A study by a British Columbia researcher suggests sea lice generated by open-net salmon farms can be just as deadly to larger fish as they are to juveniles.
The study, conducted by Simon Fraser University doctoral candidate Brendan Conner, shows sea lice can transfer from infested salmon fry to coho salmon or cutthroat trout that prey upon them.
The study, published in the online science journal Biology Letters, showed lice on juvenile salmon held in ocean enclosures in British Columbia's Broughton Archipelago transferred to predatory larger fish roughly 70 percent of the time.
Watershed Watch Salmon Society executive director Craig Orr told the Canadian Press that this is the first study proving sea lice can be transmitted up the food chain.
Another study, published in the April issue of the North American Journal of Fisheries Management, indicated that sea lice are damaging juvenile sockeye salmon and Pacific Herring.
Sea lice research in recent years has focused on the Broughton Archipelago, a B.C. region heavily concentrated with salmon farms. Many of Canada's abundant and economically valuable wild salmon and Pacific herring stocks migrate through the area, which is the chief cause of concern for environmentalists.
Late last year, a group of scientists and researchers including activist David Suzuki and National Geographic Society explorer-in-residence Wade Davis wrote an open letter to Canadian Prime Minister Stephen Campbell urging him to stop the threat that sea lice from fish farms pose to wild salmon.
Sea lice, however, occur naturally in the oceans, and critics of the studies argue that wild salmon are the source of lice, not farmed fish.
