Bluefin tuna are among the most expensive fish on the planet. Just one can sell for more than $100,000 in Tokyo, where it is highly prized by top sushi chefs. But the taste for this luxury tuna in Japan has decimated global bluefin populations. In June the European Union ended the Mediterranean fishing season early, and US Atlantic stocks may be close to collapse.
But there is hope. Last week scientists used special spearguns to implant hormones into adult bluefin in sea-cages off Italy. Three days later they spawned, producing 10 million fertilised eggs in four days. 鈥淭his is the first time anyone has got this amount of bluefin eggs,鈥� says Chris Bridges of Heinrich Heine University in D眉sseldorf, Germany. 鈥淚t鈥檚 good news for tuna,鈥� as it may allow the big fish to be farmed.
Tuna boats already deliver live-caught bluefin to sea-cages for fattening, but this does not relieve the pressure on wild stocks. Raising bluefin on farms from eggs could help, though it may also cause ecological problems, such as pollution and disease.
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Although Japanese scientists have managed to raise bluefin from eggs, the supply is unpredictable, as the adults spawn sporadically, and techniques used to induce spawing in smaller tuna species are unsuitable for 150-kilogram bluefin. This weekend鈥檚 harvest of baby bluefin has been sent to aquaculture research institutes in Malta, France, Spain, Crete and Israel to see who can raise the most adults.
Endangered species 鈥� Learn more about the conservation battle in our comprehensive special report.
