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Can angler harvest be used to reduce largemouth bass populations in northern Wisconsin lakes?

Electrofishing in northern Wisconsin


January 2012 - December 2014


Largemouth bass Micropterus salmoides abundance has increased in many northern Wisconsin lakes over the last decade and this has caused some concern for anglers and biologists due to potential negative interactions with other popular sportfish such as walleyes Sander vitreus. The Wisconsin DNR has liberalized black bass harvest regulations on some northern Wisconsin lakes in an effort to reduce bass abundance. However, available information suggests that exploitation of largemouth bass is generally low (i.e., < 10%) and it is unclear whether angler harvest will be sufficient to actually affect bass abundance in these lakes. Furthermore, several recent studies suggest that anglers voluntarily release most of the black bass they catch, so liberalization of harvest regulations may not result in substantial increases in bass exploitation. Our primary objectives for this study are to determine if: 1) angler harvest can be used to effectively reduce largemouth bass populations in some northern Wisconsin lakes and 2) certain harvest regulations are more likely to result in reduced largemouth bass abundance in these lakes. Currently, we are obtaining population estimates and demographic information for largemouth bass populations in several northern Wisconsin lakes; this information will be used in stage-structured modeling exercises to address our two research objectives. Additionally, we are collecting scales, otoliths, dorsal spines, and anal spines from largemouth bass to examine differences in age estimates and associated precision among structures. This project is funded by the Wisconsin DNR and sampling will continue through the summer of 2014.

Research Products and Activities


  • Schnell, K., and D. Isermann. February 2013. Replicating otolith ages for largemouth bass in northern lakes: a comparison of scales and spines. Wisconsin Chapter of the American Fisheries Society Annual Meeting. Rothschild, Wisconsin.
  • Schnell, K., D. Isermann, M. Hansen, and J. Hansen. February 2013. Predicted effects of angler harvest on largemouth bass abundance in northern Wisconsin lakes. Wisconsin Chapter of the American Fisheries Society Annual Meeting. Rothschild, Wisconsin.

Current Staff

Federal Staff: 1

Masters Students: 5

Phd Students: 0

Post Docs: 0

University Staff: 4

5 Year Summary

Students graduated: 13

Scientific Publications: 21

Presentations: 88



Funding Agencies

  • Wisconsin Department of Natural Resources


Wisconsin Cooperative Fishery Research Unit Cooperators

  1. U.S. Geological Survey
  2. University of Wisconsin-Stevens Point
  3. Wisconsin Department of Natural Resources