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

including wheat, peas, and lentils. Alfalfa, hay, and grasses are also grown in the lower
Clearwater as well as the lower Salmon River basin. All three a.i.s are registered for use on
alfalfa. Agricultural activities and urban communities, are concentrated along the Snake River
and near the mouths of major tributary valleys, thus stream water quality and biological
communities in the downstream portion of the upper Snake River basin are degraded.
SR Spring/Summer-run Chinook salmon spawn at high elevations in the headwater tributaries of
the Clearwater, Grande, Ronde, Salmon, and Imnaha Rivers. Spawning is complete by the
second week of September. Eggs incubate and hatch in late winter and early spring of the
following year. The fry typically overwinter in shallow off-channel habitats associated with their
natal rivers and streams. Juveniles become active seaward migrants during the following spring
as yearlings (Connor, Sneva et al. 2005).
Given the life history of SR Spring/Summer-run Chinook salmon, we expect the proposed uses
of carbaryl and carbofuran pesticide products that contaminate aquatic habitats will lead to
individual fitness level consequences and subsequent population-level consequences. The uses
of these materials along the migratory route of SR Spring/Summer-run Chinook salmon, may
cause acute lethality or temporary AChE inhibition. We expect that exposure to methomyl may
lead to individual fitness consequences, but not to an extent that would affect population growth
rates. The risk to this species’ survival and recovery from the stressors of the action is high for
carbaryl and carbofuran, but low for methomyl.
Upper Willamette River Chinook Salmon
The UWR Chinook salmon ESU includes all eight naturally spawned populations residing in the
Clackamas River and the Upper Willamette River above Willamette Falls. It also includes seven
artificial propagation programs. The population in the McKenzie River is the only population
that is naturally producing, and current estimates indicate a negative growth rate. Historically,
the Upper Willamette River supported large numbers (exceeding 275,000 fish) of UWR Chinook
salmon. Current abundance of natural-origin fish is estimated at less than 10,000.
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