"In response to an abrupt decline in Sacramento River fall Chinook (SRFC) salmon abundance, and the need to provide improved scientific advice to fishery managers, the Sacramento Index (SI) was developed in 2008. The SI is a combined-age index of adult SRFC ocean abundance comprised of three components: ocean harvest, river harvest, and spawner escapement. This paper provides comprehensive documentation of the methods used to estimate the components of the SI and the method used to forecast the SI for fishery planning purposes. Properties of the time series of SI estimates are also discussed. The SI has been an integral part of PFMC ocean salmon fishery management since its development, and will likely be used as the basis for SRFC assessment into the foreseeable future"--Abstract.

National Marine Fisheries Service (NMFS)