A genetics test has identified a fish caught near Kasilof as the first documented Atlantic salmon caught in Cook Inlet, the Alaska Department of Fish and Game reported Friday.
The fish was caught off Cohoe Beach on July 1 by a setnet fishermen, who noticed its unusually large scales one of several features that distinguishes Atlantic salmon from Pacific.
The fisherman, Joel Doner, said he did not immediately recognize the fish as an Atlantic salmon, but knew by its small mouth, X-shaped spots and other characteristics that it was not a Pacific salmon.
Although Alaska prohibits fish farmers from raising Atlantic salmon, nearly 600 fish of this exotic species have been documented in state waters, thanks to fish farms in neighboring waters. About one of every 100 Atlantic salmon raised on farms in British Colombia and Washington escapes, said Bob Piorkowski, the invasive species coordinator for Fish and Game.
“And they grow over 10 million salmon a year, so that would be about 100,000 fish,” he said.
Most escapements occur when storms damage netpens or when growing fish are transferred to larger net pens. The nets surrounding the larger pens have bigger gaps, and while most of the fish remain contained in the new netpen, some of the smaller fish escape.
Some of the worst escapements occurred in the late 1990s, resulting in large Atlantic salmon migrations into Alaska. In 1998, for example, 155 Atlantic salmon were caught in Alaska waters.
“Imagine how many more were caught and not turned in,” Piorkowski said.
Due to increased criticism and pressure from Alaska, neighboring aquaculture farms have tightened controls, reducing the number of escapes.
From 2003 to 2005, the number of documented Atlantic salmon in Alaska waters dropped to a three year total of eight fish. The Atlantic salmon caught by Doner is the first to have been documented in Alaska waters so far this year.
Even with escapement numbers down, however, controversy over the introduction of Atlantic salmon into the Pacific continues to boil.
Many worry Atlantic salmon in Pacific waters could spoil native salmon stocks through colonization, interbreeding, predation, habitat destruction and competition.
But in a debate that frequently pits Pacific salmon fishermen against salmon farmers, the controversy over the legitimacy of these concerns can be highly contentious.
Some researchers say that while the concerns are plausible, evidence is either weak or nonexistent.
A quick Internet search investigating problems caused by Atlantic salmon aquaculture might appear to support these concerns at first glance, said Andy Appleby, the former aquaculture coordinator for the Department of Fish and Wildlife in Washington.
But closer scrutiny reveals problems caused by Atlantic salmon farms have focused on the fish’s native territory in the Atlantic, rather than in the Pacific, he said.
Worldwide, the vast majority of farmed salmon are Atlantic salmon, a fact that has probably helped the Pacific aquaculture industry avoid some of the problems in the Atlantic, where farm escapees are more likely to survive, reproduce and wreak havoc in a habitat with which they are familiar, Appleby said.
“All of these things have been demonstrated, without a doubt, to have occurred in the Atlantic Ocean,” he said.
But while Atlantic salmon aquaculture in the Pacific may not reflect the troubles of its Atlantic counterpart, that doesn’t mean Pacific Northwest resource managers should ignore Atlantic salmon escapees any more than they would any other invasive species, Appleby said.
“No one has the luxury of saying we don’t care if it is a non-native species, most native species are not benign,” he said. “(And) caution should be the buzzword. At the same time, I think that it needs to be tempered with common sense and science-based evidence.”
Piorkowski, however, said evidence is likely to emerge slowly and that some already has, pointing to several British Colombia streams in which Atlantic salmon have successfully spawned.
Resource managers should think proactively rather than wait to see if problems will occur, Piorkowski said.
“We want to nip the problem in the bud,” he said. “It costs thousands of times more to deal with invasive species once they are established instead of preventing them in the first place,” he said.
To receive an Atlantic salmon identification card, or to report a fish suspected of being an Atlantic salmon, fishermen should call 1-877-INVASIV.
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