chinook and coho salmon were released in the 

 Snake River in 1964 and fall chinook and sockeye 

 salmon in 1965. Migrations from Eagle Creek near 

 the lower end of the reservoir included native 

 spring chinook salmon and rainbow trout. 



Progeny of spring chinook salmon from the 

 Weiser River were fish of age-group I that ranged 

 from 94: to 165 mm. long. This migration began 

 before but partially overlapped a migration of fall 

 chinook juveniles from the Snake River. The mi- 

 gration usually peaked in late April and early 

 May. Estimated numbers of fish were: 1962 — 

 122,500: 1963—15,000: 1964—6,800; and 1965— 

 3,200. 



The migration of juvenile fall chinook salmon 

 (age-group O) from the Snake River began in 

 mid-April, peaked in mid-May, and was almost 

 complete by mid-June. The fish were 33 to 103 mm. 

 long. Estimated recruitments to Brownlee Reser- 

 voir in 1962 and 1963 were 529,000 and 374,000. 

 Because few fish were passed above Brownlee Dam 

 after 1962, migrations of wild fish in 1964—65 were 

 negligible. 



Migrant salmon from Eagle Creek were of wild 

 populations of spring chinook salmon. The prin- 

 cipal migration of juvenile chinook salmon (age- 

 group 0; 53-125 mm.) was in the fall as irrigation 

 decreased and water flows correspondingly in- 

 creased. Temperatures ranged from 0° to 13° C. 

 A lesser migration of age-groups 0, I, and TI 

 (45-168 mm.) occurred in the spring. Estimated 

 recruitments from Eagle Creek were: 1962 — 

 117,200 (fall migration only) ; 1963—22,300; and 

 1964—7,200. 



Native juvenile kokanee salmon (70-155 mm.) 

 were observed in the Snake River each year in 

 June and July, except in 1962. Their migrations 

 were relatively short; most fish migrated in a 

 1-week period in late June or early July. Esti- 

 mated recruitment of this species was 500 in 1963, 

 5,500 in 1964, and 506,800 in 1965. 



Juvenile rainbow trout migrating from the 

 Snake River and Eagle Creek were wild steel - 

 head trout and wild and hatchery-reared rainbow 

 trout. The Snake River populations (95-382 mm.) 

 migrated in the spring from mid-March to late 

 July, peaking from mid- April to mid-May. Juve- 

 nile trout, 52-285 mm. long, migrated from Eagle 



Creek in the fall and spring, but the principal 

 movement coincided with high spring flows. 



Juvenile fall chinook salmon, reared in a hatch- 

 ery (age-group 0; 46-135 mm. long), were re- 

 leased in the Snake River above the reservoir 

 during March and April, 1964-65. Some moved 

 downstream past the trapping site within 3 days 

 after release, but the migration peaked in mid- 

 May, which was comparable to native migrations. 

 The migration ended in late June in 1964 and in 

 early July in 1965. Of 250,000 juvenile fall chi- 

 nook salmon released in 1964, 111,500 were esti- 

 mated to have entered the reservoir. In 1965, the 

 estimated recruitment was 162,800 of the 592,000 

 fish released. 



Hatchery-reared coho salmon yearlings (71- 

 166 mm.) released in middle to lat« March 1964, 

 migrated slowly; they appeared at the trap site 

 4 weeks after the first release, peaked during the 

 first week of May, and continued to migrate until 

 mid-June. Of the 375,000 coho salmon released, 

 69,000 entered the reservoir. 



Hatchery-reared sockeye salmon (86-175 mm.) 

 appeared at the Snake River trap 2 days after 

 their release in mid-March ; the migration peaked 

 in the first week of April and was complete by the 

 end of April. An estimated 360,000 of 473,000 fish 

 released entered the reservoir. 



Survival to the reservoir of hatchery -reared 

 salmon varied inversely with time spent in the 

 Snake River but was not related to distance of 

 planting site above Brownlee Reservoir. 



LITERATURE CITED 



Bates, Daniel W., and Russell Vinsonhaler. 



1957. Use of louvers for Riding fish. Trans. Amer. 

 Fish. Soc. 86 : 38-57. 

 CoNTE, F. p., H. H. Waoner, J. Fessleb, and C. Gnose. 

 1966. Development of osmotic and ionic regulation in 

 juvenile coho salnuxn Oncorhynchus kisutch. 

 Oomp. Biochem. Physiol. 18 : 1-15. 

 Deacon, James E. 



1961. A staining method for marking large numbers 

 of small flsih. Progr. Fish-Cult. 23 : 41-42. 

 DuKKiN, Joseph T., Donn L. Park, and Robert F. 

 Raleigh. 

 1970. Distribution and movement of juvenile salmon 

 in Brownlee Reservoir, 1962-65. U.S. Fish Wildl. 

 Serv., Fish. Bull. 68 : 219-243. 

 Ebel, AVesley J., and Charles H. Koski. 



1968. Physical and chemical limnology of Brownlee 

 Reservoir, 1962-64. U.S. Fish Wildl. Serv., Fish. 

 Bull. 67 : 295-335. 



216 



U.S. FISH AND WILDLIFE SERVICE 



