Yellowfin Tuna

This species is primarily caught by the purse-seine fishery, but is also taken by longlines and pole-and-line fishing.

In terms of yield, Yellowfin Tuna is the most important tuna species in the Eastern Pacific, where an important proportion of the Yellowfin Tuna catch is harvested in association with dolphins, in free schools and increasingly under fish aggregating devices (FADs). In the Western and Central Pacific purse seiners harvest about 50%, while longline and pole-and-line fleets comprise 15% and 3% respectively.

In the Indian Ocean, over 40% of purse seine Yellowfin Tuna catches are taken in log-schools along with Skipjack Tuna and Bigeye Tuna. One of the driving forces behind recent changes in the purse seine fishery has been the impact of piracy in the western Indian Ocean, which has led to a decrease of the nominal effort (number of boats, total carrying capacity, number of fishing and searching days, total number of sets) as well as changes in the fishing behaviour due to the new security measures in place (boats working in pairs with military personnel on board, restriction on fishing areas, etc.) (IOTC 2010).

Fisheries exist for this species in the eastern Atlantic between Portugal and South Africa, and in the western Atlantic between the Gulf of Mexico and southern Brazil; longline fisheries occur throughout the entire tropical and temperate Atlantic. The main gears used to catch Yellowfin Tuna in the Atlantic are: purse seines (58%), longline (22%), and pole-and-line (13%) (ISSF 2010). The purse seine fishery is the major contributor to total catches of this species. Landings from baitboats and purse seiners generally declined between 2001–2007 (STECF 2009). The nominal effort in the purse seine fishery had been declining through 2006. As an indicator, the number of purse seiners from the European and associated fleet operating in the Atlantic had declined from 44 vessels in 2001 to 24 vessels in 2006 (last year’s data included during the assessment), with an average vessel age of about 25 years. Since then, however, the number of purse seiners has increased by 50% to 36, as vessels have moved from the Indian Ocean to the Atlantic. At the same time, the efficiencies of these fleets have been increasing, particularly as the vessels which had been operating in the Indian Ocean tend to be newer and with greater fishing power (ICCAT 2009).