South Fork Eel River
Data on the number of spawning Chinook salmon, coho salmon, and steelhead trout have been collected in SF Eel River streams using two different approaches: index reach sampling (2002 to present) and California Coastal Salmonid Population Monitoring (CMP) program
techniques (2010 to present). These methods differ in sampling frequency and intensity, and in the applicability of their conclusions, however, both provide valuable information that can be used to assess the status of salmonid populations in the basin.
Index Reach Sampling
CDFW survey crews have collected data on the number of redds, live Chinook and coho salmon, and salmonid carcasses in 10 SF Eel River stream reaches. These streams were located in the northern and western portions of the SF River Basin and include the following tributaries: Bull Creek, Squaw Creek, Cow Creek, Sproul Creek, Redwood Creek and China Creek. Survey sites were not randomly selected; CDFW biologists selected index reaches based on known salmonid (primarily coho salmon) presence in areas with relatively good quality instream and riparian habitat. Annual surveys also differed in sampling duration and effort, and redds were not assigned to species; however, these data provide a continuous record of spawner survey information in select streams.
California Coastal Salmonid Monitoring Program (CMP)
Chinook salmon, coho salmon, and steelhead trout spawning ground surveys have been completed since 2010 in SF Eel River streams, as part of the CMP program. This program is designed to describe the regional status of SONCC coho salmon in coastal watersheds, including the SF Eel River (Adams et al. 2011). The CMP uses the Viable Salmonid Population (McElhaney et al. 2000) concept, with key population characteristics including: abundance, productivity, spatial structure, and diversity, to assess viability. Repeated, periodic spawner surveys were conducted on a spatially balanced random sample of stream reaches within coho distributed streams. A total of 818 surveys were completed on 151 stream reaches throughout the SF Eel River drainage between 2010 and 2014. The number of reaches sampled varied slightly by year, and sampling occurred between mid-November and late March.
Spawner survey data will be collected annually as part of the CMP in SF Eel River streams, and results will be available in annual CDFW summary reports. Depending on securing future funding, a life cycle monitoring station will be established within the Sproul Creek drainage in order to generate more accurate salmonid population estimates.
The CDFW’s Coastal Watershed Planning and Assessment Program
’s SF Eel River Watershed Assessment report (2014)
also provides a more detailed summary of these monitoring efforts and additional information concerning the salmonid resources of the SF Eel River.