Laboratory tests on other species . --Daring the first part of 

 the study a few black b-allheads ( Ameiurus m= melas), northern pike 

 (Esox luciu?)j and yellow perch (Perca flavesoe/i.?T were a-vailable„ 



Tests with these fish were made atwater tempei'atares of 36° to 39*^ F., 

 and at a time when the experinienT.,al condJ.Mons producing the Desb re- 

 sxilts with trout had not been deteiTninedo The bullheads were inactive 

 and could not be stimulated into appreciable movement. They gave little 

 outward sign of discomfort, at voltage gradients up to and including 

 those at which they were electronarcotized. 



The results obtained xjith northern pike indicated they waald 

 respond favorably if subjected to the right cambination of conditions. 



The small number of yellow perch restricted the number of 

 tests with this species. In a few triaj.s^ however^ the desired response 

 was obtained. The manner in which the perch responded was most unlike 

 that of the trout. In contrast to the rather violent and explosive 

 movement of the trout, movement of the yellow perch toward the anode was 

 slow, almost natural, yet persistent. 



Other laboratory tests . —The only other type of current tested 

 that yielded proirdsing results was half-wave, rectified, 60 cycle AC. 

 It was applied continuously and also pulsed at duty cycles of 0.25 and 

 0.66, This type of current caused involuntary movement of brook trout 

 tow3,rd the positive electrode, but the results were not as satisfactory 

 as those obtained with filtered DC at a. duty cycle of 0.66. LimitatioriS 

 in time and equipment prohibited investigation of other than essentially 

 squa:?e wave shapes. Studies of other wave shapes are desirable since it 

 has been shown by Groody, Loukaskkinj, and Grant (1952) that a somewhat 

 triangular wave was highly effecti've in controlling the movement of Paci- 

 fic sardines ( Sardinops caerulea) . The work of Kreutzer in Germany 

 (Houston,, I9I49) seems to be based on the use of a somewhat triangular- 

 shaped wave. 



Prospects and problernvS in the application 

 of an electrical leading device 



Laboratory tests demonstrated tb^t rainbow trout and brook 

 trout, subjected to an appropriate electrical stimulus, swam involuntarily 

 and persistently to the anode or positive electrode. The most satisfac- 

 tory results were obtained with pulsated direct current of an essen-tially 

 square wave shape at a duty cycle of 0.66 and a rate or frequency of 3 

 pulses per second. Direct current of tMs type can be used also under 

 field conditions to assemble white suckers and rainb^DW trout at the anode 

 or to cause them to enter a properly designed enclosure. 



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