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Tuna Certification and Aquaculture
Tuna is a popular fish, eaten in salads, sandwiches and as sushi. But where does our tuna come from? Is it caught in the wild or farm-raised? And just how sustainable is tuna?
What we call tuna comes from the genus Thunnus and there are 8 ‘true’ tunas: albacore; bigeye; blackfin; 3 bluefin tunas (Atlantic, Pacific and Southern), longtail and yellowfin. There are 7 additional species, of which the most popular is skipjack tuna. In 2015, 5,805,949 million tons of tuna were fished, with skipjack tuna contributing 49%, yellowfin tuna 23%, and bigeye tuna 7% of total wild capture production. The majority of tunas are classified as least concern by the International Union for Conservation of Nature and Natural Resources (IUCN) Red list. However, albacore and yellowfin are classified as ‘near threatened’, Pacific Bluefin tuna as vulnerable, Atlantic bluefin as endangered, and Southern Bluefin is classified as critically endangered by the IUCN. The bluefin tuna fisheries contribute only 0.7% of total wild capture tuna.
As wild capture production of bluefin tuna has declined, a heightened interest has grown in the aquaculture of these 3 species, especially Pacific bluefin. In particular, Kinki University in Japan has been working with tuna aquaculture since 1970! Despite this focus and the fact that aquaculture production of bluefin tuna has increased, it is extremely limited with only 36,827 tons produced in 2015. This is only 0.63% of all tuna production and 0.0003% of all aquaculture production. In reality, most of this production concerns wild juveniles, which are captured and fed (ranched). A number of factors have restricted growth of bluefin aquaculture, including low survival rates of cultured eggs, special live feed requirement for juveniles and the cost of live feed. For example, a tuna consumes about 5% of its body weight a day. Research continues in these areas.
While certified wild-capture tuna is available (MSC & FOS), there is currently no certified farm-raised tuna.