Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

“low” for the Wenatchee and Methow, “moderate” for the Entiat, and “high” for the
Okanogan. Overall adult returns are dominated by hatchery fish, and detailed
information is lacking on the productivity of the natural population. All UCR steelhead
populations have reduced genetic diversity from homogenization of populations that
occurred during the Grand Coulee Fish Maintenance project from 1939-1943, from 1960,
and 1981 (Chapman, Hillman et al. 1994).
Critical Habitat
Critical habitat was designated for this species on September 2, 2005 (70 FR 52488).
The critical habitat designation for this DPS identifies PCEs that include sites necessary
to support one or more steelhead life stages. They include all Columbia River estuarine
areas and river reaches upstream to Chief Joseph Dam and several tributary subbasins.
Specific sites include freshwater spawning and rearing sites, freshwater migration
corridors, estuarine areas free of obstruction, and offshore marine areas. The physical or
biological features that characterize these sites include water quality and quantity, natural
cover, forage, and adequate passage conditions.
The UCR steelhead DPS has 42 watersheds within its range. Three watersheds received
a low rating, eight received a medium rating, and 31 rated a high conservation value to
the DPS. In addition, the Columbia River rearing/migration corridor downstream of the
spawning range was rated as a high conservation value. Limiting factors identified for
the UCR steelhead include: (1) Mainstem Columbia River hydropower system mortality,
(2) reduced tributary streamflow, (3) tributary riparian degradation and loss of in-river
wood, (4) altered tributary floodplain and channel morphology, and (5) excessive fine
sediment and degraded tributary water quality. The above activities and features also
introduce sediment, nutrients, biocides, metals, and other pollutants into surface and
ground water and degrade water quality in the freshwater, estuarine, and coastal
ecosystems throughout the Pacific Northwest.
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