Resource: Dynamics of outbreak and control of salmon lice on two salmon farms in the Broughton Archipelago, British Columbia
Authors / Publisher: Martin Krkosek, Andrew Bateman, Stan Proboszcz, and Craig Orr. Published in Aquaculture Environment Interactions Vol. 1: 137-146, 2010
Date: December 2010
As part of Watershed Watch’s continued efforts to contribute to the science investigating the impact of open net cage salmon farming on wild salmon, Watershed Watch’s Craig Orr and Stan Proboszcz partnered with Martin Krkosek and Andrew Bateman to publish the peer-reviewed paper Dynamics of outbreak and control of salmon lice on two salmon farms in the Broughton Archipelago, British Columbia in the journal Aquaculture Environment Interactions. The paper uses a mathematical model to evaluate the population ecology of outbreaks of sea lice (Lepeophtheirus salmonis), and how lice levels change after treatment with a parasiticide (such as Slice™) for two salmon farms in the Broughton Archipelago. Results suggest that louse population growth within farms drive outbreaks rather than continual louse immigration from sources outside of the farm (e.g. wild salmon). This model indicates that infection pressure from farms to wild juvenile salmon may be minimized by using parasiticides to treat farmed salmon 2 to 3 months preceding the juvenile salmon outmigration. The observed timing of parasiticide use and population decline of lice on farms in the model is consistent with reported declines of lice on wild juvenile salmon. Assuming that lice treatments do not have adverse environmental effects and lice do not evolve resistance, optimized parasiticide use on salmon farms may help reduce the spread of lice to wild salmon populations.
We thank Marine Harvest Canada for allowing us access to farms and for supplying farm data. Funding came from the Natural Science and Engineering Research Council of Canada, the Gordon and Betty Moore Foundation, the Canadian National Centre of Excellence Mathematics of Information Technology and Complex Systems (MITACS) program (with nonacademic participants: the Coastal Alliance for Aquaculture Reform, the David Suzuki Foundation, the National Geographic Society, Watershed Watch Salmon Society, the Canadian Sablefish Association, Finest at Sea, BC Wilderness Tourism Association and the Pacific Salmon Forum).