Ecology and morphology of sympatric and allopatric populations of mountain whitefish, Prosopium williamsoni, and round whitefish, P. cylindraceum in lakes in western Canada

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Guinn, Brent Richard.
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Diet analysis conducted on round whitefish (Prosopium cylindraceum) and mountain whitefish (P. williamsoni) from the one lake in which they are found in equal abundance indicated that there were diet differences between species and between different sizes of each species. Counts of six body parts taken on round whitefish differed between allopatric and sympatric lakes after accounting for environmental differences between lakes. This convergent character displacement was assumed to be a result of competition for food. There was no indication of hybridization between these species. Analysis of occurrence, distribution and abundance data of coregonids in western Canada suggests that mountain whitefish colonized lower Liard River lakes before lake whitefish (Coregonus clupeaformis) and round whitefish had access to the area. Round whitefish probably did not disperse farther south because of the presence of northward dispersing mountain whitefish. Mountain whitefish are able to colonize lakes that contain round whitefish because of their ability to make use of streams tributary to such lakes. Mountain whitefish apparently never become abundant in lakes previously colonized by round and lake whitefish.