Effects of Cypermethrin (pyrethroid insecticide) on the valve activity behavior, byssal thread formation, and survival in air of the marine mussel Mytilus galloprovincialis.

Cypermethrin is a pyrethroid pesticide widely used to combat agricultural pests. However, little information is available about its toxicity in aquatic macroinvertebrates in the context of the Moroccan coastline. In this study, a suite of physiological and behavioral biomarkers for water quality surveillance using mussels are used to characterize the toxicity of Cypermethrin. In these tests, sublethal effects on valve activity behavior, byssal thread formation, and survival in air of the mussel Mytilus galloprovincialis were assessed in short-term exposure. The results show that Cypermethrin impaired the valve activity in a concentration-dependent manner, leading to a reduction in the time of normal opening. The lowest effect concentration was determined as 100 μg/l Cypermethrin. Prolonged closures of mussels were also observed for the exposures to 400 and 800 μg/l. The delay to the first detection of the pesticide was concentration dependent. The capacity to produce new byssus threads in a Cypermethrin exposure was inhibited at all concentrations and especially at high concentrations. Survival in air was not affected even at 800 μg/l Cypermethrin.