Recent biotelemetry research on lacustrine salmon homing migration

摘要

One of the most interesting aspects of the salmon's life history and the most challenging to study is the homing migration during which the fish return from their oceanic feeding grounds to the natal river to spawn. However, because of the difficulties encountered in studying the movements of fish, particularly in the sea, there is still very little information regarding this phase in the life cycle of the salmon. Lake Toya in Hokkaido, Japan supports populations of both lacustrine sockeye salmon (Onchorynchus nerka) and masu salmon (O. masou). The lake provides an ideal model for an "oceanic system" where the physiological and behavioral basis of the homing migrations of salmon can be studied. Previously a number of studies have been undertaken in Lake Toya using biotelemetry techniques to investigate and describe the homing migratory behavior of mature and sockeye salmon. The three principal biotelemetry techniques that have been utilized include ultrasonic telemetry, elec-tromyographic telemetry and micro data logging telemetry. Each of these techniques has been shown to have advantages and disadvantages in describing the movements of adult salmon. Therefore, it was decided to combine all three techniques in a single system and develop a robotic tracking platform (robot boat) that encompassed three interrelated telemetry systems, acoustic telemetry, a signal processing system and a telecommunication system for transmission of data between the boat and a land based station. This review describes the new technology that has provided the opportunity to investigate the physiological and behavioral basis of salmon homing migration using the unique Lake Toya lacustrine salmon model.