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Parasitic lampreys feed on bumper sockeye run
Eel-like species has targeted large schools of Fraser River salmon in the past
BY LARRY PYNN, VANCOUVER SUN AUGUST 30, 2014
Parasitic lampreys feed on bumper sockeye run
Sockeye salmon caught in an aboriginal commercial fishery on Kamloops Lake are showing extensive signs of lamprey bites.
The parasitic Pacific lamprey is taking a bite out of the estimated more than 21 million sockeye returning to the Fraser River this year — a bumper harvest but short of the unexpectedly high returns of 2010.
The latest median return estimates released Friday by the Pacific Salmon Commission include runs of 1.9 million early-summer sockeye, seven million summer, and 12.73 million late-summer, including the Adams River run. The early Stuart run also yielded more than 200,000 sockeye.
It’s possible the late-run estimate will be lowered next week to as much as nine million.
In 2010, the last four-year cycle for this sockeye run, a total of 28.3 million fish returned to the Fraser system, the largest in a century.
But sockeye are showing up this year with chunks taken out of their bodies, raising concerns about the lamprey’s impact on the spawning migration.
Rick Jeffries, a former commercial fisherman who is in charge of marketing a Secwepemc aboriginal commercial fishery in Kamloops Lake, said more than 50 per cent of the sockeye have bite marks, some with multiple bites cutting right to the flesh.
“We’re alarmed at what we’re seeing,” he said in an interview Friday. “These are significant wounds that must adversely influence the sockeye’s probability to survive.”
Lamprey are also being observed in the Strait of Georgia, including commission test fisheries. “They’ve pulled in sockeye with lampreys still attached,” confirmed Mike Lapointe, the commission’s chief biologist. “There’s obviously a body of them out there, and they’re taking advantage of this big group of fish.”
The Pacific lamprey is a native species and has been known to target big schools of sockeye in the past.
A study by the International Pacific Salmon Fisheries Commission in 1967 estimated that 67 per cent of sockeye headed for the Adams River had been attacked by lampreys in the lower Fraser and “six per cent bore wounds classed as severe.”
On the Adams River spawning grounds, many of the wounds showed signs of healing. An estimate of less than two per cent of the Adams River sockeye died during their river migration due to lampreys, although the study notes that mortality may have been higher earlier in the Strait of Georgia.
Lara Sloan, spokeswoman for the federal fisheries department, confirmed that sockeye in the Thompson River system this season have been caught with circular markings that could be from lampreys, but the exact cause cannot be confirmed without testing.
Sloan added that Lampreys “are not unusual in this area” and that a school of them had been observed below the Bridge River rapids, near Lillooet.
As adults in the ocean, Pacific lampreys are parasitic and feed on the body fluids and blood of marine fishes, according to the U.S. Fish and Wildlife Service. After spending one to three years in the marine environment, lampreys stop feeding and migrate back to freshwater from February to June. They overwinter in fresh water until they spawn the following year between March and July. After spawning, lampreys die within days.
The arrival of lamprey is not the only curiosity about this year’s salmon runs.
More than 95 per cent of the sockeye are migrating through B.C.’s Inside Passage rather than offshore Vancouver Island, making fewer available to U.S. fishermen and with no way under the Pacific Salmon Treaty for them to make up the losses.
The latest commission statistics show that Canada has caught about five million Fraser-bound sockeye (commercial, aboriginal and recreational sectors) compared with about 275,000 fish for the Americans. One theory is that warm ocean temperatures in January through March this year may have pushed the sockeye further up the Gulf of Alaska, Lapointe said. As they migrated back, they may have just followed the coast and avoided outer Vancouver Island.
The commission’s Fraser River Panel will meet again on Tuesday to reassess returns and fishing times.
lpynn@vancouversun.com
© Copyright (c) The Vancouver Sun
Read more: http://www.vancouversun.com/Parasitic+lampreys+feed+bumper+sockeye/10161652/story.html#ixzz3CBH42S6p
Parasitic lampreys feed on bumper sockeye run
Eel-like species has targeted large schools of Fraser River salmon in the past
BY LARRY PYNN, VANCOUVER SUN AUGUST 30, 2014
Parasitic lampreys feed on bumper sockeye run
Sockeye salmon caught in an aboriginal commercial fishery on Kamloops Lake are showing extensive signs of lamprey bites.
The parasitic Pacific lamprey is taking a bite out of the estimated more than 21 million sockeye returning to the Fraser River this year — a bumper harvest but short of the unexpectedly high returns of 2010.
The latest median return estimates released Friday by the Pacific Salmon Commission include runs of 1.9 million early-summer sockeye, seven million summer, and 12.73 million late-summer, including the Adams River run. The early Stuart run also yielded more than 200,000 sockeye.
It’s possible the late-run estimate will be lowered next week to as much as nine million.
In 2010, the last four-year cycle for this sockeye run, a total of 28.3 million fish returned to the Fraser system, the largest in a century.
But sockeye are showing up this year with chunks taken out of their bodies, raising concerns about the lamprey’s impact on the spawning migration.
Rick Jeffries, a former commercial fisherman who is in charge of marketing a Secwepemc aboriginal commercial fishery in Kamloops Lake, said more than 50 per cent of the sockeye have bite marks, some with multiple bites cutting right to the flesh.
“We’re alarmed at what we’re seeing,” he said in an interview Friday. “These are significant wounds that must adversely influence the sockeye’s probability to survive.”
Lamprey are also being observed in the Strait of Georgia, including commission test fisheries. “They’ve pulled in sockeye with lampreys still attached,” confirmed Mike Lapointe, the commission’s chief biologist. “There’s obviously a body of them out there, and they’re taking advantage of this big group of fish.”
The Pacific lamprey is a native species and has been known to target big schools of sockeye in the past.
A study by the International Pacific Salmon Fisheries Commission in 1967 estimated that 67 per cent of sockeye headed for the Adams River had been attacked by lampreys in the lower Fraser and “six per cent bore wounds classed as severe.”
On the Adams River spawning grounds, many of the wounds showed signs of healing. An estimate of less than two per cent of the Adams River sockeye died during their river migration due to lampreys, although the study notes that mortality may have been higher earlier in the Strait of Georgia.
Lara Sloan, spokeswoman for the federal fisheries department, confirmed that sockeye in the Thompson River system this season have been caught with circular markings that could be from lampreys, but the exact cause cannot be confirmed without testing.
Sloan added that Lampreys “are not unusual in this area” and that a school of them had been observed below the Bridge River rapids, near Lillooet.
As adults in the ocean, Pacific lampreys are parasitic and feed on the body fluids and blood of marine fishes, according to the U.S. Fish and Wildlife Service. After spending one to three years in the marine environment, lampreys stop feeding and migrate back to freshwater from February to June. They overwinter in fresh water until they spawn the following year between March and July. After spawning, lampreys die within days.
The arrival of lamprey is not the only curiosity about this year’s salmon runs.
More than 95 per cent of the sockeye are migrating through B.C.’s Inside Passage rather than offshore Vancouver Island, making fewer available to U.S. fishermen and with no way under the Pacific Salmon Treaty for them to make up the losses.
The latest commission statistics show that Canada has caught about five million Fraser-bound sockeye (commercial, aboriginal and recreational sectors) compared with about 275,000 fish for the Americans. One theory is that warm ocean temperatures in January through March this year may have pushed the sockeye further up the Gulf of Alaska, Lapointe said. As they migrated back, they may have just followed the coast and avoided outer Vancouver Island.
The commission’s Fraser River Panel will meet again on Tuesday to reassess returns and fishing times.
lpynn@vancouversun.com
© Copyright (c) The Vancouver Sun
Read more: http://www.vancouversun.com/Parasitic+lampreys+feed+bumper+sockeye/10161652/story.html#ixzz3CBH42S6p
