Diseased by Design: Canada’s Farmed Fish Betrayal
Tracing the toxic legacy of fish farms on Canada’s Pacific Coast. Behind nets and fences, these open-water operations discharge a slurry of feces, parasites, and chemicals into unconsenting marine ecosystems, contaminating everything in their path.
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What are fish farms?
Fish farming, or aquaculture, is the industrial practice of raising fish in controlled environments for mass consumption. At a glance, marine fish farms may appear to offer a sustainable alternative to overfishing. But beneath the surface, they often create concentrated zones of pollution, disease, and ecological disruption.
Open-Net Pens
Floating in the sea with no barrier between industrial waste and the surrounding marine environment. These create the most severe environmental problems.
Semi-Closed Systems
Designed to limit some exchange with the ocean while still maintaining connection to marine waters for operational purposes.
Closed-Containment Farms
Operating on land or in sealed tanks, providing complete separation from natural marine environments.
The Spread of Open-Net Fish Farms in British Columbia
Open-net pen fish farms first appeared along British Columbia's coast in the 1970s, then rapidly expanded throughout the 1980s. Today, over 100 open-net pen salmon farms dot the province's coastline, clustered around the Discovery Islands, Broughton Archipelago, Tofino, Barkley Sound, Ocean Falls, Campbell River, Sayward, Port McNeill, and the Sunshine Coast.
The Foreign Fish Invasion
More than 95% of the biomass produced by these farms consists of Atlantic salmon, a non-native species that has no natural place in Pacific waters. These foreign fish originate from Norwegian breeding stock, raised in freshwater hatcheries before being shipped to B.C.'s coastal farms as juvenile smolts, where they're confined in open nets directly in the ocean.
What’s going on inside a typical open-net pen?

Overcrowded fish swimming in circles. Parasites feasting. Antibiotics dumped in by the barrel. Dead fish piling up. And it doesn’t stay inside the net.

These aren’t just farms they’re floating biohazards.
Fin to Fin
These floating cages confine 500,000 to 750,000 salmon in unnaturally tight quarters, creating conditions comparable to cramming an entire city into a single room.
In such overcrowded populations, disease spreads rapidly, and fish frequently exhibit visible deformities, open lesions, and severe parasite infestations that ravage their bodies over time. Many don’t survive. Instead, they sink to the bottom of the nets, where their bodies remain, decomposing in the same confined waters the living fish are forced to endure.
Now try to imagine the extreme concentration of fish feces, rotting feed, and dead tissue constantly flowing out of these pens into the open ocean, day after day, with no filter, no cleanup, and no end.
The Outbreak Zone
Sick fish → Sick Ecosystems → Sick People: Diseased farmed fish spread parasites and pathogens into wild stocks and coastal waters, wrecking ecosystems, tainting seafood with drug/chemical residues, and leaving coastal communities to deal with the fallout.
Mouth Rot Disease
Tenacibaculum maritimum causes "mouth rot" in farmed salmon, creating severe tissue damage and making feeding difficult for affected fish.
Heart Inflammation (PRV)
Piscine orthoreovirus (PRV) causes heart inflammation and severely weakened swimming ability in salmon. PRV has been found in 65-75% of B.C.'s open-net pen farmed salmon. Studies also show that PRV can be transferred from farmed Atlantic salmon to wild Pacific salmon.
Sea Lice Infestation
Parasitic sea lice latch onto fish skin and feed on their flesh, leaving gaping open sores around the fins, head, and back. Sea lice become particularly lethal when they attach to juvenile salmon.
Photo by Tavish Campbell (juvenile chum salmon)
Impact on Wild Salmon
A Canadian study found that juvenile pink and chum salmon near fish farms in B.C. carried far more sea lice than those from areas with little or no farm exposure. The evidence is clear: proximity to farms is the biggest driver of infection. Even a small number of lice can kill a young salmon.
Crisis in Clayoquot Sound
A massive sea lice infestation was reported in May 2018 in Clayoquot Sound where fish farm operator Cermaq reported that over half of its 14 farms were infested with sea lice levels that posed a serious threat to wild salmon. Sea lice levels averaged 34 lice per fish, over 10 times the legal limit of three motile lice per adult fish.
Photo by Tavish Campbell Discovery Islands (juvenile sockeye salmon)
Pharma-SEA
To keep fish alive in these unnatural conditions, farms have become heavily dependent on a cocktail of chemicals that pose serious threats to marine ecosystems. The industry routinely deploys antibiotics that fuel the development of drug-resistant bacteria, chemical baths designed to kill parasites, and pesticides that devastate surrounding marine life.
When sea lice populations explode, fish farm operators release toxic chemicals directly into open-net pens—treatments that spread far beyond the farm boundaries into the surrounding ocean. These chemicals include hydrogen peroxide, azamethiphos, and deltamethrin. The collateral damage is severe: crustaceans, mollusks, and other essential marine species are killed alongside the intended parasites.
What starts as a treatment for diseased farmed fish becomes a poison that radiates outward, contaminating the waters we depend on for survival.
The Sinking Percentage
Death is a constant, putrid reality in B.C.’s salmon farms. What the industry sells as sustainable is, in fact, a system where fish die at alarming rates. Many don’t survive to harvest, and their decomposing bodies often remain in the pens, drifting among the living.
20%
Annual Death Rate
Up to one in five salmon die before harvest at some B.C. farms.
561
Mass Die-Offs
Mortality events recorded from 2011-2022.
The Scale of Death and Decay
  • Routine mortality: Monthly death rates of 0.5% to 1.8% compound to 6–20% annually, meaning millions of fish at BC aquaculture sites die in their cages every year.
  • Catastrophic events: In 2024, Muchalat North lost 23% of its stock in just 10 days, approximately 1,000 tonnes of salmon. Three other Grieg Seafood farms reported similar mass die-offs, with cumulative mortalities reaching 4% to 26% in a single month.
  • Escalating crisis: Mass mortality events have surged from scattered incidents to nearly 18 events per 100 active sites monthly by 2022.
These deaths represent millions of fish annually that never reach market, rotting masses of wasted life that make the environmental costs even more nauseating when weighed against actual food production.
Open-net fish farms aren’t just death traps for the salmon inside, they also wipe out massive amounts of marine life every year. Bloated carcasses rot in place, while invasive Atlantic salmon slip through torn nets, spilling into wild habitats and threatening native species already on the brink.
Bycatch Deaths
Open-net pen salmon farms in B.C. are driving a catastrophic surge in wild fish, marine mammal, and seabird deaths.
Mechanical Death Machines
As chemical treatments fail to control parasites, farms deploy hydrolicers, industrial machines that suction fish from pens and blast them with high-pressure water. Wild fish drawn into the pens by artificial lights and feed are sucked into these machines and killed during treatment.
Wild Fish Kills
Native species such as herring, and various wild salmon species are lured by artificial lighting and excess feed, only to become trapped within the pens where they inevitably die. Federal data reveals that in 2022 alone, over 817,000 herring, were killed, representing a devastating escalation from previous years.
Marine Mammal Massacre
Between 1990-2022, farms systematically killed 6,116 harbour seals, 1,426 California sea lions, and 379 Steller sea lions, shot or drowned to protect industry profits. Even humpback whales have been trapped, injured, and killed by salmon farm operations, demonstrating the industry's devastating impact on marine mammals of all sizes.
The Ripple Effect of Destruction
These mass deaths represent far more than a wildlife tragedy, they constitute a direct assault on coastal ecosystems, food security, and fisheries. Many of the species being killed, including herring and wild salmon, serve as foundational elements in the diets of larger predators, support commercial fishers, and drive the nutrient cycles that sustain healthy oceans and forests.
When these keystone species decline, the entire food web collapses, and we all pay the price.
Out of the Pen, Into the Wild
Escaped Atlantic salmon are invasive predators unleashed in Pacific waters, competing with wild salmon for resources, spreading parasites and disease, and disrupting spawning habitats that evolved over millennia. These escapes aren't rare accidents; they're routine failures of an industry that treats environmental devastation as an acceptable cost of doing business.
Systematic Net Failures
The 2017 collapse of a Cooke Aquaculture net pen at Cypress Island off Washington's coast exposed the industry's reckless negligence. Initially reporting 160,000 escaped fish, the company was later forced to admit 263,000 Atlantic salmon had been released into Pacific waters after an investigation by Washington's Department of Natural Resources.
The cause? Cooke had systematically failed to clean and maintain its nets, allowing marine growth and debris to accumulate until the structure collapsed under its own neglect.
Invasive Competition
These escapees become aggressive competitors in Pacific waters, with Atlantic salmon growing 15-20% faster than native species and showing higher territorial aggression. They directly compete with endangered Chinook, Coho, and Chum salmon for critical feeding areas.
Studies show escaped Atlantics disrupt spawning behaviors of wild salmon, with male escapees attempting to mate with wild females, potentially compromising genetic integrity of native populations .
Government Cover-Up
When DFO assumed control of salmon farms from the Province in 2010, it conveniently redefined "escape events" to include only those with "evidence of an escape", effectively erasing incidents from official records.
Previously, farms reported 400,000-800,000 escapes annually across B.C. operations. After 2010, reports mysteriously dropped to fewer than 1,000 per year. The Department now accepts ongoing "trickle losses" as simply the cost of industrial aquaculture.
The Department now accepts ongoing "trickle losses" as simply the cost of industrial aquaculture.
DFO: Compromised Science, Failed Regulation
Impartiality Undermined by Conflicted Mandates and Industry Ties
DFO has a conflict of interest, promoting aquaculture while also protecting wild fish. This dual role compromises its scientific advice, especially when it challenges industry growth.
Key Examples:
  • Revolving Door: Former DFO officials, like Trevor Swerdfager (Director of Aquaculture Science) and Dr. Dick Beamish (Head of Aquaculture at Pacific Biological Station), later worked for or chaired aquaculture industry associations (e.g., Aquaculture Association of Canada, BC Salmon Farmers Association), openly advocating for industry growth.
  • Industry-Funded Research: Much of DFO's aquaculture research is industry-funded (e.g., via ACRDP). Research funded or co-authored by the industry often minimizes risks, while conflicting findings are suppressed.
  • Industry Influence on Regulation Drafts: In 2022, MOWI Canada West warned DFO that stricter sea lice regulations would impact profits. The subsequent draft sea lice allowances proposed were noticeably weaker. DFO only reverted the original allowance after a Freedom of Information (FOI) request and public pressure.
Silencing Scientists
Canada’s Public Sector Integrity Commissioner has launched an investigation into allegations that Fisheries and Oceans Canada attempted to silence federal scientists researching the environmental risks of open-net pen salmon farms. The inquiry, launched on June 17, 2024, will examine claims that scientists were reprimanded, prevented from speaking to the media, and blocked from testifying before Parliament.
There is also the case of Dr. Kristi Miller-Saunders who was prevented from publishing and speaking publicly about her research linking PRV (Piscine orthoreovirus) to disease in Pacific salmon. Her 2012 report was only released in 2022 after intervention from the federal Information Commissioner.
Evidence-Based Decisions Compromised by Suppression and Political Pressure
DFO has repeatedly ignored the precautionary principle, delaying action unless definitive proof of harm is available, often suppressing or silencing evidence that shows otherwise.
Key Examples:
  • Federal Courts Reject DFO’s Denialism: Two federal court cases (Morton v. Minister of Fisheries and Oceans, 2015; Morton v. Canada, 2019) found that DFO unlawfully failed to apply precautionary measures regarding viral diseases in farmed salmon.
  • Suppression of Sockeye Research: Internal DFO studies showed wild sockeye salmon were severely impacted by sea lice. Despite this, DFO failed to conduct a risk assessment for the 2020 Discovery Islands review, violating a commitment from the $37-million Cohen Commission Inquiry (2012).
  • Research Blocked: In 2019, DFO denied permission for a field experiment to test the causal effect of sea lice on pink salmon survival, despite full First Nation backing. DFO claimed a lack of causal evidence to justify inaction.
When the ocean suffers, so do we. Industrial fish farming is putting wild salmon, coastal ecosystems, and the future of our food systems at risk. This isn’t just about the environment, it’s about protecting the jobs, communities, and seafood we all rely on.
Take Action for Coastal Waters
The science is clear: open-net salmon farms pollute our oceans, spread parasites and disease, and put wild salmon on the brink. It's time to act.
Call for a Transition
Urge governments to get salmon farming out of our waters. Click the button below to demand a full transition away from marine pens and toward land-based systems that protect wild fish and coastal ecosystems.
The Latest News
"Massive Area" Under Closed Containment Salmon Farm "Covered 100% with Feces and Fish Feed" - Government Records Reveal
May 21st, 2025
Damning government records and Remotely Operated Vehicle footage have exposed a "massive area" of ocean floor completely smothered in feces and rotting feed beneath Cermaq Canada's experimental salmon farm in Millar Channel, B.C. The salmon were treated with the antibiotic florfenicol at least seven times, including as recently as February, raising urgent concerns about antibiotic resistance and drug contamination in the surrounding marine environment. The overwhelming stench of decay, persistent fish oil slicks, and visible waste discharge cast serious doubt on the industry's promises about "closed containment" systems.