Klamath River Project - Recovery of Fall-run Chinook and Coho Salmon at Iron Gate Hatchery October 8, 2013 to January 21, 2014

A total of 14,754 fall-run Chinook salmon, (Chinook, Oncorhynchus tshawytscha, entered Iron Gate Hatchery (IGH) during the fall 2013 spawning season from October 8, 2013 through December 10, 2013. Klamath River Project (KRP) staff systematically sampled 1 in every 10 Chinook, as well as all adipose-clipped (AD) Chinook during recovery efforts, for a sample size of 4,055. Scale samples and sex and fork length data were collected from systematically sampled Chinook. Analysis of the length-frequency distribution for systematically sampled Chinook males indicates that the preliminary cutoff point between grilse and adults occurred at ≤ 59 cm. fork length. Systematically sampled male Chinook ranged in size from 41 to 103 cm. fork length (FL), and systematically sampled female Chinook ranged from 53 to 93 cm. FL. Based on scale age analysis, the Klamath River Technical Team (KRTT) estimated that 8.9% (1,323) of the run were grilse. Females accounted for 48.5% (7,153) of the run while males accounted for 51.5% (7,601). The 2013 Chinook return to IGH contributed roughly 8.2% to the total (Klamath basin) in-river run and 16.7% to the total spawner escapement. Based on coded wire tag expansion, KRP staff estimated that 92% of the Chinook entering IGH during the 2013 season were of hatchery origin.