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

approaching 1. Nevertheless, many spawning aggregates have been extirpated, which has
increased the spatial separation of some populations. Populations are widely distributed
in a diversity of habitats although roughly one-half of historic habitats are inaccessible.
There is no evidence of wide-scale genetic introgression by hatchery populations. The
high variability in life history traits indicates sufficient genetic variability within the DPS
to maintain distinct subpopulations adapted to local environments. Despite the recent
increases in total spring/summer-run Chinook salmon returns to the basin, natural-origin
abundance and productivity remain below their targets. SR spring/summer Chinook
salmon remains likely to become endangered (Good, Waples et al. 2005).
Critical Habitat
Critical habitat for these salmon was designated on October 25, 1999 (64 FR 57399).
This critical habitat encompasses the waters, waterway bottoms, and adjacent riparian
zones of specified lakes and river reaches in the Columbia River that are or were
accessible to listed SR salmon (except reaches above impassable natural falls, and
Dworshak and Hells Canyon Dams). Adjacent riparian zones are defined as those areas
within a horizontal distance of 300 ft from the normal line of high water of a stream
channel or from the shoreline of a standing body of water. Designated critical habitat
includes the Columbia River from a straight line connecting the west end of the Clatsop
jetty (Oregon side) and the west end of the Peacock jetty (Washington side). Critical
habitat also includes all river reaches from the estuary upstream to the confluence of the
SR, and all SR reaches upstream to Hells Canyon Dam; the Palouse River from its
confluence with the SR upstream to Palouse Falls, the Clearwater River from its
confluence with the SR upstream to its confluence with Lolo Creek; the North Fork
Clearwater River from its confluence with the Clearwater river upstream to Dworshak
Dam.
Limiting factors identified for this species include: (1) Hydrosystem mortality, (2)
reduced stream flow, (3) altered channel morphology and floodplain, (4) excessive fine
sediment, and (5) degraded water quality (Myers, Kope et al. 1998). The above activities
and features also introduce sediment, nutrients, biocides, metals, and other pollutants into
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