Northwest Fisheries Science Center

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Document Type: Contract Report
Center: NWFSC
Document ID: 6564
Title: Salmonid bioassay of supersaturation of dissolved gas in water
Author/Editor: Earl M. Dawley, Bruce H. Monk, Michael H. Schiewe, Frank J. Ossiander, Wesley J. Ebel
Publication Year: 1976
Publisher: National Marine Fisheries Service
Place Published: Corvallis, Oregon
Contracting Agency: U.S. Environmental Protection Agency, Environmental Research Laboratory, Western Fish Toxicology Station
Project Number: EPA-IAG-0155-D
Delivery Order: PE 330801
Date: 03/01/1975

Tests were conducted in shallow (0.25 m) and deep (2.5 m) tanks of water at 10°C with concentrations of dissolved atmospheric gas ranging from 100 to 127% of saturation to determine the lethal and sublethal affects of the dissolved gas on juvenile fall Chinook salmon Oncorhynchus tshawytscha and steelhead trout Salmo gairdneri.  Fall chinook salmon (average fork length 42 mm) were much more resistant to supersaturation than juvenile steelhead trout (average fork length 180 mm).  Salmon tested in the shallow tanks at 120% of supersaturation incurred 50% mortality after 22 d, whereas trout tested at the same level incurred 50% mortality in 30 h.  Signs of gas bubble disease were noted on dead fish and on subsamples of live fish from deep-water tests at 110% saturation and above and in shallow-water tests at 105% and above.  Vertical distribution of both salmon and trout in the deep tanks appeared to compensate for about 10% and 10-15%, respectively, of effective saturation.  Average depth of fish in deep tanks increased with increased gas concentration.  Significant differences in growth and condition factor of salmon and trout were not found between stressed and control fish during the test period.

Notes: Ecological Research Series report, 46 pages