MARSEILLE - It has been a long few weeks for captain Jean-Louis Donnarel and the crew of the Provence-Cote d'Azur II. Long, rough and not very profitable.

After sailing a total of 6600 nautical miles - first to Cyprus, then the length of the Egyptian coast, to Malta, around the Balearics and then home - the Provence-Cote d'Azur II returned with 84 tonnes of bluefin tuna, a catch that will barely cover the costs of the voyage.

"We found fish on the last day," Donnarel said. "Without that, we would have been finished. Someone has to take a decision. Do they want us to fish or not? If not, they should put us out of our misery."

Donnarel and his crew are at the sharp end of an increasingly bitter row: one that links globally known restaurants, top celebrities, huge international conglomerates, sushi shops and supermarkets across half the world to the livelihoods of a few thousand fishermen.

At stake is the survival of the bluefin tuna, a single specimen of which can be sold for tens of thousands of dollars - a price that has seen stocks decline in some areas by up to 90 per cent.

Last month Sienna Miller, Elle Macpherson, Jemima Khan, Sting and others signed a letter to Nobu, a famous upmarket restaurant chain part-owned by Robert De Niro, threatening a boycott of their favourite haunt.

The British entertainer Stephen Fry, one of the celebrity campaigners, wrote: "It's astounding lunacy to serve up endangered species for sushi. There's no justification for peddling extinction, yet that is exactly what Nobu is doing in restaurants around the world."

The restaurant has so far refused to take it off the menu, citing its cultural importance in Japan and "enormous demand", but the battle goes on.

According to the World Wildlife Fund (WWF), the Atlantic bluefin will be wiped out in three years unless radical action is taken.

Fishermen such as Donnarel are unimpressed by the celebrity-inspired pressure on their livelihoods. "We have become hooligans, bandits," he said. "Tuna fishing has become politically incorrect and we are pariahs. Once it was fine to fish; now it isn't."

With their 40-metre, £3 million ($7.65 million) boats, the vast nets used to encircle and sweep up entire schools of tuna making their way into the Mediterranean, and their apparent disregard for the limits the European Union have previously tried to impose, the French fishermen have been cast as the villains of the piece.

The fishermen themselves are very defensive - angry with consumers, governments, conservationists and the EU. Few speak to the press.

And they are now being closely watched. When this year's season ends this week, France's fleet of tuna boats will have fished less than its quota of just over 3000 tonnes.