Review of Underwater Biotelemetry, with Emphasis on Ultrasonic Techniques

Abstract

Underwater biotelemetry includes studies of movements, behavior, and physiological functions of underwater animals, as well as environmental conditions surrounding them. In such studies data are received via signals from a transmitter on or in an animal. Ultrasonic signals were used in early work. More recently both ultrasonic and radio signals have been used.In the two decades since the first underwater biotelemetry studies in the mid-1950s there have been considerable technical advances. Transmitters have become smaller, more powerful, and have longer operating life. Coding of individual transmitters has become more reliable and decoding more automated. Transmitters capable of sensing environmental, behavioral, and physiological factors from free-swimming animals have been built. Receiving systems ranging from small ones for tracking from canoes to large ones for oceangoing vessels have been developed.With this equipment about 60 species of underwater animals have been studied. Various techniques of transmitter attachment have been developed and different methods of tracking explored.Underwater biotelemetry has been applied to studies of fish migration, orientation mechanisms, movement patterns at obstructions, ecology, behavior, and physiology of animals. Key words: telemetry, underwater biotelemetry, tracking, sonic tags, transmitters, receivers, hydrophones