Native Fish Status Report – Volume II

Upper Snake Spring Chinook

Existing Populations The Upper Snake Spring Chinook SMU consists of six extinct populations within tributaries to the above Hells Canyon Dam (Table 78).

Table 78. Population list and existence status for the Upper Snake Spring Chinook SMU. Exist Population Description No Pine Pine Creek basin. No Eagle Eagle Creek basin (Snake River tributary). No Powder basin. No Burnt Burnt River basin. No Malheur basin. No Owyhee Owyhee River basin.

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Pine – Upper Snake Spring Chinook

The Pine Creek spring Chinook population is extinct. Completion of the Hells Canyon Dam complex in 1967 eliminated anadromous passage to all populations to the upper Snake. Hydromodifications before the completion of the Hells Canyon Dams had serious consequences for this SMU. Small irrigation dams and diversions degraded freshwater conditions in the first half of the 20th century. Assessment Outcome Existence Distribution Abundance Productivity Independence Hybridization Fail ------

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Eagle – Upper Snake Spring Chinook The Eagle spring Chinook population is extinct. Completion of the Hells Canyon Dam complex in 1967 eliminated anadromous passage to all populations to the upper Snake. Hydromodifications including small irrigation dams and diversions degraded freshwater conditions in the first half of the 20th century.

Assessment Outcome

Existence Distribution Abundance Productivity Independence Hybridization Fail ------

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Powder – Upper Snake Spring Chinook

The Powder River spring Chinook population is extinct. Completion of the Hells Canyon Dam complex in 1967 eliminated anadromous passage to all populations to the upper Snake. Hydromodifications including small irrigation dams and diversions degraded freshwater conditions in the first half of the 20th century. Thief Valley Dam (RM 69.5) was constructed in the early 1930s and created a complete barrier for anadromous fish to upstream areas of the Powder River. Assessment Outcome Existence Distribution Abundance Productivity Independence Hybridization Fail ------

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Burnt – Upper Snake Spring Chinook

The Burnt River spring Chinook population is extinct. Completion of the Hells Canyon Dam complex in 1967 eliminated anadromous passage to all populations to the upper Snake. Hydromodifications including small irrigation dams and diversions degraded freshwater conditions in the first half of the 20th century. Unity Dam (RM 77) was completed in the mid 1930s and created a complete barrier to anadromous fish to upstream areas of the Burnt River.

Assessment Outcome Existence Distribution Abundance Productivity Independence Hybridization Fail ------

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Malheur – Upper Snake Spring Chinook

The Malheur spring Chinook population is extinct. Completion of the Hells Canyon Dam complex in 1967 eliminated anadromous passage to all populations to the upper Snake. Hydromodifications including small irrigation dams and diversions degraded freshwater conditions in the first half of the 20th century. Passage to the Malheur basin was eliminated with the construction of Warm Springs Dam (1919) and Agency Dam (1935). Assessment Outcome Existence Distribution Abundance Productivity Independence Hybridization Fail ------

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Owyhee – Upper Snake Spring Chinook

The Owyhee spring Chinook population is extinct. Completion of the Hells Canyon Dam complex in 1967 eliminated anadromous passage to all populations to the upper Snake. Hydromodifications including small irrigation dams and diversions degraded freshwater conditions in the first half of the 20th century. Assessment Outcome Existence Distribution Abundance Productivity Independence Hybridization Fail ------

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