Genetic population structure of the round whitefish (Prosopium cylindraceum) in North America: multiple glacial refugia and regional subdivision

• Main Author: Morgan, Thomas David
• Other Authors: Somers, Christopher, Manzon, Richard, Cameron, Andrew
• Format: Thesis
• Language: English
• Published: Faculty of Graduate Studies and Research, University of Regina 2016
• Subjects: Yukon; Northwest Territories; Regina; Alaska
• Online Access: http://hdl.handle.net/10294/7712; http://ourspace.uregina.ca/bitstream/handle/10294/7712/Morgan_Thomas_200351761_MSc_Biol_Spring2017.pdf

A Thesis Submitted to the Faculty of Graduate Studies and Research In Partial Fulfillment of the Requirements for the Degree of Master of Science in Biology, University of Regina. ix, 93 p. The round whitefish (Prosopium cylindraceum) is an understudied species of freshwater fish found throughout northern North America and eastern Eurasia. Little is known about the ecology or population genetics of this species. Round whitefish are sensitive to environmental disturbance and have declined in regions of eastern North America, prompting interest in their conservation and management. Understanding the population genetics and phylogeography of round whitefish will inform planning for this species. I genetically characterized round whitefish from 16 locations across North America, and one site in eastern Russia, using microsatellites, mtDNA sequencing, and thousands of SNP loci using a nextRAD approach. I determined phylogeographic and population genetic relationships across sites in Alaska, Yukon, and Northwest Territories as well as the Laurentian Great Lakes region. Genetic analyses resolved strong delineation between eastern and western populations of round whitefish, indicating that they originated from separate glacial refugia. Analyses of regional relationships highlighted the importance of Lake Huron as a source for round whitefish populations, and Lake Ontario as being disjunct from the other Great Lakes. Populations in Alaska and the Yukon showed evidence of historical gene flow, with contemporary patterns linked to the connectivity of river basins in that region. I conclude that round whitefish population structure exists on multiple spatial scales in North America reflecting the deeper phylogenetic relationships of Pleistocene glacial lineages, and shallower divergences reflecting contemporary connectivity due to hydrology. Management of round whitefish needs to consider these major scales by recognizing separate Designatable Units for eastern and western glacial lineages, and appropriate Management ...