Sustainability advocates generally favor wild fish. Advocates for farm-raised (sometimes called "artisan aquaculture") fish say there is no difference. Farm-raised salmon is fed coloring agents to mimic wild salmon's deep color; its flesh is sometimes deemed softer and its flavor milder.
"We believe that a majority of aquaculture (fish farming) systems actually promote ecological destruction and further protein loss," states the Web site for sustainable table.org, an organisation devoted to sustainable food production. "Research shows that wild salmon are healthier for you and the environment, and are (more) environmentally friendly than farmed salmon.
Because salmon are carnivorous, requiring fish meal in their diet, each pound of farmed salmon requires between two and five pounds of wild fish. This means a net loss of marine resources. Moreover, scientists have found evidence of dioxin and PCB contamination in the fishmeal fed to farmed salmon, raising further food-safety concerns.
Salmon of the Americas, which represents salmon aquaculturists, counters on its Web site.
Ocean-farmed salmon are grown under carefully controlled conditions, with constant monitoring of growing conditions and production inputs. Every fish that's raised can be traced from the hatchery to the store where it is bought.
And continuous testing by Salmon of the Americas and others indicates that PCB limits in ocean-farmed salmon are almost equal to those found in wild salmon ...
Numerous independent research reports — including those by the Harvard School of Public Health and the National Academy of Sciences — have concluded that PCB levels in ocean-farmed salmon are not a cause for concern. "I prefer to buy wild salmon, myself," said Mike Shipp, seafood manager at a Chicago co-op. "But if we don't support the fish farmers and help them survive while they figure out how to do this better, we won't have any fish at all."
Source: Green Bay Press Gazette