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.
© The Vancouver Sun 2006