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eceived a high rating of conservation value to the ESU. The Columbia River
rearing/migration corridor downstream of the spawning range was rated as a high
conservation value. Factors contributing to the downward trends in this ESU include:
(1) Mainstem Columbia River hydropower system mortality, (2) tributary riparian
degradation and loss of in-river wood, (3) altered tributary floodplain and channel
morphology, (4) reduced tributary stream flow and impaired passage, (5) harvest impacts,
and (6) degraded water quality.
Puget Sound Chinook Salmon
Distribution
The boundaries of the Puget Sound ESU correspond generally with the boundaries of the
Puget Lowland Ecoregion (Figure 11). The Puget Lowland Ecoregion begins in
Washington at approximately the Dungeness River near the eastern end of the Strait of
Juan de Fuca and extends through Puget Sound to the British Columbia border and up to
the Cascade foothills. The Puget Sound ESU includes all runs of Chinook salmon in the
Puget Sound region from the North Fork Nooksack River to the Elwha River on the
Olympic Peninsula. This ESU is comprised of 31 historical populations. Of these, 22
populations are believed to be extant. Thirty-six hatchery populations were included as
part of the ESU and five were considered essential for recovery and listed. They include
spring Chinook salmon from Kendall Creek, the North Fork Stillaguamish River, White
River, and Dungeness River, and fall run fish from the Elwha River (Table 10). Table 10
identifies populations within the Puget Sound Chinook salmon ESU, their abundances,
and hatchery input.
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