Why publish Animal Biotelemetry?

“Biotelemetry” refers to the sending of biological measurements from a transmitter on an animal to a receiver. The information is transmitted either with an ultrasonic (kHz) or radio signal (MHz). The ultrasonic signal is propagated by a ceramic ring, or piezo-electric transducer (PZT), whereas the radio signal is propagated by a conductive wire, or antenna. Which mode of telemetry is chosen to remotely monitor the behavior and movements of animals depends on the transmission properties of the medium. Marine scientists have utilized ultrasonic telemetry because a signal composed of those frequencies propagates quickly with little attenuation in salt water, whereas radio signals are absorbed quickly in this medium. Scientists working in the freshwater and terrestrial environments have mainly utilized radio telemetry because the signals of those frequencies propagate far in freshwater and air. Telemetry has often been used to study large marine vertebrates because poor visibility has limited direct observation. Tagged marine fish were first followed by boat, while determining the direction of the subject with a directional hydrophone and estimating its position by situating the boat above it and recording a position. The first transmitters were beacons that enabled researchers to describe the daily offshore migrations of tunas off Hawaii [1]. Later tags were equipped with multiple sensors such as those used to record the depths and headings of scalloped hammerhead sharks, and the water temperatures and underwater illumination to understand their navigational abilities [2]. Additional sensors continue to be developed such as an accelerometer used to identify behaviors from records of an individual’s movement along three axes [3] and pH sensors to detect feeding by a change in pH in the stomach associated with digestion [4]. Shipboard tracking of animals is an arduous activity. The recent development of coded beacons and small automated receivers have made it possible to describe simultaneously the “homing” behavior of multiple individuals to