Sashimi lovers are urged not to dine on bluefin tuna after a Hong Kong sushi restaurant chain again won the most expensive fish at an auction in Japan yesterday. Itamae Sushi and its Japanese partner Kyubei Sushi paid HK$1.37 million at the Tsukiji fish market auction in Tokyo for a wild bluefin tuna weighing 232.6 kilograms. The wining bid was the second highest since 2001, reflecting the rarity of the fish. The auctioned fish belongs to the Pacific bluefin species which marine scientists say has been heavily harvested and may become endangered as the northern and southern bluefin species. The international community is to discuss in March a proposed global trade ban on the northern bluefin tuna, which may be amended to include the two other species. Activists from the WWF Hong Kong last night 'mourned' for the fish outside the Wan Chai branch of Itacho, a sister restaurant of Itamae. They also distributed pamphlets urging customers to boycott bluefin tuna dishes. The green group condemned the sushi chain, saying it was irresponsible and that its bid was a 'promotional gimmick' to encourage people to consume the endangered fish. 'Money has taken precedence over corporate responsibility. In places like Hong Kong, people are rich enough to choose something else as it is not a matter of survival,' said Dr Guillermo Moreno, the group's marine head. Itamae owner Ricky Cheng Wai-tao defended its bidding, saying there was nothing wrong about it since harvesting and trading the tuna were still legal. 'We would have stayed away from the auction if the Hong Kong or Japanese government made importing the fish illegal. But this is not the case,' he said. The former television host was well known for making high-price bids for tuna. He paid HK$813,000 for a 128kg fish last year and HK$430,000 for a 276kg catch in 2008. Cheng said the bluefin tuna was widely sought around the world because of its unique taste. Apart from the highest-bid fish, the chain also bought a second tuna at a lower price. 'If we hadn't bid for that, there would have been other Hong Kong restaurants attending the auction winning that too,' Cheng said in Tokyo yesterday. Cheng said he was unsure if the fish was going to be extinct as there were more than 50 bluefin tuna available for auction yesterday, compared with only three last year. The tuna would be equally divided with its bidding partner and shipped back to Hong Kong tomorrow, he said. Itamae and Itacho Sushi have more than 20 outlets. Rival sushi chains Genki and G Sushi yesterday said they did not participate in the bidding.