Four miles off the shore of Anacortes, the American Gold Seafoods fish farm is the floating home of 600,000 salmon living in eight square net pens, 30 feet deep. Grated metal walkways form a connecting path between and around each pen. The fish have been there for 14 months and are approximately 9 pounds. In 2001, U.S. consumers purchased nearly 165,000 metric tons of farmed salmon like these.
In the late 1990s, the United States produced approximately 33 million pounds of farmed salmon. “Essentially, a salmon farm, just like a chicken farm, is a factory unit with the whole process becoming chemically dependent,” said Don Staniford, a campaigner for Friends of Clayoquot Sound in Canada, an organization against the expansion of fish farms. Staniford has studied the chemicals used in fish farms in Scotland, Ireland, Spain, Australia, New Zealand and Chile.
He said farms use five chemical categories to raise and treat the fish: antiparasitics, antibiotics, artificial colorings, disinfectants and antifouling agents, which come primarily in the form of copper- or zinc-based paints used on the nets to prevent the growth of marine organisms such as mussels and barnacles.
During salmon production, farmers used approximately 25,143 to 41,905 pounds of antibiotics, according to a 2002 report by Dr. Charles Benbrook of the Northwest Science and Environmental Policy Center in Idaho.
Farmers use saltwater cages for the controlled harvesting of primarily Atlantic salmon. Farmers first raise the salmon in freshwater hatcheries at the farm site, and when the fish reach the proper age and size, the farmers transport them to the farms’ near-shore saltwater cages. Here the salmon live for 18 months until harvested.
Staniford said chemical seepage is one of his main concerns. Anything discharged into the pen will flow directly into the natural environment around the pen, affecting other marine species.
The uptake rate for antibiotics in salmon is 30 percent to 40 percent, which means the majority of the antibiotics end up directly in the water column. Because of this, chemicals the farmers use might alter the microbial and marine community around the farm, according to the David Suzuki Foundation, a Canadian environmental organization.
According to the foundation, antibiotics such as oxytetracycline have been shown to reduce the number of bacteria in the sediment around farms and reduce the ability of these organisms to recycle nutrients, reducing the conversion rates of sulphates and nitrates surrounding fish farms.
To control contamination, the Food and Drug Administration has a list of approved drugs for aquacultural use. Each state also has its own regulations, typically more strict than the FDA regulations. The Washington State Department of Ecology has approved the discharge of two antibiotics: oxytetracycline and sulfadimethoxine, which must be administered in the fish feed.
Kevin Bright, regulatory permit coordinator at American Gold Seafoods, said the company uses two chemicals on its salmon farm, one of which is oxytetracycline.
Antibiotic use is kept to a minimum to avoid high costs of the drugs and to avoid breeding resistant bacteria, Bright said. Typically, less than 2 percent of the feed used in one year contains antibiotics. Some years it’s less than 1 percent.
“I want to keep these fish as pure as possible,” Bright said.
Canada also prevents the use of premedicated feed in fish farms, said Mary Ellen Walling, executive director of the British Columbia Salmon Farmers Association. Unlike terrestrial farms, in which farmers can buy feed with medication already included, veterinarians must specifically prescribe medication for individual fish farmers who then have the antibiotics milled into the feed. Overall, less than 3 percent of feed used in British Columbia each year contains antibiotics, Walling said.
Along with antibiotics, salmon farmers use a chemical dye in the feed to turn the salmon’s flesh pink. Wild salmon get their pink color from their diet, mostly from eating krill, which contain a natural pigment called astaxanthin. Farmers use a synthetically produced version of this pigment to turn the farmed fish pink because they don’t get the color naturally in their diet.
The FDA also has approved the use of canthaxanthin as a dye. This chemical has some possible health risks, reportedly contributing to eye defects; however, according to an FDA study, an adult would have to eat almost 55 pounds of salmon every day to experience these problems.
Because of the risks and concerns, the United States has regulations in place to prevent contamination of the environment and reduce threats to human health from chemicals.
The only U.S. salmon farms are in Washington state and Maine. To meet consumer need, the United States imports approximately 70 percent of its seafood. Nearly 59 percent of its Atlantic salmon imports come from Chile.
Other countries, however, do not have the same regulations the United States has regarding aquaculture. In his contribution to the book “A Stain Upon the Sea,” Staniford lists Chile, Norway, Scotland and Canada as the worst four countries in the business, along with the Faroe Islands, a Danish possession north of Great Britain.
According to the Living Oceans Society, a fish farm in British Columbia confirmed the use of malachite green in its farmed salmon. Used as a fungicide and antiparasitic, malachite green is a banned substance in the United States and Canada and a suspected carcinogen. The chemical has been linked to tumors, birth defects and skin and eye injuries, Staniford said. The chemical has been detected in farmed fish from Chile, Scotland and several European nations as recently as 2003.
In four to six months the salmon at Bright’s farm will be ready for harvest and sale. In the last two months, they switched color additive to an all-natural yeast formula instead of the synthetically produced astaxanthin, allowing them to label the fish as naturally pigmented instead of as “color added.” Changes like this are numerous in the aquaculture industry. As long as consumer demand for salmon continues to rise, environmentalists and aquaculture farmers will have to work together to make the best and safest product available to customers.