Use of dual frequency identification sonar to estimate salmonid escapement to Redwood Creek, Humboldt County, California

Graduation Date

2012

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources: Fisheries Biology, 2012

Committee Chair Name

Walter G. Duffy

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Humboldt State University -- Theses -- Fisheries, Escapement, DIDSON, Redwood Creek, Salmon

Abstract

I used dual frequency identification SONAR (DIDSON) to estimate escapement of adult coho salmon, Chinook salmon, steelhead and coastal cutthroat trout entering Redwood Creek to spawn. Effective estimates of salmonid escapement include a quantifiable error associated with the number of fish. The errors associated with DIDSON estimates were described and computed to assess whether or not the technology is appropriate for monitoring salmonid escapement in Redwood Creek. DIDSON counts of unidentified fish were assigned a species using models developed from spawning survey observations in the Redwood Creek watershed. The DIDSON deployment on Redwood Creek worked well during flows below 3000 cubic feet per second. Multiple regression of environmental variables showed no clear relationships with daily fish passage rates. Between 17 November 2009 and 18 March 2010, I estimated that 2,435 Chinook salmon, 375 coho salmon, 775 steelhead and 400 coastal cutthroat trout entered Redwood Creek to spawn. Calculation of sampling variance and a census of 88 hours suggested that a sample of 10 minutes to represent the hour resulted in a 9-13% confidence interval around the point estimate.

https://scholarworks.calstate.edu/concern/theses/ks65hf453

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