The fish is one of the Mediterranean's top predators, weighing up to half a tonne and capable of accelerating faster than a sports car.

William Hogarth, Director of the US fisheries service, NOAA, said in a statement he would ask the autumn meeting of the International Commission for the Conservation of Atlantic Tuna (ICCAT) to implement a moratorium over the fishery for three to five years.

"Given continued blatant violations of catch limits, closed areas, and reporting requirements, a moratorium is the best hope if we want to avert disaster for eastern Atlantic and Mediterranean bluefin tuna," said Hogarth, who is also chairman of the European Union-dominated body of 44 nations.

Gerald Scott, a NOAA expert and chairman of ICCAT's scientific committee, said in a Reuters interview last month that stocks could be on the verge of a downward spiral from which it would be difficult to return.

ICCAT ignored the advice of its scientists in setting quotas at twice the level recommended, which environmentalists say are in any case widely flouted in a high-tech chase for fish which can fetch up to US$15,000 each.

Last month the European Commission threatened to take Greece, Malta, Portugal, Spain, Italy, France and Cyprus to the European Court of Justice if they failed to prove that they were not overfishing the species.

Although thousands of miles from its own fisheries, NOAA said it sought the Mediterranean ban because the eastern stock mixed with its own, much smaller population, when not spawning between April and July.