|Young salmon infested with sea lice. Juveniles migrating out to sea are particularly vulnerable because they are small and thin-skinned. Pic: Alexandra Morton
The new research found a direct connection between the rapid growth of fish farming in the waters of the Broughton Archipelago off British Columbia and the abrupt decline of the region's wild pink salmon. What linked the two, the researchers found, were widespread infestations in the open-net salmon pens by sea lice. Older salmon easily tolerate the parasite, but young ones migrating through the same waters do not.
Source: Washington Post
"These young salmon wouldn't be dying if it wasn't for the salmon farms and all those sea lice," said lead author Martin Krkosek, a fisheries ecologist at the University of Alberta. "The wild population is dropping so fast that there isn't much time left to act."
With Americans' increasing appetite for fresh salmon, and with the farmed variety making up almost three-quarters of all salmon served, the finding is an unwelcome guest at the feast. Salmon farms have been suspected in the declines of wild salmon for some time, but the study published online yesterday by the journal Science is seen by some as the strongest evidence so far of a significant connection.
"This is the broadest look so far at the effects on a total population" of salmon farms, said Andrew Rosenberg, a former deputy director at the National Oceanic and Atmospheric Administration (NOAA) and an expert in the field.
"We're not talking about being mean to some individual fish; we're talking about a possible extinction within the next few years" of an important local population of pink salmon, he said.