December 14, 2007 - SFB Staff — Canadian researchers have new evidence that sea lice originating from British Columbia salmon farms are threatening nearby wild pink salmon runs at a rate fast enough to drive them to extinction within four years.

In a study to be published in today’s edition of the journal Science, researchers found that pink salmon north of Vancouver Island have shown harmful effects of parasitic infestation of sea lice brought on by the increased density at salmon farms. The study used a computer model to analyze pink salmon runs in 64 rivers without exposure to salmon farms and seven rivers where young fish migrate past at least one salmon farm.

“We’ve seen sea lice infestations on juvenile salmon in Norway, Ireland, Scotland and Canada, but it’s been unclear and very contentious what the impact of the sea lice is on the wild salmon population,” said Martin Krkosek, lead author of the study and a doctoral candidate at the Center for Mathematical Biology at the University of Alberta.

“What’s really new and exciting about this paper is this is the first time scientists have had enough detailed data to actually measure the impact of sea lice on wild salmon populations,” he said.

Brian Ridell, head of the salmon science branch for Canada’s Department of Fisheries and Oceans, told the Associated Press that the study overstates the risks of salmon farms.

“They are asking us to believe 80 percent mortality is from one source,” he said. “That’s simply unrealistic.”

The study was financed primarily by the Canadian Natural Sciences and Engineering Research Council.