Why Spring-Run? Central Valley Spring-Run Chinook Salmon Recovery and the San Joaquin River

Historically, California’s Central Valley is estimated to have supported spring-run Chinook salmon runs as large as 600,000 fish between the late 1880s and 1940s (CDFG, 1998).  The majority of these fish originated in the San Joaquin River Basin, where higher elevations of the southern Sierra Nevada provided summer refuge off the hot, dry valley floor.  Construction of large dams in the foothills and major water diversions from the San Joaquin River and its tributaries began in the late 1800’s.  By the mid-1900’s spring-run Chinook salmon were largely extirpated from the San Joaquin River basin.  When the species was listed by the National Marine Fisheries Service (NMFS) as threatened in 1999, spring-run were known from only 3 wild and one hatchery supported population on the Sacramento River system. The NMFS recovery plan for this species calls for protecting and enhancing existing populations, and the reintroduction of populations to the San Joaquin River Basin. Restoration actions on Butte, Clear, and Battle creeks are showing significant results in the Sacramento River Basin.  The rationale for reintroduction through the San Joaquin River Restoration Program and other enhancements for recovery will be discussed.