Conservation News
Five Reasons Not to Buy Farmed Salmon
By Dougald Scott
Five Reasons Not to Buy Farmed Salmon
By Dougald Scott
Fresh, farmed salmon has been in local markets for a number of years now. Not only is it available year around, it is usually cheaper than wild caught salmon. I've got to admit, it's awfully nice to be able to serve fresh salmon through the winter months. Unfortunately, there is a price to pay.
Parasites from farmed fish harm wild fish
Farmed salmon are raised in vast networks of floating pens, usually located in bays or inlets in major migration corridors for juvenile wild salmon. Parasitic crustaceans known as sea lice are normally found in wild populations of Pacific salmon. They normally attach to adult fish, and usually donŐt cause major physical damage. In contrast, sea lice have always been rare in juvenile salmonŃat least, until the advent of salmon farming. Unfortunately, sea lice can be life-threatening to juvenile fish.
In migration corridors where there are no salmon farms, adult salmon are scarce at the time juveniles are in their out-migration, and have very little chance for infection by sea lice. On the other hand, juveniles who must migrate past salmon farms in their journey to the open ocean are placed in close proximity to massive numbers of infected adult salmon. Recent scientific studies have clearly shown greatly increased infection and mortality in these areas. Juvenile pink and chum salmon seem to be the most vulnerable. It is not uncommon to find juvenile pink and chum salmon with more than a dozen sea lice attached to them. This number would be of little consequence to an adult, but it greatly impairs the chances of survival of a four inch juvenile.
Pollution
Farmed fish are crowded into pens and fed food pellets consisting mostly of fish meal. As with other farming enterprises where animals are raised in densely packed conditions, disease becomes a problem, and massive doses of antibiotics are necessary to combat the diseases. The sources of chemical pollution from salmon farms include antibiotics and other medications, feed additives, anti-parasitics, paints and anti-foulants used on net cages and boats to prevent marine growth, and disinfectants. In 2003, almost 30 tons of antibiotics were used in British Columbia salmon farms.
The main source of organic pollution from salmon farms is fish excrement and uneaten feed. The amount of feces produced by farmed salmon can vary depending on feed formulations. Studies show that 25 - 50 % of the dry feed consumed can end up as feces. Other contributions to organic waste are from fish mortalities that sink to the seabed, and fish blood from farms that harvest and bleed fish on site. Wild fish are spread out over large areas, and the effect of their excrement is actually beneficial to the environment. It is when the excrement is concentrated in a small area that environmental damage ensues.
Introduction of non-native species
In British Columbia most of the salmon farmed are Atlantic salmon. Escaped farmed salmon compete with wild salmon and steelhead for habitat and food, thereby putting wild stocks at increased risk. A total of 556 Atlantic salmon have been caught in Alaskan waters to date. No salmon farms exist in Alaska and the nearest BC farm is over six hundred miles to the south. One Atlantic salmon was even caught in the Bering Sea. The most disturbing catches and sightings of Atlantic salmon in BC have been those of freshwater juveniles produced by escaped Atlantic salmon breeding in the wild. On the Northeast coast of Vancouver Island, a recent study reported 153 such juveniles between 1998 and 2000.
"As these Atlantic salmon colonize these rivers, they are taking up space. It's an ecological ratchet. Every time a square yard is turned over to the Atlantic salmon, that square yard is not available to the Pacific steelhead - they've lost their habitat." Canadian fisheries ecologist Dr. John Volpe.
Depletion of other fish stocks
Salmon are carnivores. In order to produce 1 pound of farmed salmon, from 2 to 4 pounds of other fish proteins are fed to them in the form of fish meal. Sardines, anchovies and herring from developing countries are the main ingredients of the fish meal. This use of edible protein by the aquaculture industry represents a net loss of proteins available for human consumption. In addition, the fishing methods and sustainability of the fisheries providing the fish meal are questionable. From the standpoint of world food supply and fisheries stocks, feeding fish meal to farmed salmon is not a good idea.
Nutrition and health concerns
In a 2004 study published in the journal Science, researchers found that farmed salmon have significantly higher levels of PCBs, dioxins, and dieldrin than wild salmon from the same areas. The source of the contaminants, as many researchers suspected, is the feed.
After comparing toxin amounts in wild and farmed salmon against EPA health guidelines, the researchers made these recommendations:
* People should eat farmed salmon no more than once a month to avoid risk from the cancer-causing toxins they contain.
* It is safe to eat as many as eight meals of wild salmon a month.
Alternatives
What can you do to avoid farmed salmon and still enjoy a succulent salmon treat? First, catch the fish yourself! Monterey Bay provides a thriving sport fishery for Chinook salmon from May through September. Many club members have boats and frequently fish for salmon. If you want to get connected, run a notice in the "Hook-Ups" column of the newsletter. The next best thing is to buy fresh, locally caught salmon in the market. The local commercial salmon fishing season varies from year to year, depending on conditions, but generally it is from late spring to early fall. Always ask the market if the fish you are buying is wild caught. Finally, if it's the middle of January (just like now), and you really want that salmon meal, buy fresh frozen wild salmon. Admittedly, frozen will never match fresh, but this is still a better alternative to farmed salmon.