Overfishing of bigeye tuna continues in the western and central Pacific tuna fishery, the world's biggest tuna fishery, according to the 2010 tuna fishery assessment report released this month by the Secretariat of the Pacific Community (SPC).

Though the species is not at risk of extinction, and is never likely to be, the assessment found that bigeye fishing effort needs to be reduced by at least 32% from the average levels for 2006-2009 to ensure long-term sustainability.

Using fisheries and biological data, some going back to the 1950s, SPC has assessed the trends and current stocks of the four tuna species mainly targeted by fishers: skipjack, yellowfin, bigeye and south Pacific albacore.

The 2010 catch for all four species is estimated at 2,421,113 tonnes, the second highest annual catch on record. It represents 83% of the total Pacific Ocean catch and 60% of the global tuna catch.
"Overall, the fishery is in the best shape of all the tuna fisheries in the world", says John Hampton, SPC's Oceanic Fisheries Programme Manager. "On a scale of 1-10, we estimate it as 6-7, a green traffic light tinged with orange.

"But there has been an upward trend in total tuna catch for many years, mainly due to increases in purse-seine fishery catches, which accounted for 75% of the 2010 catch."

Bigeye represents just 5% of the fishery's total tuna catch. Most of the bigeye catch is taken in equatorial areas, both by purse seine and longline. The purse-seine fisheries and domestic surface fisheries of the Philippines and Indonesia take large numbers of small bigeye.

The assessment report states that yellowfin, skipjack and south Pacific albacore tuna stocks are being fished at a moderate level and stocks are reasonably healthy. But Hampton cautions against complacency and stresses the need for responsible management actions to keep the stocks healthy.

"Though some species are being fished within generally accepted levels, this does not mean that there is potential for higher catches," he says. "Now is the time to think about limiting catches, or fishing effort, at around the current levels."

In particular, the report recommends that the yellowfin catch in the western equatorial Pacific be limited to around current levels and that limits on skipjack fishing be considered.