Winter Habitat Utilization and Movement by Snake River Cutthroat Trout

Authors(s): D. Harper

Publication:

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Publication Date: 0000-00-00

Type: annual report

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Abstract: Objectives To determine the habitat used by Snake River cutthroat trout (SRCT) during winter, and to determine patterns in movement in response to winter conditions using radio-telemetry. In high elevation streams, winter conditions are frequently the limiting factor in salmonid populations. We are trying to determine the over-wintering habitat used by SRCT to identify habitat that is critical to overwintering survival. We are also trying to determine if SRCT migrate over long distances to avoid harsh winter conditions, and if they are migrating, what type of habitat are they selecting. Habitat use by SRCT was assessed by SRCT was assessed by using radio telemetry to identify fish locations and measuring; water depth, water velocity, substrate, cover and habitat type (run, riffle, pool, or backwater), and marking each location using GPS. Findings and Status SRCT move to backwater pool areas and deep runs with low water velocity during the winter. They appear to select areas with warm groundwater seepage when possible. Backwater areas are uncommon within the Snake River between Moose and Wilson bridge, but approximately 40% of habitat measurements were taken in backwater areas, indicating that a strong positive selection is occurring. Deep run habitats are also selected, but are common within the study area. SRCT do not appear to undergo long migration (>40 km) during winter, however, a trend toward gradual downstream movement has been observed.

Keywords: Grand Teton National Park, animal, ichthyology, fish, Pisces, trout, cutthroat trout, Snake River cutthroat trout, Oncorhynchus clarki bouvieri, Jackson Lake, habitat, migration, radio collar, Snake River, Jackson Hole, Teton County, Salmonidae, management, population, mortality