474 



MECHANICAL AND ACOUSTICAL SENSES 



Daily Movement, Home Range 



The most basic information obtained from telemetry of a free-ranging 

 animal is the individual's location throughout the tracking, from which its 

 home range, day -night movements, and so forth, can be plotted as was 

 done by Standora (1972) for the Pacific angel shark (Figure 26). This is 

 the original purpose of ultrasonic fish tracking, and it can be accomplished 

 with simple pingers without sensors, which yield approximate location as a 

 function of signal strength and direction. Better plots can be obtained, how- 

 ever, by using one of the systems more suitable to accurate location fixing, 

 e.g., transponding, timefix, or multiple-receiver arrays (Table 1). 



meters 



SANTA CATALIXA ISLAND 



Figure 26 Positions of nine angel sharks, each tracked by E. Standora 

 for approximately one day-night cycle. The two individuals retaining the 

 transmitters beyond the first day (no release mechanism) were relocated 

 3 days later at the positions indicated, still within the general home area. 

 All transmitter applications were at Ship Rock. (From Standora and 

 Nelson 1977.) 



