odes 



Figure 5. — Wiring diagram of electrode connections of array. 



These conditions were selected on the basis of 

 laboratory research to determine the optimum 

 conditions of a sequentially pulsed d.c, elec- 

 trical field to lead squawfish into enclosures 

 or traps (Maxfield, Liscom, and Lander, 1959). 

 The fish were released in the electrical field. 

 Frequencies of 2, 5, and 8 pulses per second 

 were tested; 2 pulses per second gave the best 

 results. To ensure that fish moving upstream 

 would encounter a frequency of 2 pulses per 

 second in the array at Cascade Reservoir, 

 each of its five electrode sections, or groups. 



were energized at this rate, or 10 pulses per 

 second for the total array. Because the results 

 in the laboratory with 5 pulses per second 

 were considerably inferior to those with 2, we 

 decided also to test 3 pulses per second per 

 array section, or 15 pulses per second for the 

 total array. As pulse duration and amplitude 

 might cause significant differences under these 

 conditions, two durations, 25 and 50 msec, 

 and two amplitudes, 140 and 180 v., were 

 tested. 



