Date of Award


Publication Type

Doctoral Thesis

Degree Name



Biological Sciences


Biology, Conservation


Lynda D. Corkum


Nicholas E. Mandrak




Many species in North America range northward and barely into southern Canada. Some of these species are classified as species at risk and afforded legal protection in Canada, yet the decision to protect these populations at the edge of their range is controversial. To determine if edge populations are more likely to be listed as at risk, fish species were grouped based on whether they are listed as at risk in Canada then assigned values for several life history and ecological traits and a discriminant function analysis was conducted. Conservation status was correctly predicted 93% of the time. Traits that predicted conservation status were endemic distribution, recognized distinct populations, edge distributions and long-lived. Northern edge populations of Spotted Gar ( Lepisosteus oculatus ) were investigated for the presence of local adaptations. Adaptations in the form of delayed age at maturity and lower body condition were seen in the Rondeau Bay population of Spotted Gar. Differences in habitat selection and offshore distance were also seen in the Rondeau Bay population when compared to southern core populations of the species. Microsatellite analyses showed that northern edge populations were divergent from southern core populations and the Rondeau Bay population carried the entirety of the genetic diversity found in the north. A phylogeny based on mitochondrial gene sequences was created and used to identify five commercially obtained gar samples. Four individuals obtained at a pet shop in Kitchener, Ontario, labeled as Spotted Gar, were identified as Florida Gar ( Lepisosteus platyrhincus ). A specimen obtained at a commercial fish market in Toronto, Ontario was identified as a Spotted Gar and likely originated from Long Point Bay, Lake Erie. The presence of local adaptation affirms the need to protect edge populations to conserve the overall diversity within the Spotted Gar and other species in Canada.