Modeling parasite dynamics on farmed salmon for precautionary conservation management of wild salmon

• Published in: PloS one Vol. 8; no. 4; p. e60096
• Main Authors: Rogers, Luke A, Peacock, Stephanie J, McKenzie, Peter, DeDominicis, Sharon, Jones, Simon R M, Chandler, Peter, Foreman, Michael G G, Revie, Crawford W, Krkošek, Martin
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 05.04.2013; Public Library of Science (PLoS)
• Subjects: Abiotic factors; Abundance; Agriculture; Analysis; Animals; Aquaculture; Aquaculture industry; Biology; Conservation; Conservation of Natural Resources - statistics & numerical data; Copepoda - growth & development; Copepoda - physiology; Crustaceans; Ecosystem components; Farms; Fish; Fish as food; Fish migration; Fish populations; Fisheries - statistics & numerical data; Guidelines as Topic; International economic relations; Lepeophtheirus salmonis; Lice; Management; Mariculture; Mathematical models; Migration; Models, Statistical; Oncorhynchus; Oncorhynchus gorbuscha; Oncorhynchus keta; Oncorhynchus kisutch; Oncorhynchus mykiss; Parasites; Population biology; Population Dynamics; Population growth; Probability; Protection and preservation; Salinity; Salmo salar; Salmon; Salmon - growth & development; Salmon - parasitology; Seafood industry; Seawater - chemistry; Social and Behavioral Sciences; Sympatric populations; Temperature; Time Factors; Veterinary Science; British Columbia Canada; Canada; Campbell River
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0060096

Conservation management of wild fish may include fish health management in sympatric populations of domesticated fish in aquaculture. We developed a mathematical model for the population dynamics of parasitic sea lice (Lepeophtheirus salmonis) on domesticated populations of Atlantic salmon (Salmo salar) in the Broughton Archipelago region of British Columbia. The model was fit to a seven-year dataset of monthly sea louse counts on farms in the area to estimate population growth rates in relation to abiotic factors (temperature and salinity), local host density (measured as cohort surface area), and the use of a parasiticide, emamectin benzoate, on farms. We then used the model to evaluate management scenarios in relation to policy guidelines that seek to keep motile louse abundance below an average three per farmed salmon during the March-June juvenile wild Pacific salmon (Oncorhynchus spp.) migration. Abiotic factors mediated the duration of effectiveness of parasiticide treatments, and results suggest treatment of farmed salmon conducted in January or early February minimized average louse abundance per farmed salmon during the juvenile wild salmon migration. Adapting the management of parasites on farmed salmon according to migrations of wild salmon may therefore provide a precautionary approach to conserving wild salmon populations in salmon farming regions.