Escaped Atlantic farm salmon are successfully reproducing in at least one Northwest river, according to Canadian government documents released last week by the British Columbiabased David Suzuki Foundation. The Department of Fisheries report describes last month’s accidental discovery of a dozen one- and two-year-old juvenile Atlantic salmon in Vancouver Island’s Tsitika River. “[T]his appears to be the first verified report of successful reproduction of introduced Atlantic salmon, anywhere in the world,” according to a position statement from the Ministry of Fisheries. DNA and scale analysis confirmed the salmon were Atlantics and had not escaped from nearby hatcheries.
Fish farmers and government officials in Washington and British Columbia have long argued that Atlantic salmon raised in net-pen farms pose little threat because they are unable to survive in local rivers. However, as reported here two weeks ago (“Killer Fish,” 9/17), scientists and conservationists argue that continued escapes of farm fish increase the risk that some will successfully spawn and begin to colonize local watersheds.
In the past two years, more than 400,000 farm fish have escaped Puget Sound net-pen farms. British Columbia loses 60,000 Atlantics each year. Atlantic salmon have been spotted in all major Puget Sound drainages.
While Atlantic salmon compete with native fish and prey upon baby Pacific salmon, the greatest threat is from the spread of new diseases to native fish. Fisheries professor Carl Walters of the University of British Columbia says that diseases from net-pen farms may have played a role in the declines of native chinook and coho. “If they can establish themselves here,” warns David Hocking with the David Suzuki Foundation, “we see no reason they wouldn’t do it down there.”
But Atlantics haven’t established themselves, according to the Department of Fisheries. Though there’s “fairly strong evidence” the Tsitika River Atlantics have been naturally spawning for two years, there’s no evidence they’re capable of fulfilling a natural salmon life cycle, by migrating to the open ocean, then returning to spawn.
Canadian conservation groups are not content to wait for that to happen and have called for the closure of net-pen farms currently in use in British Columbia and Puget Sound. The call is echoed by Pete Knutson, representative of the Puget Sound Gillnetters Association. In light of developments in BC, he says, state officials must require land-based fish pens. Salmon farmers oppose such measures, saying it would shut down the industry.