Mackerel Wreaking Havoc With Salmon
Hard-hit Pacific salmon stocks are being dealt yet another devastating blow.
Schools of voracious mackerel have invaded British Columbia waters on a warm El Nino current just as millions of smolts are moving out to sea.
“It may already be too late,” one fisheries biologist said. “They may already be gone and there’s nothing we can do. The fish that are supposed to return for three years starting in the year 2000 already may have been wiped out.”
The mackerel were spotted off the San Juan Islands two weeks ago. Now they are being reported off the west coast of Vancouver Island as far north as Cape Scott.
“This is really bad news. They are like vacuum cleaners,” said Ray Volk of the Robertson Creek hatchery near Port Alberni on Vancouver Island.
“It could be devastating.”
Volk says he fears that most of the just-released 8.3 million chinook, 800,000 coho and 120,000 steelhead smolts have been eaten.
Sport fishermen say the mackerel are gobbling up smolts, newly spawned herring and the tiny shrimp that fish feed on.
“We’ve even found mackerel that have been eating wood chips that were floating in the water,” said Dennis Chalmers of the Canadian Ministry of Fisheries and Oceans.
“We’ve got some test boats out there now. It is a potential crisis.”
Chalmers says he hopes against hope that the mackerel, normally found off California, are localized schools rather than a coastwide invasion.
Isolated schools could be caught by seine boats, but that has its own dangers. The nets may scoop up mature returning salmon that are just recovering from El Nino mackerel invasions in 1992 and 1993.
Those invasions cost the commercial fishery an estimated $70 million and the sport-fishing industry an estimated $250 million and 2,000 jobs.
A similar invasion in 1982 and 1983 almost wiped out salmon stocks from three hatcheries and hundreds of streams and rivers on the west coast of Vancouver Island.
Volk said only 0.01 per cent of fish from the Robertson Creek hatchery returned to spawn in the 1982-83 season.
The only good news this year is that sockeye smolts from lakes in the British Columbia Interior may have made it to the ocean before the mackerel moved in.
Marine biologist Howard Freeland of the Institute of Ocean Sciences said the warm current that brought the mackerel is part of the “spectacular changes in the climatic conditions” along the west coast of North and South America in recent weeks.
“What started out as a gentle warming trend has become ferocious,” he said.
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