The test facilities are housed on two 33.5 X 10.5 m 

 covered barges which are moored in the estuary at 

 Prescott, Oreg., on the Columbia River approximately 

 117 km (75 miles) downstream from Bonneville Dam 

 (Fig. 1). To simulate water quality conditions of the 

 Columbia River, water is pumped directly from the 

 river through the control and test tanks. 



Test Fish and Fish-Holding Procedures 

 Prior to Experiment 



Two species of test fish were used — coho and 

 Chinook salmon, all juveniles. The coho salmon were 

 obtained from the Washington State Department of 

 Fisheries hatchery on the upper Kalama River; the 

 chinook salmon were obtained from Little White 

 Salmon Hatchery, Bureau of Sport Fisheries and 

 Wildlife, near Carson, Wash. When they were taken 

 to the test facility, the coho salmon averaged 20 g in 

 weight and 127 mm in length; the chinook salmon 

 averaged 2.3 g in weight and 59 mm in length. The 

 fish were transported to the facility (in a l,5(X)-liter 

 hauling tank) in hatchery water maintained at the 

 same temperature as in the hatchery (10°C); holding 

 water temperature at the facility was 1°C lower than 

 the hatchery water temperature. The fish were held in 

 Columbia River water with a gas content of about 

 IW'c of saturation for approximately 10 days prior to 

 the beginning of the test. 



Because of mechanical failure, the test in the deep 

 tank was started 10 days subsequent to the other 

 tests. 



Test Tanks and Fish-Holding Procedures 

 During Experiment 



Three 1.8-m (6-foot) diameter redwood tanks were 

 used for fish holding — a deep test tank, a shallow test 

 tank, and a control tank. 



The deep test tank was supplied with water at a 



Figure 1.— Location of study area and National Marine Fish- 

 eries Service facility on the Columbia River near Prescott, 

 Oreg. 



flow rate of 75 liters/min; total capacity of the tank 

 was 6,400 liters. Water depth was maintained at 2.5 m 

 (8 feet). It was stocked (at beginning of test) with 950 

 subyearling chinook and 500 yearling coho salmon. 



The shallow test tank was supplied with water at a 

 flow rate of 75 liters/min; total capacity of the tank 

 was 2,800 liters. Water depth was maintained at 1 m 

 (3 feet). It was stocked (at beginning of test) with 505 

 subyearling chinook and 297 yearling coho salmon. 



River Wat«r 



CAS 

 EQUIUBRATOB 



1.2 nMters rattt 



l.z nettrs Ufk 



Figure 2.— Schematic diagrmta of boldiiig tank* and water supply system. 



2 



