Aquaculture Canada and WAS North America 2022

August 15 - 18, 2022

St Johns, Newfoundland, Canada

CHALLENGES WITH SEA LICE MANAGEMENT IN BRITISH COLUMBIA

 

Kathleen Frisch*

 

Cermaq Canada

Campbell River, BC, Canada

kathleen.frisch@cermaq.com

 



Sea lice management in British Columbia, Canada is a significant challenge for Atlantic salmon farmers. Sea lice pressure has become more intense due to environmental factors exacerbated by climate change. Sea lice management in BC is regulated by the Department of Fisheries and Oceans Canada through the Marine Finfish Conditions of License and are based on keeping lice levels low during the outmigration of wild juvenile salmonids during the March to June period. As a result, sea lice are managed to a precautionary threshold to prevent risk of harm to wild juvenile salmonids. Preventative measures to reduce lice infesting farmed salmon, such as sea lice tarps are being investigated but can be difficult to implement due to environmental conditions. Control measures are limited with only one medicinal treatment, emamectin benzoate, that has a prolonged action against re-infestation. On top of this, Lepeophtheirus salmonis in BC are showing reduced sensitivity to the drug and the industry has no alternatives to protect their fish against re-infestation. All other forms of sea lice control require handling of the fish, cannot treat the whole farm or area at once, have seasonal limitations based on water quality and have no residual effect on sea lice re-infestation. Many of these difficulties stem from the regulatory confines resulting from the Conditions of License from DFO, the lack of new drugs being approved by Health Canada and the need to have Pesticides use Permits from the BC Ministry of Environment for using pesticides such as hydrogen peroxide. As a result of all these factors, it is challenging to practice effective integrative pest management.