Salmonid Fishery Resources
The Van Duzen River supports important populations Chinook (Oncorhynchus tshawytscha) and coho salmon (O. kisutch), winter run and summer run steelhead, and resident rainbow trout (O. mykiss) and coastal cutthroat trout (O. clarkii). Streams in the Lower and Yager Creek subbasins provide the largest amount of Chinook and coho salmon habitat of all the subbasins. Steelhead are the most widely distributed anadromous salmonid in the basin. Table 1 lists streams in the Van Duzen Basin that support salmonids.
Salmon Falls, located approximately at River Mile (RM) 38 and approximately 7.5 miles below the confluence of the South Fork and Mainstem Van Duzen is a natural barrier to upstream passage of Chinook and coho. Adult steelhead are the only anadromous salmonid that consistently migrate above Salmon Falls to populate the South Fork Van Duzen River. Steelhead migration on the Mainstem Van Duzen River is blocked at a Eaton Falls located (~RM 46) and just above the confluence with the S.F Van Duzen.
A resident trout population exists above Eaton Falls on the upper Van Duzen mainstem and its tributaries as well as other streams of the basin. Prior to 1964 the resident rainbow trout fishery in the upper mainstem was very popular with sportfishers.
Coastal Cutthroat are known to occur in only a few streams located in the Yager and Lower subbasins. Very few coastal cutthroats have been observed in recent fish sampling efforts. These data suggest that coastal Cutthroats may be the least abundant salmonid species in the Van Duzen Basin.
Anadromous salmonid populations have declined in numbers and distribution throughout the Van Duzen Basin. A similar decline has been observed in most of California’s streams, prompting coho, Chinook and steelhead of the Van Duzen Basin to be listed as “threatened” under the state and federal endangered species acts. A number of factors have been noted as contributors to the decline in salmonids, but degradation of freshwater habitat needed for adult spawning and juvenile rearing is considered a leading cause for declining populations.