New Sea Lice Data Debunks Activist Claims Against Salmon Farms in B.C.

For years, activists said removing salmon farms would cut sea lice on wild salmon. The farms went, taking 1,500 jobs and more than $1 billion in aquaculture investment with them. New data now shows the parasite stayed and, in some years, increased.

By Fabian Dawson
SeaWestNews

New monitoring from two of British Columbia’s most closely watched aquaculture regions shows sea lice still infecting wild juvenile salmon years after ocean salmon farms, which activists blamed for spreading the parasites, were removed.

The 2026 findings from the Discovery Islands and Broughton Archipelago add another year of evidence challenging one of the core claims used in the campaign to shut down ocean salmon farming along the B.C. coast.

For years, activists argued that the farms concentrated naturally occurring sea lice and spread them to juvenile wild salmon as they migrated to sea.

That claim became a major factor in the political pressure that led to salmon farms being removed from both regions, resulting in the loss of an estimated 1,500 jobs, $640 million in economic activity, more than $1 billion in cancelled investment and about 35,000 tonnes of B.C. salmon production.

Yet the sea lice remain and, in some years, have increased in numbers.

The latest data, covering a decade of monitoring in the Broughton Archipelago and nine years in the Discovery Islands, show the parasites continuing to fluctuate on wild juvenile salmon even after farms were removed.

The results come from Mowi Canada West’s Wild Juvenile Salmonid Monitoring Program, which tracks sea lice during the spring migration period and records both prevalence and intensity on juvenile wild salmon.

Independent scientists are currently analyzing these data to further 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.

The growing post-farm closure record directly contradicts the activist claim that no salmon farms would mean no sea lice, a message that continues to feature prominently in their fundraising appeals and campaigns against the industry.

The B.C. Salmon Farmers Association says the latest findings reinforce earlier research showing sea lice levels cannot be explained simply by the presence or absence of salmon farms.

“BC Salmon Farmers are committed to ensuring that salmon farms coexist with wild salmon in coastal British Columbia,” said 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.”

Sea lice are naturally occurring parasites in the marine environment and can be carried by wild salmon and other fish. Their numbers are influenced by several factors, including water temperature, salinity, ocean currents and the movement and abundance of wild hosts.

That complexity has become increasingly important as more years of data accumulate from areas where salmon farming no longer exists.

A study examining Discovery Islands monitoring between 2017 and 2024 found lice remained on wild juvenile salmon after farms were removed. Some of the highest levels in that dataset were recorded in 2024, two years after farm production had fallen to zero.

The Broughton produced a similar contradiction.

Salmon farm production there fell by more than 95 per cent between 2019 and 2024, dropping from more than 21,000 tonnes to just 614 tonnes. Sea lice prevalence did not decline in step. Levels rose in some years as farming activity fell and remained variable even as production was dismantled.

The continuing presence of sea lice after farm removals also raises questions about the broader federal policy now hanging over the rest of the industry.

The Trudeau government, under sustained pressure from the anti-salmon farming lobby, announced in June 2024 that ocean salmon farming would be prohibited in B.C. coastal waters after June 30, 2029.

The Carney government inherited that policy and is now sitting on a plan that will determine the future of ocean aquaculture in B.C.

The remaining sector generates about $1.17 billion in annual economic activity and supports roughly 4,560 full-time jobs, including more than 1,000 held by Indigenous workers. All remaining farms operate under agreements, negotiations or partnerships with First Nations in whose territories they are located.

The issue is also colliding with Ottawa’s growing emphasis on food security and domestic production.

Kingzett said B.C. salmon farmers are ready to increase Canadian production at a time of higher food prices and greater uncertainty around global supply chains.

“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.”

As farms were removed from the Discovery Islands and Broughton, B.C. salmon production fell sharply and Canada became more dependent on imports.

Farmed salmon production in the province has dropped by more than 40 per cent since 2015, while Canada imported more than $1 billion worth of salmon in 2025.

While BC farmed salmon production decreased, Canada imported over $765 million worth of farmed Atlantic salmon from countries such as Norway and Chile in 2025, according to Statistics Canada.

(Main file image shows a Mowi salmon farm in the Discovery Islands)