The lethality of anti-sea lice formulations Salmosan® (Azamethiphos) and Excis® (Cypermethrin) to stage IV and adult lobsters (Homarus americanus) during repeated short-term exposures

Stage IV and adult lobsters (Homarus americanus) were exposed repeatedly to one of two pesticide formulations currently in use as anti-sea lice treatments: Salmosan(R) (azamethiphos) and Excis(R). (cypermethrin). Stage IV lobsters were affected by these exposures only at the highest concentrations and longest exposure periods but no deaths occurred. Exposure to concentrations equivalent to 10 or 25% of that recommended for sea lice treatment for periods of 15 or 30 min resulted in significant mortalities in adult lobsters. Adult lobsters exposed to Excis(R) were affected over a wider range of concentrations and exposure times than those exposed to Salmonsan(R). The No Observed Effect Concentration (NOEC) for azamethiphos and adult lobsters is 1.03 mu g/l (as azamethiphos) when exposed repeatedly for 120 min. The NOEC for Excis(R) is 0.025 mu g/l (as cypermethrin) when exposed repeatedly for 60 min. (C) 2000 Elsevier Science B.V. All rights reserved.