Potential effects of sea lice bath treatments on sensitive non-target organisms in southwest New Brunswick

Description

This project helped to determine the potential effects of the bath treatments, AlphaMax® and Salmosan® used to treat sea lice on farmed salmon on commercially important non-target organisms. The toxicity of larval and adult lobster and sand shrimp was determined by establishing the lethal threshold (24-H LC50), and the no observable effects of concentration (NOEC – concentration at which no effects are observed).

Studies determined the response of adult lobsters to repeated short-term (pulsed) exposures to AlphaMax® at three water temperatures (5℃, 10℃, and 15℃). Acute studies determined the long-term exposure of adult lobsters to low concentrations of the pesticide. In conjunction with dye dispersion studies in southwest New Brunswick, water samples were collected for toxicity testing with crustaceans. The results from this work provided guidance for the development of integrated pest management plan.

Findings

AlphaMax was highly lethal to the arthropods (American lobster, Crangon shrimp and mysid shrimp). The 24 hour lethal threshold was only a small fraction of the recommended treatment concentration of 2,000 ng/L. When shrimp were exposed to effluent from an operational treatment, exposure was lethal. Mysids were more sensitive to the treatment effluent than Crangon shrimp. Crangon died when exposed to samples collected within the cage during treatment. Mysids died in samples within the cage and also in the samples very near the cage.

Program Name

Program for Aquaculture Regulatory Research (PARR)

Year(s)

2010 to 2013

Principal Investigator(s)

Les Burridge, Research Scientist, Fisheries and Oceans Canada, St. Andrews Biological Station, Maritimes Region