Robert de Niro restaurant chain, Nobu, to mark endangered bluefin tuna on its menu

Customers will have to decide whether to order the fish despite environmental qualms, or to choose a "greener" alternative.

The move comes after The Sunday Telegraph revealed that investigators from the environmental group Greenpeace had used DNA tests to prove that two Nobu restaurants in London were serving bluefin tuna without telling customers.

Ritchie Notar, the New York-based managing partner of the chain, said it was "unacceptable" that customers had not been told what they were eating.

He said: "We are going to describe what's on our menu but I'm also going to put an asterisk next to [bluefin] and next to that we are going to say that it is environmentally endangered."

Mr Notar said he would like to take bluefin off the menu altogether, but the move was being resisted by the chain's Japanese chefs who serve it in sushi and sashimi. In Japan, bluefin is considered the most delicious of all tuna species.

Willie Mackenzie from Greenpeace said, "It's all very well labelling endangered species on the menu, but the simple fact is, if it's endangered they shouldn't be serving it up anyway."