FISHERY BULLETIN: VOL. 78. NO. 2 



cept for steelhead returns to Dworshak Hatchery 

 from releases in 1971, transport/control ratios 

 computed from these data indicated that the ben- 

 efits from transportation were greater than those 

 indicated from returns to Little Goose Dam. 



This was particularly evident in returns of 

 chinook salmon and steelhead from releases in 

 1973. At Little Goose Dam the combined 

 transport/control ratio was 15.4:1 for chinook 

 salmon and 13.4:1 for steelhead; the ratios at the 

 hatcheries were 23.5:1 for chinook salmon (Rapid 

 River Hatchery) and 16.4:1 (Dworshak) and 28:1 

 (Pahsimeroi) for steelhead. One possible reason 

 for the difference might be a differential in benefit 

 which favored hatchery stocks. Because returns to 

 Little Goose Dam were a mixture of hatchery and 

 wild stocks, the proportion of each stock in a sam- 

 ple could alter the transport/control ratio. 



Spawning ground surveys for adult chinook 

 salmon were conducted in 1972, 1973, 1975, and 

 1976. No surveys were made in 1974 because of the 

 small number of marked fish available for recov- 

 ery. The location of streams surveyed was identi- 

 cal to that described by Ebel et al. ( 1973). Fourteen 

 marked fish were recovered during the 4 yr of 

 surveys. Of these, 12 were identified as having 

 been released as transports and 2 as controls. Al- 

 though the recoveries of adults on the spawning 

 grounds were very low, recoveries at Rapid River 

 Hatchery were substantial (Table 14). The fact 

 that 12 adult fish, transported as juveniles from 

 Little Goose Dam, were recovered on the spawning 

 grounds indicates that transported wild stocks as 

 well as hatchery stocks continued their upstream 

 migration after leaving Little Goose Dam. 



Straying of Experimental Groups 



The chinook spawning grounds of the Okanogan 

 and Methow Rivers and other spring chinook 

 hatcheries in the Columbia River drainage were 

 checked to determine if adult returns from release 

 groups had "strayed" to spawning locations other 

 than their parent stream or hatchery. No strays 

 were indicated in checks of hatcheries and spawn- 

 ing areas in the Columbia River above the mouth 

 of the Snake River, but a few strays (16 chinook 

 salmon and 3 steelhead) were recovered at Pelton 

 Dam on the Deschutes River in Oregon. Of the 16 

 chinook salmon recovered, 10 were from groups 

 transported as juveniles, 2 from controls, and the 

 remaining 4 could not be positively identified as to 

 release group because tag codes were lost. The 



502 



three steelhead recovered were also from groups 

 transported. These recoveries indicate that the 

 homing behavior of a portion of the chinook salm- 

 on transported as juveniles may have been ad- 

 versely affected. However, the proportion of the 

 transported groups affected to this degree must 

 have been small; 857 chinook salmon and 2,720 

 steelhead were identified at Little Goose Dam 

 from the same release groups. The homing be- 

 havior of these fish obviously was not damaged. 

 Additional data are needed to quantify the degree 

 of straying that occurs from transporting 

 steelhead and chinook salmon from Little Goose 

 Dam. 



DISCUSSION 



Comparison of Results With Other Studies 



The results of this study are similar to an earlier 

 study done by Ebel et al. (1973) in which survival 

 was definitely increased by transporting the fish 

 downstream as juveniles. Percentage returns of 

 adults to Little Goose Dam from transported fish 

 were greater than that from control fish for the 

 Dalton Point as well as the Bonneville Dam re- 

 lease sites for all 3 yr. However, the estimated per- 

 centage returns of chinook salmon were much 

 lower than those reported by Ebel et al. (1973) 

 when fish were collected and transported from Ice 

 Harbor Dam in 1968. Estimated returns of adult 

 chinook salmon, transported as juveniles from Ice 

 Harbor Dam, ranged from 4.3 to 9.0%; whereas, 

 returns of adult chinook salmon, transported as 

 juveniles from Little Goose Dam in this study, 

 ranged from 0.11 to 0.78% — substantially lower 

 than achieved at Ice Harbor Dam. 



There are several factors which could have 

 caused the lower percentage returns from Little 

 Goose Dam: 1 ) some homing ability may have been 

 lost because the fish were intercepted and trans- 

 ported from a location about 130 km farther up- 

 stream; 2) the fish collected at Ice Harbor Dam 

 may have been more hardy individuals because 

 they migrated a greater distance, which would 

 have allowed more of the weaker individuals to be 

 eliminated from the populations; 3) the stocks col- 

 lected at Ice Harbor Dam in 1968 were primarily 

 wild stocks and thus hardier — more able to stand 

 the stress of handling, marking, and hauling; or 4) 

 the general condition of the fish at the time of 

 marking may have been better because the collec- 

 tion, handling, and hauling system used at Ice 



