Muskellunge were once extirpated from lower Green Bay and the Fox River, but re-introduction efforts have resulted in a world-class muskellunge fishery that attracts anglers from across North America. However, the fishery remains largely reliant on stocked fish and establishing a self-sustaining population is a recovery goal for many agencies affiliated with Green Bay.

Multiple agencies have invested millions of dollars in habitat restoration within lower Green Bay and the Fox River. Identifying habitat conditions that promote successful reproduction of muskellunge can be used to help guide these investments in the future. The need for continued rearing and stocking of muskellunge requires significant funding and hatchery space; identifying ways to promote successful natural reproduction would alleviate the need for these resources.

Using a combination of acoustic and radio telemetry, WICFRU staff identify muskellunge spawning locations which are subsequently sampled for both eggs and young muskellunge to determine what habitat conditions result in successful hatching. Side-scan sonar mapping is used to determine the availability of this critical habitat within Green Bay and its tributaries. Sixty adult muskellunge will be implanted with transmitters to achieve these goals.

The researchers will provide habitat maps depicting probability of muskellunge egg deposition and/or larval production. Specifically, the researchers will identify those areas where the probability of these events might increase with changes to habitat conditions Therefore, the researchers will be able to provide recommendations regarding both the “where” and “how” aspects of future habitat improvements.

Green Bay provides a world-class muskellunge fishery that represents one of the best opportunities in North American to catch a fish over 50 inches long, which is an important benchmark for many anglers. Consequently, anglers from across North America visit Green Bay with hopes of catching one of these giant fish. Local anglers and guides recognize the importance and value of these fish and are actively engaged in efforts to improve the fishery and this has led to the involvement of a variety of stakeholders in the research effort. WICFRU staff are consistently asked to provide informal presentations on this research to angler organizations around the state.

Information obtained from the study will be used by resource agencies to develop future habitat improvements and to guide stocking strategies that may result in greater utilization of available habitat. The researchers will be able to provide recommendations regarding both the “where” and “how” aspects of future habitat improvements. Specific recommendations might include additions of woody cover, efforts to increase aquatic plant growth, flow/wave diversion and these recommendations could vary by location. Habitat maps will be electronically available, so both the public and resource professionals can use them for a variety of needs.

The ONB features articles from Cooperative Fish and Wildlife Research Units across the country. Working with key cooperators, including WMI, Units are leading exciting, new, fish and wildlife research projects that we believe our readers will appreciate reading about. This article was written by Daniel Isermann, the Wisconsin Cooperative Fishery Research Unit leader.