Mainstem Klamath River Coho Salmon Redd Surveys 2001 to 2005

Results of annual coho salmon Oncorhynchus kisutch redd surveys conducted on the mainstem Klamath River in November and December, 2001 through 2005 are summarized. The survey reach covers 136.5 river kilometers (rkm) located between Iron Gate Dam (IGD; rkm 310.3) near Hornbrook and the Indian Creek confluence at Happy Camp, California (rkm 173.8). A combined total of 38 coho salmon redds were observed within the survey reach for all five years combined. In 2001, eight additional redds were observed in the mainstem Klamath River downstream of the lower boundary of the study reach at Indian Creek. Within the survey reach, the highest annual redd count occurred in 2001 (n = 13). Seven redds were observed in 2003 and 6 redds were documented annually in 2002, 2004, and 2005. Coho salmon redds were observed in the mainstem Klamath River between November 15 and December 18, with the majority of new redds (63%) counted in mid December. About 68% of observed redds were located within 20 rkm of IGD and all redds were constructed within 1.5 rkm of a tributary mouth. Mean redd area (3.6 m2), mean pit depth (0.61 m), mean mound depth (0.38 m), mean adjacent depth (0.55 m), and focal velocity range (0.49-1.05 m/s) were greater than values reported in the literature for other systems, but sample sizes were too low for statistical comparison.