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Assessing The Effects Of Myxobolus Cerebralis And Other Environmental Factors On The Dynamics, Abundance, And Distribution Of Trout Populations In The Logan River, Utah, Ernesto A. De La Hoz Franco

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The presence of nonnative trout and the recent introduction of Myxobolus cerebralis in the Logan River drainage pose a threat to the native Bonneville cutthroat trout population (Oncorhynchus clarki Utah). The variability in the response of susceptible trout populations to M. cerebralis, causing agent of whirling disease, suggests that environmental factors may influence the effects of the parasite in infected environments. I investigated the relationship between temperature, discharge, substrate size, nutrient concentration (nitrogen and phosphorus), periphyton (chlorophyll a), and the relative abundance of Tubifex tubifex to the distribution, and prevalence of M. cerebralis in wild salmonid populations and …

An Ecological/Life History Comparison Of Two Whitefish Species In Bear Lake, Utah/Idaho, Brett W. Thompson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Ecological traits of the endemic Bear Lake whitefish Prosoopium abyssicola and the Bonneville whitefish prosopium silonotus were investigated. Spatial distributions indicated distinctive differences in depth contour preference. Catch per unit effort data indicated that Bonneville whitefish prefer shallow depths and warmer water temperatures, whereas Bear Lake whitefish prefer deep, cold water.

Diet differences between the two species were large. Differences in both age distribution and growth rate patterns were also observed. The Bonneville whitefish population was predominantly composed of juvenile age classes. Very large adults reached ages of 12-14 years. Bear Lake whitefish exhibited a different population structure with few …