488 U. S. BUREAU OF FISHERIES 



Thus we have absolute scientific proof that the operation of the 

 electric screen was in no way responsible for the electrocution of 

 salmon in the Rogue River and the unwarranted removal of this 

 screen from the tailrace of the Gold Ray plant has deprived the 

 river of an effective means of fish conservation. 



Check of fish in Yakwia ditches. — Check on the efficiency of the 

 electric screens in the Yakima country is obtained by observation of 

 fish found in the systems. As in the seasons of 1929 and 1930, 

 comprehensive check of fish left stranded in the system at the end 

 of the irrigation season was made and, in addition, during the past 

 summer special checking operations were conducted at strategic 

 points in the Sunnyside and Wapato systems. Likewise, W. N. 

 Wagner, the bureau's inspector, paid close attention to the fishing 

 conditions reported to exist in the canal systems and the rivers and 

 himself fished these waters on numerous occasions for the purpose 

 of obtaining data at first hand. 



In the Sunnyside Canal (ditch capacity, 1,500 second-feet) ; irri- 

 gation season February 20 to October 20; main canal, 60 miles long; 

 electric fish screen installed) check of the fish left stranded at the 

 end of the season showed the following: 75 salmon, 807 trout,^ and 

 36,300 whitefish. 



As in the past, cull fish (suckers, squawfish, chisel mouth, etc.) 

 predominate all other types. The great amount of whitefish found 

 this year as well as last indicates that the electric screen is not effi- 

 cient against this species. It is the opinion of competent observers 

 that the bulk of the whitefish enter the system when they are very 

 small (perhaps about l^^^ inches long), which is the time when the 

 electric screen would be least effective against them. 



In addition to this comprehensive check made at the end of the 

 season, a special check was conducted early in the summer in lateral 

 71.66 (Benton extension) at the lower end of the Sunnyside system. 

 This location was the point at which some 10,000 young salmon were 

 rejDorted last year. The check was made by placing a stationary 

 screen at an irrigation drop. The check was continued over the 71- 

 hour period from noon June 18 to 11 a. m. June 21, during which 

 period observers were in constant attendance. The flow of the lateral 

 at the checking point was 35 second-feet. Results showed but 36 

 young salmon, no trout, 3 whitefish, and 517 cull fish. This check 

 was made at a time when large schools of young salmon and trout 

 were observed near the intake at Sunnyside Dam. 



Salmon and trout were especially numerous in the Yakima River 

 this year, and the small number of anadromous fish found in the 

 system indicates that the electric screen functioned to prevent the loss 

 of a large percentage of these fish. 



The best possible comparison between fish conditions as existing on 

 a screened and unscreened diversion in the Yakima country is fur- 

 nished by the check upon the Tieton and Selah-Naches systems. On 

 the Selah-Naches Canal, diverting about 300 second-feet and oper- 

 ated by a private irrigation company, there is no screening device of 

 any kind installed. Two checks of fish left stranded in the Selah- 



• Total of 807 trout includes 400 reported by a local fisherman who, with rod and line, 

 fished along 12 miles of canal and reported his own catch and those of several other 

 fishermen as well. 



