EPA's Vessel General Permit and Small Vessel General

parts of pools, while winter rearing occurs more uniformly at lower densities across a wide range
of fast and slow habitat types. Some older juveniles move downstream to rear in larger
tributaries and mainstem rivers (Nickelson et al. 1992).
There is a high degree of overlap in spawn timing between populations regardless of run type
(Busby et al. 1996). Difficult field conditions at that time of year and the remoteness of
spawning grounds contribute to the relative lack of specific information on steelhead spawning.
Unlike Pacific salmon, steelhead are capable of spawning more than once before death, although
steelhead rarely spawn more than twice before dying; most that do spawn more than twice tend
to be female (Nickelson et al. 1992, Busby et al. 1996).
Juvenile steelhead migrate little during their first summer and occupy a range of habitats
featuring moderate to high water velocity and variable depths (Bisson et al. 1988). Steelhead
hold territories close to the substratum where flows are lower and sometimes counter to the main
stream; from these, they can make forays up into surface currents to take drifting food (Kalleberg
1958). Juveniles rear in fresh water from 1 to 4 years, then smolt and migrate to the ocean in
March and April (Barnhart 1986). Winter steelhead juveniles generally smolt after 2 years in
fresh water (Busby et al. 1996). Juveniles feed primarily on insects (chironomids, baetid
mayflies, and hydropsychid caddisflies (Merz 1994) while adults feed on aquatic and terrestrial
insects, mollusks, crustaceans, fish eggs, minnows, and other small fishes (including greenling
and other trout; (Chapman and Bjornn 1969) .
Threats
Natural Threats. Steelhead, like other salmon, are exposed to high rates of natural predation
each stage of their life stage. Mortality is high early in life and decreases with age. For example,
Puget Sound steelhead leaving freshwater and estuarine habitats experience 55-86% survival to
the point of reaching Hood Canal and 0-49% from Hood Canal to the Strait of Juan de Fuca, with
survival increasing greatly upon entering the Pacific Ocean (Moore et al. 2010). In fresh water,
fry fall prey to older steelhead and other trout, as well as birds, sculpin, and various mammals.
In the ocean, marine mammals, and other fish prey on steelhead but the extent of such predation
is not well known.
Anthropogenic Threats. Steelhead have declined under the combined effects of overharvests in
fisheries, competition from hatchery fish and exotic species, dams that block their migrations and
alter river hydrology, hydrogeomorphological changes, destruction or degradation of riparian
habitat and land use practices that destroy or degrade fresh water, estuarine, and coastal
ecosystems throughout the species’ range (These threats for are summarized in detail under the
Chinook salmon section).
Central California Coast Steelhead
Distribution and Description of the Listed Species
The Central California Coast steelhead DPS includes all naturally spawned anadromous
steelhead populations below natural and manmade impassable barriers in California streams
from the Russian River (inclusive) to Aptos Creek (inclusive), and the drainages of San
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