Tuesday, July 31, 2007

Bigeye tuna fact sheet

Thunnus obesus | Bigeye tuna


The bigeye tuna has a metalic blue colouration on its dorsal and a white ventral. They can be distinguished from other tuna species by the presence of an irridescent blue longitudinal band and its eyes which are larger than in other tuna species. They occur in waters ranging from 13 - 29° C, with the ideal range being 17 - 22° C, and can dive down to about 500 m deep. Bigeye tuna are distributed throughout the Atlantic, Pacific and Indian Oceans, but they do not occur in the Mediterranean. They prefer open ocean, but can also be in coastal waters, especially around oceanic banks and seamounts. Spawning can occur several months with a frequency of every day or second day. Bigeye tuna is highly valued  in the fishing industry and in the Azores it is the second most captured tuna species, after the skipjack tuna. In the Azores they may be found between April and October but are most abundant from mid April to mid June. 


Length: 2.39 m (maximum)

Weight: 30 – 130 (Azores), maximum 210 kg

Diet: Smaller pelagic fish, such as Atlantic chub mackerel, blue jack mackerel, boar fish and cephalopods (octopus and squid) in the Azores

Reproduction: Oviparous with external fertilization (Average 2.9 – 6.3 million eggs per spawning)

Longevity: 
Western pacific: 16 years
Indian Ocean: 8 years
Atlantic Ocean: 9 years
Eastern Pacific: 5 years

Conservation Status: Vulnerable (population decreasing). 
Estimated decline: 42 % over 15 years (1992-2007)
Atlantic and Indian Oceans: Fully Exploited
Pacific stocks: Over-exploited


In other languages:
Portuguese: Patudo
Spanish: Atún patudo
French: Thon obèse 
Italian: Tonno obeso
German: Großaugen-Thun
Dutch: Grootoogtonijn
Swedish: Storögd tonfisk
Norwegian: Storøyd tunfisk
Danish:   - 
Finnish: Isosilmätonnikala
Polish:  - 
Russian: Большеглазый тунец


Bigeye tuna

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