Drug-resistant sea lice ‘out of control’ on coast

Researchers concerned about salmon population after infestation in juvenile fish

Sea lice are “out of control” at salmon farms on the west coast of B.C. this year because they have become drug resistant, said a new report by two environmental groups.

The groups, Living Oceans and Raincoast Research, also claim industry regulators have failed to protect wild juvenile salmon and other fish from the parasites.

The report, “Lousy Choices” released Tuesday, said sea lice at fish farms on Clayoquot Sound have evolved a resistance to SLICE, an emmamectin benzoate drug, approved for use to eradicate the parasite in Canada. The researchers say some resistance to the drug has also been observed at fish farms in the Broughton area.

This has “grave implications” for both the salmon farming industry and wild salmon, the report said.

This year, sea lice are responsible for “considerable losses” to wild salmon in Clayoquot Sound and at least one salmon farming company, Cermaq, the report finds.

This spring, independent researchers in Clayoquot Sound discovered juvenile wild salmon were heavily infected with sea lice. This after Cermaq Canada was found to have sea lice above management levels at its Clayoquot Sound farms. The company was forced to close one of its fish farms, Fortune Channel, this summer after a high number of lice were found at the site.

The report said that 96 per cent of wild juvenile salmon in the area were infected with an average of eight lice per fish, according to the researchers.

Some were found with as many as 50 lice, the report notes, which concerns researchers, who say it only takes one to three lice to kill the young fish.

The report claims Fisheries and Oceans Canada knew as early as 2014 that resistance was developing in sea lice, but did not take measures to ensure the protection of wild juvenile salmon from the parasite. Measures could have included alternate treatments for sea lice ready for deployment when SLICE failed, the report said.

The DFO has been contacted to comment on these claims, but the Vancouver Sun has not yet received a response. Cermaq has also been contacted. Neither release public records of the drug treatments used on farmed salmon.

“Eighteen years after this issue was brought to DFO’s attention there is still no protection for wild salmon,” said Alexandra Morton, one of the report’s authors with Raincoast Research, and an outspoken critic of salmon farming.

“I don’t hold hope that much of this generation of wild salmon survived,” said Morton.

Karen Wristen, executive director of Living Oceans Society, said at a meeting in Tofino this summer, Cermaq reported resistance in the sea lice on their farms.

She said now they are trying to set up another meeting the DFO to discuss the sea lice drug resistance. “The last meeting we had [with the DFO] they were still denying that they are resistant to the drug,” said Wristen.

In June, the environmental groups were outraged that the NDP government refused to cancel 20 fish farm tenures in the Broughton Archipelago that were up for renewal.