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

estimated escapement in the Klamath River is about 2,000 fish. The Rogue River spawner run
ranged from 7,800 to 12,213 coho salmon from 1999 to 2001, though many are of hatchery
origin.
The threats to this ESU include road crossings and other migration barriers, timber harvest and
agricultural activities, and water management. Adverse effects on the SONCC coho salmon
consist of barriers that limit access to tributaries, lack of large instream woody debris, reduced
riparian vegetation, and elevated water temperature. The Klamath River, one of the largest
rivers, is 303(d) listed because aquatic habitat has been degraded due to excessively high water
temperatures and algae blooms associated with high nutrient loads, water impoundments, and
agricultural water diversions (USEPA 1993). Pesticides used in land management activities are
expected to enter stream mainstems and tributaries during application as drift and as runoff.
A large portion of the agricultural and municipal land uses within this ESU is concentrated in the
upper Klamath and Rogue Rivers. A diverse array of crops is produced in these areas each year.
Some agriculture and smaller urban centers are dispersed on the lower alluvial coastal plains and
in rivers valleys of coastal rivers. Active forest management occurs throughout the watersheds
within this ESU, and application of pesticide products is anticipated.
Spawning occurs from November through January, depending on the occurrence of fall and
winter storms. Fry incubate for four to eight weeks before emergence in the spring. Newly
emerged fry rear in backwater, side channels, and shallow channel edges for up to 18 months.
During winter, juveniles inhabit side channels, sloughs, backwater, and other protected channel
features. The off-channel and floodplain habitats provide feeding and growth opportunities that
are important before smoltification and seaward migration in spring. The three-year life cycle of
coho salmon, with limited exchange between cohorts, makes them more vulnerable to
environmental perturbations than other salmonids.
Agricultural and urban land uses overlap substantially with this ESU, particularly in the Interior
Rogue and Klamath rivers. Because of this overlap, we expect that the proposed uses of
carbaryl, carbofuran, and methomyl will result in both individual fitness and population-level
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