Migration depths of adult steelhead Oncorhynchus mykiss in relation to dissolved gas supersaturation in a regulated river system
Abstract:Adult steelhead Oncorhynchus mykiss tagged with archival transmitters primarily migrated through a large river corridor at depths >2 m interspersed with frequent but short (<5 min) periods closer to the surface. The recorded swimming depths and behaviours probably provided adequate hydrostatic compensation for the supersaturated dissolved gas conditions encountered and probably limited development of gas bubble disease (GBD). Results parallel those from a concurrent adult Chinook salmon Oncorhynchus tshawytscha study, except O. mykiss experienced greater seasonal variability and were more likely to have depth uncompensated supersaturation exposure in some dam tailraces, perhaps explaining the higher incidence of GBD in this species.
Document Type: Research Article
Affiliations: 1: Department of Fish and Wildlife Resources, College of Natural Resources, University of Idaho, Moscow, ID 83844-1136, U.S.A. 2: Idaho Fishery Resource Office, U.S. Fish and Wildlife Service, 4147 Ahsahka Rd, Ahsahka, ID 83520, U.S.A. 3: Pacific Northwest National Laboratory, P.O. Box 999, MS K9-36, Richland, WA 99352, U.S.A.
Publication date: April 1, 2010