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Fisheries Research

Four small tubes containing fish scales collected from harvested fish at the Northern Highland Fishery Research Area.

The Office of Applied Science employs highly skilled staff equipped with a broad range of expertise across fisheries and ecological research. 

Our team of fisheries research scientists, biologists and technicians produce objective, applicable science for the DNR that helps inform fisheries management decisions. Staff are engaged in high-priority research projects related to Wisconsin sport fishes and specialize in many research specialties, including applied fisheries management and ecology, quantitative stock assessments, fish habitat, propagation science and population dynamics.

The fisheries research team works together to cover the diversity of Wisconsin's aquatic habitats and species with three stations across the state: Escanaba Lake Research Station in the Northern Highland Fishery Research Area (NHFRA), the Science Operations Center in Madison, and the DNR Service Center and Tommy G. Thompson State Hatchery in Spooner. The team collaborates with anglers, universities, state hatcheries, tribal partners and conservation groups across the state and country to help meet fisheries research needs. 

Northern Highland Fishery Research Area Studies

The Northern Highland Fishery Research Area (NHFRA) provides a suite of experimental lakes in the Boulder Junction area for the long-term purposes of monitoring angler behaviors, fish population dynamics, and ecosystem-scale studies to benefit fisheries across Wisconsin. Numerous studies have been conducted in the NHFRA over its long history on a variety of topics, including fisheries regulations, angler habits and effects on fish populations, fish biology, fish species interactions, and fisheries regulations. The research area also serves as a collaborative training ground and study site for students, early career fisheries professionals, and academics. Below is a list of current research projects being conducted in the NHFRA, along with a project summary. 

A fallen tree trunk near the shore provides micro-habitats for fish species

Fish Production with Coarse Woody Habitat Additions

Goal: Measure the effects of adding coarse woody habitat on the fish-carrying capacity of Wisconsin lakes.


Juvenile walleye being measured on a wooden measuring board.

Walleye Recruitment in Ceded Territory Lakes

Goal: Identify characteristics of lakes associated with successful walleye reproduction and recruitment in the Ceded Territory.


DNR staff member holds up a large musky.

Sustainable Muskellunge Exploitation

Goal: Develop a catch-at-age model for estimating sustainable exploitation rates for muskellunge in the Ceded Territory.


Fish Community Production Distribution in Walleye Lakes

Goal: Determine how fish production is being (re)distributed in declining walleye lakes compared to walleye lakes that have remained stable in recent years.


Evaluating Potential Sex Ratio Bias In Hatchery Reared Walleye

Goal: Identify whether there is a sex ratio bias in extended-growth walleye hatchery products and determine the timing and influential factors of walleye sexual differentiation.



Statewide Fisheries Research Studies

Fisheries scientists in the Office of Applied Science also work on projects across the state, from the cold waters of Lake Superior to the streams and lakes of southern Wisconsin. Staff work around the state to meet research needs and are currently working on the following projects:

Survival and Fitness of Stocked Brook Trout

Goal: Calculate the relative stocking success of three generations of brook trout produced by hatcheries.


Beaver swimming in a lake

Beaver Influences on Trout Populations

Goal: Examine the way beavers affect coldwater streams and trout populations in ecoregions and beaver management zones across Wisconsin.


Juvenile musky in a holding tank, waiting to be released into Wisconsin lakes.

Muskellunge Age and Growth Study

Goal: Evaluate non-destructive means for determining muskellunge age and growth, as well as determine the effects of catch-and-release on muskellunge mortality and size structure.


An icy lakeshore in northern Wisconsin.

Spawning Phenology

Goal: Test for phenological shifts in the spawning of sport fishes around Wisconsin, understand what may be driving these shifts and determine their implications for recruitment.


DNR staff holds a beautiful trout, picked from a bucket below.

Temporal Trends in Trout Populations

Goal: Measure environmental conditions over time to help understand how and why trout populations vary in response to water temperature, stream flow and other habitat variables.


Chinook Salmon

Reassessing the Predator-Prey Balance on Lake Michigan

Goal: Reassess the predator-prey balance in Lake Michigan to account for recent changes in the prey fish community and associated shifts in feeding dynamics.


Lake Whitefish kept on ice

Spatially-Explicit Modeling of Lake Whitefish on North-Moonlight Bays

Goal: Explore the need to develop spatially explicit assessment modeling based on likely productivity changes in North, Moonlight and Green Bay's lake whitefish stocks.


Three bluegill fish in a white bucket.

Panfish Responses to Angling and Predation

Goal: Assess trends in Wisconsin's panfish populations (abundance and size structure) in response to angler exploitation and predator management.


Steelhead from the Brule River

Age-Structured Stock-Recruitment Assessment of Steelhead

Goal: Assess steelhead biological reference points like spawning stock sizes and sustainable yield in the Brule River and western Lake Superior.


Scientific Consulting

In addition to the research projects above, the Office of Applied Science also provides consultation services to the Division of Fish, Wildlife and Parks. These consultation services are often in the form of population analyses, scientific design or analysis services and consultation on management issues to ensure the best possible scientific information is available to decision-makers.

The open dialogue between the Office of Applied Science and the Bureaus of Wildlife Management and Fisheries Management helps drive our research foci so that research directly fills the research needs of decision-makers.  

Publications and reports

View a list and links to our recent journal publications and reports. For NHFRA-specific peer-reviewed papers, please see NHFRA Publications.