Sainsbury's pioneers 'colour-coded' fish

J Sainsbury, the UK's third biggest supermarket group, is exploiting growing concerns over shrinking fish stocks by bringing in a colour-coded scheme to warn its customers about endangered species.

The scheme, which gives wild fish cuts a green, amber or red light depending on the risk level, is the first of its kind in the UK and has been hailed by Greenpeace, the lobby group, as a model for the rest of the high street.

Sainsbury's has pledged to stock only green- or amber-rated fish by the end of December, costing it £1.5m in lost sales. To avoid confusion with a separate traffic-light scheme it uses to warn shoppers about the nutritional value of their purchases, the colour coding will appear on its website and on its fish counters rather than on the front of its packaging.

Oliver Knowles, the oceans' campaigner at Greenpeace, said Sainsbury's had caught up Marks & Spencer and Waitrose, which top the supermarket industry for their ethical sourcing strategies. "To see a big retailer make these changes is where it starts to get interesting," he said.

Sainsbury's claimed it had devised the sector's most rigorous checklist to help it determine whether it was buying fish from sustainable sources. It came up with its new scheme after it had to drop its goal of selling only fish certified by the Marine Stewardship Council, the pressure group, by 2010 because it realised that not enough fisheries would carry the requisite certification in time.

"It is a robust decision-making process that is having real and practical changes on the shelves," Mr Knowles said. Sainsbury's has a 16.5 per cent share of the grocery market, but a 21.4 per cent share of the fresh fish market.

Earlier this month, the National Consumer Council criticised supermarkets for not making it easier for shoppers to buy sustainable fish. The issue has become one of the hot topics in the battle to be Britain's "greenest" grocer.