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SEA lice from infected fish farms are responsible for the deaths of up to 95% of young wild salmon migrating out to sea, according to a new report from Canada.
New research from Canada claims that young wild salmon are dying after swimming through plumes of lice from infected fish farms, The Sunday Times has reported.
According to the report, concentrations of sea lice are 30,000 times higher around fish farms in coastal waters than in deep waters.
“We know that fish farms raise sea lice levels, and we know that sea lice kill fish,” the report’s author, Martin Krkosek, a mathematical biologist at the University of Alberta, reportedly said. “This is the first study to estimate the total impact.”
In the research, to be published this week by America’s National Academy of Sciences, an international team of biologists, mathematicians and environmentalists studied young salmon on their 37-mile migratory passage past open-net fish farms off the coastline of British Columbia, western Canada. They sampled fish at regular intervals along the route, documenting the effect on the salmon as they swam down it. Young salmon reportedly carried almost no sea lice before reaching the fish farms, but became heavily infected as they approached them and swam through the plumes. Post-mortems were conducted on the fish that died. The researchers estimated that 9% died in early spring when the sea lice population was low, while 95% were killed later in the season when sea lice numbers swelled. The lice, which survive by eating flesh and tissue, pose a risk to juveniles because their scales and outer tissue are soft and cannot protect vital organs against attack.
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