• behaviour;
  • intraspecific variation;
  • muskellunge introductions;
  • stocking program;
  • stocks;
  • telemetry

Abstract  Intraspecific, seasonal and diel variation in movement behaviours of three stocks of juvenile (age-2; 399–610 mm total length) muskellunge, Esox masquinongy Mitchill, were assessed using radio telemetry in Forbes Lake (225 ha), IL, USA. Experimental populations included muskellunge from the Upper Mississippi (Leech Lake, MN, USA) and Ohio (Cave Run Lake, KY, USA) river drainages, as well as progeny from North Spring Lake, IL, a mixed-origin stock. No differences in hourly movement rates or home ranges were detected among stocks. Movement rates were greatest during spring (mean ± SE = 42 ± 4 m h−1), lowest during summer (16 ± 3 m h−1) and intermediate in autumn (28 ± 5 m h−1). Additionally, movement rates during the summer were greater at night than crepuscular periods. Home range sizes were similar during spring and autumn (mean ± SE = 17–18 ± 3–4 ha) and decreased during summer (5 ± 3 ha). Although habitat selection characteristics were generally similar among stocks, fish from the Upper Mississippi River drainage occupied deeper water more frequently and selected the pelagic zone more strongly during the spring than those from the Ohio River and mixed-origin stocks. Within the littoral zone, muskellunge selected coarse woody habitat and aquatic macrophytes. Collectively, these findings suggest little behavioural differentiation among genetically divergent stocks when evaluated in a common reservoir environment.