Fish Research Project Oregon; Aspects of Life History and Production of Juvenile Oncorhynchus Mykiss in the Grande Ronde River Basin, Northeast Oregon, 1995-1999 Summary Report.
Rotary screw traps, located at four sites in the Grande Ronde River basin, were used to characterize aspects of early life history exhibited by juvenile Onchorhychus mykiss during migration years 1995-99. The Lostine, Catherine Creek and upper Grande Ronde traps captured fish as they migrated out of spawning areas into valley rearing habitats. The Grande Ronde Valley trap captured fish as they left valley habitats downstream of Catherine Creek and upper Grande Ronde River rearing habitats. Dispersal downstream of spawning areas was most evident in fall and spring, but movement occurred during all seasons that the traps were fished. Seaward migration occurred primarily in spring when O. mykiss smolts left overwintering area located in both spawning area and valley habitats. Migration patterns exhibited by O. mykiss suggest that Grande Ronde Valley habitats are used for overwintering and should be considered critical rearing habitat. We were unable to positively differentiate anadromous and resident forms of O. mykiss in the Grande Ronde River basin because both forms occur in our study area. The Grande Ronde Valley trap provided the best information on steelhead production in the basin because it fished below valley habitats where O. mykiss overwinter. Length frequency histograms of O. mykiss captured below upper spawning and rearing habitats showed a bimodal distribution regardless of the season of capture. Scale analyses suggested that each mode represents a different brood year. Length frequency histograms of O. mykiss captured in the Grande Ronde Valley trap were not bimodal, and primarily represented a size range consistent with other researchers' accounts of anadromous smolts.
- Research Organization:
- Oregon Department of Fish and Wildlife
- Sponsoring Organization:
- United States. Bonneville Power Administration.
- DOE Contract Number:
- 1994BI33299
- OSTI ID:
- 785592
- Report Number(s):
- DOE/BP-33299-7; TRN: AH200131%%393
- Resource Relation:
- Other Information: PBD: 1 Jul 2001
- Country of Publication:
- United States
- Language:
- English
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