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

and spawner estimates for the Tucannon, Grande Ronde, and Imnaha Rivers. The 2001
return over Lower Granite Dam was substantially higher relative to the low levels seen in
the 1990s; the recent five-year mean abundance (14,768 natural returns) was
approximately 28% of the interim recovery target level. The 10-year average for naturalorigin
steelhead passing Lower Granite Dam between 1996 and 2005 is 28,303 adults.
Parr densities in natural production areas, which are another indicator of population
status, have been substantially below estimated capacity for several decades. The SR
supports approximately 63% of the total natural-origin production of steelhead in the
Columbia River Basin. The current condition of SR Basin steelhead (Good, Waples et al.
2005) is summarized below:
There is uncertainty for wild populations given limited data for adult spawners in
individual populations. Dam counts are currently 28% of interim recovery target for the
SR Basin (52,000 natural spawners). Only the Joseph Creek population exceeds the
interim recovery target. Regarding population growth rate, there are mixed long- and
short-term trends in abundance and productivity. Regarding spatial structure, the SR
Basin steelhead are well distributed with populations remaining in six major areas.
However, the core area for B-run steelhead, once located in the North Fork of the
Clearwater River, is now inaccessible to steelhead. Finally, genetic diversity is affected
by the displacement of natural fish by hatchery fish (declining proportion of naturalorigin
spawners). Homogenization of hatchery stocks occurs within basins, and some
stocks exhibit high stray rates.
Critical Habitat
Critical habitat was designated for this species on September 2, 2005 (70 FR 52488).
The critical habitat designation for this ESU identifies PCEs that include sites necessary
to support one or more steelhead life stages. Specific sites include: (1) Freshwater
spawning, (2) freshwater rearing, (3) freshwater migration, (4) estuarine areas free of
obstruction, (5) nearshore marine areas free of obstructions, and (6) offshore marine areas
with good water quality.
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