Blackfin tuna

The blackfin tuna (Thunnus atlanticus) is a species of tuna in the family Scombridae. It is sometimes called the Bermuda tuna, blackfinned albacore, or deep bodied tunny. Blackfin tuna are the smallest tuna in the genus Thunnus, usually growing up to about 100 cm (39 in) long and weighing around 21 kg (46 lb).

These fish live in warm tropical waters and are found along the eastern coasts of North and South America, from Massachusetts down to Rio de Janeiro in Brazil. They also live in the Gulf of Mexico and the Caribbean Sea.

Although blackfin tuna are not as commonly sold as other types like yellowfin, bluefin, and skipjack tuna, they are popular among sport fishers in places like Florida, Cuba, and the Bahamas. Their meat tastes just as good as other tuna and can be cooked in many ways, including being used for sushi. Fishers catch them using methods such as trolling, drift fishing, or fishing with a pole and live bait.

As of 2022, blackfin tuna were listed as "least concern" worldwide by the International Union for Conservation of Nature, meaning they are not in danger of disappearing.

Description

Blackfin tuna are the smallest type of tuna. The largest ever caught weighed about 20.6 kg. They have a dark blue or black back and silver sides that shine in the water, with a yellow stripe along their side. Their bodies are oval-shaped, and they have a mouth that leans to the side.

These tuna have small, brown dorsal finlets with white edges, which helps set them apart from other tuna that have yellow dorsal fins. They also have fewer gill rakers than most tuna, with only 20 to 23. This is the fewest of any tuna species. Additionally, the surface of their liver feels smooth, unlike other tuna which have a striped texture.

Biology and ecology

Blackfin tuna hunt fish and squid that live near the surface and in deeper water. They also eat small animals like shrimp, crabs, and larvae by filtering the water or chasing them down.

These fish can have tiny creatures called parasites living on them, such as certain worms and small shrimp-like animals. Cookiecutter sharks are also known to attach to them from the outside.

Life history

Blackfin tuna are a short-lived, fast-growing fish. By the time they are five years old, they are considered old. They grow up quickly and become ready to have babies when they are two years old and weigh about 4 to 6 pounds.

These fish usually lay their eggs off the coast of Florida between April and November. In the Gulf of Mexico and near northern Brazil, this happens from June to September. The Gulf of Mexico is a very good place for baby blackfin tuna to grow because of its special water conditions, which may be helped by nutrients from the Mississippi River.

Blackfin tuna like warm water, preferring temperatures above 20 °C (68 °F). The females release eggs into the water where they meet sperm, creating baby fish that float near the surface down to depths of 164 feet.

Larger fish like mahi-mahi, blue marlin, and skipjack tuna sometimes eat blackfin tuna. Birds also hunt them, and sometimes blackfin tuna eat each other.

Sustainable consumption

In 2010, an organization called Greenpeace International chose not to include the blackfin tuna on its list of seafood that should be avoided, unlike other types of tuna.