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Filters: Contacts: Stephen R. Carpenter (X)

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Abstract (from http://onlinelibrary.wiley.com/doi/10.1002/ecy.1853/full): Predicting species responses to perturbations is a fundamental challenge in ecology. Decision makers must often identify management perturbations that are the most likely to deliver a desirable management outcome despite incomplete information on the pattern and strength of food web links. Motivated by a current fishery decline in inland lakes of the Midwestern United States, we evaluate consistency of the responses of a target species (walleye (Sander vitreus)) to press perturbations. We represented food web uncertainty with 196 plausible topological models and applied four perturbations to each one. Frequently the direction of the focal...
We classified walleye ( Sander vitreus) recruitment with 81% accuracy (recruitment success and failure predicted correctly in 84% and 78% of lake-years, respectively) using a random forest model. Models were constructed using 2779 surveys collected from 541 Wisconsin lakes between 1989 and 2013 and predictor variables related to lake morphometry, thermal habitat, land use, and fishing pressure. We selected predictors to minimize collinearity while maximizing classification accuracy and data availability. The final model classified recruitment success based on lake surface area, water temperature degree-days, shoreline development factor, and conductivity. On average, recruitment was most likely in lakes larger than...
Abstract (from Ecological Society of America): Successful management of natural resources requires local action that adapts to larger‐scale environmental changes in order to maintain populations within the safe operating space (SOS) of acceptable conditions. Here, we identify the boundaries of the SOS for a managed freshwater fishery in the first empirical test of the SOS concept applied to management of harvested resources. Walleye (Sander vitreus) are popular sport fish with declining populations in many North American lakes, and understanding the causes of and responding to these changes is a high priority for fisheries management. We evaluated the role of changing water clarity and temperature in the decline...
Abstract (from AFS): Many Bluegill Lepomis macrochirus populations are dominated by fish ≤125 mm total length (TL) that may be underrepresented when using standard sampling gears. To identify efficient sampling methods for these populations, we compared catch per unit effort (CPUE) and TL frequency distributions of Bluegill captured in cloverleaf traps, boat electrofishing, mini‐fyke nets, and beach seine hauls from two northern Wisconsin lakes supporting populations dominated by fish ≤125 mm TL. Mean Bluegill CPUE ranged from 41 (SE = 11) fish per cloverleaf trap lift to 16 (SE = 8) fish per beach seine haul. Cloverleaf traps generally captured smaller Bluegill relative to other gears and were the only gear to...
Abstract (from http://www.tandfonline.com/doi/full/10.1080/03632415.2014.996804#.VSbE2I7F8qY): Freshwaters are being transformed by multiple environmental drivers, creating uncertainty about future conditions. One way of coping with uncertainty is to manage for resilience to unanticipated events while facilitating learning through adaptive management. We outline the application of these strategies to freshwater recreational fisheries management using a case study in Wisconsin, USA, where black bass (Micropterus spp.) populations are increasing, while Walleye (Sander vitreus) populations are decreasing. Managing for heterogeneity in functional groups (e.g., age classes and prey species of sport fishes), fishery objectives,...
Abstract (from http://www.tandfonline.com/doi/full/10.1080/02755947.2014.943860#.VJhyqUACo): Invasive Rainbow Smelt Osmerus mordax have been associated with reductions in Walleye Sander vitreusrecruitment, and predation by adult smelt on age-0 Walleyes has been identified as one of the potential mechanisms contributing to recruitment failure. Predation effects could be mitigated by stocking Walleye fingerlings based on smelt and Walleye morphometric relationships. By combining 0.95 quantile regression of smelt gape size on TL and 0.05 quantile regression of Walleye body depth on TL, we constructed a stocking tool to determine the appropriate size to stock Walleye fingerlings in lakes invaded by smelt such that few...