James Weeks, a member of Young's 1833 fur brigade wrote: "They broke up all the beaver lodges on the lake, I believe the finest and largest beaver we caught there, we arrived at the Russian River and pitched camp sent out, trappers found signs set traps caught beavers..." The Russian River State Marine Reserve and Russian River State Marine Conservation Area protect the Russian River Estuary.

Like underwater parks, these marine protected areas help conserve ocean and freshwater wildlife and marine ecosystems.

This vulnerability was demonstrated in March 1982 when a tank car of formaldehyde was vandalized in Ukiah.

Emergency response personnel were able to clean up approximately half of the 21,000 US gallons (79,000 l) spilled, and a fortuitous combination of Lake Mendocino reservoir inventory and late winter storms helped flush the remainder through the river and into the ocean before local water storage inventories were exhausted.

It is very safe at that time for swimming and boating, with a gentle current. Holway wrote of the Russian River in his paper "The Russian River: A Characteristic Stream of the California Coast Ranges".

The river is dangerous in the winter, with swift current and muddy water. Originally, the Russian River was one of several rivers draining westward from the Mayacamas Mountains through the Mendocino Plateau to the sea, a region lifted up by tectonic forces. Being at a lower elevation, the Russian River began cutting north into the drainage area of the Navarro River.

Recent genetic studies on steelhead collected at 20 different sites both above and below passage barriers in the watershed found that despite the fact that 30 million hatchery trout were stocked in the river from 1911 to 1925, the steelhead remain of native and not hatchery stock.

Until recently, most reviews indicated that Chinook salmon (Oncorhynchus tshawytscha) were always scarce on the Russian River.

The Russian River springs from the Laughlin Range about 5 mi (8 km) east of Willits in Mendocino County.

It flows generally southward to Redwood Valley, then past Calpella, where it is bordered by U. Route 101, to join the East Fork Russian River just below Lake Mendocino. Route 101, it descends into the Alexander Valley, where it is joined by Big Sulphur Creek.

The authors found historic information dating to 1881 suggesting the presence of an ancestral population, and their genetic analysis found the Chinook both above and below barriers to fish passage to be of native, and not hatchery stock.

In 2001 the Coho salmon (Oncorhynchus kisutch) had dwindled to less than four returning spawners per year.

Water transferred from the Eel River and released from Lake Mendocino flows through the Russian River channel to withdrawal points in Sonoma County.