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

Critical Habitat
Critical habitat was designated for this species on June 16, 1993 (58 FR 33212). The
following areas consist 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 other
specified estuarine waters. Factors contributing to the downward trends in this ESU
include: (1) Reduced access to spawning/rearing habitat, (2) possible loss of genetic
integrity through population bottlenecks, (3) inadequately screened diversions, (4)
predation at artificial structures and by nonnative species, (5) pollution from Iron
Mountain Mine and other sources, (6) adverse flow conditions, (7) high summer water
temperatures, (8) degraded water quality, (9) unsustainable harvest rates, (10) passage
problems at various structures, and (11) vulnerability to drought (Good, Waples et al.
2005).
Snake River Fall­Run Chinook Salmon
Distribution
Historically, the primary fall-run Chinook salmon spawning areas occurred on the upper
mainstem Snake River (SR) (Connor, Sneva et al. 2005). A series of SR mainstem dams
blocks access to the upper SR, which significantly reduced spawning and rearing habitat
for SR fall-run Chinook salmon (Figure 13).
The present range of spawning and rearing habitat for naturally-spawned SR fall-run
Chinook salmon is limited to the SR below Hells Canyon Dam and the lower reaches of
the Clearwater River. SR fall-run Chinook salmon spawn above Lower Granite Dam in
the mainstem SR and in the lower reaches of the larger tributaries.
As a consequence of lost access to historic spawning and rearing sites in the Upper SR,
fall-run Chinook salmon now reside in waters that are generally cooler than the majority
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