More consumers are eating salmon because of its heart-healthy omega-3 fatty acids, its ease in preparation and its rich, versatile flavor. But farmed salmon, which is less expensive and more readily available than its wild-caught counterpart, has gotten a bad rap in recent years. Studies have shown that some farmed salmon contains high levels of cancer-causing PCBs and dioxins. Environmentalists have also raised concerns about the impact of salmon farming (aquaculture) on surrounding marine life and wild salmon populations.

Last month, two companies with local ties helped form stringent new purchasing guidelines for farmed king salmon, and the hope is that other companies nationwide will also adopt the policy. Wegmans Food Markets, Inc. and Bon Appétit Management Co. — a food corporation based in Palo Alto, Calif., that contracts with St. John Fisher College in Pittsford — developed the criteria in collaboration with Environmental Defense, a national environmental advocacy organization.

The new standards work to mitigate the most pressing environmental problems caused by salmon aquaculture. The policy also sets tighter rules on allowable PCB and dioxin levels, prohibits hormones and genetically modified stock, and minimizes anti-biotic use.

"There are no purchasing policies that have such an emphasis on environmental impact," says Becky Goldburg, an Environmental Defense scientist who worked with both companies developing these guidelines. "We wanted to write a policy that was both aggressive yet achievable."

Salmon aquaculture involves an open net cage or pen in coastal waters where the salmon are raised and harvested. These pens allow fish waste and chemicals that are used to treat the fish to spread beyond the cages.

Occasionally farmed fish escape, endangering wild fish with diseases and interbreeding.

George Leonard, science program manager at Monterey Bay Aquarium's Seafood Watch program in California, which educates the public on sustainable seafood choices, points to two different strategies on improving salmon aquaculture.

The first embraces fully enclosed containment systems that would be located either on land or in water. While a closed system would eliminate nearly all environmental risks, its cost could make farmed salmon too expensive for most consumers. (Such closed-system tanks for farmed salmon are still mostly in the research and development stages, though they work well with other seafood, such as tilapia and shrimp, says Environmental Defense scientist Bruce Hammond.)

The other strategy, which guided Environmental Defense in this current purchasing policy, calls for much stricter controls and monitoring of open-container systems. These guidelines address all the major environmental concerns that conventional salmon aquaculture poses, says Leonard. More importantly, the guidelines mandate that farmers continuously improve their practices.

"This is a good first step. But this is not the be-all, end-all in sustainable salmon," says Leonard.

Both Seafood Watch and Environmental Defense's Oceans First program classify the farmed king salmon that follow these rules as environmentally preferable to conventional farmed Atlantic salmon, but would still recommend wild salmon as the most eco-friendly.

Alex Trent, executive director of Salmon of the Americas, a salmon aquaculture trade organization based in Princeton, N.J., says the Environmental Defense policy is but one of a proliferation of policies and standards that are being developed in the 25-year-old salmon farming industry. The public doesn't often hear about these policies because they are generally proprietary information shared only among the companies involved. These policies have similar criteria, such as low PCB tolerance and reduced reliance on wild-caught fish meal and oil for salmon feed.

While numerous policies and standards are confusing for retailers and consumers, it is unlikely that the industry will adhere to a single uniform set of standards, Trent adds.

Wegmans is now selling farmed king salmon under its Food You Feel Good About label in its stores' fresh seafood case. Farmed king (also called Chinook) salmon is a new product for the company, says spokeswoman Jeanne Colleluori. Wegmans sells wild king salmon and other wild Pacific salmon varieties during the wild salmon run and offers the more common farmed Atlantic salmon year-round.

The farmed king salmon costs a little more than the farmed Atlantic salmon — $9.99 a pound versus $7.99 a pound — but is far less expensive than wild king salmon, which currently sells for $27.99 a pound. These prices are subject to seasonal fluctuations, notes Colleluori.

Wegmans gets the environmentally friendlier farmed king salmon from Marine Harvest, a British Columbian producer and so far the only farmed salmon supplier to meet these new guidelines. Wegmans will have farmed king salmon now through mid- or late May, and then availability will resume in December.

"Bon Appetit's first preference is and always will be for wild salmon. But they do support efforts in the aquaculture industry to improve," says spokeswoman Haven Bourque. She adds that it will probably be at least a year until that company starts making the farmed king salmon available to its clients.

At St. John Fisher College, salmon is offered about once a month, as it "does not have wide appeal to students," says Bon Appétit general manager Jim Liebow.

Meanwhile Wegmans is working to expand these purchasing standards to all its farmed seafood, including Atlantic salmon, shrimp, tilapia and trout.

"This is not just a program for Wegmans. We encourage all retailers to get involved," says Colleluori.