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

effects. In several streams, one or more BYs are at the verge of extinction. Exposure to the three
a.i.s can result in loss of weak BYs. Low population abundance levels and the discrete cohort
life history of the coho salmon make the SONCC ESU more vulnerable to environmental
stressors. Therefore the risk to the survival and recovery of the SONCC ESU from the stressors
of the action is high.
Oregon Coast Coho Salmon
The OC coho salmon ESU includes 11 naturally spawned populations in Oregon coastal streams
south of the Columbia River and north of Cape Blanco and one hatchery stock. While none of
the populations have become extinct, the ESU’s current abundance levels are less than 10% of
historic populations. OC coho salmon abundance estimates from 2000 to 2007 ranged from a
low of 51,875 to a high of 260,000 naturally produced spawners. Long-term trends in ESU
productivity remain strongly negative.
The major threats to this ESU identified in the Status of Listed Resources and Environmental
Baseline sections are habitat degradation from logging, road construction, urban development,
mining, agriculture, and recreation. Within the various types of habitat, elevated temperature,
water diversions, and poor water quality also affect the status of OC coho salmon. The
combined impacts from these multiple threats continue to affect OC coho salmon.
Crop rotation patterns and crop types influence the distribution and frequency of pesticides
within an area. Based on limited agricultural activities, we expect that carbaryl and existing
stocks of carbofuran may be applied on a limited scale throughout the growing season.
Registered 24(c) uses in Oregon include carbofuran application to potatoes, nursery stock, sugar
beets, and watermelons. We also expect carbaryl use within urban and residential areas
throughout the entire year. However, we expect no to very low applications of methomyl
throughout the growing season. Although carbaryl and carbofuran may be applied to pine
seedlings, we expect no to low applications in these forests. As runoff from urban and
agricultural areas may drain into adjacent streams, ESU exposure to these pesticides is likely.
However, given the above land uses and expected low application of the three carbamates, we
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