Overfishing pushing salmon stocks near collapse, study warns

MARK HUME
Globe and Mail
December 3, 2008

VANCOUVER – Salmon stocks in British Columbia are on the brink of collapse largely because the federal Department of Fisheries and Oceans has consistently allowed too many fish to be killed in commercial and recreational fisheries, according to a new research paper.The high exploitation of stocks – which draws parallels with the destruction of Atlantic cod by overfishing – may be more to blame for the decline of Pacific salmon than global warming or poor ocean conditions, says the study assessing salmon management practices, published today by the Canadian Journal of Fisheries and Aquatic Sciences.

The researchers, from the Raincoast Conservation Foundation and the University of California, also conclude that DFO has been managing on the basis of biased data because it has stopped monitoring hundreds of streams with weak runs, choosing to focus on stronger runs only. As a result, managers have a flawed picture that suggests salmon stocks are much healthier than they really are.

The researchers said that based on the monitoring of 137 streams between 2000 and 2005, DFO found 35 per cent of salmon runs in northern B.C. were classified as depressed. But an assessment based on 215 streams that included weak stocks rated 75 per cent of runs as depressed.

“The lack of information [fisheries managers have] is troubling,” said Misty MacDuffee, one of three biologists on the research team.

“The precautionary approach has to be at the forefront of fisheries management … but not having accurate information will lead to overfishing, as it did with Atlantic cod,” she said.

The paper examined data over a 55-year period in order to evaluate DFO’s effectiveness in hitting escapement targets. Escapement targets refer to the number of salmon that escape commercial, recreational and native food fisheries to make it to the spawning grounds. Escapement targets are considered the bottom line in fisheries management and are used to justify fishery catch limits.

If an adequate number of fish are allowed to spawn, the rest are considered surplus and can be caught in commercial, sport or native food fisheries.

But the research paper, “Ghost runs: management and status assessment of Pacific salmon returning to British Columbia’s central and north coasts,” found that since 1950 DFO has failed to reach escapement targets 50 per cent of the time.

And during the 2000-2005 period, chum, sockeye and chinook runs failed to hit escapement targets up to 85 per cent of the time.

“Data … which span nearly six decades, show that management has repeatedly not met DFO’s own target levels. This resulted in diminished runs for all species in nearly every decade,” the researchers state.

“Although climate and ocean survival likely play substantial roles, multiple lines of evidence suggest that over exploitation may be the greatest cause of salmon declines across the Northeast Pacific,” they say.

The researchers say cutting catch rates can have dramatic results and they note some stocks that recovered when fishing over-exploitation was stopped.

The researchers were Michael Price, Nicola Temple and Ms. MacDuffee, all staff biologists with Raincoast, a B.C. non-profit organization, and Chris Darimont, Department of Environmental Studies, University of California.

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