Fine-Scale Features of Muskellunge Spawning Grounds in Georgian Bay
American Fisheries Society Symposium 85
Loss and degradation of spawning habitat has been identified as a major stressor in the widespread decline of Muskellunge Esox masquinongy populations. Protection of spawning habitat has therefore been designated a management priority, and research is needed to permit efficient identification of these areas. One avenue of research has been to model spawning habitat based largely on the characteristics of spawning sites (i.e., locations where confirmed spawning events have occurred). However, characterization of more general spawning grounds remains comparatively unexplored. We analyzed radio telemetry data collected from three regions of Georgian Bay (from southeastern to northern Georgian Bay) to determine if adult Muskellunge have predictable, fine-scale movement patterns when using spawning grounds. A total of 49 individuals were tracked for up to three spawning seasons during 2012–2015. Both male and female Muskellunge exhibited staging behaviour during the spawning season and appeared to travel along areas with moderate slopes (between 1° and 10°). Females staged further offshore in deeper waters (maximum depth ranged from 1.7
to 2.9 m) and were consistently more mobile than males. By comparison, males staged in shallower waters (maximum depth ranged from 1.3 to 2.6 m) towards the offshore edges of coastal wetlands and waited at access points for females to move inshore to spawn. In all three regions of Georgian Bay, we found adult Muskellunge staging in water deeper than what has typically been defined as spawning sites (>1.5 m), making brief forays into shallower areas to spawn. We suggest that deeper areas and moderately sloping areas used as travel corridors are important components of spawning grounds that need to be protected, in addition to the typical shallow wetland areas where Muskellunge actually spawn.