The acute lethality of three anti-sea lice formulations: AlphaMax®, Salmosan®, and Interox®Paramove™50 to lobster and shrimp

Several pesticide formulations have been used in eastern Canada to treat infestations of sea lice on Atlantic salmon since the mid-1990s. Traditionally 48 and 96 h exposure periods are used to assess potential hazards of chemicals to non-target organisms. Exposure of this duration is not considered representative of exposure scenarios in southwest New Brunswick, Canada. Lobsters and shrimp were exposed to the pesticide formulations, AlphaMax (R) (active ingredient deltamethrin), Salmosan (R) (azamethiphos) and Interox (R) Paramove (TM) 50 (hydrogen peroxide) for 1 or 24 h and lethal thresholds were determined. The recommended treatment concentrations reflect the relative toxicity of the three formulations to the sea louse. AlphaMax (R) is applied at 2 mu g L-1 as deltamethrin, Salmosan is applied at 100 mu g L-1 as azamethiphos and Interox (R) Paramove (TM) 50 is applied at 1200-1800 mg L-1 as hydrogen peroxide. The formulations also affect the species used in our studies in the same relative order. AlphaMax (R) is the most toxic formulation with LC50s reported in the ng L-1 (as deltamethrin) range, up to a 2000-fold dilution of the recommended treatment concentration. Lethal thresholds for Salmosan (R) are in the mu g L-1 (as azamethiphos) range with a maximum 30-fold dilution of the recommended treatment concentration to reach the lethal threshold for the most sensitive species tested. Interox (R) Paramove (TM) 50 was the least toxic formulation tested in our studies with the lowest LC50 approximately equal to the recommended treatment concentration, as hydrogen peroxide. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.