Blackfin Tuna Facts, Habitat, Size, Location, Lifespan

Blackfin tuna, also known as the Atlantic blackfin tuna, is the smallest species of tuna in the genus Thunnus, growing to a peak length of 100 cm (39 in) and the highest weight of 21 kg (46 lbs). Generally, blackfin tuna have oval-shaped bodies, with black backs and finlets that have a slight yellowish hue, as well as yellow on the sides of their bodies. 

They enjoy the warm coastlines of the Western Atlantic ocean, where they gather in big colonies with skipjack tuna and strain prey from the water, including smaller fish, squid, and shrimp, to feed on during the winter months. These strong swimmers have a torpedo shape and are dark on top. The lower side is initially light silver and then turns to white, with shimmering spots on their sides in certain light conditions. They have small bronze-colored finlets that run towards their crescent caudal (tail) fin. This fish, which can grow to be approximately 39 inches long and 46 pounds in weight, is important to both commercial and recreational fisheries.

Blackfin Tuna Facts

The rear side of the blackfin tuna is bluish-black, with grayish-silver edges and a white underbelly. Along the upper region of the eye, there is a thick brown line. On the sides, there is a prominent yellow to a golden-colored lateral band that usually fades away upon death.  Dorsal finlets are dusky with coppery color reflections and white edges, whereas ventral finlets are typically grey. These finlets distinguish the blackfin tuna from all other tunas due to the lack of yellow pigmentation on their fins. However, the dorsal finlets occasionally turn yellow after death. 

Blackfin Tuna Habitat

The blackfin tuna is found in oceans close to the coastline, preferring water that is clear and warm temperatures. It is a migratory fish that is known for its strong schooling behavior, frequently forming large mixed schools with skipjack tuna (Katsuwonus pelamis). The blackfin tuna migrates in the summer months from tropical to temperate waters, where the water remains above 70°F (21°C). Autumn, winter, and spring are the best times to see it off the Florida coast.

Blackfin Tuna Size

Blackfin tuna can grow up to 39 inches long and weighs approximately 46 lbs (21 kg). They're usually taken when they're around 19.75 inches long and weigh around 7 pounds (3.2 kg).

Blackfin Tuna Location

The blackfin tuna is one of only a few tuna species with a narrow range. It is only found in the western Atlantic Ocean, between Massachusetts (US) and Rio de Janeiro (Brazil), including the Gulf of Mexico and the Caribbean Sea. It is abundant in tropical regions, but yellowfin tuna (Thunnus albacares) is more prevalent in the northern Gulf of Mexico than blackfin tuna. It is believed that the blackfin tuna migrates extensively during the summer months, settling in more temperate water.

Blackfin Tuna Lifespan

The average lifespan that has been reported for Blackfin Tuna is approximately 5 years. It takes 2 years to get fully mature and ready to breed.