as to be non-orienting. No difference 

 could be detected among them in guiding 

 effectiveness, demonstrating that the effec- 

 tiveness of a single-row array is due to 

 avoidance rather than to electrotaxis. 



When release lots of 15, 50, and 100 

 fish were used, a decrease in variance 

 occurred with am increase in size of fish 

 release groups. The mean effectiveness, 

 however, for all the release lot sizes was 

 similar. 



ACKNOWLEDGMENTS 



The stock of silver salmon fingerlings 

 and the necessary fish food were provided 

 by the Washington State Department of Fish- 

 eries through the cooperation of the super- 

 visor of hatcheries, C. E. Ellis, Eind 

 personnel of the hatchery at Issaquah, Wash- 

 ington. Their cooperation and assistemce 

 are appreciated. 



LITERATURE CITED 



COLLINS, GERALD B. , CHARLES D. VOLZ, 

 AND PARKER S. TREFETHEN 



1954. Mortality of salmon fingerlings 

 exposed to pulsating direct current. 

 U. S. Fish and Wildlife Service, 

 Fishery Bulletin, No. 92, vol. 56, 

 pp. 61-81. 



RAYMOND, HOWARD L. 



1956. Effect of pulse frequency and 

 duration in guiding salmon finger- 

 lings by electricity. U. S. Fish 

 and Wildlife Service, Research Report 

 43, 19 pp. 



SNEDEOOR, GEORGE W. 



1950. Statistical methods. 4th ed. , 

 4th printing. Iowa State College 

 Press, 485 pp. 



TREFETHEN, PARKER S. 



1955. Exploratory experiments in guiding 

 salmon fingerlings by a naorrow d.c. 

 electric field. U. S. Fish and 

 Wildlife Service, Special Scientific 

 Report--Fisheries No. 158, 42 pp. 



