Thesis Title: Tubifex habitat analysis to assess whirling disease risk in Alberta, Canada.
Author: Sergio Bazan
Abstract
During July 2021, 30 sampling sites at Bow River Watershed and 6 sampling sites at Crowsnest River were visited to perform tubifex relative abundance counts and the collection of environmental conditions associated to each site, such as stream characteristics, water physicochemical parameters, sediment composition and quality. Relative abundance of tubifex worms at Crowsnest River was significatively higher than any Hydrologic Unit 8 (HUC8) of Bow River Watershed except for Jumpingpound Creek (p-value 0.372). Higher relative abundance of tubifex worms were found in Jumpingpound Creek and Highwood River within Bow River watershed, but the difference with the other HUC8 was not statistically significant. The land use analysis results show higher relative abundance of tubifex worms around urban and farmland areas. However, the differences between all land use categories were not statistically significant (p-value 0.515), The same results were found for Silt-Clay type of sediments over of Granular sediments with no statistically significant difference (p-value 0.543). A multivariable linear model of tubifex relative abundance for the study area was built. The adjusted r-squared value was (R 2 = 0.1755). The variables included in the model were: the water pH, the wetted width, the stream velocity, the estimated flow, and the sediment classification. However, the assumption of linearity and homogeneity of variances were not meet by the proposed linear model.