Development of a Multichannel, Ultrasonic Telemetry System for the Study of Shark Behavior at Sea

摘要

A telemetry system is described which is capable of monitoring the behavior of free-swimming sharks in the natural environment. The transmitters emit 10 msec ultrasonic pulses at 40 kHz, have a life of up to one week, and a maximum range of over 3 miles. The units can transmit one, four, or eight channels of information using either of two types of electronic multiplexing: one interpulse interval/channel, or fixed time/channel. The pulse rate varies with the value of resistive sensors and ranges from .5/sec to 5/sec. Sensors are described for measuring depth, swimming speed, compass heading, ambient light, and temperature. Single-channel and multichannel transmitters have been used successfully and recovered from pelagic species (blue sharks, Prionace glauca) and from bottom-dwelling species (angel sharks, Squatina california). (Author)