. The United States has also maintained its minimum size limit for yellowfin of 27 inches, which is greater than the minimum size recommended by ICCAT (before the organization repealed their recommendation).

Life History and Habitat

Life history, including information on the habitat, growth, feeding, and reproduction of a species, is important because it affects how a fishery is managed.

• Geographic range: In tropical and subtropical oceanic waters.
• Habitat: Juveniles form mixed schools with skipjack and juvenile bigeye tuna and are mainly limited to surface waters. Larger fish are found in surface and sub-surface waters.
• Life span: About 7 years.
• Food: Yellowfin tuna are opportunistic feeders, preying on a wide variety fishes and invertebrates associated with Sargassum, a floating algae.
• Growth rate: Variable with size - relatively slow initially and increasing by the time the fish leave the nursery grounds.
• Maximum size: Up to 400 pounds.
• Reaches reproductive maturity: Most yellowfin are capable of reproduction at the age of 2 or 3 years and around 39 inches in length.
• Reproduction: Female yellowfin are multiple spawners, with an average spawning frequency of 46 times or about one spawn every three days. Females have an average of 1 million to 4 million eggs.
• Spawning season: From May to August in the Gulf of Mexico and from January to April in the eastern Atlantic Ocean.
• Spawning grounds: The main spawning ground is the equatorial zone of the Gulf of Guinea (southwest of Africa). Spawning also occurs in the Gulf of Mexico, in the southeastern Caribbean Sea, and off Cape Verde (off the northwestern coast of Africa).
• Migrations: Yellowfin are highly migratory, moving from west to east across the Atlantic Ocean.
• Predators: Sharks and large bony fishes prey on yellowfin tuna.
• Commercial or recreational interest: Both
• Distinguishing characteristics: Yellowfin tuna are torpedo-shaped fish. They are metallic dark blue on the back and upper sides, changing from yellow to silver on the belly. True to the name yellowfin, their dorsal and anal fins, and finlets are bright yellow. Tuna species are difficult to distinguish. Bigeye, blackfin, albacore, and yellowfin are similar in shape and are often caught together. Characteristics that distinguish the yellowfin from other species are its elongated anal and dorsal fins on large fish, a moderately smooth, nonstriated ventral surface of the liver, and 26 to 34 gill rakers on the first arch.

Role in the Ecosystem

Yellowfin tuna are towards the top of the food chain and prey upon many aquatic species such as fish, cephalopods, and crustaceans. They are also prey for top predators such as sharks.

Additional Information

Market name: Tuna
Vernacular name: Ahi

Biomass

Biomass refers to the amount of Atlantic yellowfin tuna in the ocean. Scientists cannot collect and weigh every single fish to determine biomass, so they use mathematical models to estimate it instead. These biomass estimates can help determine if a stock is being fished too heavily or if it may be able to tolerate more fishing pressure. Managers can then make appropriate changes in the regulations of the fishery.

The latest stock assessment (2008) used two different models to determine current biomass of the Atlantic yellowfin tuna stock. The models differed slightly, with one estimating biomass slightly over maximum sustainable yield, and one estimating biomass slightly under maximum sustainable yield. Therefore, current biomass levels are believed to be near the target level recommended by ICCAT.

Landings

Landings refer to the amount of catch that is brought to land. Yellowfin tuna is the principal species of tropical tuna landed by U.S. fisheries in the western North Atlantic. Total estimated landings were 5,562 metric tons in 2005, 7,075 metric tons in 2006, and 5,559 metric tons in 2007. A high proportion of these landings are due to rod and reel catches by recreational anglers.

Biomass and Landings

Landings and biomass data can sometimes be used to detect trends in a fishery. There does not seem to be much of a trend in U.S. landings since 2002, and the 2008 stock assessment estimates that the biomass is near maximum sustainable yield. This may indicate that fishing effort is at a level that allows the population to maintain itself near maximum sustainable yield, but other factors, such as positive changes in environmental conditions, may be helping to maintain the population level as well. Also, because yellowfin tuna is a highly migratory species that moves outside of U.S. waters, fishing practices of foreign countries could affect U.S. Atlantic yellowfin tuna landings and the biomass of the population.

Data sources:
Landings from NOAA Highly Migratory Species Division, 2008 U.S. National Report to ICCAT

Important Dates

Early 1900s – Sport fishery develops off New York and New Jersey
1950s-1960s – Rod and reel fishery expands rapidly along mid-Atlantic coast
1958 – Commercial purse seining for Atlantic tunas begins and expands during the early 1960s
1960s – Pelagic longline fishery for Atlantic tunas develops, comprised mainly of Japanese vessels fishing in the Gulf of Mexico
1966 – International Convention for the Conservation of Atlantic Tunas is signed creating the International Commission for the Conservation of Atlantic Tunas (ICCAT)
1972 – ICCAT passes recommendation that prohibits the landing of yellowfin less than 7 pounds due to concern of the high proportion of juvenile yellowfin that are landed
1990 – Magnuson Act amended, giving authority to Secretary of Commerce to manage Atlantic tunas; secretarial authority is delegated to NMFS
1992 – NMFS creates the HMS Management Division to manage Atlantic tunas, sharks, swordfish, and billfish
1993 – ICCAT recommends that there be no increase in the level of fishing effort over 1992 levels
1999 – NMFS publishes the Final Fishery management Plan for Atlantic Tunas, Swordfish, and Sharks, the first FMP for Atlantic tunas; measures include prohibition of pelagic driftnets for tunas, implementation of the ICCAT Rebuilding Program for western bluefin tuna and a recreational retention limit for yellowfin
2006 – Consolidated Atlantic Highly Migratory Species FMP is approved and implemented; combines the management of all Atlantic HMS into one comprehensive FMP; also allows the use of speargun gear in Atlantic tuna recreational fisheries and shifts the fishing year to a calendar year for all HMS species
2008 – NMFS authorizes the use of green-stick gear to harvest Atlantic tunas

Notes and Links

General Information:
Atlantic Tunas Description

International Commission for the Conservation of Atlantic Tunas

Introduction to NMFS Highly Migratory Species Management Division

Fishery Management:
Consolidated Atlantic Highly Migratory Species Fishery Management Plan

Stock Assessments:
ICCAT 2008 Report of the Standing Committee on Research and Statistic (Stock assessment update)

2007 Stock Assessment and Fishery Evaluation Report for Atlantic Highly Migratory Species