The interactive effect of anti-sea lice pesticide azamethiphos and temperature on the physiological performance of the filter-feeding bivalve Ostrea chilensis: A non-target species

The pesticide azamethiphos used by the salmon industry to treat sea lice, is applied as a bath and subsequently discharged into the sea. The effects of azamethiphos concentration (0, 15 and 100 mu g L-1) on the physiology of the Chilean oyster (Ostrea chilensis) at two temperatures (12 and 15 ?) was examined. In all azamethiphos treatments, oysters kept at 15 ? had clearance rates (CR) higher than oysters kept at 12 ?. The oxygen con-sumption rate (OCR) increased at higher temperatures, except with 100 mu g L-1 of azamethiphos, where no changes were observed. Sixty days after the exposure, survival rates of 91 and 79% (15 and 100 mu g L-1, respectively), were observed compared to the controls, a situation independent of the experimental temperature. The interaction between temperature and pesticide has detrimental effects on the physiological performance and survival of O. chilensis, and these effects should also be assessed for other non-target species.

Automated summary

The effects of azamethiphos concentration and temperature on the physiology and survival of Chilean oysters were examined. Higher temperatures and lower pesticide concentration resulted in higher clearance rates and oxygen consumption rates. However, the survival rates were lower when exposed to higher pesticide concentration, regardless of the temperature. The interaction between temperature and pesticide had detrimental effects on the physiological performance and survival of O. chilensis.