Long-Term Activity Recording in Small Aquatic Animals

Abstract

We have built an activity-recording device based on the principle of detecting slight changes in the heat conductance of an aquatic environment by means of a thermistor. A major advantage of the device is that it can be used with a simple event recorder, thus combining high sensitivity with low cost. The equipment has been tested with automatic mechanical stimulation, and has been used for long-term recording of the swimming of small marine crustaceans. Problems of stability and reliability have been solved, and potential applications of the device seem widespread.