Bivalve molluscs as biosensors of water quality: state of the art and future directions

Abstract Biological early warning systems (BEWSs) monitor the behaviour or physiology of living organisms as an indirect mechanism to sense local environmental changes, and have become a widely established tool for monitoring water pollution. Complementary conventional chemical physical techniques, their strength lies in ability continuously quality, providing direct rapid toxic discharges. Bivalve molluscs (mussels clams) are ideal sensing BEWSs, owing their: high filtration capacity; sensitivity numerous, diverse pollutants; considerable longevity; abundance; wide range responses change. Two behavioural metrics bivalves dominated ecotoxicological studies, consequently spawned development into BEWSs: valve movements, typically measured using electromagnetic techniques; bivalve cardiac activity, infrared photoplethysmography. However, other, less studied behaviours may exhibit pollutant impacts, including shell growth dissolution, premature egg/larval release, horizontal movement, burial. Such may, with further research, provide bases future some through current movement technology, others potentially acoustic telemetry. Future bivalve-based BEWSs more informative sensitive greater nuance that integration different simultaneously and/or multi-species monitoring. directions seek techniques reduce disturbance enable observation natural mode behaviour, untethered, entirely unequipped, specimens. With rigorous controls individual- population-level variation, great power biosensors and, bolstered by scope advancements, this field has potential make significant contributions quality management.