Salmon is currently the fourth most consumed seafood in America, due mostly to the presence of salmon aquaculture facilities, or salmon farms. Farmed salmon has increased availability to the public. Nutritionally it is rich in omega-3 fatty acids, making it a heart-healthy protein source. Its cost is comparable to chicken, another reason for its popularity.
However, research suggests that salmon farming is not an efficient use of natural resources. Carnivorous fish such as salmon require a high protein diet. Several pounds of wild fish are required as feed to produce each pound of farmed salmon.
In general, salmon farms are most prevalent in the following countries: Norway, Netherlands, Chile and Canada. Interestingly enough, salmon are not native to Chile, or for that matter, the southern hemisphere. In 2003, five companies produced nearly half of the world’s farmed salmon; now that number is two.
Salmon farming is essentially the same regardless of location or type of salmon. Salmon eggs are hatched and raised in freshwater tanks on land for the first 12–18 months. Then the juvenile salmon, or smolts, are transferred to net pens or cages anchored in coastal waters and fed pelleted feed until they are mature in about two years.
Cages are usually comprised of nets supported by PVC or steel, depending on cost. Usually the mesh enclosures of salmon cages are not an effective barrier between the farm and the surrounding aquatic environment. This means that fecal waste, diseases, lice and farmed fish can escape into the surrounding water. Closed or recirculating systems have physical barriers in their operations and are significantly safer. They are, however, more expensive.
Consumers that are aware of the ecological impacts or controversy of salmon farming have turned to labeled farmed salmon as a better choice. Organic aquaculture standards have been developed in several countries, and aquaculture products certified to these standards and labeled as “organic” are appearing in American markets. While the USDA has started a process to develop organic standards of its own for seafood, it is likely to be several years before regulations are in place and USDA-certified organic seafood is available. But make NO mistake, these fish are not truly organic.
Wastes from salmon farms are discharged directly into the ocean, which is contrary to general organic practices that material should be recycled or re-used. Furthermore, salmon feed that depends on wild fish or fish by-products to make the feed pellets is unlikely to meet the standard for organic ingredients.
Major Concerns of Parasites & Diseases
Naturally, diseases and parasites appear at low levels, but they are a significant concern in fish farming practices, where they could become an epidemic. In fish farming, many fish are held in is a confined space. Such proximity not only poses a risk to the farm but also to nearby fishing areas. For example, a recent study has linked the spread of parasitic sea lice from salmon farms along a river in British Columbia to wild pink salmon in that river.
The ability of farmed seafood to taint wild populations was one of the top stories of 2008. When the North Atlantic’s stocks of fish neared collapse in the 1990s, consumers and conservationists thought that fish farming, raising pellet-fattened fish in net pens was the answer.
However, salmon farms were already known to weaken wild populations by exposing them to lice infestations, interbreeding with escaped farmed fish, and contaminants such as antibiotics, pesticides, and disinfectants.
A goal of closed-containment salmon aquaculture is to reduce the impacts associated with conventional net pen systems. Advantages include reduced escapes and disease transmissions as well as improved waste management. For these reasons, environmental groups, along with a few industry members, have advocated the use of closed containment systems.
While they may soften or eliminate ecosystem impacts, the materials and energy required by such systems have other environmental costs. In a closed water system, water recirculation technology is used to minimize costs and more than 99 percent of the water is reused. More than 99 percent of the fish wastes and phosphorous is reclaimed and processed to be used a fertilizer. Filtering is used to reduce the need for antibiotics and pesticides.