TOKYO—A multinational organization that coordinates fishing activities in the western Pacific is throwing a lifeline to heavily overfished Pacific bluefin tuna stocks.
Speaking today at a press briefing, Japanese officials provided details on a plan agreed to last week that aims to rebuild the spawning population by halving the catch of juveniles and limiting takes of mature fish as well. The proposal calls for total Pacific bluefin catches to be kept below the 2002 to 2004 annual average levels and for catches of fish weighing fewer than 30 kilograms—juveniles too young to spawn—to be reduced to 50% of those levels.
Conservation organizations see the proposed limits as a step in the right direction. But they are "far from enough," Wakao Hanaoka, senior ocean campaigner for Greenpeace, tells ScienceInsider. He says that Pacific bluefin tuna stocks have shrunk to just 4% of the historical population, making proper stock management a matter of urgency.
A subcommittee of the Western and Central Pacific Fisheries Commission (WCPFC) agreed to the Japan-sponsored draft at a meeting last week in Fukuoka. The full commission will almost certainly adopt it at a meeting to be held in Samoa starting 1 December, explained Masanori Miyahara, an adviser to the ministry of agriculture who chaired last week's meeting. Reducing the take of juveniles that haven't yet spawned is one key to achieving the plan's initial goal of rebuilding spawning stock biomass—the fish population able to reproduce—to the historical median of 42,592 tons within 10 years. The biomass is now thought to be 26,000 tons, very near its all-time low. "Eating fish before they spawn is very wasteful," Miyahara says.
Miyahara says that 80% of all captured bluefin tuna—prized for sushi—end up in Japan. But rebuilding stocks is an international challenge. Pacific bluefin spawn in waters stretching between southern Japan, Taiwan, and the Philippines but migrate to the eastern Pacific, where they mature before returning to the spawning grounds.
The United States and Mexico are major fishers of bluefins. The United States is one of the 26 members of WCPFC and will be bound by the agreement. But Mexico belongs to the Inter-American Tropical Tuna Commission, which manages fishing in the eastern Pacific. "Both organizations have to cooperate to realize the conservation of Pacific Ocean tuna," said Hisashi Endo, an official with Japan's Fisheries Agency, at the briefing.
WCPFC member countries will have to develop schemes to ensure compliance with the new restrictions. Japan will monitor catches by its 20,000 artisanal fishers and several dozen large operators, Miyahara says, and will issue a warning when landings hit 70% of the limit. "When the catch reaches 95% we will close the fishery," Miyahara says.
Conservation organizations had hoped for more stringent limits. Prior to last week’s meeting, the World Wildlife Fund had called for the total bluefin catch to be cut by half. Miyahara says they had to aim for something achievable, but the plan, which takes effect in 2015, will be reviewed and could be amended as early as 2016 depending on the state of spawning stocks.
Hanaoka says Greenpeace will continue to push for tighter regulations. But it is also trying to shift market demand toward sustainable seafood. In August, it surveyed 15 leading supermarket chains about their bluefin tuna procurement policies. None of the 13 companies who responded currently restrict purchases of juvenile fish or those caught just before spawning, but Hanaoka says they did find some reason for optimism. Some companies agreed that conservation efforts shouldn't be left just to government action; a few said they were planning on reviewing their procurement practices.
To keep up the pressure, Greenpeace Japan will add an assessment of bluefin purchasing policy to the criteria it uses to rank supermarkets according to their support for sustainable seafood. Since December, the organization has offered a free smart phone application that allows consumers to check if fish on sale are endangered or overfished. It's gotten 10,000 downloads. "We're trying to make supermarkets realize that many consumers are demanding sustainable seafood," Hanaoka says.