Sea Lice From Fish Farms May Wipe Out Wild Salmon

December 13, 2007

Four years from now wild pink salmon may vanish from Canada's Broughton Archipelago, a new study warns.

The killers, according to the research, are sea lice from fish farms.

Scientists previously demonstrated that juvenile wild pink salmon often catch lethal sea lice infestations when they swim through areas where salmon are raised in open-net farms.

Now for the first time researchers have used a data-driven model to calculate the impact on the wild salmon population.

"It's severe," said Martin Krkosek, a fisheries ecologist at the University of Alberta in Edmonton, Canada, who led the study.

(Krkosek is a National Geographic Society Expeditions Council grantee. The National Geographic Society owns National Geographic News.)

According to the data, the current rate of decline will take the salmon from their historical abundance to extinction in eight years, or four generations. The decline started two generations ago.

"We're halfway there," Krkosek said. "There's only two generations left before these fish are gone."

But a fish-farming industry representative said the analysis is flawed, and a university scientist said the conclusion reaches too far.

The stakes for the industry are high, noted another university scientist independent of the study—the findings could shut it down.

Exposed vs. Unexposed

Sea lice are naturally occurring parasites that latch on to mature fish in the open ocean and feed on their skin and muscle tissue.

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