Endangered fish such as skate is still being sold by supermarket chains despite a growing awareness of the perils of overfishing, Britain's biggest marine conservation charity has warned.
Lidl, Iceland, Somerfield and Asda were rated at the bottom of 10 national retailers in a league table of fish sales compiled by the Marine Conservation Society.
Atlantic cod, Dover sole and plaice from over-fished stocks were among the vulnerable or unsustainably fished species found in shops. Atlantic halibut, swordfish, monkfish, marlin, huss, grouper, red fish, and snapper were also being sold.
The society assessed each chain according to a set of criteria that included purchasing policies, the species of fish on sale, and customer information.
Marks & Spencer topped the league, with 43 out of 50 points, followed by Waitrose, with 40 points.
Iceland scored just 0.5 points, although the chain differed from its competitors because it sold few fish.
Tesco, Morrisons and Waitrose sell skate, which is particularly threatened. Somerfield also sells skate but will stop in April.
Asda sold six species of endangered fish: Atlantic cod and plaice, swordfish, monkfish, marlin and red snapper.
Bernadette Clarke, from the Marine Conservation Society, said: "Supermarkets play a huge role in shaping how our fisheries and fish farms are managed.
"While the most responsible retailers are making an effort to remove all over-exploited and biologically vulnerable fish from their shelves, others continue to sell them."
Lidl did not provide any information for the charity's league table and came bottom by default.
Shoppers were often unable to make informed choices because of poor labelling, the society said. It wanted details about capture methods and the stock where fish were caught to appear on packs.
Supermarkets do not generally have good enough fish purchasing policies in place to ensure they are buying from sustainable sources, the society warned.
Marks & Spencer and Waitrose were the only chains surveyed which employed dedicated fish buyers.
But the Marine Conservation Society praised some chains for increasing their efforts to sell fish from sustainable sources.
Asda, Co-op, Tesco, Sainsbury's, Somerfield, Waitrose, and Morrisons have stopped selling some species that were vulnerable to exploitation since a provisional survey by the society in October.
The society produces a guide detailing fish to buy.Reuse content