Study by conservation group finds elevated pathogen levels near B.C. fish farms

The Pacific Salmon Foundation says it found that water near active open-net farms contains four times more pathogens harmful to wild salmon than water near inactive farms.

Conservationists have opened a new front in the ongoing battle over open net pen salmon farming in B.C.

The Pacific Salmon Foundation says its latest study has found that water near active open-net farms contains four times more pathogens harmful to wild salmon than water near inactive farms.

The foundation argues the research proves open-net farms contain and amplify pathogens that can affect wild salmon outside the nets.

The group looked at 11 sites in the Broughton Archipelago, seven with active fish farms and four that were decommissioned.

“We were sampling live and dead fish in the farms, but we were also collecting environmental DNA … the water inside and outside the farm in order to assess what is in the water,” foundation researcher Emiliano Di Cicco said.

“The problem is if a wild salmon gets infected and gets sick, it can either die directly from the disease or itself, or is more likely going to get weaker and not be able to feed properly and die or is not going to be able to evade predation.”

Di Cicco said the findings are particularly important for Chinook salmon, which spend their first year in the ocean close to shore in inlets and bays — the same terrain favoured by fish farms.

“The first year in the ocean is very critical,” he said.