BC hatcheries flagged in salmon disease risk study—but overall threat from fish transfers remains low.
A new Canadian study has mapped how farmed Atlantic salmon are moved between hatcheries and marine sites in British Columbia—and found that while some hatcheries could, in theory, act as “superspreaders” for disease, current regulations appear to keep the risk low.
The research, published in Frontiers in Veterinary Science, analysed over 800 live fish transfers between farms from 2015 to 2022. It found that a handful of hatcheries are highly connected to many marine sites, meaning that if an undetected infection occurred at one of these locations, it could potentially spread more widely.
However, the study also found no evidence that such outbreaks are happening in BC, and points to strong regulatory controls—such as routine health checks and testing—as a likely reason.
“Atlantic salmon transfers might not play a significant role in the spread of pathogens between facilities in the British Columbian Atlantic salmon farming industry,” the researchers concluded.
The study used network analysis to examine how fish move through the production system. This kind of modelling is increasingly used to identify where targeted disease monitoring could be most effective, without requiring blanket restrictions across the sector.
The researchers suggest that authorities and producers could focus extra surveillance on a few key “high centrality” sites, rather than treating all farms equally when responding to potential disease risks.
While the paper focused on fish movements, it also acknowledged that other risk factors—such as shared vessels, equipment, or staff—are not captured in the model.
The findings come as Canada’s Department of Fisheries and Oceans continues its transition planning for salmon farming in BC, which includes a focus on biosecurity, wild salmon protection, and long-term licensing frameworks.
This is the first study of its kind to map the full network of farmed salmon movements in BC, offering a new tool for understanding how disease could spread—and how to stop it early.
Read the full study HERE.