Scientists and conservationists have long warned that bluefin stocks in the eastern Atlantic Ocean and Mediterranean Sea are facing imminent collapse after years of mismanagement by ICCAT. Stocks in the Gulf of Mexico and West Atlantic have already declined so significantly that U.S. and Canadian fleets routinely fail to even meet their annual ICCAT catch quota, while catch limits are routinely ignored and wildly exceeded by European and Japanese vessels.

Studies cited in the Monaco proposal report that Atlantic bluefin stocks have fallen by about 75 percent from 1957 to 2007, with 60 percent of that loss occurring in just the past 10 years as overfishing has accelerated. Scientists warn that continuing to fish the bluefin at current levels will push the population to 94 percent below the size it was before commercial exploitation began, effectively collapsing the fishery and putting some populations at risk of extinction.

Caught off the coast of northern Japan, the big tuna was among 570 put up for auction Tuesday. About 40 percent of the auctioned fish came from abroad, including from Indonesia and Mexico, the representative said.

Japan is the world's biggest consumer of seafood with Japanese eating 80 percent of the Atlantic and Pacific bluefins caught. The two tuna species are the most sought after by sushi lovers.