EPA's Vessel General Permit and Small Vessel General

100,000 fish by the mid-1960s with about 43% originating from this ESU. Brown et al., (1994)
estimated that the California portion of this ESU was represented by about 7,000 wild and
naturalized coho salmon (Good et al. 2005). In the Klamath River, the estimated escapement has
dropped from approximately 15,400 in the mid-1960s to about 3,000 in the mid 1980s, and more
recently to about 2,000 (Good et al. 2005). The second largest producing river in this ESU, the
Eel River, dropped from 14,000, to 4,000 to about 2,000 during the same period. Historical
estimates are considered “best guesses” made using a combination of limited catch statistics,
hatchery records and the personal observations of biologists and managers.
Most recently, Williams et al., (2006) described the structure of historic populations of Southern
Oregon/Northern California Coast coho salmon. They described three categories of populations:
functionally independent populations, potentially independent populations and dependent
populations. Functionally independent populations are populations capable of existing in
isolation with a minimal risk of extinction. Potentially independent populations are similar but
rely on some interchange with adjacent populations to maintain a low probability of extinction.
Dependent populations have a high risk of extinction in isolation over a 100-year timeframe and
rely on exchange of individuals from adjacent populations to maintain themselves.
Critical Habitat
NMFS designated critical habitat for Southern Oregon/Northern California Coast coho salmon
on May 5, 1999 (64 FR 24049). Critical habitat for this species encompasses all accessible river
reaches between Cape Blanco, Oregon, and Punta Gorda, California. Critical habitat consists of
the water, substrate and river reaches (including off-channel habitats) in specified areas.
Accessible reaches are those within the historical range of the ESU that can still be occupied by
any life stage of coho salmon. Of 155 historical streams for which data are available, 63% likely
still support coho salmon. These river habitats are important for a variety of reasons, such as
supporting the feeding and growth of juveniles and serving as spawning habitat for adults.
Limiting factors identified for this species include: loss of channel complexity, connectivity and
sinuosity, loss of floodplain and estuarine habitats, loss of riparian habitats and large in-river
wood, reduced stream flow, poor water quality, temperature and excessive sedimentation, and
unscreened diversions and fish passage structures.
Final Protective Regulations
On June 28, 2005, as part of the final listing determinations for 16 ESUs of West Coast salmon,
NMFS amended and streamlined the 4(d) protective regulations for threatened salmon and
steelhead (70 FR 37160) as described in the Protective Regulations for Threatened Salmonid
Species section of this document. Under this change, the section 4(d) protections apply to
natural and hatchery fish with an intact adipose fin, but not to listed hatchery fish that have had
their adipose fin removed prior to release into the wild. The amended June 2005 4(d) rule
applies to the Southern Oregon/Northern California coast coho salmon.
Oregon Coast Coho Salmon
Distribution and Description of the Listed Species
The Oregon Coast coho salmon ESU includes all naturally spawned populations of coho salmon
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