ACOUSTIC TELEMETRY FROM FISH

Methods are described for monitoring physiological parameters s)Jch as temperature and electrocardio­ gram from free swimming fish. Information is telemetered as sound radiating from an acoustic transmitter implanted on the fish. Limitations of the technique and construction details of representative devices are covered. Uses in both behavior and physiology are considered. Acoustic telemetry allows an investigator to study the behavior and physiology of fish under conditions which approximate their natural state. Improvements in electronic techniques permit construction of devices the size of one's little finger; these devices can transmit data such as heartbeat and temperature over ranges of sev­ eral hundred meters for as long as a month. We describe here the use and constraints on sound as a means of transmitting these data. We then dis­ cuss, in detail sufficient for duplication, the con­ struction of sample devices for transmitting, re­ ceiving, and interpreting the data. Finally, we show how these devices have been applied to specific experimental problems, and discuss the results we have obtained.