Spatial heterogeneity in sea lice infestations on farmed salmon in British Columbia
In British Columbia, emamectin benzoate (EMB) has been an effective treatment for salmon lice since 2000. Since 2004, sea lice management has been linked to wild salmon conservation with coast-wide regulations that ensure motile sea lice abundance remain below 3 per salmon between March and July, usually by treatment or harvest. Prescribed use of EMB between 2012 and 2015 was 242% higher than between 2000 and 2003. In 2014, approval of hydrogen peroxide as a sea lice treatment was required because of apparent reductions in EMB efficacy. In other regions, onset of resistance to EMB is well documented and associated with increased treatment frequency. The primary goal of this research is to identify the opportunities for reducing EMB treatment frequency in BC, thereby reducing the risk of EMB-resistant sea lice. Sea lice abundances differ among Fish Health Management Zones and understanding the factors contributing to this spatial heterogeneity will better inform the risk of infection and the need to use drugs or pesticides to manage sea lice on Atlantic salmon farms.
Program for Aquaculture Regulatory Research (PARR)
Research scientist, Pacific Biological Station, Nanaimo, BC
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