Table 5. — Fish-guiding efficiency {in percent) of the elec- 

 trode array (power on), without the array trap, for each 

 water velocity, test period, and fish species; values were 

 determined by subtracting percentage of fish collected with 

 the power off from percentage guided with the power on 



Table 6 was prepared from the above formula 

 and shows, by fish species, the adjusted fish-guid- 

 ing efficiency of the electrical system for each 

 experimental condition. Figure 16 shows the mean 

 percentage fish-guiding efficiency of the electrode 

 array (power on), without the array trap, for 

 each test velocity and species. In general, efficiency 

 was inversely related to velocity — it was highest 

 at 0.2 m.p.s., second highest at 0.5 m.p.s., and 

 lowest at 0.8 m.p.s. Mean guiding efficiency by 

 species was highest for chinook salmon, inter- 

 mediate for coho salmon, and usually lowest for 

 rainbow-steelhead trout. 



QUALIFICATIONS OF COMPUTATION METHODS 



Because tlie inclined-screen trap was several 

 liundred meters downstream from the array trap, a 

 slight delay existed between the time that fish of a 

 particular school or gi'oup entered the array trap 

 and the remainder of that school or group entered 



100 



0.2 



CHINOOK SALMON 

 COHO SALMON 

 RAINBOW-STEELHEAD TROUT 



0.5 

 VELOCITY (M.P.S.) 



0.8 



FiGUBE 16.— Fish-gulding efficiency (mean i)ercent) of the electrode array (power on), 

 without the array trap, for each water velocity and fish species. 



322 



U.S. FISH AND WILDLIFE SERVICE 



