Walleye Habitat Model Assumptions Can be Tested with Acoustic Telemetry in Lake Erie

Suitable walleye habitat in Lake Erie is currently defined for area-based fishery quota allocation as depths <13 m.  A recent model based upon gillnet data shows that temperature, water clarity, and dissolved oxygen also explain significant variability in walleye distribution, prompting resource managers to consider alternative habitat metrics. We addressed limitations of the gillnet habitat model via acoustic telemetry of walleye with receiver transects deployed along depth gradients in the central basin of Lake Erie.  During the 2013 season, we logged 23,485 detections from 88 different fish on 18 receivers.  Diel patterns of detections revealed variations in movement that can better inform the gill net model of habitat use.  Further, proportions of detections at receiver depths >13m showed a higher than expected utilization of deeper offshore habitats.  Dissolved oxygen loggers placed at a subset of receiver locations are allowing us to examine the influence of hypoxic episodes on walleye movements and basin-wide hydroacoustic surveys are providing spatially matched estimates of forage fish abundance as another explanatory variable.  This work improves our understanding of walleye habitat use as it relates to spatial management of the most valuable fishery in the Great Lakes.