Purdue University

Lake Sturgeon Research

Potential for Habitat Rehabilitation in Lake Michigan Tributaries
Lake sturgeon Acipenser fulvescens were historically one of the most numerous fish species in the main basin of Lake Michigan and Green Bay. Throughout the Great Lakes, lake sturgeon abundance declined dramatically during the 1800s, with populations reduced to remnant levels by the early 1900s. Factors attributed to these declines include water pollution, physical habitat alterations, impediments to migration, and commercial overexploitation. Although improvements in water quality and harvest reductions have allowed for some recovery, limited availability of staging, spawning, and nursery habitats in historically important tributaries remains an impediment to rehabilitation. Many of the rivers that presently support or historically supported lake sturgeon populations have been altered by the construction of hydropower dams, changes in land-use practices, and other anthropogenic impacts. As a result, the extent to which these factors continue to limit habitat availability, and consequently recovery efforts, remains unknown. Enhancement or rehabilitation of degraded habitats, including the addition of proper substrates, creation of backwater areas, maintenance of adequate and natural stream flows, removal of barriers, and installation of fish-passage structures, will be necessary to restore lake sturgeon tributaries throughout the Lake Michigan watershed. Assessment of past and present habitat availability is necessary, and replacement, enhancement, or renewed accessibility to habitats will be essential for successful restoration. Therefore, habitat enhancement or rehabilitation must be a priority for tributaries of Green Bay in order to allow for the long-term sustainability and recovery of lake sturgeon. Specific objectives of this research include: (1) assessment and quantification of lake sturgeon spawning, nursery, and adult habitats currently available and potentially available above existing barriers; (2) examination of spatial (i.e., longitudinal) relationships of lake sturgeon habitats below and above existing barriers; and (3) development of a decision tool for prioritizing Green Bay tributaries, identifying appropriate rehabilitation strategies, and directing future enhancement or restoration of important habitats or habitat features for lake sturgeon populations.

Funding Source: Great Lakes Fishery Trust, U.S. Fish and Wildlife Service, and Purdue University

Personnel: Daniel Daugherty (current doctoral student)

• Project not yet completed; project completion date: December 2006

Collaborators: Robert Elliott, Mark Holey, Edward Baker, and Thomas Meronek

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