Klamath River Fall Chinook Salmon Age-Specific Escapement, River Harvest, and Run Size Estimates, 2015 Run

This report describes the data and methods used by the Klamath River Technical Team (KRTT) to estimate age-specific numbers of fall Chinook salmon returning to the Basin in 2015. The estimates provided in this report are consistent with the Klamath Basin Megatable (CDFW 2016) and with the 2016 forecast of ocean stock abundance (KRTT 2016). Age-specific escapement estimates for 2016 and previous years, coupled with the coded-wire tag (CWT) recovery data from Basin hatchery stocks, allow for a cohort reconstruction of the hatchery and natural components of Klamath River fall Chinook salmon (Goldwasser et al. 2001, Mohr 2006a, KRTT 2016). Cohort reconstruction enables forecasts to be developed for the current year’s ocean stock abundance, ocean fishery contact rates, and percent of spawners expected in natural areas (KRTT 2016). These forecasts are necessary inputs to the Klamath Ocean Harvest Model (Mohr 2006b), the model used by the Pacific Fishery Management Council to forecast the effect of fisheries on Klamath River fall Chinook salmon.