'Pilchards' and 'slimehead' fish renamed to boost popularity

Yet describe the same dish as Cornish sardines and they will be eagerly snapped up by health- conscious customers keen to enjoy the benefits of eating oily fish.

Marks & Spencer has seen a sales boom in fresh pilchards by the simple expedient of giving them the new name - dispelling memories of the mushy tinned product in tomato sauce.

And around the country fishmongers and restaurants are having similar success by replacing traditional names such as rat-tails and witch with the less off-putting grenadier and Torbay sole.

Scroll down for more

Faced with dangerously low stocks of traditional favourites such as cod because of over-fishing, the industry is desperate to tempt consumers to try lesser-known species.

So the slimehead is now orange roughy, and Patagonian toothfish sells better as Chilean sea bass.

An M & S spokesman said of the rebranding: "It's a good way to encourage people to try different types of fish as part of our sustainable fish policy."

Fishermen have long argued that traditional names such as slimehead have - understandably - deterred shoppers from trying something new.

They have been behind other changes such as rockfish being sold as Pacific red snapper, and dogfish as rock salmon, and there are moves to have the megrim renamed as Cornish sole.

Scroll down for more

Conservationists back moves to encourage shoppers away from over-fished species including monkfish and sole, and say the consumer can play a vital role in reversing the decline of fish stocks by choosing not to buy those at risk.

Conscientious shoppers have been advised to try coley, gurnard and cape hake as alternatives.

The TV chef Hugh Fearnley-Whittingstall, who has just written a book on fish, said renaming species might encourage customers to be more adventurous and steer clear of endangered stocks.

But there have also been complaints that the demand for some species has led to deliberate mislabelling. Genetic analysis on fish being sold as red snapper found that up to 70 per cent was in fact other species.

And researchers from the University of British Columbia found that more than 200,000 tons of farmed salmon was sold worldwide as the much more expensive wild fish in the last 12 months.