A MINIMALLY INVASIVE TECHNIQUE TO MONITOR VALVE-MOVEMENT BEHAVIOR IN BIVALVES

A real time, minimally invasive method to observe valve movement of bi valves using proximity sensors and a personal computer has been develo ped. The method is being evaluated as a tool to assess both episodic t oxicity events and ambient toxicity. The method described minimizes co ntact with the animal to the anchoring of one valve and the placement of a small aluminum foil disk on the other valve, and allows the measu rement of the distance that a clam's valves are open. Using proximity sensors and an aluminum foil target, valve movements of the Asiatic cl am, Corbicula fluminea were measured and digitally recorded using a da ta acquisition board and a personal computer. One advantage of this me thod is its use of readily available stock electronics. In its final f orm, we envision an in situ biological monitoring system using C. flum inea deployed in aquatic systems in association with automated physica l/chemical monitoring systems like those found at USGS gauging station s. A tool such as this could be used as a warning system to increase t he probability of detecting toxic events as they occur.