A quiet environmental revolution is happening in the world of commercial fishing. For seven years an independent organisation called the Marine Stewardship Council (MSC) has been trying to harness consumer purchasing power to encourage environmentally friendly fisheries. In much the same way as the now widely recognised Soil Association does, the MSC puts its label on fish products from sustainable sources.
Now this small, London-based organisation has pulled off a real coup. Wal-Mart, the world's biggest retailer, has set itself a target of buying only MSC-certified fish for its North American operations in three to five years.
The environmental benefits could be enormous. But hang on, Wal-Mart has long been hated by environmentalists. Is this just a trick, designed to tap into consumer guilt while the company somehow banks the cash anyway?
No, says Rupert Howes, MSC's chief executive, Wal-Mart's commitment is genuine and, given the company's size and clout in the market place, this is a landmark. Wal-Mart, he points out, has not taken the easy option of switching to suppliers already certified by the MSC, but has committed to working with existing suppliers to raise awareness and encourage more fisheries into the MSC assessment process.
Mike Boots, of the consumer group Seafood Choices Alliance, agrees. "MSC is the gold standard that people are working towards. This is great news for the consumer. It has the potential to reach every home in North America." Boots hopes European retailers will follow Wal-Mart's move.
And just weeks after the decision, it seems that a sense of momentum is building. Scott Burns, senior programme director at the US branch of WWF, the worldwide fund for nature, said: "We are already seeing the ripple effects of Wal-Mart's announcement, with other businesses making new commitments over the past several weeks."
UK chains such as Waitrose and Marks & Spencer have recently unveiled sustainable procurement policies for fish. Not to be outdone, Sainsbury's quickly moved to ban skate and huss from its stores, and will now focus on selling fish from seasonal and sustainable sources.
Wal-Mart's UK outlet Asda, which has been subject to a Greenpeace campaign for the past four months, has also now agreed not to stock skate and dogfish, species that Greenpeace considers as being at risk. Greenpeace welcomed the move and the Wal-Mart announcement, although it was keen to point out that it did not fully endorse the MSC, as there were some certified fisheries, such as hoki, Patagonian toothfish and Alaskan pollock, that it still considered vulnerable.
None of the changes by other companies matches the promise Wal-Mart has made for long-term commitment. For some environmentalists, any negotiation with a multinational such as Wal-Mart is tantamount to striking a pact with the devil, but even big companies sometimes have to answer to customer concerns.
As the company's president, Lee Scott, remarked at the end of last month, the reason Wal-Mart is taking this step is that "it's very, very good for the environment and also very, very good for business".