It isn't just Yahoo News and at the end it says a UW professor said the same thing. I made it red. I still don't understand at all how that could hurt wild salmon.
http://seattlepi.nwsource.com/local/343 ... mon14.html
Last updated December 13, 2007 9:32 p.m. PT
New evidence fish farms hurt wild salmon
Sea lice threaten to wipe out runs, researchers say
P-I STAFF AND NEWS SERVICES
Researchers have new evidence that as the density of salmon farms increases, they can drive nearby wild salmon runs to extinction.
The problem is sea lice, a natural parasite that normally attaches to adult salmon with little ill effect and has little contact with vulnerable juvenile salmon. All that changes, however, when fish farms move in.
A study in the journal Science on Friday shows that sea lice infestations around salmon farms in British Columbia's Broughton Archipelago have reached a density so high they could completely wipe out pink salmon in rivers where migration routes cross ocean-based farms. Fish numbers in those waters have already dropped by more than 80 percent.
"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."
In Washington there are Atlantic salmon pens near Anacortes, in Skagit Bay, near the south end of Bainbridge Island, and at Port Townsend.
For an unknown reason, sea lice numbers have stayed low in pens in Puget Sound, said Dan Swecker, state senator and a spokesman for the Washington Fish Growers Association, an industry group.
"We've never had a problem with it here," he said. "It's so few and far between we don't do anything. We ignore it here."
Swecker and others questioned whether it was fair to blame the fish deaths on sea lice.
"The sea lice infestations go up and down and so do survival of the salmon," said Walt Dickhoff, a division director for the Pacific Northwest Fisheries Science Center in Seattle, who read the study.
"There are so many factors in there, it's hard to say it's the sea lice," he said.
Principally funded by the Canadian Natural Sciences and Engineering Research Council, the peer-reviewed study is the latest in a series by scientists trying to push the Canadian government to place more strict regulations on salmon farms to control sea lice.
Based on government stream surveys, the study used a computer model to analyze pink salmon returns in 64 rivers without exposure to salmon farms and seven rivers where young fish must migrate past at least one salmon farm. The study considered returns before and after sea lice infestations were noticed in wild fish in 2001.
The Canadian Department of Fisheries and Oceans, which regulates salmon farms and is responsible for protecting wild salmon, said the study overstates the risks, which are not consistent with figures for pink salmon returns since 2002, when populations collapsed.
The authors suggested that the simple solution is to move fish farms out of salmon migration corridors. But that's unrealistic given the prevalence of wild salmon, said Brian Riddell, head of the salmon science branch of the department's Pacific Biological Station in Nanaimo, B.C.
Wild pink salmon are not a commercially important species, but they are an important food source for orcas and other salmon in the ocean.
They also provide food for bears and other wildlife and nutrients for trees.
The study suggested that the density of fish farms reached a tipping point in 2001 that triggered a killer sea lice infestation.
Ray Hilborn, a professor of fisheries at the University of Washington who was not associated with the study, said he replicated the analysis and agreed with the conclusions. But the data are "noisy," with a lot of variability, because stream surveys are far from exact, he said.
P-I reporter Lisa Stiffler contributed to this report from The Associated Press.