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Effects of organophosphate aquaculture pesticide azamethiphos on stage I and stage IV American lobster (Homarus americanus) larvae


Salmosan® (active ingredient: azamethiphos) is one of two pesticides currently permitted for use as a bath treatment to control sea lice (Lepeophtheirus salmonis) in farmed Atlantic salmon (Salmo salar) in Atlantic Canada. The release of pesticides from fish farms has raised concern regarding the potential for indigenous, non-target species to be affected. In particular, there are growing concerns regarding the potential for effects to American lobsters (Homarus americanus), a commercially important species in Atlantic Canada that is found in the near-shore environment where fish farms are located. Lobsters have been found to be the most sensitive species tested in laboratory assays examining the acute lethality of azamethiphos in the Salmosan® formulation (Burridge et al., 2014).

Lobster larvae, like other crustaceans, are known to be more susceptible to contaminants than adults (Burridge et al. 2008). The transition from the pelagic zone to benthic settlement by stage IV (post-larvae which settle to select habitats) is considered a critical stage of development. Laboratory exposures have revealed various pesticide effects on larval survival, behaviour, development and immunity.

The objective of this laboratory study was to examine the effect of Salmosan® on the survival and development of early lobster life stages. Stage I and stage IV lobsters were exposed for 3-h to Salmosan® at concentrations representative of dispersion estimates of a pesticide plume from an aquaculture site. Larvae were then held in clean seawater until they moulted to the next stage (approximately 20-25 days), which represents a sensitive time in their development. This study will provide information on delayed and developmental effects to a sensitive life stage of lobster at environmentally relevant concentrations and exposure durations.

Program Name

National Contaminants Advisory Group (NCAG)


2015 - 2016


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

Principal Investigator(s)

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

Dr. Dounia Daoud
General Director
Homarus Inc.

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