Several groups are advocating against net-pen salmon farms in favor of wild salmon stocks due to pollutants and environmental concerns.

“That innocuous piece of salmon on your plate has a sordid history,” said Lauren Hornor, of Fraser Riverkeeper in Vancouver, British Columbia, Canada, co-creator of the Stand Up for Pacific Salmon (SUPS) campaign. “As citizens of the Pacific coast, we’re concerned about the impact our buying choices have on wild salmon.”

The group Fraser Riverkeeper is one of more than 20 Waterkeeper organizations from Alaska to California that launched the SUPS campaign in their watersheds. Using a cartoon, a documentary film and informational pamphlets, the groups are educating West Coast consumers about the impact of purchasing net-pen farmed salmon—and calling on the “Big Six” grocery retailers to remove the product from their shelves.

“Many people who care about the oceans and their own health have thought choosing farmed salmon was a sustainable and wise choice, but this is definitely not the case,” said Ms. Hornor. “Net-pen salmon farms are floating feedlots that have spread sea-lice, pollution, chemicals and infectious diseases into pristine habitats all around the world, including British Columbia and Washington, and are having a devastating impact on wild salmon stocks.”

The SUPS campaign asks customers of Costco, Safeway, Tesco, Kroger, SuperValu and Trader Joe’s to follow the example of their fellow retailer Target. In January the discount chain, on the advice of the Monterey Bay Aquarium’s SeafoodWatch program, dropped net-pen salmon from more than 1700 stores. “Consumers can turn the industry around, promoting major reform by voting with their wallets,” said Ms. Hornor. “This would not only help our oceans and wild salmon, it would lessen risks to human health.”

“Reforming the industry has been like trying to get tobacco companies to admit that cigarettes cause cancer,” said Tyee Bridge, co-creator of the SUPS program and a member of the BC-based volunteer group Wild Salmon Circle. “At one point the salmon farmers even hired the same PR agency used by Big Tobacco. They seem capable of doing anything to make consumers believe their product is sustainable, except actually becoming more sustainable by moving to closed-tank systems.”

Because of the presence of PCBs and other substances, the journal Environmental Research recommends that farmed salmon should be eaten no more than “between 0.4 and 1 meal per month.” This confirmed a similar 2005 study in the Journal of Nutrition, recommending that pregnant women, children and nursing mothers avoid farmed salmon because of high levels of pollutants.

Other concerns for consumers include the industry’s use of antibiotics and artificial coloring. “The truth about net-pen salmon is outrageous, and not all that appetizing,” said Mr. Bridge. “Without the orange and pink dyes put into their feed, for instance, farmed salmon flesh would be an unappealing shade of gray.”