Canadian salmon farm closures haven't cut sea lice numbers
Four years after the last fish were harvested from net pens in the Discovery Islands, monitoring shows that the burden of parasites on wild smolts remains the same
Monitoring of wild juvenile salmon in Canada has again found that the removal of salmon farms from the Discovery Islands and the Broughton Archipelago in British Columbia has not reduced the numbers of lice on migrating fish.
Salmon farms were removed from the Discovery Islands by order of the federal government in 2022 and from the Broughton Archipelago in a more phased manner in 2024, largely due to concerns raised by activists claiming that salmon farms were concentrating and releasing sea lice in regions that would, in turn, impact out-migrating wild salmon smolts.
The BC salmon sector said that these closures caused significant economic impacts, including 1,500 fewer jobs, CAD 640 million in lost economic activity, the cancellation of more than CAD 1 billion in investment, and 35,000 tonnes of farmed salmon removed from production.
Monitoring of sea lice levels during wild juvenile salmon out-migration, carried out by independent registered professional biologists contracted by salmon farmer Mowi Canada West, has continued in the Discovery Islands and the Broughton Archipelago after the closures, providing a baseline for the natural pressures of sea lice on wild juvenile pink and chum salmon.
Widespread beach seine sampling of fish was conducted during two separate sampling events in April and May 2026, selected to coincide with the peak outmigration period of juvenile salmonid.
The BC Salmon Farmers’ Association (BCSFA) said the results of the annual sampling again show that the prevalence of sea lice (the percentage of juvenile salmon that are infected with sea lice) and the intensity of sea lice (the average number of sea lice on infected fish), do not decrease or disappear, as is repeatedly reported to the public by anti-salmon farming activists. Instead, a natural year-to-year variability is shown in the data.
The data collected are being further analysed to investigate relationships between specific farm salmon stocking levels, oceanographic conditions, and other factors that will further improve scientific understanding of sea lice biology in the Pacific Northwest. This research will be submitted for peer review.
“BC salmon farmers are committed to ensuring that salmon farms coexist with wild salmon in coastal British Columbia,” said BCSFA executive director Brian Kingzett. “Sea lice monitoring and innovation to ensure that sea lice levels on farmed salmon cannot spread to wild salmon are a critical part of operations.”
Closure by mid-2029
Salmon farmers in BC are currently facing closure of open-net pen farms by mid-2029 under a “transition” policy instigated by former Liberal Party leader and prime minister Justin Trudeau following a manifesto pledge ahead of the 2019 general election.
The Liberals promised “to develop a responsible plan to transition from open net pen salmon farming in coastal waters to closed containment systems by 2025”, despite evidence from nine studies by its own Department of Fisheries and Oceans (DFO) that the sector posed no more than a minimal risk to wild fish.
The BSCFA hoped that Trudeau’s replacement as Liberal leader and prime minister by former Bank of England governor Mark Carney would lead to reformation or repeal of the transition policy but that hasn’t happened, even though salmon production fits Carney’s food security strategy.
Food security
“During a time of unprecedented economic instability and rising food costs, BC salmon farmers are ready to answer the call in support of the government’s National Food Security Strategy by producing more Canadian-made food for Canadian plates,” said Kingzett.
BCSFA said its members are committed to science-based innovation, transparency, and coexistence with wild salmon in their operations.
It has produced “Modern Salmon Farming in BC: A Review”, which it describes as a comprehensive summary dedicated to uncovering the world of salmon farming in BC.
“We aim to bring clarity and transparency by utilising data, research findings, and insights from many researchers, scientists, and subject matter experts to address 13 distinct topics related to salmon farming in BC,” states BCSFA.
