Tunas Barracudas Marlins and Relatives: Scombroidei

Physical characteristics: Atlantic bluefin tuna reach a length of 10 feet (3 meters) but usually are about 6 feet (2 meters) long. The body is a symmetrical oval with pointed ends. The back is metallic dark blue, and the lower sides and belly are silvery white. The first dorsal fin is yellow or bluish, and the second is reddish brown. The second dorsal and anal fins are followed by seven to ten tiny fins. The second anal fin is silvery gray, and the small fins that follow it are dusky yellow edged with black. The front of the fish is wrapped in large scales, and the rest of the body is covered with small scales. Tunas have nets of tiny blood vessels that help them stay cool.

Geographic range: Atlantic bluefin tuna live in the Atlantic Ocean.

Habitat: Atlantic bluefin tuna live near the surface in open water.

Diet: Atlantic bluefin tuna eat fish, crustaceans, and squid.

Atlantic bluefin tuna reach a length of 10 feet (3 meters) but usually are about 6 feet (2 meters) long. (Illustration by Barbara Duperron. Reproduced by permission.)

Behavior and reproduction: Atlantic bluefin tuna travel far from their spawning grounds in the Gulf of Mexico and the Mediterranean Sea. Eastern and western Atlantic fish mix, but scientists are not sure how many fish travel all the way across the ocean. Atlantic bluefin tuna can reproduce when they are about four years old. Females weighing about 660 pounds (300 kilograms) produce as many as ten million eggs per spawning season.

Atlantic bluefin tuna and people: Atlantic bluefin tuna are important food and sport fish.

Conservation status: Atlantic bluefin tuna are not threatened or endangered. ∎