Yellowfin tuna

Yellowfin tuna live in warm oceans.

They swim near the top of the sea, far from land. Sometimes they dive down deep.

Yellowfin tuna live in the warm, tropical and subtropical parts of the Pacific, Atlantic and Indian Oceans. Most stay between about 20 degrees north and 20 degrees south of the equator, but in summer some swim much farther toward the poles.

They usually swim near the surface, in water from about 18 to 31 degrees Celsius. Yellowfin are great travelers: they are highly migratory and can swim across an entire ocean.

The IUCN describes a worldwide range in tropical and subtropical seas, mainly between 20°N and 20°S, with summer catches as far as 45 to 50 degrees in both hemispheres. In the eastern Pacific they commonly range from southern California to Peru, and they have been caught south of the Cape of Good Hope in the southern summer.

They are pelagic, living in open water at sea-surface temperatures of 18 to 31 °C. Their vertical movements are limited less by the thermocline than by how fast their bodies cool and by low oxygen below the mixed layer. Daytime bounce dives to 150 to 250 meters are common, dives averaging about 1,000 meters are not unusual, and the deepest recorded dive reached 1,602 meters.

Yellowfin tuna hunt other sea animals.

They eat fish, squid and little shrimp-like animals. They use their eyes to find food.

Yellowfin tuna are hunters near the top of the ocean food chain. They eat many different animals, but most of their food is fish, squid and crustaceans, the group of animals that includes shrimp and crabs.

They hunt by sight. Big yellowfin can stay longer in cold, deep water, so they can search for food far below the surface. Tuna are food for others, too: sharks and large fish eat them, and seabirds and dolphins catch young tuna.

The IUCN describes yellowfin as opportunistic visual predators that take a wide diversity of prey; by volume, fishes, squids and crustaceans are the most important items. Larger yellowfin tolerate lower temperatures and oxygen levels than small ones, which lets them spend more time foraging below the mixed layer.

NOAA Fisheries places them near the top of the food chain. Adults are eaten by top predators such as sharks and large fish, while larval and juvenile tuna are taken by fish, seabirds, dolphins and other animals.

Yellowfin tuna swim together in groups called schools.

They like to swim near floating logs and other big sea animals.

Yellowfin tuna swim in schools, usually with other fish about the same size. Young yellowfin often travel in mixed schools with other kinds of tuna, such as skipjack and young bigeye tuna.

Yellowfin like to gather around things floating in the sea, such as drifting logs, buoys and floating rafts that fishers put out, called fish aggregating devices. They also swim with dolphins and other large sea animals.

The IUCN describes surface schools formed mainly by size, either single-species or mixed, and often associated with floating objects. NOAA Fisheries lists drifting natural debris, fish aggregating devices (FADs), anchored buoys, dolphins and other large marine animals as things yellowfin gather around; in the eastern Pacific, the IUCN notes that fish larger than about 85 centimeters frequently travel with porpoises.

Fishers use these habits: the IUCN reports that purse seiners target yellowfin with dolphins, in free schools and around floating objects. In the eastern Pacific, purse seiners also work under the International Dolphin Conservation Program, which aims to reduce the bycatch of dolphins, and since 2000 the U.S. Dolphin-Safe Tuna Tracking and Verification Program has checked dolphin-safe claims on tuna products.

Many people eat yellowfin tuna.

There are rules about how many can be caught. Scientists count the tuna to make sure enough are left.

Yellowfin tuna are important to fishers all over the world. Because they swim across whole oceans, countries work together in international groups to set fishing rules.

Scientists check each population. NOAA Fisheries says the Atlantic yellowfin is not overfished (2024 check), and neither are the two Pacific populations. The IUCN lists the species as Least Concern, which means it is not at risk overall, but in 2021 it reported that the Indian Ocean population was being overfished.

The IUCN (assessed January 2021) lists yellowfin as Least Concern, down from Near Threatened in 2011, with an estimated global decline of 8 to 17 percent over three generations (10 to 14 years) and a decreasing trend. Global catches exceeded 1.4 million tonnes a year in the years before the assessment. The IUCN then reported the Indian Ocean stock overfished and subject to overfishing, and warned that Atlantic catches had exceeded recommended levels since 2015.

NOAA Fisheries states that, according to the 2024 assessment, Atlantic yellowfin is not overfished and not subject to overfishing; the eastern Pacific stock is in the same condition (2023 assessment), as is the western and central Pacific stock (2020 assessment). The stocks are managed internationally by ICCAT in the Atlantic and by the IATTC and WCPFC in the Pacific.