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Date Permissions Signed


Date of Award


Document Type

Masters Thesis

Degree Name

Master of Science (MS)


Environmental Sciences

First Advisor

Helfield, James M.

Second Advisor

Bodensteiner, Leo R., 1957-

Third Advisor

Matthews, Robin A., 1952-


The Salish sucker (Catostomus sp.) is a recently described endemic fish species with a patchy distribution and a narrow geographic range in western Washington and southwestern British Columbia. In this study I examined populations within the Nooksack River watershed, attempting to elucidate the environmental factors contributing to observed patterns of distribution and abundance. I hypothesized that hypoxic and hyperthermic conditions during the summer months would restrict Salish sucker distribution. I tested this hypothesis by measuring dissolved oxygen concentrations, temperature, and Salish sucker abundance and movement at eight sites in the Bertrand Creek and Fishtrap Creek sub-basins. The results of this study did not support my original hypothesis; instead it seems more likely that physical habitat characteristics rather than water quality exert greater influence in patterns of abundance and distribution. My findings emphasize the importance of maintaining the quality and connectivity of habitat for Salish sucker conservation.





Western Washington University

OCLC Number


Subject – LCSH

Catostomus--Washington (State)--Nooksack River Watershed; Catostomus--Effect of temperature on--Bertrand Creek Watershed (B.C. and Wash.); Catostomus--Effect of temperature on--Fishtrap Creek Watershed (B.C. and Wash.); Hypoxia--Environmental aspects--Bertrand Creek Watershed (B.C. and Wash.); Hypoxia--Environmental aspects--Fishtrap Creek Watershed (B.C. and Wash.)

Geographic Coverage

Nooksack River Watershed (Wash.); Bertrand Creek Watershed (B.C. and Wash.); Fishtrap Creek Watershed (B.C. and Wash.)




masters theses




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