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

Life History
Most MCR steelhead smolt at two years and spend one to two years in saltwater prior to
re-entering freshwater. Here they may remain up to a year prior to spawning (Howell,
Jones et al. 1985). Within this ESU, the Klickitat River is unusual as it produces both
summer and winter steelhead. The summer steelhead are dominated by age two ocean
steelhead. Most other rivers in this region produce about equal numbers of both age one
and two ocean steelhead.
Status and Trends
MCR steelhead were listed as threatened in 1999 (64 FR 14517), and their status was
reaffirmed on January 5, 2006 (71 FR 834). The ICBTRT (2003) identified 15
populations in four MPGs (Cascades Eastern Slopes Tributaries, John Day River, the
Walla Walla and Umatilla Rivers, and the Yakima River) and one unaffiliated
independent population (Rock Creek) in this species. There are two extinct populations
in the Cascades Eastern Slope MPG: the White Salmon River and Deschutes Crooked
River above the Pelton/Round Butte Dam complex.
Seven hatchery steelhead programs are considered part of the MCR steelhead species.
These programs propagate steelhead in three of 16 populations and improve kelt survival
in one population. No artificial programs produce the winter-run life history in the
Klickitat River and Fifteenmile Creek populations. All of the MCR steelhead hatchery
programs are designed to produce fish for harvest. However, two hatchery programs are
also implemented to augment the naturally spawning populations in the basins where the
fish are released. The NMFS assessment of the effects of artificial propagation on MCR
steelhead extinction risk concluded that these hatchery programs collectively do not
substantially reduce the extinction risk. Artificial propagation increases total species
abundance, principally in the Umatilla and Deschutes Rivers. The kelt reconditioning
efforts in the Yakima River do not augment natural abundance and benefit the survival of
the natural populations. The Touchet River Hatchery program has only recently been
established, and its contribution to species viability is uncertain. The hatchery programs
affect a small proportion of the species. Collectively, artificial propagation programs
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