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Bigeye tuna (Thunnus obesus)

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Common name - Bigeye tuna
Scientific name - Thunnus obesus
Rating
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Caught at sea Purse seine (non FAD associated)
Capture Area Indian Ocean  FAO 51,57
Stock Area Indian Ocean
Stock Detail All Areas
Summary
The most recent advice for this stock suggests that it is being harvested sustainably. However management is largely ineffective in terms of addressing issues such as bycatch, illegal fishing (IUU) and shark fining. Fish Aggregation Device (FAD) associated purse seine fisheries have significant impacts on threatened, endangered and protected species such as marine turtles, sharks and seabirds and are best avoided (See fishing methods for details).
Biology
Tuna belong to the family Scombridae. They are large, oceanic fish and are seasonally migratory, some making trans-oceanic journeys. Bigeye tuna is a tropical and subtropical species found from the surface down to 250m in the Atlantic, Indian and Pacific oceans. It is slower growing than skipjack or yellowfin tuna, maturing at about 3 years old and reaching a maximum size of 250cm in length and 200kg in weight, with a maximum age of 11 years. Bigeye are considered moderately resilient to exploitation.
Stock Information
Indian Ocean stocks are managed by IOTC - the Indian Ocean Tuna Commission.The current stock assessment for Indian Ocean Bigeye tuna (December 2011) suggests that the stock is neither overfished (B>BMSY), nor experiencing overfishing (F<FMSY), a situation possibly attributable to piracy in the western Indian Ocean. The resource is currently harvested sustainably. It is unlikely however that the stock could sustain an increase in effort thus it is important that the Indian Ocean Tuna Commission step up measures to better regulate the fishery.
Capture Information
Purse seining is commonly an industrial scale fishery used to catch tuna destined for canneries. Purse seining is associated with bycatch of marine mammals and discarding of immature tuna. The size of fish caught varies with method of capture - small (3-4kg) for purse seine fisheries. Many juvenile fish are discarded in purse seine fisheries. However,non FAD associated purse seine fisheries have much less impact on the pelagic ecosystem than those that make use of FADs.
Alternatives
(Based on method of production, fish type, and consumer rating: only fish rated 3 and below are included.)
Read what the consumer pages of the Good Fish Guide say about this species.