Dying fish had twice the sea lice
SFU study: 'One more solid piece of evidence' that lice from farms kills salmon Research links listless, dying salmon to
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By Jonathan Fowlie
Published: Monday, January 16, 2006
Researchers say the discovery that listless, dying young salmon had more than twice the sea lice of healthy ones provides more direct evidence than ever before that sea lice from fish farms are killing salmon.
"What it really represents in my mind is one more solid piece of evidence pointing to the fact that sea lice from fish farms kill young wild fish," Rick Routledge, Simon Fraser University researcher and member of the university's Centre for Coastal Studies, said on Sunday.
"To date, all we have had in terms of the ability of the lice to kill fish are data coming back from adult [salmon] returns that show in the years where there were a lot of sea lice on the fish, the returns were very small," he said.
Routledge and fish biologist Alexandra Morton, who co-authored a research paper on the issue, made their discovery about the number of sea lice on dying young fish when they looked at juvenile pink and chum in the Broughton Archipelago.
Routledge said the young fish are exposed to sea lice as they pass fish farms there on the way from spawning grounds out to sea.
"Fish farms are crowded just like a human refugee camp and they are an ideal breeding ground for fish lice," he said.
Routledge and Morton co-authored a research paper on the issue for the Jan. 5 edition of The North American Journal of Fisheries Management.
Mary Ellen Walling, executive director of the British Columbia Salmon Farmers Association, said on Sunday that Routledge and Morton's research reflects the polarization of scientific opinions on aquaculture issues.
"What we have is one group of scientists, including [Department of Fisheries and Oceans] scientists saying one thing, and then we have a very polarized debate from the environmental community saying something that is completely the opposite," she said.
Walling said she is hopeful about last week's announcement that the salmon farming company Marine Harvest Canada and environmental groups allied under the banner of the Coastal Alliance for Aquaculture Reform have teamed up to resolve conflicts over the potential threat that fish farms pose to B.C.'s wild salmon populations.
In their research, Routledge and Morton also said their results cast doubt on the Department of Fisheries and Oceans's current method for assessing the health of salmon once they've passed the farms.
In an interview, Routledge said DFO has been using a method that essentially compares the weight of those fish to that of healthy fish to determine whether they are suffering ill effects from the lice.
"It's like going to the doctor with your kid who's got a big infestation of body lice or head lice and the doctor weighs the kid and says 'He isn't losing weight yet; he must be fine,' " he said.
Routledge said his research with Morton showed the affected fish do not lose weight until shortly before they become listless, and the fish die shortly after they show signs of a problem.
"It's time the DFO stopped using this superficial examination as evidence they have looked for evidence of health problems and not found any," Routledge said
.
On Sunday, DFO spokeswoman Deborah Phelan said the department has been conducting its own research in the Broughton Archipelago for the past three years, and the results will be ready within the coming months.
She said no scientists were available on the weekend to comment on Routledge and Morton's findings, or concerns about DFO methods of gauging salmon's health.
Routledge called for a halt to fish-farm expansion in the area, and for the government to make changes so young fish don't have to pass by farms on the way out to sea.
jfowlie@png.canwest.com© The Vancouver Sun 2006
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Topic: Sun article on sea lice (Read 1421 times)