Summary of results in 195>2 



(1) General 



The electromechanical weirs and traps as initially installed 

 in the Kewaunee River and Squaw Creek effectively killed, or diverted 

 and trapped, all sea lampreys moving upstream; they continued to func- 

 tion efficiently as reductions in electrode systems and changes in cir- 

 cuitry were made until deliberately altered so as to fall below the 

 threshold of 100-percent effectiveness. Mortality among simultaneous 

 fish runs meeting the electrical fields of these devices was negligible. 

 Unlike the similar device installed in the Ocqueoc River in 195>1 3 these 

 structures caused no significant blockade of migrant fishes. Such mi- 

 grants "led™ well along the fringe of the electrical field and readily 

 entered the electromechanical weir-traps. 



The electrical barriers as installed in Hibbards" Creek and 

 Carp Creek effectively blocked the movement upstream of all sea lampreys 

 and other migrant fishes. They likewise continued to function efficiently 

 as reductions in numbers of suspended electrodes were made until they 

 were deliberately rendered ineffective. 



Several simplified structures were developed from both the 

 electromechanical weirs and traps and the electrical barriers which, in 

 general, require less physical plant and power input than the pilot model 

 structures installed in 1952. These developments are embodied in three 

 recommended designs for electrical sea lamprey control devices which are 

 presented in the final section of this report. 



Although considerable effort has been directed at determining 

 effective electrical field patterns and voltage gradients (for blocking 

 sea lampreys) and at improving the mechanical design and electrical cir- 

 cuitry of developed structures, comprehensive and detailed investigations 

 of numerous variables having only a nominal effect on the operating effec- 

 tiveness and efficiency of the devices have not been made. Exploratory 

 researches only in such matters as the effect of varying water and bottom 

 resistivity on power drain or the effect of extremes in water level on 

 power requirements were conducted with the intent of providing "yardsticks" 

 or guides in designing equipment to fit specific streams in the immediate 

 future. Because of the urgency of the problem, a sea lamprey control pro- 

 gram, when effected, must operate as it grows. In such circumstances, 

 ample opportunity will present itself to evaluate further the effect of 

 these variables on the functioning of electrical mechanisms used. 



Specific findings obtained during the 195>2 season are incorpor- 

 ated in Sections 2 to 8 following. 



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