T. H. Blahm 

 B. McConnell 

 G. R. Snyder 



Gas Supersatura- I 



tion Research 



National Marine Fisheries Service 



Prescott Facility— 1971 to 1974 



ABSTRACT 



In 1969, the NMFS constructed a field facility for "on-site" en- 

 vironmental testing. The facility is housed on two 110 x 32 foot 

 barges moored on the Columbia River near Prescott, Oregon 

 (RM 72). Research on the effects of nitrogen supersaturation was 

 begun in 1971. Survival is better in the 2.5-m deep tanks than in 

 1-m deep tanks. Results of tests done in "shallow" test tanks are 

 not representative of what might occur in the river, as fish are 

 not restricted to "shallow" depths. Intermittent exposure to high 

 (130, 120, and 110%) and equilibrated (110%) levels of N 2 satura- 

 tion generally enhanced test fish survival over that recorded for 

 fish held in constant high levels. Preliminary tests indicate that 

 the fish are not able to detect and avoid lethal conditions of 

 supersaturation. Dissolved gas levels have been monitored at 

 Prescott since 1971. 



WASHINGTON 



In 1969 the National Marine Fisheries Service ini- 

 tiated "on-site" environmental research on the 

 lower Columbia River. The research facility 

 (Snyder, Blahm, McConnell, 1970) is housed on two 

 33.5 x 10 m (110 x 32 ft) barges moored near Pres- 

 cott, Oregon. (Fig. 1). 



Research on the effect of nitrogen supersatura- 

 tion was begun in 1971. The primary emphasis has 

 been on bioassay of prevailing Columbia River 

 water at the site; however, several other types of 

 tests have been conducted e.g. avoidance and 

 detection of gas supersaturation, vertical depth 

 distribution of fish, intermittent exposure to super- 

 saturated and equilibrated N2 levels. In addition 

 to the biological tests, daily N 2 monitoring at 

 Prescott has been done since 1971; also in relation 

 to monitoring, a study was initiated (in 1974) to 

 determine the gas equilibration characteristics in 

 the Columbia River between The Dalles Dam and 

 Prescott, Oregon. Exploratory tests have been done, 

 and will continue, on 2 consumption and stamina 

 of fish in relation to N 2 saturation. The effects of 

 hydrostatic pressure on the survival of N 2 stressed 

 fish is also being examined. Results of the explora- 

 tory tests will not be included in this report. 



The objective of this summary report is to out- 

 line representative tests and results to demonstrate 

 the types and diversity of studies completed at the 

 Prescott Facility. 



Test results included herein are brief descrip- 

 tions of general samplings from the total effort; 

 more detailed information will be made available 

 on request. A list of published and non-published 

 data will be included in this report. Following is 

 the sequence in which the various projects will be 

 discussed: 



FIG. 1 Lower Columbia River and locale of Prescott Field 

 Facility. 



Blahm, McConnell, and Snyder: Environmental Conservation 

 Division, National Marine Fisheries Service, Seattle, Washing- 

 ton. 



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