Like the bad smell that won’t go away, another piece of research in
the scientific jigsaw puzzle links British Columbia’s salmon farms to
sea lice infestations that affect migrating wild salmon.

This time the link is to the iconic wild sockeye stocks of the Fraser River.

Fraser
River sockeye are the most important food and subsistence species for
more than 40 aboriginal communities, the much-prized foundation for the
province’s most valuable commercial fishery and a growing target for
sports anglers.

The study by scientists from the University of
Victoria, Simon Fraser University and several environmental
organizations with an interest in salmon conservation used genetic
analysis to determine the origin of sockeye from Canada’s two most
important salmon rivers, the Fraser and the Skeena.

Skeena River sockeye smolts migrate through waters where there are no net cage salmon farms, so it served as a control.

Migrating
Fraser River sockeye smolts, on the other hand, must run a gauntlet of
fish farms scattered among the islands that choke the narrows between
Vancouver Island and the mainland north of Campbell River.

The
scientists found that Fraser River sockeye passing salmon farms in the
Discovery Islands and Broughton Archipelago picked up a heavier load of
sea lice than Skeena River fish migrating through waters where there
were no salmon farms.

How important is this discovery?

“It’s
quite important,” says Mike Price, a graduate student at UVic who is
one of the researchers. “It indicates that fish farms are a source of
one potentially lethal pathogen for migrating sockeye smolts. Is this an
indicator for other pathogens? Like most scientific research, ours
generates more questions than answers.”

But the research paper,
Sea Louse Infection of Juvenile Sockeye Salmon in Relation to Marine
Salmon Farms on Canada’s West Coast, published Tuesday in PloS One, a
peer-reviewed open access scientific journal of the Public Library of
Science, is the first to demonstrate clearly the potential role of
salmon farms in transmitting sea lice to juvenile sockeye salmon.