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Summary of Field Data Collection Efforts for Fall-Run Chinook Salmon

at Iron Gate Hatchery During the 2010 Season

Klamath River Project, Yreka, CA

January 4, 2011

The following provides a brief summary of field data efforts conducted by the KRP Yreka Office at Iron Gate Hatchery:

During the 2010 spawning season, every 10th Chinook entering Iron Gate Hatchery (IGH) was sampled by the KRP. Every tenth Chinook along the process line was identified as random (R). Non-random (NR) fish included adipose clips that were sampled outside of the tenth sample. Therefore, ad-clip samples could be identified as either random (if tenth sample) or nonrandom if not the tenth sample. The information gathered for every sample during the recovery effort included a fork length (cm) measurement, sex determination, scale sample, and identification of any marks or tags present. Tissue and otolith samples were collected from every 10th random (or every 100th) Chinook along the process line. Heads were recovered from every ad-clipped sample encountered for later CWT recovery.

A total of 11,347 Chinook were recovered at IGH, of which 1,980 were sampled by the KRP. Heads were recovered from a total of 950 ad-clip Chinook observed in both the random and non-random sample. A total of 1,980 scale samples were collected which include 1,121 random samples and 859 non-random samples.

Of the 950 heads that were collected, positive reads of coded wire tags were obtained for 878 Chinook salmon. Based on coded wire tag analysis and expansion, it is estimated that 94% of the Chinook that entered IGH in 2010 were of hatchery origin. Three (3) of the 878 tag codes recovered originated from Trinity River Hatchery, and the rest from IGH. Based on examination of length frequency distributions and fork lengths of known age Chinook observed, grilse were determined to include Chinook < 63cm. in fork length. Based on this grilse determination, the Chinook run at IGH was comprised of 1,113 grilse (9.8%) and 10,234 adults (90.2%) for a total run size of 11,347 Chinook.

FL (cm) / grilse / grilse / adults
< 60 / 90 / 0.08 / 0.92
< 61 / 96 / 0.09 / 0.91
< 62 / 102 / 0.09 / 0.91
< 63 / 110 / 0.10 / 0.90


1

Grilse 63 cm

1

Grilse 63 cm