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ARCATA FWO:Fall Chinook Salmon Run Characteristics and Escapement Estimates for the Main Stem Klamath River, California
California-Nevada Offices , January 31, 2009
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YTFP and AWFO field crews deploy catarafts for a carcass survey on the Klamath River (Photo:  Steve Gough, USFWS).
YTFP and AWFO field crews deploy catarafts for a carcass survey on the Klamath River (Photo: Steve Gough, USFWS). - Photo Credit: n/a
A portion of Chinook salmon carcasses are marked with an individually numbered tag fixed to the lower jaw as part of the tag-recovery protocol (Photo:  Steve Gough, USFWS).
A portion of Chinook salmon carcasses are marked with an individually numbered tag fixed to the lower jaw as part of the tag-recovery protocol (Photo: Steve Gough, USFWS). - Photo Credit: n/a

by Steve Gough, Arcata FWO
Statistical carcass surveys of fall-run Chinook salmon (Oncorhynchus tshawytscha) have been conducted on the Klamath River since 2001 in a joint effort by the U.S.Fish and Wildlife Service's Arcata Fish and Wildlife Office (AFWO), Yurok Tribal Fisheries Program, and USGS Fort Collins Science Center.  Escapement estimates of adult fall-run Chinook salmon in the Klamath River from Iron Gate Dam to the Shasta River confluence are derived using postmortem tag/postmortem recovery methods.  Spawner estimates generated by the carcass tag/recovery survey conducted within the more densely used spawning reaches are summed with estimates derived from a redd survey (conducted by AFWO and the Karuk Tribe of California) for the less densely used spawning reaches (Shasta River confluence to the Indian Creek confluence) to establish an estimate of escapement in the entire main stem Klamath River. 

Escapement estimates of fall Chinook salmon adults and jacks throughout the Klamath River basin are assessed by the Klamath River Technical Advisory Team (KRTAT) and used for stock projection and harvest management.  As a second main purpose, accurate numbers of spawners in this reach, coupled with our ongoing fry outmigrant study, are needed for calibration of the young-of-year salmon production model, SALMOD.  Data collected during carcass surveys on the Klamath River are also used to characterize this specific run in terms of age class proportions, juvenile-to-adult and adult sex ratios, female spawning success/pre-spawn mortality, fork length frequency, carcass tag/recovery estimate-redd count relationships, hatchery prevalence, and egg deposition.

The unstratified Petersen tag/recovery estimator yielded an escapement estimate of 4,894 in 2008.  Petersen estimates from 2001 to 2007 ranged from 3,587 (2006) to 14,165 (2002) with a mean of 7,525.  Included in the 2008 estimate are 836 (17.1%) jacks.  Estimates of jacks from 2001 to 2007 ranged from 3 (0.1%; 2005) to 734 (9.4%; 2001) with a mean of 312.  Despite low adult estimates in 2008, jack estimates were high, portending good returns of 3 year old spawners in 2009 and of 4 year old spawners in 2010.


Contact Info: Steve Gough, (707) 616-2326, steve_gough@fws.gov



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