The Atlantic bluefin tuna is one of the best-known species of tuna. It lives throughout the world’s oceans but is most commonly found in the eastern Atlantic Ocean and the Mediterranean Sea. It used to live in the Black Sea but has since become extinct there. It’s one of the largest species of fish in the ocean.
Yellowfin tuna is another well-known species. It’s found in tropical and subtropical oceans around the world and can weigh up to 400 pounds.
The Atlantic bigeye tuna is another interesting species of tuna. It’s known for its migration patterns, moving thousands of miles through the ocean when it’s time for yearly spawning.
Bigeye tuna usually live to be around nine years old and release millions of eggs when they spawn. Some other species of tuna are known to eat bigeye tuna (because of their relatively smaller size). They only grow to be around 5.5 feet in length (only half of the largest species).
The fish ranges from quite small to rather large, depending on the species. Some the species of tuna include:
- Bullet tuna
- Atlantic bluefin tuna
- Skipjack
- Yellowfin
- Bigeye
Appearance
Tuna range in appearance based on the species. Some are very small, growing to around 1.6 feet in length (the bullet tuna), while others are far larger, like the Atlantic bluefin tuna that grows to over 15 feet and over 1,500 pounds.
There are several different groupings of tuna fish that one might find in their research. The primary groups, those that are said to consist of the “true” tuna fish, are the bluefin and yellowfin groups. The bluefin group includes these species:
- Albacore tuna
- Southern bluefin tuna
- Bigeye tuna
- Pacific bluefin tuna
- Atlantic bluefin tuna
While the Yellowfin group includes:
- Blackfin tuna
- Longtail tuna
- Yellowfin tuna
There are seven other species of tuna in the Thunnini tribe.
Generally, the tuna is a sleek-looking fish that can move very quickly through the water. Seven to ten small fins run along their backs to their tails. Their tail fins are crescent-shaped with a blue dorsal side and a whiteish underside for better camouflage in the water.
Amazingly, some tuna fish are incredibly fast swimmers. This includes the yellowfin tuna, which can reach speeds of up to 47 mph.
Habitat
Tuna are found around the world in a variety of ecosystems in the Atlantic, Pacific, and Indian Oceans, and more. They can also be found in lakes, wetlands, streams, and the open ocean. They prefer the open ocean rather than spending too much time near the shore. But they are found near coastlines as well.
Some tuna are well-known for swimming impressive distances during migration. For example, some species swim between the Gulf of Mexico to Europe to feed.
Diet
The eight true tuna species are known for their carnivorous diets. They prefer to hunt and eat smaller fish, squid, crustaceans like crabs and lobsters, and invertebrates.
Reproduction
Tuna generally only spawn once a year, usually swimming vast distances to reach their preferred breeding ground. For example, Atlantic bluefin tuna swim all the way to the Gulf of Mexico while others travel to the Mediterranean Sea.
Tuna fish release eggs near the surface of the water, with external fertilization taking place. During one spawning, a female tuna can release as many as 2.5 million eggs. They lay up to 10 million years per year.
Once born, tuna develop quickly and migrate to their preferred feeding territory.
Threats
One of the biggest threats that species of tuna face is overfishing. The fish is highly prized around the world and is fished throughout the world’s oceans. Some species, like the southern bluefin tuna, may become extinct in the near future.
Individual fish can sell for thousands of dollars if they are large enough. Additionally, some species of tuna are hunted as game fish. This mostly includes the largest species.
For example, the endangered Atlantic bluefin tuna has declined by more than 50% in the last decade in the East Atlantic and even more in the Western Atlantic.
Most tuna fish are apex predators due to their size, but that doesn’t mean that they are without equal in the world’s oceans. They are commonly hunted by larger fish, sharks, and sometimes orcas and pilot whales. Seabirds and large fish are also known to prey on juvenile tuna fish. But, as they age, their predators grow fewer.
Facts about Tuna Fish
- The tuna fish preys on smaller fish, squid, crustaceans, and invertebrates of all varieties.
- The fish is incredibly commercially important.
- Bluefin tuna are endangered due to overfishing.
- Some tuna fish migrate huge distances during a single year.
- Tuna fish is an incredibly healthy meat that’s eaten around the world.
- Due to the popularity of tuna fishing, some species are considered to be endangered.
