The Native Fish Investigations Project began researching questions pertinent to the conservation of bull trout in 1995. The intent of this research is to provide scientific information about the general ecology of bull trout. This will allow threats to existing bull trout populations to be correctly evaluated and management decisions pertaining to bull trout conservation and recovery to be effectively implemented and monitored. Data will also be collected to measure the expected biological outcomes of various management actions and to describe the relative health of bull trout populations. Such data include bull trout distributions at various life stages, description and availability of habitats critical to each life stage, population abundance, genetic description of populations and their relationships to each other, identification of migratory corridors, and description of the interactions between bull trout and sympatric brook trout. Some of these data have already been incorporated into draft recovery plans, and new data will help refine those plans.
Our initial emphasis focused on life history, population structure, and potential limiting factors of bull trout such as the influence of temperature and interactions with brook trout. Field activities occurred throughout the range of Oregon bull trout, and were concentrated in the John Day, Walla Walla, and Grand Ronde River basins. Current and ongoing research also evaluates methods to estimate abundance, and monitor populations at a landscape scale, and assess impacts to bull trout reproduction caused by co-occurring spawning Kokanee salmon in Odell Lake.
1) Characterize the fine-scale population structuring of bull trout within the John Day River and Grande Ronde River subbasins.
2) Estimate the abundance of migratory and resident adult bull trout in Mill Creek, a tributary to the Walla Walla River, and compare this abundance to counts of redds.
3) Determine the seasonal movements of fluvial bull trout of the Umatilla and Lostine Rivers.
4) Employ a pilot study to evaluate an EMAP probabilistic sampling design to characterize the status, trends, and distribution of adult bull trout populations at the Provincial and Subbasin scale in the Columbia Plateau Province.
5) Assess the impacts to bull trout reproduction caused by kokanee salmon that spawn at the same locations.
6) Develop acceptable methods to separate bull trout and kokanee that spawn in Trapper Creek, Odell Lake.
1) Determine the genetic characteristics of Oregon bull trout populations. (Spruell et al. 2003)
2) Determine distribution of juvenile and adult bull trout and associated habitats in portions of the Grande Ronde, John Day, Deschutes and Walla Walla subbasins.
3) Determine relationships between stream temperature and distribution of bull trout.
4) Determine fluvial and resident life history patterns in the upper John Day and Walla Walla subbasins.
5) Characterize relationships among bull trout and sympatric species. (Gunckel et al. 2002)
6) Establish guidelines to monitor the abundance of bull trout using spawning surveys.
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