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

Life History
Although run time variation is inherent to coho salmon life history, the ESU includes two
distinct runs: early returning (Type S) and late returning (Type N). Type S coho salmon
generally migrate south of the Columbia once they reach the ocean, returning to
freshwater in mid-August and to the spawning tributaries in early September. Spawning
peaks from mid-October to early November. Type N coho salmon have a northern
distribution in the ocean, return to the Columbia River from late September through
December and enter the tributaries from October through January. Most Type N
spawning occurs from November through January. However some spawning occurs in
February and as late as March (LCFRB 2004). Almost all LCR ESU coho salmon
females and most males spawn at three years of age.
Status and Trends
LCR coho salmon were listed as endangered on June 28, 2005 (70 FR 37160). The vast
majority (over 90%) of the historic population in the LCR coho salmon ESU appear to be
either extirpated or nearly so. The two populations with any significant natural
production (Sandy and Clackamas) are at appreciable risk because of low abundance,
declining trends, and failure to respond after a dramatic reduction in harvest. Most of the
other populations are believed to have very little, if any, natural production.
The Sandy population had a recent mean abundance of 342 spawners and a very low
fraction of hatchery-origin spawners. Trends in the Sandy are similar to the Clackamas.
The long-term trends and growth rate estimates over the period 1977 to 2001 have been
slightly positive and the short-term trends have been slightly negative. Other populations
in this ESU are dominated by hatchery production. There is very little, if any, natural
production in Oregon beyond the Clackamas and Sandy rivers. The Washington side of
the ESU is also dominated by hatchery production. There are no populations with
appreciable natural production. The most serious threat facing this ESU is the scarcity of
naturally-produced spawners, with attendant risks associated with small population, loss
of diversity, and fragmentation and isolation of the remaining naturally-produced fish. In
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