Thursday, 09 March 2017 06:32
In recent years, international meetings on managing the Pacific bluefin tuna (Thunnus orientalis) and seafood auctions for this species have sparked headlines, such as those below, advocating urgent action to reduce overfishing or exclaiming at the astronomical prices for a single large fish.
The fishery for Pacific bluefin tuna is in serious trouble, more so than for any other tuna, even the other bluefin tuna stocks (for a summary, see the ISSF Status of the Stocks Report). The wild population of Pacific bluefin tuna is officially overfished, and overfishing is still going on.
- Pacific bluefin tuna is economically and ecologically important due to its high market value and its role as a large predator in pelagic ecosystems. It is highly migratory and very widely distributed in the Pacific Ocean, seasonally inhabiting subarctic, temperate, and tropical waters in the North Pacific Ocean, and temperate waters in the south around Australia and New Zealand. It also undertakes large vertical movements.
- Pacific bluefin tuna has only one stock and spawning has only been recorded in the north western Pacific Ocean. It is the second largest of all the tunas. Only the Atlantic bluefin tuna (Thunnus thynnus) is larger. Until 1999, Pacific and Atlantic Bluefin tuna were considered the same species.
- About 14,000 tonnes is caught from the wild per year, most in the Western Pacific Ocean. Many of the smaller Pacific bluefin tuna are caught live in coastal waters, and taken to coastal cages in Japan and Mexico, and grown out, adding weight and value to the wild catch. In 2002 in Japan, the life cycle was closed in captivity and a small amount of production now comes from full aquaculture. Pacific bluefin tuna is caught both as targeted catch and as non-targeted bycatch, by many different fishing methods, including by several types of small-scale Japanese fisheries.
- Pacific bluefin tuna is managed jointly by two tuna Regional Fisheries Management Organisations (RFMO), namely the Western and Central Pacific Fisheries Commission (WCPFC) and the Inter-American Tropical Tuna Commission (IATTC) and their country members. Given the concerns for the status of the stock and its fisheries, environmental non-government organizations have campaigned for much stronger catch restrictions.
- The Pacific bluefin tuna stock is assessed as overfished and subject to overfishing. The 2016 stock assessment from the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC) estimated that the spawning stock biomass was 2.6% of its estimated unfished level.
- Pacific bluefin tuna is a most prized commodity in the sashimi market.
- Under global climate change predictions, the relative abundance, spatial distribution ranges, and predator-prey dynamics in food webs of Pacific bluefin tuna are expected to change in response to altered oceanographic regimes that govern life cycle and seasonal movements.
The profiles have been written by Victoria Jollands and peer reviewed by many experts. Information has been drawn from peer reviewed sources which are given for each page of the profile. See Contributors and Reviewers for details and acknowledgements.