Fish farms have long been thought to run the risk of sea lice outbreaks because of the tight proximity of fish in closed settings. But new results from the British Columbia salmon farm association puts that link into question. Farm closures in recent years, the association says, have not reduced infestations of the parasite that has been responsible for mortality in both farmed and wild fish populations. It is the wild population’s health that has been the driving force behind farm closures, as escapes of farmed fish are believed to transmit the parasite into the wild. Research into wild populations of Pacific salmon shows that sea lice infestation among these populations has not changed in the last 20 years, the association reports, even though multiple arms were shut down between 2019 and 2023 because of opposition from First Nations in the province. First Nations blame the farms for wild salmon population declines. The federal government has announced that all open net pen salmon farming in British Columbia must end by June 30, 2029.
A Canadian subsidiary of salmon farmer Mowi commissioned the research, carried out by a contractor, Mainstream Biological Consulting, in the spring of 2024. Sampling of juvenile chum and pink salmon on their way to sea was conducted in areas near former farms and based on historical sampling in the areas. The finding that the closures have no impact on sea lice in wild populations is consistent with a 2023 report from the Canadian Science Advisory Secretariat (CSAS) and long-term data collected annually in the Discovery Islands—an area in British Columbia where salmon farms have been removed by the federal government—also concluded that sea lice on farm-raised salmon do not impact sea lice levels on wild juvenile salmon.
Brian Kingzett, executive director of the BC Salmon Farmers’ Association, said that the continued exaggeration of wild salmon populations declining due to sea lice from salmon farms does not help conservation efforts of wild salmon. Ongoing research and data support that the salmon farming sector poses minimal risk to wild Pacific salmon, yet government decisions continue to ignore the science and threaten the sector’s future. He added that BC salmon farmers support wild salmon restoration, climate action, and food security and that it was time for the federal government to stop using salmon farming as a scapegoat, making unrealistic and unachievable political decisions about our sector, and focus on reliable data and science to address the real issues impacting wild Pacific salmon.