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

The registered uses of the three carbamates indicate substantial overlap with the CCV steelhead
populations, especially in the lower Sacramento River and Delta. We expect that the proposed
uses may contaminate spawning and rearing habitats and lead to both individual fitness and
population-level consequences. Thus, the risk to this species’ survival and recovery from the
stressors of the proposed action is high for carbaryl, carbofuran, and methomyl.
Lower Columbia River Steelhead
The LCR Steelhead DPS includes 23 historical, naturally-spawned steelhead populations in
Columbia River tributaries on the Washington side between the Cowlitz and Wind Rivers in
Washington and on the Oregon side between the Willamette and Hood Rivers. Historical counts
from the Cowlitz, Kalama, and Sandy Rivers suggest the ESU probably exceeded 20,000 fish.
During the 1990s, fish abundance dropped to 1,000 to 2,000 fish. Many of the populations in
this DPS are small, and the long- and short-term trends in abundance of all individual
populations are negative. The annual population growth rate known for nine independent
populations ranged from 0.945 to 1.06.
The major threats to this DPS identified in the Status of Listed Resources and Environmental
Baseline sections include dams; water diversion; destruction or degradation of riparian habitat;
and land use practices (logging, agriculture, and urbanization). Tributary hydropower
development has created barriers and reduced fish access, ultimately affecting the spatial
structure within the independent populations. Within the various types of habitat, water
diversions, elevated temperature, and poor water quality also affect the status of LCR steelhead.
Pesticides have also been detected in LCR steelhead habitats. NAWQA sampling from 1991-
1995 in surface waters within the DPS range detected more than 50 pesticides in streams. Ten
pesticides exceeded EPA’s criteria for the protection of aquatic life from chronic toxicity. These
pesticides include carbaryl, carbofuran, atrazine, chlorpyrifos, and malathion. The combined
impacts from these multiple threats continue to affect this DPS.
Most of the highly developed land and agricultural areas in this DPS’s range are adjacent to
salmonid habitat. Registered uses of carbaryl, carbofuran, and methomyl include applications to
crop agricultural sites, residential sites, and urban sites. Registered 24(c) uses in Oregon include
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