and a cathode placed in various positions downstream from the electro- 

 mechanical weir. Three different cathode locations were tried in a 

 series of tests of this system. 



Operation and testing procedures 



The electromechanical weir and trap was operated almost con- 

 tinuously from May 9 until June 8 with interruptions only for changes 

 in circuitry and electrode configuration. It was originally intended 

 that the permanent Ocqueoc River sea lamprey weir and trap,, located 

 about 200 feet upstream from the electrical device, should serve as a 

 checking structure of the effectiveness of the electromechanical weir. 

 To a certain extent the permanent weir and trap served this checking 

 function and catches in both devices were compared regularly through- 

 out the test period. However, small escapements of migrants through 

 the electrical device occurred during periods in which the power was 

 shut down for the purposes of making certain checks and measurements. 

 The permanent weir and trap, therefore, could not serve as a true 

 measure of the efficiency of the electrical device. All conclusions 

 concerning this device are based primarily on direct, visual observa- 

 tion of the very large sea lamprey run entering the river during the 

 period of the tests. Fairly clear water, low river levels and good 

 observational facilities left no doubt in the investigators' minds as 

 to the effectiveness of the device under any of the applied conditions. 



At least two men were present during every hour of operation, 

 observing the individual behavior of lampreys and fishes approaching 

 and/ or entering the electrical field. Observations at night were aided 

 by several spot-lights. 2/ Service crews emptied the traps of both the 

 electromechanical device and the checking weir regularly and turned over 

 catch records to the observers on duty as supplemental evidence concern- 

 ing the device's efficiency at any given time. 



In the initial tests a 2 : 1 voltage ratio was maintained be- 

 tween the upstream and downstream rows of electrodes. Numerous voltage 

 levels ranging from 1^0/75 down to £0/2!? were employed. Power consump- 

 tion at these limits was approximately 9 KW and 1 KW, respectively, vary- 

 ing slightly with water level. Further tests were conducted maintaining 

 a voltage ratio of 1 : 1 between the upstream and downstream rows of 

 electrodes. Voltage levels were employed ranging from UO/llO down to 

 3>0/5>0. In these tests, power consumption ranged from 7.5 KW to l.k KW. 



2/ It is a point of some biological interest that in none of our obser- 

 vations did we find that illumination of any intensity, within the range 

 which we employed, had any effect on the normal migratory behavior of the 

 sea lampreys. 



