EPA's Vessel General Permit and Small Vessel General

prevented fish from ascending past the falls. The Upper Willamette spring-run Chinook salmon
are one of the most genetically distinct Chinook salmon groups in the Columbia River Basin.
Upper Willamette River Chinook salmon enter the Columbia River and estuary earlier than other
spring Chinook salmon ESUs (Meyers et al. 1998). Fall-run Chinook salmon spawn in the
Upper Willamette but are not considered part of the ESU because they are not native.
Status and Trends
NMFS originally listed Upper Willamette River Chinook salmon as threatened on March 24,
1999 (64 FR 14308), and reaffirmed their status as threatened on June 28, 2005 (70 FR 37160).
The total abundance of adult spring-run Chinook salmon (hatchery-origin plus natural-origin
fish) passing Willamette Falls has remained relatively steady over the past 50 years (ranging
from approximately 20,000 to 70,000 fish), but it is an order of magnitude below the peak
abundance levels observed in the 1920s (approximately 300,000 adults). Until recent years,
interpretation of abundance levels has been confounded by a high but uncertain fraction of
hatchery-produced fish. Although the number of adult spring-run Chinook salmon crossing
Willamette Falls is in the same range (about 20,000 to 70,000 adults) it has been for the last 50
years, a large fraction of these are hatchery produced. Estimates of the percentage of hatchery
fish range according to tributary, several of which exceed 70 percent (Good et al. 2005). The
Calapooia River is estimated to contain 100 percent hatchery fish. Insufficient information on
hatchery production in the past prevents a meaningful analysis of the population trend; therefore
no formal trend analysis is available.
Most natural spring Chinook salmon populations of the Upper Willamette River are likely
extirpated or nearly so, with only one remaining naturally reproducing population identified in
this ESU: the spring Chinook salmon in the McKenzie River. Unfortunately, recently short-term
declines in abundance suggest that this population may not be self-sustaining (Meyers et al.
1998). Abundance in this population has been relatively low (low thousands) with a substantial
number of these fish being of hatchery origin. The population increased substantially from 2000
to 2003, probably due to increased survival in the ocean. Future survival rates in the ocean are
unpredictable, and the likelihood of long-term sustainability for this population has not been
determined. Of concern is that a majority of the spawning habitat and approximately 30 to 40%
of total historical habitat are no longer accessible because of dams (Good et al. 2005).
Individuals from the ESU migrate far north and are caught incidentally in ocean fisheries,
particularly off southeast Alaska and northern Canada, and in the mainstem Columbia and
Willamette rivers during spring.
Critical Habitat
NMFS designated critical habitat for Upper Willamette River Chinook salmon on September 2,
2005 (70 FR 52630). Critical habitat for upper Willamette River Chinook salmon includes
defined areas within subbasins of the middle fork Willamette River, upper Willamette River,
McKenzie River, Santiam River, Crabtree Creek, Molalla River and Clackamas River. This
designation includes the stream channels within the designated stream reaches, and includes a
lateral extent as defined by the ordinary high water line. In areas where the ordinary high-water
line is not defined the lateral extent is defined as the bankfull elevation. The critical habitat
designation for this ESU identifies primary constituent elements that include sites necessary to
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