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Fish often exhibit complex movement patterns, and quantification of these patterns is critical for understanding many facets of fisheries ecology and management. In this study, we estimated movement and fishing mortality rates for exploited walleye (Sander vitreus) populations in a lake-chain system in northern Michigan. We developed a state-space model to estimate lake-specific movement and fishery parameters and fit models to observed angler tag return data using Bayesian estimation and inference procedures. Informative prior distributions for lake-specific spawning-site fidelity, fishing mortality, and system-wide tag reporting rates were developed using auxiliary data to aid model-fitting. Our results indicated that postspawn movement among lakes was asymmetrical and ranged from approximately 1% to 42% per year, with the largest outmigration occurring from the Black River, which was primarily used by adult fish during the spawning season. Instantaneous fishing mortality rates differed among lakes and ranged from 0.16 to 0.27, with the highest rate coming from one of the smaller and uppermost lakes in the system. The approach developed provides a flexible framework that incorporates seasonal behavioral ecology (i.e., spawning-site fidelity) in estimation of movement for a mobile fish species that will ultimately provide information to aid research and management for spatially structured fish populations.

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The purpose of this study was to identify spawning habitat, determine home ranges, and examine movement patterns for a naturally reproducing population of Great Lakes muskellunge in the lower Antrim County chain of lakes, Michigan. Muskellunge spawning sites were identified by tracking of implanted muskellunge using a directional hydrophone and by nighttime spotlight surveys. All spawning fish tagged in Torch or Clam Lake spawned in Clam Lake, while most spawning fish tagged in Elk or Skegemog Lake spawned in the Torch River; one appeared to spawn in Lake Skegemog. Of the 32 potential spawning sites, 28 (87.5 %) contained submerged aquatic vegetation as the dominant habitat type, while the remaining 4 sites were divided equally between woody debris (6.25 %) and bare substrate. All but one implanted muskellunge returned from spawning sites to the same lake in which they were captured and implanted. Of the 24 tagged muskellunge, four were harvested via angling or spearing within 1 year after tagging, and two additional fish were assumed harvested when contact was lost. Implanted muskellunge tended to remain in the lakes during the winter, then move into spawning areas in spring, eventually returning to open lake sites where they resided over summer. Muskellunge movement behavior diverged after spawning each year, with 11 tagged fish (61.1 %) remaining in Skegemog or Clam Lake for the summer, and seven individuals traveling to Elk or Torch Lake. Muskellunge home ranges averaged 612 ha and ranged from 17 to 5,287 ha.