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

Given the life history of the Puget Sound Chinook salmon, we expect that the proposed uses of
carbaryl, carbofuran, and methomyl pesticide products may lead to individual fitness
consequences and subsequent population-level consequences, i.e., reductions in population
viability. Therefore, the risk to this species’ survival and recovery from the stressors of the
action is high for carbaryl, carbofuran, and methomyl.
Sacramento River Winter­run Chinook salmon
The Sacramento River Winter-run Chinook salmon ESU includes only one population in
Sacramento River, California. The current spawning distribution of Sacramento River Winterrun
salmon is restricted to a short portion of the mainstem Sacramento River below Keswick
Dam. Historic run estimates for the Sacramento River are as large as 200,000 fish (Brown et al.
1994). Estimated natural production has fluctuated greatly over the past two decades. In 2007,
estimated natural production was 4,461 fish. The population’s annual growth rate ranged from
0.870 to 1.090.
The major threats to this ESU identified in the Status of Listed Resources and Environmental
Baseline sections indicate impaired or loss of habitat, predation, contamination, and water
management negatively affect this ESU. Reservoir dams in the Sacramento River have
eliminated the ESU from its historic spawning locations. Today, the ESU depends on the ability
of the BOR to manage cold water through reservoir storage and releases to support adult holding,
spawning, incubation, and rearing. The physical channel habitat has been altered through
sediment input from mining, levee construction, and removal of riparian vegetation for levee
maintenance. Pesticides are frequently detected in the Sacramento River including thiobencarb,
carbofuran, molinate, simazine, metolachlor, dacthal, chlorpyrifos, carbaryl, and diazinon.
Carbofuran is commonly detected in agricultural areas but less so in urban sites while carbaryl is
commonly detected in all urban sites. Modification of hydrology has resulted in increased
mortality through stranding, increased predation, prolonged migration, and entrainment at water
diversion facilities.
About 10% of the land within this ESU is developed; large areas of urban centers occur along the
Sacramento River and San Francisco Bay. As about 21% of land within the ESU is cultivated,
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