Consumers try to buy responsibly and not choose fish that come from exhausted supplies but are often confused by the range of products and information surrounding them. Both main supermarkets yesterday announced steps they are taking to provide fish sourced from sustainable fisheries.

Woolworths is working in partnership with the London-based Marine Stewardship Council (MSC) to introduce two new lines of canned tuna and salmon carrying the MSC blue tick of approval, and to delist orange roughy and yellowfin tuna. The company said it was undertaking an assessment with the Sustainable Fisheries Partnership Foundation of its wild-caught fish to identify the top four species which are available in sustainable supply.

Coles also announced a partnership with the World Wildlife Fund to review fresh seafood and to take advice on sourcing fish on a sustainable basis.

Far from being another battle in the ongoing war between the two supermarket powerbrokers, the move is seen as a positive step towards ethical attitudes towards dwindling resources.

A Greenpeace spokeswoman, Dr Cat Dorey, said it was exciting to see supermarkets move towards a sustainable policy.

She said the relationship with the Sustainable Fisheries Partnership - a non-government organisation - gave the move credibility as that organisation was a strong driver for change, but she was more sceptical of the arrangement with MSC - an independent London-based organisation, once owned by Unilever and WWF.

''When it comes to MSC we have quite a lot of concern. We don't think their standards are strong enough,'' Dr Dorey said.

Doubts have been raised at times about MSC's certification process and whether it is compromised by commercial concerns. Armineh Mardirossian, group manager of corporate responsibility at Woolworths, said the supermarket was confident of its credentials.

''For us the Marine Stewardship Council is the most credible and most rigorous certification process around,'' she said.

Ms Mardirossian said the two organisations had taken two years to research the supply chain, which found that ''the two species that we've delisted are on the significant amount of stress from a stock density perspective'' and that they were now analysing ''each of the species and which fisheries they come from to better understand what the issues are''.

A spokesman for MSC, Patrick Caleo, said companies were slower to adopt sustainable products - ''it may be because the issues associated with marine environment aren't so often talked about so often here in Australia'' - but participation from large retailers would provide momentum for other companies to follow.

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