Effects of chemicals on mobility in the bivalve mollusc Dreissena polymorpha

The freshwater bivalve Dreissena polymorpha is largely used in ecotoxicology for applications including biomonitoring, based on tools including measurement of sub-individual effects (i.e. biomarkers). Technological advances and the increasing occurrence of neuroactive compounds in the environment have led to studies increasingly focusing on the behaviour of aquatic species in ecotoxicology. This could provide potentially sensitive and/or early individual behavioural responses as toxicity indicators. This study aimed to investigate the effects of seven chemicals on the mobility of mussels after dislodgement, using continuous motion tracking (i.e. video tracking). Several metrics were used to describe mobility, based on motility and metrics for distance travelled. Mussels exposed to fluoxetine were particularly more likely to move significantly sooner and over larger distances. Other chemicals may induce non-linear responses with bell-shaped patterns. Behaviour could expand the range of biological responses studied, often on a sub-individual level, in ecotoxicology. More in-depth study of behavioural endpoints in Dreissena polymorpha appears promising, as this could provide potentially sensitive and/or early individual responses integrating physiological endpoints up to highest level.