Yellowfin tuna are highly migratory and can be found throughout the warm waters of the world. Yellowfin tuna is most often found in a can—as light meat or chunk light tuna—where it is mixed with other tuna species such as skipjack. Fresh and frozen yellowfin steaks are also popular eaten raw or lightly seared and are often marketed using the Hawai’ian name, ahi. Ahi is also the market name for fresh bigeye tuna (Thunnus obesus), which is considered a threatened species.
Large yellowfin tuna is usually caught by longline or hook-and-line, whereas smaller tuna for canning are usually caught by purse seine. Just over 4,000 MT (8.8 million pounds) of yellowfin tuna are landed in the U.S. each year, with an additional 29,000 MT (64 million pounds) imported. Yellowfin can grow to over 400 pounds, but most of the commercial longline catch consists of fish that are less than 100 pounds.In 2002 and 2003, Hawai’i tuna catches were at near record levels and amounted to 38 percent of the U.S. yellowfin tuna catch (1,360 MT). In an effort to reduce sea turtle and sea bird bycatch, the longline fleet has adopted mitigation methods and the fishery must close if set parameters are exceeded.
The most recent recommendations from conservation groups list pole- or troll-caught yellowfin as the best environmental choice, as these fishing methods minimize bycatch and avoid excess catch of juveniles. Conservation groups are more cautious in their recommendation of longlined yellowfin, due to concern over high levels of bycatch associated with this type of gear. One exception to this is the U.S. Hawai’i longline fishery, which is considered a good alternative due to strong management measures adopted by this fishery.
Purse seiners catch 60 percent of the world’s catch of yellowfin tuna, most of which ends up in cans. Yellowfin tuna in the Eastern Pacific Ocean run with dolphins, which led to high dolphin mortality in the past. All tuna sold in the U.S. now comes from fleets that do not set nets on dolphins, even though fishing methods have since been modified to allow dolphins to escape. Alternative purse seine methods are now catching numerous non-target species and high numbers of juvenile tuna, which are then discarded, putting future populations at risk.New evidence suggests that yellowfin tuna in the Pacific Ocean and Indian Ocean cannot sustain additional fishing pressure. Scientists believe populations are fully exploited in all oceans, with evidence that overfishing is occurring in many places.
© 2006 Seafood Choices Alliance