Synonym/common names:

Atlantic bluefin tuna, blue fin tuna, bluefin tunny, blue-fin tunny, northern bluefin tuna, and squid hound.

Names in different languages:

Netherlands: Blauwvin tonijn, Spain: Atún rojo, Italy: Tonno, Denmark: Blåfinnet tun, Germany: Atlantischer Thunfisch, Portugal: Atum-rabilho, France: Thon rouge de l'Atlantique, Japan: Kuromaguro, China: 金枪鱼.

Habitat:

There are at two subspecies of the Northern Bluefin, one in the Atlantic and one in the Pacific:

The Atlantic Bluefin is found from Labrador and Newfoundland south into the Gulf of Mexico and the Caribbean Sea and is also found off Venezuela and Brazil in the western Atlantic. In the eastern Atlantic the Atlantic Bluefin occurs from the Lofoten Islands off Norway south to the Canary Islands and the Mediterranean Sea. There is also some population off South Africa.

The Pacific Bluefin is found from the Gulf of Alaska to southern California and Baja California in the eastern Pacific. In the western Pacific Bluefin is found from Sakhalin Island in the southern Sea of Okhotsk south to the northern Philippines.

Distinctive Features:

Adults are typically 3m in length, but can reach 4m, making the Atlantic tuna one of the largest bony fishes and the largest of all tuna species. Adults average 130-680kg, although the upper weight range is rarer now.

Northern Bluefin tuna are built like torpedoes. Not only do they have a hydrodynamic shape, their pectoral (side) fins can be retracted and, unlike other fish, their eyes are set flush to their body. This means their bodies create little drag as they swim through water.

Very large species, first dorsal fin is near to the middle. Gillrakers 34 to 43 on first arch, the second dorsal fin is higher than the first one. Their pectoral fins are very short less than 80% of head length.

bluefin

Coloration:

The body has a metallic deep blue color above, the lower sides and belly are silvery white. In fresh specimens alternating colorless lines and rows of dots can be seen along the lower sides of a Bluefin tuna. The first dorsal fin has a yellow or blue color; the second is red or brown. The anal fin and finlets are yellow, edged with black. The central caudal keel is black.

Size, Age, and Growth:

Northern Bluefin tuna grows more slowly than other tuna species and have a long life span, up to 20 years or more. The biggest size of a Northern Bluefin tuna in the various North Atlantic fisheries range between 540 and 560 kg in the recent years. In more wormer waters off the Canary Islands, the biggest in commercial catches range between 350 and 400 kg.

Reproduction:

Northern Bluefin tuna spawn just once a year and do not reach reproductive maturity until they are 8-12 years old. This makes this tuna species more vulnerable to overfishing than some of the smaller tuna species that can spawn several times in a year.

Large adults (age 10+) are known to spawn in the Gulf of Mexico and in the Mediterranean Sea. In the Pacific spawning occurs northeast of the Philippines. Females weighing between 270 to 300 kg may produce as many as 10 million eggs per spawning season.

Stock Status Bluefin Tuna 

Conservation:

The International Union for the Conservation of Nature and Natural Resources (IUCN) listed Northern Bluefin in their “red list” 2011 under the category Endangered.

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