Seeding of the spatming gravel in 19^9 appeared to be successful. Since 

 this was a small run it gave th5 i9li9 adult soawners a selection of the beot 

 spaxvning gravel with a minimum possibility of crowding. The 19^9 run did not 

 fare well during the upstream Migration however. Only uO percent of the 

 bluebacks were counLed past Rock Island Darii (table 1) 5 and only a small por- 

 tion of the remaining population reached the spawning grounds above. 



Seeding of the spawning grounds in 1951 probably will not be as success- 

 ful as Rock Island counts indicate because of injuries lAiich may have resulted 

 from partial blockage and delay at McNary Dan,. It is estimated that 8 per- 

 cent of the females had internal injuries which affected the ripening of 

 part or all of the eggs. Discussion on this subject will follow. Spawning 

 conditions J otherwise^, were favorable for blueback that survived without 

 injury during the upstream migration of 195l. 



SURVIVAL IN THE REARING LAKE 



Bluebacks normally remain during their first year in Lake Wenatchee 

 or Lake Osoyoos and migrate seaward in their second year. Other species 

 compete Td.th them for food and predatory fish reduce their number during 

 the time they remain in the lakes. Experimental predatory-fish sampling 

 by means of gill-nets was done in Lake Wenatchee during 19li9-$l to deter- 

 mine what species inhabited the lake and to what extent they were preying 

 on the Kokanee (landlocked bluebacks) and the young sea-run bluebacks which 

 cannot be distinguished from each other. Four species., squawfish ( Ptycho - 

 cheilus Oregon ensis) J, suckers (Catostomus species') , Dolly Varden ( Salvelinus 

 malma) , and whitefish ( Prosopium species)^ were taken by gill-net, T^ro 

 species which were found to contain identifiable 0^ nerka (bluebacks or * 

 kokanee) in their stomach contents, vp.re squawfish and Dolly Varden trout. 

 A total of 113 squawfish examined contained 12 0. nerka plus a number of sculpiHj 

 lampreys,, and unidentified partially digested fish. Thirty-nine Dolly Var- 

 den charrs contained a total of 26 0. "n erka in their stomachs, 



Ro E. Foerster and W. E, Ricker (I9U2) stated that the principal food 

 of squawfish in the Cultus Lake, British Columbia area is young sockeye salmon. 

 Their predator-control program conducted by means of gill-netting is re- 

 ported to have benefited the fishing industry by thousands of dollars. 



FUTURE 0? THE RUNS AND RECOMMENDATIONS 



The Columbia River blueback salmon runs face difficulties. The 

 Canadian government is planning a flood-control project which will destroy 

 more than 75 percent of the spawning area available to bluebacks m the 

 Okanogan region^ The stream which now vdnds through the Okanogan valley 

 will be straightened by channelizing and will have a series of low dams at 

 intervals along its course. This wj.ll be for the purpose of drawing off 

 water more rapidly from Lake Okanogan which lies to the north. Thousands 

 of square yards of suitable spawning rubble will thus be bypassed by the 

 new channel. 



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