486 U. S. BUREAU OF FISHERIES 



found that a good many fish were passing through the electric screen 

 and being trapped between it and the trash rack. Accordingly, use 

 of this electric screen was discontinued late in May. It was found 

 that the newly improved fish ladder with its illuminated entrance 

 proved a very attractive by-pass for fish, even without the aid of a 

 screen in the intake. 



Gold Ray tailrace screen. — The first electric screen installed by 

 the Bureau of Fisheries in the tailrace of the Gold Ray power 

 l^lant of the California-Oregon Power Co., was put into operation 

 in the spring of 1929. Its purpose was to keep the mature upstream- 

 migrating salmon and steelhead out of the tailrace waters and headed 

 up the main channel of the river to the fish ladders at the dam. 

 For more than two years this screen operated, keeping the tailrace 

 waters entirely free of upstream migrants and accomplishing its 

 mission substantially without injury to the fish. Upon July 17, 

 1930, the old grounded type of screen was replaced by the new, im- 

 proved type, consisting of a double row of 6-inch diameter pipe 

 electrodes. The effectiveness of the new screen was early proved by 

 its successful operation against the fall run of silver salmon and 

 the run of steelhead which continued throughout the winter and 

 spring of 1931. 



On May 25 the Bureau of Fisheries was notified by an official 

 of the Jackson County Game Protective Association, a local sports- 

 mens' organization of Medford, Oreg., that hundreds of salmon were 

 being electrocuted at the Gold Ray installation. Investigation was 

 made May 27 and a large number of electrocuted salmon were found 

 in the main channel of the Rogue River below the Gold Ray power 

 plant. At this time, also, some salmon were found ahead of the 

 electric screen in the tailrace. It is evident that these salmon had 

 penetrated the screen very recently, for on April 25, when the site 

 was inspected, a good run of Chinook was in progress, with schools 

 of these salmon leaping in the tailrace just below the electric screen 

 and the tailrace above the screen was entirely free of salmon. 



A great deal of publicity had been given to the electrocution of 

 salmon in the Rogue River, and the electric-screen installation was 

 blamed for the condition. After field investigation on May 27 the 

 voltage of the tailrace screen was reduced from 65 to 50 volts, and 

 this potential was maintained for a short period of time, during 

 which observations could be made. On May 30 the officials of this 

 sportsmen's organization, acting without authority from the State 

 Commission of Oregon or the Bureau of Fisheries, prevailed upon 

 the vice president and general manager of the California-Oregon 

 Power Co. to order the screen disconnected. Upon June 1 the elec- 

 trodes were removed from the water. Upon June 2 and 3 the in- 

 vestigators, in company with representatives of the power company 

 and the sportsmen's organization, inspected conditions in the field. 

 At that time there were at least from 1,200 to 1,500 mature Chinook 

 salmon in the tailrace, these having come in within a few hours after 

 the electric screen had been deenergized. This was striking evidence 

 of the effectiveness of the electric screen in having prevented the 

 entrance of these salmon over a long period of time. At the end of 

 this conference the bureau was advised by the officials of the Jackson 

 County Game Protective Association that reinstallation of the tail- 



