presumably some adults could have passed up- 

 stream through the navigation locks at Ice Harbor 

 and Little Goose dams. 



Throughout this section of the report, percent- 

 age figures are given which indicate either an 

 increase or decrease in survival of groups of 

 juveniles transported downstream in comparison 

 to control groups not transported but released 

 near the collection point. Some of the increases are 

 statistically significant, some are not; generally 

 those that are significant are indicated. We 

 present the data even though some of it is not 

 statistically significant because it parallels earlier 

 data reported by Ebel et al. (1973). 



The combined adult returns— of spring- and 

 summer-run chinook salmon from juveniles 

 transported from Ice Harbor Dam and, sub- 

 sequently, released at Bonneville Dam— were 

 greater than adult returns from control releases 

 made at Ice Harbor Dam. The combined transpor- 

 tation benefit (Table 2) for spring- and summer- 

 run chinook salmon released in 1969 was 27%; in 

 1970, 47%. 



An analysis of comparative survival to adults 

 for spring- and summer-run chinook salmon by 

 year of transport are presented in Table 3. The 

 transportation benefit indicated for juveniles 

 released in 1969 was 27% for spring-run chinook 

 salmon and 29% for summer-run chinook salmon. 

 Benefits from the 1970 release were 40% for 

 spring-run chinook salmon and 57% for summer- 

 run chinook salmon. 



Combined spring and summer adult returns 

 from the John Day release were 34% less in 1969 

 and 65% less in 1970 than returns from the con- 

 trols. Although the lower adult returns from 

 juvenile releases at John Day are unexplained at 

 this time, it is possible that the cumulative stress 

 from collection, handling, and hauling combined 

 with the stress from having to pass two dams (The 

 Dalles Dam and Bonneville Dam) may have been 

 detrimental for fish released at this site. 



Returns of Adult Steelhead Trout to Ice Harbor 

 and Little Goose Dams 



Table 4 lists the returns of adult steelhead trout 

 (released as juveniles in 1969-70) that were suc- 

 cessfully detected, separated, and identified at the 

 automatic separator at Ice Harbor and Little 

 Goose dams. We identified 148 adult steelhead 

 trout from those released in 1969. Of these, 46 were 

 from the control release and 102 from the John 

 Day transport release, which give a transportation 

 benefit of 174%-a significant (X^ = 34.370; df = 1) 

 increase. 



Adult steelhead trout returns from the 1970 

 juvenile releases totaled 324 fish. Of these, 71 were 

 from the control release, 75 from the John Day 

 transport release, and 178 from the Bonneville 

 transport release. The transportation benefit from 

 the Bonneville release was 47% (X- = 7.315; df = 1); 

 however, no benefit was derived from transport of 

 juveniles to the John Day release site (adult re- 



Table 3. -Comparison between transported (released at Bonneville and 

 John Day dams in 1969-70) and nontransported (control) groups of chinook 

 salmon based on numbers of transported and nontransported juvenile fish 

 recaptured as adults at Ice Harbor and Little Goose dams, 1971-73. 



'Seasonal races of chinook salmon in the Columbia River system are 

 classified as spring, summer, or fall chinook depending on the time of year 

 that the adults enter the river to spawn. 



^Numbers recaptured adjusted in relation to numbers released (Table 1). 



927 



