EPA's Vessel General Permit and Small Vessel General

This ESU consists of a single spawning population that enters the Sacramento River and its
tributaries in California from November to June and spawns from late April to mid-August, with
a peak from May to June (Good et al. 2005). Sacramento River winter-run Chinook salmon
historically occupied cold, headwater streams, such as the upper reaches of the Little
Sacramento, McCloud and lower Pit Rivers. Young winter-run Chinook salmon venture to sea
in November and December, after only four to seven months in fresh water (Groot and Margolis.
1991).
Status and Trends
NMFS listed Sacramento River winter-run Chinook salmon as endangered on January 4, 1994
(59 FR 440), and reaffirmed their status as endangered on June 28, 2005 (70 FR 37160), because
dams restrict access to a small fraction of their historic spawning habitat and the habitat
remaining to them is degraded. Sacramento River winter-run Chinook salmon consist of a single
self-sustaining population which is entirely dependent upon the provision of suitably cool water
from Shasta Reservoir during periods of spawning, incubation and rearing.
Construction of Shasta Dams in the 1940s eliminated access to historic spawning habitat for
winter-run Chinook salmon in the basin. Winter-run Chinook salmon were not expected to
survive this habitat alteration (Moffett 1949). However, cold water releases from Shasta Dam
have created conditions suitable for winter Chinook salmon for roughly 60 miles downstream
from the dam. As a result the ESU has been reduced to a single spawning population confined to
the mainstem Sacramento River below Keswick Dam, although some adult winter-run Chinook
salmon were recently observed in Battle Creek, a tributary to the upper Sacramento River.
Quantitative estimates of run-size are not available for the period before 1996, the completion of
Red Bluff Diversion Dam. However, winter-runs may have been as large as 200,000 fish based
upon commercial fishery records from the 1870s (Fisher 1994). The California Department of
Fish and Game estimated spawning escapement of Sacramento River winter-run Chinook salmon
at 61,300 (60,000 in the mainstem, 1,000 in Battle Creek, and 300 in Mill Creek) in the early
1960s. During the first 3 years of operation of the county facility at the Red Bluff Diversion
Dam (1967 to 1969), the spawning run of winter-run Chinook salmon averaged 86,500 fish.
From 1967 through the mid-1990s, the population declined at an average rate of 18% per year, or
roughly 50% per generation. The population reached critically low levels during the drought of
1987 to 1992; the 3-year average run size for the period of 1989 to 1991 was 388 fish. Based on
the Red Bluff Diversion Dam counts, the population has been growing rapidly since the 1990s.
Mean run size from 1995-2000 has been 2,191, but have ranged from 364 to 65,683 (Good et al.
2005). Most recent estimates indicate that the short term trend is 0.26, while the population
growth rate is still less than 1(Good et al. 2005). The draft recovery goal for the ESU is an
average of 10,000 female spawners per year and a population growth rate >1.0, calculated over
13 years of data (Good et al. 2005).
Critical Habitat
NMFS designated critical habitat for Sacramento River winter-run Chinook salmon on June 16,
1993 (58 FR 33212). The following areas consisting of the water, waterway bottom and adjacent
riparian zones: the Sacramento River from Keswick Dam, Shasta County (river mile 302) to
Chipps Island (river mile 0) at the westward margin of the Sacramento-San Joaquin Delta, and
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