Spring and Summer Distribution and Habitat Use by Adult Threatened Spotted Gar in Rondeau Bay, Ontario, Using Radiotelemetry

The spotted gar Lepisosteus oculatus is designated as threatened in Canada under the federal Species at Risk Act. Identification and protection of critical habitat is an important component of recovering species at risk. To understand the habitat utilization of the adult life stage of the spotted gar in Rondeau Bay, a shallow coastal wetland of Lake Erie, external radio transmitters were surgically attached to 37 specimens in May 2007. These individuals were tracked at 224 discrete locations throughout the spring and summer of 2007. Aquatic macrophytes were present at 201 (90%) of these sites. Habitat and water chemistry data were collected at all tracked locations occupied by spotted gars. On the basis of electivity indices, in spring spotted gars showed a strong preference for shallow (<0.5‐m) and deep (>2.5‐m) waters with pH values <8.5. In summer, strong preference was shown for areas with mixed macrophyte beds. Spotted gars were found to relate to specific depths and cover rather than to shoreline features in Rondeau Bay. The study results are being used by the spotted gar Recovery Team to identify critical habitat in Rondeau Bay. This critical habitat designation will be used to ensure the protection of habitat needed to preserve the species in Canada, in part by curtailing the removal of aquatic vegetation in Rondeau Bay.