Fisheries research

Effective management of Minnesota’s fisheries relies on access to the best available science to inform decisions. The fisheries research unit consists of researchers and support staff who work in area fisheries offices statewide.

Staff conduct applied research that evaluates management practices; develops new management tools and sampling techniques; and anticipates responses of fisheries to new and existing stressors.


Invasive species: unexpected impacts

A spiny water flea perched on a human fingertipWater clarity research on Mille Lacs Lake shows that the impacts of invasive species can offset each other.

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What are predator fish eating?

A muskie eating a smaller fishA project designed to look at the diets of muskellunge, walleye, northern pike and largemouth bass in Minnesota lakes continues this year.

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Big cats inhabit the Minnesota

A large yellow perchA three-year study of Minnesota River flathead catfish between Mankato and Shakopee showed an abundant population of large fish topping 20 inches.

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Are perch getting smaller?

A large yellow perchA project designed to find out why the number of yellow perch are declining in fish population counts continues this summer in 25 Minnesota lakes.

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Project archive


Investigational reports: Minnesota DNR fisheries section publications for research studies that have more local or regional management implications.

Special publications: DNR manuals, lake management plans, guidelines or reviews.

Peer-reviewed publications: Research studies that are published in scientific journals and have gone through a rigorous peer review process. Results of these studies influence fisheries management beyond Minnesota. Copies of these reports can usually be received by contacting the author.


Fisheries research unit staff have a broad range of skills and expertise including population and fish community dynamics; bioenergetics and food web dynamics; genetics; stock assessment; statistics; fish habitat; assessment methodologies and hydroacoustics; watershed and landscape ecology; and long term monitoring.

Patrick SchmalzFisheries research managerSt. Paul
John HoxmeierResearch supervisorSt. Paul
Patrick SchmalzResearch supervisorDuluth
Tyler AhrenstorffResearch scientistBrainerd
Bethany BethkeResearch scientistDuluth
Doug DietermanResearch scientistLake City
Will FrenchLong-term monitoring biologistSt. Paul
Brian HerwigResearch scientistBemidji
Beth HolbrookResearch scientistBrainerd
Tom JonesTreaty fisheries coordinatorAitkin
Dale LogsdonResearch scientistWaterville
Tim MartinLong-term monitoring biologistSt. Paul
Loren MillerResearch scientistSt. Paul
Devon OliverResearch scientistLake City
Kristen PattersonResearch scientistBemidji
Heidi RantalaResearch scientistDuluth
Jeff ReedResearch scientistGlenwood
Casey SchoenebeckResearch scientistGlenwood
Steve ShroyerResearch scientistWaterville
Chris SmithResearch scientistGlenwood
David StaplesBiometricianSt. Paul

Patrick Schmalz, fisheries research supervisor, St. Paul
[email protected]
tel. 651-259-5231

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