California’s once prolific salmon and steelhead rivers have suffered from severe habitat loss.
California is the southernmost extent of salmon and steelhead in North America. It is also the most populous state in the US and the third largest land area behind Alaska and Texas. While the northern most portion of the state remains relatively unpopulated and still supports some relatively robust populations of salmon and steelhead, populations south of the San Francisco bay are for the most part in dire straits.
The Sacramento and Klamath are the crowned jewels of California’s salmon rivers and historically were the 2nd and 3rd most productive Chinook rivers on the planet, behind only the mighty Columbia. Today dam construction has dramatically altered both watersheds, but while Klamath Chinook and steelhead are depressed relative to their historic abundance they do not appear to be threatened with extinction in the immediate future. Sacramento Chinook on the other hand are in critical condition. Unique winter-run Chinook, which historically spawned only in the Little Sacramento, Pit, Fall and Hat Creeks, the McCloud River and Battle Creek are listed as Endangered under the endangered species act. Today they are blocked from all of their historic spawning areas persisting only in a small cold water refuge below Keswick Dam. Spring Chinook and steelhead are also listed as threatened owing primarily to habitat loss from dam construction and irrigation practices in the Sacramento and its estuary, and fall Chinook have been almost entirely replaced by a hatchery monoculture. Recent record low returns of Sacramento Fall Chinook highlighted the lack of resilience inherent in the hatchery programs on the Sacramento.
Along the California Coast all four distinct population segments (DPS) of steelhead are listed under the ESA, with the South California grouping listed as endangered and the South Central, Central and Northern California coast DPS’s all listed as threatened. These populations are depressed due to the usual litany of impacts. Logging, dewatering of rivers, historic overharvest and urbanization have all contributed, but perhaps the greatest threat to their persistence, and one that is in some ways unique to California at least for the immediate future is an increasingly inhospitable ocean. In many instances along the California Coast, freshwater habitat is recovering from decades of abuse at the hands of the timber industry, yet salmon and steelhead populations have been slow to respond and a growing body of research suggests ocean survival may be limiting the rate of recovery.