10 figs., 1 teble. 



ABSTRACT 



Model V was installed within the Stanfield li- 

 riKation Canal near Echo, Oreg. The Bureau of 

 Commercial Fisheries developed the screen to meet 

 the need for improved jruidinK of juvenile fish of all 

 sizes and to reduce capital and operational costs. 



Field tests with the model V screen showed a 

 head loss of only 9.1 mm. with waterflow of 73 

 centimeters per second. From 97 to 100 percent of 

 the juvenile migrant coho salmon, Oucorhyiichus 

 kisutch, and steelhead trout, Salmo gairdneri, that 

 entered the Stanfield Irrigation Canal were diverted 

 into a bypass. 



The self-cleaning screen, supported by a wire- 

 rope suspension system, traverses the 8..i m. wide, 

 1.8 m. deep, earth-lined section of the canal at a 20° 

 angle to the waterflow. Torsion induced in the 

 structure by water forces on the screen is resisted 

 by a main torque tube with track support arms 

 placed at intervals along the tube. The support arms 

 are tied with wire rope to anchors on shore. To 

 minimize drag, the speed of the screen in the water 

 can be matched to water velocity and the screen 

 returned upstream above the water. Screen panels 

 are cantilevered from carriers on a continuous track. 



609. Annotated Bibliography of Zooplankton 

 Sampling Devices. By Jack W. Jossi. July 

 1970, iii -I- 90 pp. 



ABSTRACT 

 The bibliography gives references to publications 

 issued since 1873. It has information on many 

 characteristics of these devices. The references are 

 listed by author and by KWIC inde.x. 



610. Limnological Study of Lower Columbia 

 River, 1967-68. By Shirley M. Clark and 

 George R. Snyder. July 1970, iii -I- 14 pp., 



15 figs., 11 tables. 



ABSTRACT 

 Limnological data were collected from late July 

 1967 through December 1968 at seven sampling 

 stations from above the mouth of the Willamette 

 River to below Puget Island. Items studied were: 

 physical (water temperature, turbidity, conductivity, 

 and salinity), chemical (pH, dissolved oxygen, 

 phosphate, silicate, calcium, magnesium, and sodi- 

 um), and biological (chlorophyll » and zooplankton). 

 Dissolved o.\ygen was lower in 1967-68 than it has 

 been in previous studies in 19.")4-.5.5 and I960: water 

 temperature was higher in 1967-68 than in the other 

 two periods. 



611. Laboratory Tests of an Electrical Barrier 

 for Controlling Predation by Northern Squaw- 

 fish. By Galen H. Maxfield, Robert H. Lander, 

 and Charles D. Volz. July 1970, iii + 8 pp., 

 4 figs., 5 tables. 



ABSTRACT 



Northern squawfish (Ptychocheilns oregoneiish) 

 prey extensively on the young of sport and com- 

 mercial fishes. Of particular concern to us was their 

 heavy predation during early spring and summer 

 on salmon {Oncorhynchus spp.) that are released 

 from upstream hatcheries on the Columbia River 

 and must pass through squawfish-infested areas 

 on their way to the sea. Control of these predators 

 entailed finding a means of blocking their passage 

 into the release areas of the hatchery -reared salmon 

 without interfering with the outmigration. P'or this 

 purpose, we explored in the laboratorj' the effective- 

 ness of electrical fields previously found to direct the 

 movements of salmon fingerlings. 



Electrical fields were produced by two rows of 

 hollow aluminum electrodes suspended in the water 

 across a laboraton,- tank. Exploratory- tests were 

 run to determine what combinations of electrode 

 arrays, voltage gradients, and electrical conditions 

 would give results warranting systematic testing. 

 Ten fish were tested individually in each of these 

 elimination tests. 



On the basis of test results, four electrode arrays, 

 with capacitor discharge pulses at 8 pulses per 

 second and a pulse duration equivalent to that of 

 40 niilli-second "rectangular pulse," were tested at 

 three voltage gradients. A staggered array of 

 electrodes in which the electrodes were spaced at 

 61-cm. intervals in rows 200 cm. apart was most 

 effective. At the voltage gradients of 0.7,5, 1.00, and 

 1.2.5 volts per centimeter, 85, 93, and 96 percent 

 respectively, of the squawfish were blocked. 



612. The Trade Wind Zone Oceanography Pilot 

 Study. Part VIII: Sea-level meteorological 

 properties and heat exchange processes, July 

 1963 to June 1965. By Gunter R. Seckel. June 

 1970, iv + 129 pp., 6 figs., 8 tables. 

 ABSTRACT 

 Meteorological data were summarized and large- 

 scale heat exchange processes computed, in 5° 

 square units of the area lat. 0° to 3.t° N., long. 130° 

 to 170° W., for each month. The result complement 

 time-sequence oceanographic observations of the 

 Trade Wind Zone Oceanography Pilot Study in the 

 area lat. 10° to 26° N., long. 148° to 1.57° W.. Febru- 

 ary 1964 to June 196.5. The source and processing 

 of meteorological data, and the computation of the 

 radiation from sun and sky. the effective back 

 radiation, the heat of evaporation, and the con- 

 duction of sensible heat are described. The results 

 are consistent with monthly heat exchange processes 

 computed from long-term mean meteorological 

 properties in the North Pacific. Despite inade- 

 quacies in the distribution and quality of data, the 

 meteorological data summaries and the derived heat 

 exchange processes are adequate for interseason 

 and interyear comparison of large-scale, sea-air 

 interactions. 



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