Spawning migration dynamics of ocean-returning salmonids (Oncorhynchus spp.) in Freshwater Creek, California

Graduation Date

2009

Document Type

Thesis

Program

Other

Program

Thesis (M.S.)--Humboldt State University, Natural Resources: Fisheries Biology, 2009

Committee Chair Name

Terry Roelofs

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Freshwater Creek, Salmonids, Humboldt State University -- Theses -- Fisheries, California, Pacific Ocean--Humboldt Bay, Spawning migration

Abstract

Anadromous adult salmonids (Oncorhynchus spp.) were tracked to describe spawning migration in the mainstem and five tributaries of Freshwater Creek, Humboldt County, California. A permanent weir and trapping station was operated to document freshwater entry. Passive integrated transponder (PIT) tags and stationary antennas were employed to detail movement to spawning grounds and determine numbers of tributaries utilized by adult salmonids. A mobile PIT tag reader was used to ascertain what portion of the coho salmon (O. kisutch) population spawned at more than one location and how far apart multiple spawning locations were. Stream discharge was positively correlated with movement into freshwater and tributaries at low to moderate flows. Fish movements were less sensitive to higher flow and at times negatively correlated. A majority of individuals entering the stream early in the spawning season exhibited holding behavior in downstream reaches of the mainstem. Many coho salmon entered tributaries during spawning migration. Males utilized multiple tributaries more often than females. Several individuals of both sexes spawned at more than one location. Steelhead trout (O. mykiss) and Chinook salmon (O. tshawytscha) primarily utilized mainstem habitat. Male coho salmon and steelhead trout generally moved greater distances and had longer residence times than females. Residence times were negatively correlated with date of freshwater entry.

https://scholarworks.calstate.edu/concern/theses/r494vn65k

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