Uj 



o 



1 — 



1. Willard National Fish Hatchery (truck loading site) 



2. Drano Lake (barge loading site) 



3. Downstream Bonneville Dam (barge release site) 



4. Little White Salmon River Hatchery (homing site) 



Snake 

 River 



McNary Dam 



John Day Dam 



OREGON 



40 



_L_ 



80 km 



_l 



FIGURE l.— Lower Columbia River and features of the study on transported coho salmon. 



ment were to 1) determine if juvenile coho salmon 

 transported by barge around Bonneville Dam would 

 return as adults to the Little White Salmon River 

 Hatchery and 2) determine if survival to the adult 

 stage could be enhanced by barging the fish around 

 Bonneville Dam. 



Methods 



Two lots of coho salmon from Willard Hatchery 

 were identified by tagging with magnetic microwire 

 tags (Ebel 1974), and adipose fins were excised from 

 fish in both lots to identify them as wire-tagged. A 

 control lot (20,625 fish) was released at the hatchery 

 on 18 April 1977. On 22 April 1977 the test lot 

 (19,785 fish) was transported by tanker truck about 9 

 km to Drano Lake on the Columbia River, where the 

 fish were loaded via flexible hose onto a waiting 

 barge. Shortly after loading, the barge departed; 

 about 4 h later the coho salmon were released into the 

 river downstream from Bonneville Dam. 



The barge, with a steel cargo tank 33.2 m long X 8.5 

 m wide, was essentially a floating raceway (McCabe 

 et al. 1979). One or two stern pumps supplied river 

 water to a bow spray bar. After exiting the spray bar, 

 water flowed through eight screened compartments 

 and exited via four stern overflow scuppers. One 



complete turnover of water took about 20 min with 

 both pumps operating. 



Evaluation of the effectiveness of barging was 

 based on a comparison of the percentage of fish from 

 control (hatchery-released) and test (barged) lots 

 that either 1) returned to the Willard Hatchery in the 

 fall of 1977 (these early-arriving fish were precocious 

 males), 2) returned to the hatchery in 1978 as full- 

 term adults, or 3) were intercepted by commercial or 

 sport fisheries. Adult fish returning to the Willard 

 Hatchery were collected in a trap at the Little White 

 Salmon National Fish Hatchery, located about 7 km 

 downstream from Willard Hatchery. All coho salmon 

 collected in this trap in 1977 and 1978 were ex- 

 amined for the wire tags used in this experiment. Tag 

 information on coho salmon caught in sport and com- 

 mercial fisheries was provided by fish and wildlife 

 agencies in Washington, Oregon, California, and 

 Canada. 



Results And Discussion 



Returns of coho salmon to the trap at Little White 

 Salmon Hatchery and to the fisheries (both sport and 

 commercial) are presented in Table 1. Total recover- 

 ies of tagged releases were 0.19% for the control 

 group and 0.39% for the test group. There was no dif- 



413 



