A better understanding of the potentially complex life history requirements of westslope cutthroat trout in headwater basins is critical to managing for the persistence of the subspecies. This study investigated cutthroat trout habitat use and movement over the course of a year and at the headwater basin-scale; and used radio telemetry, a method that permits the detection of movement over long distances. This study answered two important questions:

1) How do the habitat associations of westslope cutthroat trout in headwater basins change seasonally?

2) How does the spatial distribution of habitat patches influence the seasonal movements of westslope cutthroat trout in headwater basins?

In order to accomplish these objectives, adult westslope cutthroat trout (>200 mm) habitat associations were assessed at several spatial scales over a 17-month period. A stream habitat inventory of the entire study area was completed in July 2001. To assess the seasonal dynamics of the study area, continuous year-round stream temperature and weekly discharge data were recorded. Habitat use information was gathered by tracking 70 cutthroat trout tagged with surgically implanted radio transmitters, from August 2000 to January 2001. Each fish was located on a weekly basis, and stream habitat variables and movement distance were recorded each time a fish was located. From these data, habitat associations based on an electivity index were calculated for several spatial scales, including the channel unit, reach (sensu Montgomery and Buffington 1997), and valley segment (sensu Frissell et al. 1986) and compared for differences among seasons. To assess the influence of habitat on movement, the movement of fish tagged in stream areas of high spatial habitat heterogeneity (e.g., abundant instream large wood, high pool frequency and residual pool depth, and unconstrained reach) was compared to the movement of fish tagged in areas with low spatial habitat heterogeneity.

Annual Reports and Publications:

Starcevich, S.J. 2005. Seasonal movement patterns and habitat use of westslope cutthroat trout in two headwater tributary streams of the John Day River. Master's thesis. Oregon State University, Corvallis.

Hemmingsen, A. and S.J. Starcevich. 2001. Native Trout Studies, 2001 Annual Progress Report. Oregon Department of Fish and Wildlife, Sport Fish Restoration Project F-136-R-14, Annual Progress Report, Portland.

Hemmingsen, A. and S. Starcevich. 2000. Native Trout Studies, 2000 Annual Progress Report. Oregon Department of Fish and Wildlife, Sport Fish Restoration Project F-136-R-13, Annual Progress Report, Portland.

Hemmingsen, A. 2000. Native Trout Studies, 1999 Annual Progress Report. Oregon Department of Fish and Wildlife, Sport Fish Restoration Project F-136-R-12, Annual Progress Report, Portland.