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

Table 21. Northern California Steelhead salmon populations, abundances, and hatchery
contributions (Good, Waples et al. 2005).
River
Historical
Abundance
Most Recent
Spawner
Abundance
Hatchery
Abundance
Contributions
Redwood Creek 10,000 Unknown Unknown
Mad River 6,000 162-384 Unknown
Eel River 82,000 3,127-21,903 Unknown
Mattole River 12,000 Unknown Unknown
Ten Mile River 9,000 Unknown Unknown
Noyo River 8,000 Unknown Unknown
Big River 12,000 Unknown Unknown
Navarro River 16,000 Unknown Unknown
Garcia River 4,000 Unknown Unknown
Gualala River 16,000 Unknown Unknown
Other Humboldt County streams 3,000 Unknown Unknown
Other Mendocino County streams 20,000 Unknown Unknown
Total 198,000 Unknown
Life History
Steelhead within this DPS include winter and summer steelhead. Half-pounder juveniles
occur in the Mad and Eel Rivers. Half-pounders are immature steelhead that returns to
freshwater after only two to four months in the ocean, and generally overwinter in
freshwater. These juveniles then outmigrate in the following spring.
Status and Trends
NC steelhead were listed as threatened on June 7, 2000 (65 FR 36074). They retained
that classification following a status review on January 5, 2006 (71 FR 834). Long-term
data sets are limited for this NC steelhead. Before 1960, estimates of abundance specific
to this DPS were available from dam counts in the upper Eel River (Cape Horn Dam–
annual avg. no. adults was 4,400 in the 1930s), the South Fork Eel River (Benbow Dam–
annual avg. no. adults was 19,000 in the 1940s), and the Mad River (Sweasey Dam–
annual avg. no. adults was 3,800 in the 1940s). Estimates of steelhead spawning
populations for many rivers in this DPS totaled 198,000 by the mid-1960s.
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