Upper Salmon Fish Tracking Study

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Populations of spring/summer Chinook salmon (hereafter Chinook salmon) within the Snake River Evolutionary Significant Unit (ESU) are listed as threatened under the Endangered Species Act (ESA) (NMFS 1992). Within the Upper Salmon River major population group of the Snake River ESU, extensive time and resources have been spent towards the monitoring and restoration of depleted Chinook salmon populations. However, a significant knowledge gap still exists regarding the winter movement, distribution, and habitat use of juvenile Chinook salmon in upper Salmon River populations. Research is currently being conducted to better understand how various habitat characteristics determine the juvenile rearing capacity (summer and winter), and adult spawner capacity of watersheds containing depressed salmon populations. Results from the research will ultimately be used to evaluate how various habitat restoration actions might differentially improve the capacity of habitat, thus providing the potential to improve population productivity. This research aims to identify whether winter rearing capacity is, in fact, a factor limiting the productivity of these populations. However, it is clear, that a large portion of juveniles from these populations currently emigrate downstream of their natal areas to maximize winter survival and increase adult recruitment. Thus, an understanding of the overwinter movement and distribution of these populations during the winter rearing period is essential to prioritize restoration actions.

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