Continuous remote monitoring of fish activity with restricted home ranges using radiotelemetry

Abstract

Signal strength received by a fixed antenna increased as a transmitter was positioned closer to it and decreased as the transmitter was positioned further away. Depth and transmitter orientation also influenced signal strength, but these were less pronounced than the effect of distance. The variations in signal strength recorded from fixed distances, depths or orientations were low, suggesting that variation in signal strength only occurs if the transmitter is moved. The use of signal strength variation as a measure of fish activity over a 24 h period was compared with observed patterns of point habitat use of a live fish. Close correspondence of assessments of activity using signal strength variation and habitat use was observed. This study demonstrated the potential utility of radiotelemetry in association with point-in-time habitat use data to determine home-range and diel and seasonal patterns of fish activity over 24 h periods. © 2001 The Fisheries Society of the British Isles.