ABSTRACT 



Special sonic devices are being developed for obtaining detailed information on 

 individual fish behavior. A miniature underwater sonic tag is attached to an adult 

 salmon and the movements of the fish are observed on calibrated sonic receiving 

 equipment. The position of the fish can be pin-pointed, and movements plotted for 

 periods of time up to 100 hours. The equipment can be used in varied hydraulic 

 conditions and in fresh or salt water to track the movements of adult fish and other 

 aquatic animals . 



The transducer is attached behind the dorsal fin of adult salmon by a nickel - 

 chromium "hog-ring" clamped into the back with special pliers. It is attached 

 underwater without handling or immobilizing the fish. Visual observations indicate 

 that the transducer does not affect the natural movements of an adult salmon. 



CONTENTS 



Page 



SONIC EQUIPMENT 1 



Miniature underwater sonic transducer (sonic tag) 1 



Automatic -tracking receiver 4 



Portable receiver 5 



ATTACHMENT OF TRANSDUCER TO ADULT SALMON 5 



Materials and methods 5 



Effect on natural behavior 5 



USES OF SONIC EQUIPMENT 10 



SUMMARY 10 



ACKNOWLEDGMENTS 11 



REFERENCES 11 



