Table 1. — Summary of test and control releases of coho salmon 

 from Willard National Fish Hatchery and returns to the hatchery and 

 fisheries. 



'Only precocious males were recovered at Bonneville Hatchery. 



'Numbers of fish landed in the following areas: Washington 5; Oregon 1 6; Califor- 

 nia 3. 



3 Numbersof fish landed in the following areas: Washington 20; Oregon 34; Califor- 

 nia 7; Canada 1 



ference in hatchery returns between the control and 

 test groups; however, there was a highly significant 

 difference between the two groups in returns to the 

 fisheries (Table 2). The overall contribution to the 

 fisheries was 170% greater (adjusted for the differ- 

 ence in numbers released) from the test group than 

 from the control group. 



Although it was expected that both groups of fish 

 (controls were released 4 d earlier) would mix below 

 Bonneville Dam and encounter the same environ- 

 mental conditions, we do not know for certain that 

 this occurred. However, when the catches were 

 separated by fisheries in Washington, Oregon, and 

 California and compared, the proportion of test to 

 control fish did not differ significantly from one 

 fishery to another (chi-square, df = 2, P>0.05), in- 

 dicating that the test and control groups were mixed 

 as adults. Consequently, we believe the two groups 

 were adequately mixed as juveniles. 



The degree to which the trucking of coho salmon 

 from Willard Hatchery to the barge contributed to 

 their increased survival is unknown; no information is 

 available on juvenile mortality of the control group 

 during its migration from Willard Hatchery to Drano 



TABLE 2.— Chi-square tests of null hypotheses regarding catch and 

 return data on coho salmon in the Columbia River. 



Hypothesis 



Chi-square' 



Returns of adult coho salmon to the Little White Salm- 

 on River Hatchery are the same for transported (test) 

 as for nontransported (control) 



Coho salmon from the transport and control groups 

 contribute equally to sport and commercial fisher- 

 ies. 



Total returns of coho salmon (to fisheries and hatch- 

 eries) are the same for both transport and control 

 groups. 



0.00 



17. 55"* 



12. 64*** 



'Adjusted chi-square, using Yates correction for continuity. 

 ••* = /><0.001. 



Lake. Although coho salmon from the test group did 

 return to the Little White Salmon River (the homing 

 site) , the number of returns was smaller than expect- 

 ed, based on returns to the fisheries. This seems to 

 indicate that the homing ability of the test group 

 was impaired. 



Columbia River flow was unusually low (averaging 

 <4,245 m 3 /s) in the spring of 1977, and there was es- 

 sentially no water passing over the spillways at Bon- 

 neville Dam during the experimental release. 

 Consequently, fish released from the hatchery had to 

 pass Bonneville Dam via the turbines. These unusual 

 conditions no doubt contributed to the significantly 

 lower survival of the hatchery release. However, with 

 the completion of the second powerhouse at Bon- 

 neville Dam in the early 1 980's, reduction or elimina- 

 tion of spills will become an increasing reality. 

 Therefore, transportation may be a practical way to 

 enhance survival of salmonids reared in hatcheries 

 above Bonneville Dam. 



Other researchers have studied the effect of trans- 

 portation on the survival and homing ability of Pacific 

 salmon and steelhead in the Columbia River system. 

 Ebel et al. (1973) collected migrating juvenile chi- 

 nook salmon, 0. tshawytscha, and steelhead trout at a 

 lower Snake River dam and transported them via 

 tanker truck to a release site downstream from Bon- 

 neville Dam. Based on the number of returning 

 adults, they concluded that survival of the transport 

 group was higher than that of the control group; in ad- 

 dition, the homing ability of the transported fish was 

 not impaired. Slaticketal. (1975) also concluded that 

 the homing process of chinook salmon and steelhead 

 trout transported from the same lower Snake River 

 dam had not been impaired. Ellis and Noble (1960) 

 were unable to increase adult returns to the Klickitat 

 Hatchery (Fig. 1) by transporting juvenile fall chi- 

 nook salmon; both trucks and a screened barge were 

 used in their tests. In the barge test, fall chinook 

 salmon from the Klickitat Hatchery were loaded into 

 the barge (from a truck) at the confluence of the Klick- 

 itat and Columbia Rivers, transported 265.5 km 

 downstream, and released. Returns to the Klickitat 

 River were less for fall chinook salmon barged as 

 juveniles than for hatchery-released controls; also 

 there was considerable straying among returning 

 transported adults. Adult returns were less for fall 

 chinook salmon transported as juveniles in trucks 

 from the Klickitat Hatchery and released in the lower 

 Columbia River than were returns from hatchery- 

 released controls. Ebel et al. (1973) and Slatick et al. 

 (1975) transported juvenile salmonids that were ac- 

 tively migrating and had completed part of their 

 seaward journey, whereas Ellis and Noble's (1960) 



414 



