SEE ALSO: King Salmon in Search of a Future

Can Salmon Farmers Clean up Their Act?

IN SCOTLAND, RUNS OF WILD SEA TROUT recede, weakened by a debilitating parasite, the sea louse. The source: salmon pens, where sea lice multiply among captive salmon.

Coastal fishermen around the world are becoming increasingly concerned about the threat salmon farms and other forms of marine aquaculture pose to their stocks (see Coast & Ocean, Summer 1998). Some governments that once encouraged this industry are now having second thoughts.

Fish farmers, like their land-based counterparts, use antibiotics to control disease outbreaks. Heavy drug use can cause bacteria to develop resistant strains. A 1998 report by the National Research Council, The Use of Drugs in Food Animals, found that such strains can be passed from food animals, including fish, to humans. The number of cases of human sickness linked to such transfers is low, but the report warns that much more research is needed to determine the public health risks.

Salmon farm pens in Puget Sound, Washington State

Atlantic salmon that escape from pens pose more than just a disease threat to native stocks. Arthur Whitely, a zoologist with the University of Washington, has been predicting since 1990 that escapees from pens in Puget Sound and British Columbia would compete with native stocks for food and habitat. Consultants retained by salmon farmers ridiculed Whitely as an eco-crank. But by 1996, Atlantic salmon had been found in 30 streams, dining on wild salmon eggs and other natural fare. Not to worry, responded the consultants: the aliens would not reproduce and would die off. On September 23, 1998, the Vancouver Sun reported that 12 juvenile Atlantic salmon had been found in the Tsitika River on Vancouver Island - the first firm evidence of successful reproduction in the wild. With 60,000 Atlantic salmon escaping from pens in British Columbia each year, this region now has a voracious pest, another threat to declining native salmon stocks.

Coastal fishermen also worry about fallout from other practices. Captive salmon, shrimp, and other farmed marine species are fed protein-rich fishmeal produced from sardines and other small fish - the very same small fish that wild fish, seabirds, and many marine mammals subsist on. During the 1997-98 El Niño year, when warm temperatures depressed populations of small fish off Chile and Peru, salmon farmers shifted to vegetable proteins. But this resulted in inferior fish with a gelatinous texture.

Because of these and related concerns, British Columbia has placed a ban on new salmon farms while it assesses the need for stronger controls. Washington State has classified escaped farmed salmon as a "living pollutant" that must be regulated. Up to 300,000 salmon a year have escaped in Washington.

Some coastal states have concluded that the environmental risks posed by pen culture can never be adequately controlled. Alaska, Oregon, and California do not permit commercial salmon farming in pens. In British Columbia, the Sierra Club Legal Defense Fund and Greenpeace want to ban pens from coastal waters and require that salmon be raised in "tank farms," closed systems on land.

The aquaculture industry claims such bans are instigated by commercial fishermen to shut out seafood competitors. But some members of the industry think it's time for serious reforms. Some salmon farmers in New Zealand and Europe certify their crop as organic - stocking lower densities without drugs or pesticides. A United Nations agency, the Food and Agriculture Organization, has developed guidelines for sustainable aquaculture which include these key points: no more loss of natural habitat, and more reliance on closed systems and on farm fish that do well on vegetable proteins, such as catfish, tilapia, and mollusks.    --WM