EFFECT OF CERTAIN ELECTRICAL PARAMETERS AND WATER RESISTIVI- 

 TIES ON MORTALITY OF FINGERLING SILVER SALMON 



By John R. Pugh, Fishery Research Biologist 



Bureau of Commercial Fisheries 



Biologists liave been searching for many years 

 for an effective method of diverting sahnon 

 fingerhngs from hazardous areas, such as turbine 

 intakes, spillways, and high-velocity channels. 

 In their search, they have explored the possi- 

 bilities of phj^sical barriers, sound-producing 

 instruments, air bubbles, lights, controlled water 

 velocities, chemicals, and electricity. 



To further this research, the electrical guiding 

 project of the Bureau of Commercial Fisheries 

 Biological Laboratory, Seattle, Wash., conducts 

 extensive studies to determine the effectiveness of 

 guiding or diverting sahnon fingerlings with 

 electricity. We have progressed from small-scale 

 laboratory studies to field sites on small streams ' 

 and, currently, to a large-scale field investigation.^ 



With each of these field studies there has been 

 associated laboratory work to determine whether 

 the electrical conditions to be tested are harmful 

 to the fish. Collins, Volz, and Trefethen (1954) 

 found that mortality increased with an increase 

 in total voltage, pulse frequency, duration of 

 exposm'e, water temperature, or with combinations 

 of these factors. Raymond (1956) noted a slight 

 loss in fish in tests with duty cycles of 0.10 or 

 greater. Maxfield ^ found, over the range of 

 electrical conditions which he tested, that the 

 electric shock did not affect the future reproduc- 

 tive ability of young rainbow trout exposed as 

 yearling fish. Trefethen (1955) and Newman 

 (1959b) conducted laboratory investigations in 

 guiding sahnon fingerlings with electricity, but 



Note.— Approved for publication, June 21, 1961. Fishery Bulletin 208. 



' Hunter, Charles J. Manuscript in preparation. Experimental guiding 

 of salmonids by electricity. Bureau of Commerlcal Fisheries Biological 

 Laboratory, Seattle, Wash. 



'Mason, James E., and Rea E. Duncan. Manuscript in preparation. 

 Development and appraisal of methods of diverting fingerling salmon with 

 electricity at Lake Tapps. Bureau of Commercial Fisheries Biological 

 Laboratory, Seattle, Wash. 



' Ma.xfield, Galen H. Manuscript in preparation. Effect of electricity on 

 reproductive ability of rainbow trout. Bureau of Commerlcal Fisheries 

 Biological Laboratory, Seattle, Wash. 



made httle or no mention of mortality; however, 

 personal interviews with each investigator revealed 

 that very few mortalities occurred in cither 

 experiment. 



The potential application of electrical guiding 

 techniciues depends on the degree of safety, as 

 well as efficiency, with which electrical fields guide 

 or divert fish. Although observations indicate 

 that the number of injuries and mortalities caused 

 bj' electrical fields is negligible, the question of 

 mortality invariablj' arises with each new experi- 

 mental method of diverting fish with electricity. 



The objective of this study was to determine, 

 under controlled laboratory conditions, the im- 

 mediate and delayed effects of certain electrical 

 parameters and water resistivities on the mortality 

 of fingerling silver salmon {Oncorhynchus kisutch). 



Rea E. Duncan and Donald D. Worlund 

 assisted in the planning of the experimental design 

 and in making the statistical analyses, and Charles 

 C. Gillaspie was responsible for the operation and 

 maintenance of the electronic equipment. 



METHOD AND MATERIALS 



Experimental design 



The experiment was conducted in Latin square 

 sequence using water resistivity, wu'ing pattern, 

 pulse shape, voltage, and frec[uency as variables 

 (see table 1). Throughout tlie experiment the 

 pulse duration was 8.3 milliseconds, the water 

 deptli 1 foot, and the average water velocity 1 foot 

 per second. Some of these experimental con- 

 ditions were similar to conditions tested in earlier 

 research. This similarity enabled us to correlate 

 the results of this experiment with our previous 

 studies. Other conditions were more rigorous in 

 an attempt to establisli the maximum level of 

 electrical intensity that could be used at future 

 installations without causing mortalities among 

 the migi-ating fish. 



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