Annual report: Upper Redwood Creek juvenile salmonid downstream migration study, 2000-01

Sparkman, Michael

From the Abstract: "Juvenile anadromous salmonid trapping was conducted in upper Redwood Creek [in Humboldt County] from March 26- August 4, 2001 to estimate population size of downstream migrating juvenile 0+ chinook salmon, 1+ steelhead trout, and 2+ steelhead trout using stratified mark/recapture methodology. The trap operated 129 nights out of 131 nights possible, and captured 120,692 0+ chinook salmon, 21 1+ chinook salmon, 102,408 0+ steelhead trout, 14,775 1+ steelhead trout, and 1,360 2+ steelhead trout. No juvenile coho salmon were captured. 1+ and 2+ steelhead catches were positively related to the relative gage height of the stream and at the trapping site. 0+ chinook salmon and 1+ steelhead trout average fork length and weight by week significantly increased over the course of the study. No significant relationships of fork length and weight with time were found for 2+ steelhead. Trap efficiencies for 0+ chinook salmon, 1+ steelhead trout, and 2+ steelhead trout by week averaged 55.3, 24.0, and 10.9%, respectively. 0+ chinook salmon trap efficiencies were negatively related to stream gage height. 1+ steelhead and 2+ steelhead trap efficiencies showed positivie relations with gage height. Total population estimates for 0+ chinook salmon, 1+ steelhead trout, and 2+ steelhead trout were 378,063, 50,654 and 12,668, respectively. Peak population out-migration for 0+ chinook salmon, 1+ steelhead trout, and 2+ steelhead trout occurred during May-June, April-May, and April-June, respectively, and followed trends of actual catches. Comparisons are made with downstream migration data collected in 2001 and 2000."

Annual report: Upper Redwood Creek juvenile salmonid downstream migration study, 2000-01

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