Study links lice to wild salmon
Researcher calls for more stringent regulation
Ashley Ford, The Province
Published: Wednesday, March 15, 2006
It's a lice theory, but will it hold water?
The ongoing debate between the marine farming industry and various researchers, scientists and environmentalists over the impact of B.C. fish farms on wild salmon populations is about to be notched up to a new level with a new study claiming that it provides "direct evidence" that sea lice, which have been linked to fish farms, are killing juvenile migrating wild salmon in B.C.'s Broughton Archipelago.
The study, co-authored by SFU researcher Rick Routledge and biologist Alexandra Morton of the Raincoast Research Society, was published March 3 in the Alaska Fishery Research Bulletin.
The study "provides direct evidence and a simple explanation for recent, major declines in pink and chum returns to the area," Routledge says in an interview in SFU News.
"Namely, that a large fraction of the out-migrating juvenile salmon were killed by the heavy lice infestations reported on them.
"The evidence further shows that these tiny, scale-less juvenile pink salmon are substantially more vulnerable to lice infestations than are the juvenile Atlantic salmon that European scientists have been studying."
While agreeing there needs to be further research, Routledge suggests "to protect more vulnerable Pacific species more stringent regulations are needed than the existing European standards, which are designed to protect larger, less vulnerable [farmed] Atlantic salmon."
Routledge did not return The Province's call.
Mary Ellen Walling, executive director of the B. C. Salmon Farmers Association, said in a telephone interview from Boston, where she is attending the Boston Seafood Show, that she had not seen the study but "we are certainly interested in good science."
"In the Broughton Archipelago, we are seeing healthy returns of pink salmon," she said. The industry, which now exports $400 million of farmed product a year, B.C.'s largest food export, wants to see strong wild salmon runs, Walling added.
She also said it is a very complex matter that various scientists and groups are wrestling with.
The industry employs 4,000.
But, she added, lice infestation in the industry has been low and is constantly monitored by the B.C. government.
"From an industry perspective we have low infection rates from lice," she noted.
Routledge and Morton also question the federal fisheries methods of appraising wild salmon once they have passed salmon farms.
The method, called the Fulton Condition Factor, uses the weight of a healthy fish as a baseline for determining whether a fish has lice, on the theory it will become progressively more emaciated and listless as it is attacked by more lice.
The pair say they have found affected fish don't lose weight until shortly before they show indications of being sick.
But any definitive action or agreement would seem far off. A B.C. government special committee on sustainable agriculture, struck to look at open-net pen salmon farming, is not due to report its findings until 2007.