estuary seasonally to feed, such as night smelt (Spirinchus starski), while a variety of coastal species pass in and out of the estuary year-round, including cabezon (Scorpaenichthys marmoratus), tidepool sculpin (Oligocottus maculosus), and kelp greenling (Hexogrammos decagrammus). California golden beaver (Castor canadensis subauratus) were restored to Big River in the early to mid-twentieth century despite extirpation in the California Fur Rush of the late eighteenth and early nineteenth centuries. A specimen was collected by J. G. Hall east of Mendocino on the Big River at elevation (precise location 39.31148, -123.6396) in 1966 for the California Academy of Sciences mammal collection. Beaver ponds help restore salmonid habitat by capturing sediment and improving water quality, providing pools for juvenile salmonid over-summering, raising water tables which recharge streams in the dry season, increasing the area of aquatic and riparian habitat providing fish cover, and attenuating flashy storm flows. A recent comprehensive literature review of the effects of beaver impoundments on fish illustrates that loss of beavers was directly related to significant population declines of now threatened or endangered California salmonids, including three species listed under the Endangered Species Act: Coho salmon (Oncorhynchus kisutch) (endangered), steelhead (Oncorhynchus mykiss) (threatened) and Chinook salmon (Oncorhynchus tshawytscha) (threatened). Other semi-aquatic mammals living in Big River include river otter (Lontra canadensis) and mink (Neogale vison). Land Use Timber production is the primary land use in the area. The California Lumber Company built the first sawmill on the Mendocino County coast at the mouth of the river in 1852. By 1873, the name had changed to Mendocino Lumber Company and the mill was the most important in Mendocino County. The mill operated until 1931, and was briefly reopened in 1938 to mill logs salvaged when a log raft broke up off the coast. Logs were transported either to the mill pond during annual water release at the splash dams, or directly to the mill via a railway that extended up the Big River. The North Fork Big River was logged by the Caspar Lumber Company. Logs were transported to the sawmill in Caspar from Camp 20 at California State Route 20 (milepost MEN 17.3) by Caspar, South Fork and Eastern Railroad. Caspar Lumber Company timberlands became the Jackson Demonstration State Forest in 1955. Jackson State Forest forms roughly a third of the area in the watershed, and land owned by Mendocino Redwood Company, Pioneer Resources, Hawthorne Timber Company and