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The effects on adult American lobsters (Homarus americanus) consuming marine benthic infauna exposed to Atlantic salmon sea lice chemotherapeutants


Sea lice (predominantly Lepeophtheirus salmonis) are large ectoparasitic copepods having a pan-global distribution and found on salmonid fishes in marine waters. These host-specific parasites are very pathogenic to salmonid species (e.g., Atlantic salmon), especially populations in cage culture where the stocking density is unnaturally high. Large numbers of sea lice can quickly cause severe skin and tissue damage resulting in fish stress and mortality. The global economic impact associated with loss of stock, product downgrades at harvest and the cost involved in monitoring and managing sea lice infection is estimated to exceed US$480M annually (Costello et al. 2009).

A common approach to reduce infection of sea lice to farmed Atlantic salmon involves use of in-feed pharmaceutical products termed chemotherapeutantsFootnote 1. The active ingredients from such products used in Canada include the in-feed drugs emamectin benzoate and ivermectin. The effects of these molecules on non-target species such as the American lobster have been studied in the past for adult and juvenile American lobsters. Recently, an in-life phase study was completed (un-published data) that exposed juvenile lobsters to spiked sediment of each molecule thereby providing insight of effects within a more environmentally relevant scenario. This study will provide further essential non-target ecotoxicology data associated with the response of adult American lobsters following voluntary ingestion of softshell clams (Mya arenaria) that were exposed to sediment of varying concentrations of the two test molecules (emamectin benzoate and ivermectin) alone and in combination. The primary objectives were to produce predator-prey ecotoxicology data associated with exposure and identify any effects (e.g., health, behavior impairment) on the lobster after consuming exposed prey. This approach will initiate the study of food chain effects on American lobsters for the scenario in which residues from these products find their way to the benthicFootnote 2 environment.

Program Name

National Contaminants Advisory Group (NCAG)


2016 - 2017


Atlantic: Newfoundland and Labrador Shelves, Scotian Shelf, Gulf of St Lawrence

Principal Investigator(s)

Jason Bernier (Lead)
Manager, Environment and Planning
CBCL Limited

Chris Bridger
Manager Aquatic Services
Huntsman Marine Science Centre

Dr. Dounia Daoud
General Director
Homarus Inc.

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