People must stop eating popular fish varieties such as cod, hake and haddock in order to save the fish from extinction, according to marine conservationists.

The Marine Conservation Society (MCS) has launched a new website to inform consumers which types of fish are from well managed sources and/or caught using methods that minimise damage to marine wildlife and habitats.

"We are trying to encourage people to diversify away from overfished species to more sustainable stocks," MCS fisheries officer Dawn Bache told Reuters.

"We realise people won't automatically stop eating cod just because of our website. But we are trying to give them enough information about the stock status and suggest alternatives. If they don't ask for it, shops won't supply it," she added.