A decision analytic approach to hierarchical decisions for double-crested cormorant conflict resolution

Authors

• Kelly F. Robinson, US Geological Survey, Georgia Fish and Wildlife Unit, Warnell School of Forestry and Natural Resources, University of Georgia, Athens GA
• Travis O. Brenden, Quantitative Fisheries Center, Department of Fisheries and Wildlife, Michigan State University, Lansing MI
• Alex Maguffee, Quantitative Fisheries Center, Department of Fisheries and Wildlife, Michigan State University, Lansing MI
• Charles R. Bronte, US Fish and Wildlife Service, Green Bay Fish and Wildlife Conservation Office, New Franken, WI
• Randall M. Claramunt, Michigan Department of Natural Resources
• Thomas R. Cooper, US Fish and Wildlife Service, Division of Migratory Bird Management
• Robin L. DeBruyne, USGS Great Lakes Science Center, Ann Arbor, MI
• Brian S. Dorr, US Department of Agriculture, Wildlife Services, National Wildlife Research Center, Mississippi State University MS
• James F. Farquhar, New York State Department of Environmental Conservation
• Jana R. Lantry, New York State Department of Environmental Conservation
• James R. Jackson, Cornell Biological Field Station, Cornell University, Bridgeport, NY
• David G. Fielder, Michigan Department of Natural Resources
• Rachel L. Pierce, US Fish and Wildlife Service, Division of Migratory Bird Managemen
• Doug Schultz, Michigan Department of Natural Resources

ORCID IDs

Kelly Robinson - 0000-0001-8109-9492           

Travis Brenden - 0000-0002-4373-1503                   

Brian S Dorr - 0000-0001-6857-8560\

James Farquhar - 0000-0003-3388-612X

David Fielder - 0000-0002-7278-986X

Jana Lantry - 0000-0002-3310-7926

Document Type

Article

Date of this Version

9-2026

Citation

Robinson, K.F., Brenden, T.O., Maguffee, A. et al. A decision analytic approach to hierarchical decisions for double-crested cormorant conflict resolution. Environ Syst Decis 46, 81 (2026). https://doi.org/10.1007/s10669-026-10071-4

Abstract

Double-crested cormorants (Nannopterum auritum) are piscivorous, migratory waterbirds that often conflict with fisheries interests in North America, stemming from depredation effects on fish populations. A new permitting process in the United States allows natural resource agencies to request permits for lethal take of cormorants in special instances like depredation of managed fish stocks. This rule does not include guidance for when cormorant take might be actionable. We developed a hierarchical structured decision making (SDM) framework for evaluating whether, when, and how much cormorant take might be necessary. A broad-scale, or “umbrella,” SDM framework established the overarching problem, objectives that likely are relevant for permitting decisions (i.e., minimizing loss of ability to harvest fish and sustaining cormorant presence on the landscape), and methods for evaluating the extent of management that might be necessary. A local-scale SDM process can then be applied for individual systems to determine the need for and magnitude of a permit request. We provide an example of such a local-scale SDM process for Brevoort Lake, Michigan, United States, where walleye (Sander vitreus) are sustained through stocking. We found that decisions for cormorant permitting on Brevoort Lake were influenced by uncertainties about the level of cormorant feeding on walleye, per capita level of daily cormorant consumption, number of days the cormorants spent feeding on the lake, and number of walleye stocked in the lake. This case study highlights the importance of uncertainty and risk in decisions for cormorant management, both of which can be accounted for more fully within the SDM framework.