Grocery stores across the U.S. are contributing to the demise of global fisheries by stocking shelves with fragile fish varieties and failing to develop sustainable purchasing strategies, according to a new report.

Even the grocers that ranked at the top of the heap -- such as Whole Foods, Ahold USA and Harris Teeter -- failed to score more than four out of 10 possible points in Greenpeace’s “Carting Away the Oceans: How Grocery Stores are Emptying the Seas.”

The report graded 20 of the country’s top supermarket chains on seafood procurement policies, labeling and transparency, support for sustainability initiatives and the number of products for sale from the “Red List,” a compilation of 22 fished and farmed species with the most significant environmental impacts.

Whole Foods, Ahold USA and Harris Teeter toped the list with four out of 10 points. Wegmans, Wal-Mart and Target followed with three out of 10 points. Safeway, Aldi, Kroger and Costco rounded out the top 10 supermarkets by scoring two out of 10 points. The remaining grocers scored a single point out of 10, including Trader Joe’s and Publix.

All grocers surveyed sold fish from the Red List, which includes certain tuna varieties, Atlantic halibut, orange roughy and Chilean Sea Bass.

“Those with the highest scores are doing the most to work toward seafood sustainability by developing comprehensive, transparent policies to procure sustainable seafood,” the report said. “Supermarkets in the second tier have demonstrated support for seafood sustainability, but fall short on developing policies to ensure long-term commitment to sustainability.”

Yet the authors predict that the state of seafood sustainability in supermarkets will improve because several large retailers are in the process of creating more sustainable practices. Supermarkets are well-positioned to take advantage of the current drive toward sustainability, and the issue will likely offers a competitive edge for those that embrace it.

The market for supermarket seafood is huge -- and growing. The domestic seafood market generates some $16 billion in annual sales with an average 32 percent gross margin, the report said. Supermarket seafood sales increased 7 percent between 2006 and 2007.

But the demand for seafood has led scientists and conservationists to sound the alarm about the future of global fish stocks. In late 2006, a group of scientists from around the world warned that the world’s seafood supply would run out by 2048 due to overfishing, pollution and other environmental factors.

Download the report (pdf, 75p, 9MB) here.