Source: BBC News 
Bluefin tuna stocks in the East Atlantic and the Mediterranean are being stripped bare by illegal fishing, WWF has warned in a report.
Traditional tuna-trap fishermen in the Gibraltar Straits have caught 80% less fish in the last three years compared with the 1990s, the report claims.
It also says that demand for tuna in the UK is being driven by "fast sushi" bars and by supermarket sales.
Fleets exceed quotas and some are failing to report catches, WWF says.
The fishery is running out of control, fuelled by the unrestricted expansion of tuna farms across the Mediterranean Sea and driven by the high prices paid by traders in Japan and elsewhere.
The report's main findings include:
WWF found that the annual fishing quota of 32,000 tonnes, set by ICCAT, has been smashed for the past two years. In 2004, the actual catch was 44,948 tonnes and this rose to 45,547 in 2005.
The campaigner says the real figure may be well over 50,000 tonnes.
Fleets from several countries around the Mediterranean are implicated, including some from the European Union, says WWF.
"The European Commission risks bearing witness to the collapse of this centuries-old fishery," said Dr Simon Cripps, director of WWF's global marine programme.
"We urge EU Fisheries Commissioner [Joe] Borg to show leadership and call for an immediate total closure of the fishery, and request that he supports strong management measures at this November's ICCAT meeting that guarantee a future for the fishery."
Over the last two years, Britain imported 1,613 tonnes of processed fresh and frozen bluefin tuna, which exclusively came from the Mediterranean, worth some £8.6m (12m euros).
A spokesperson for Tesco said it was the supermarket's policy to obtain its food from sustainable sources wherever possible.
WWF called for an immediate closure of the fishery - pending the implementation of a recovery plan and "strong" management measures.