Cat Island Chain Information

Cat Island Chain During Low and High Water Levels
(1966 and 1976)

Credit: Thomas Erdman

A chain of small islands once formed the backbone of extensive wildlife habitat in southern Green Bay. Known as the Cat Islands, they were washed away in the 1970s by high water levels, storm waves, and ice shoves. Today, UW Sea Grant is working with the Brown County Port, the U.S. Army Corps of Engineers (USACE), the U.S. Fish and Wildlife Service, the Wisconsin Department of Natural Resources, and coastal engineers W.F. Baird & Associates to design a plan for rebuilding the islands and restoring the many ecological functions they once provided for the bay.

There are several reasons why the Cat Island Chain should be restored. Habitat loss is a critical factor in the impaired health of the lower bay ecosystem. The Cat Island Chain historically functioned much like coastal barrier islands, protecting a large expanse of shallow bay waters and wetlands that provided fish and wildlife habitat.  When the islands are rebuilt, nearby coastal marsh and underwater plant communities will be protected from destructive wave action. These habitats are critical in sustaining important sport and commercial fisheries, such as the yellow perch. The restored islands also will provide needed habitat for shorebirds, waterfowl, colonial nesting birds, amphibians and reptiles. Island habitats are essential to colonies of nesting water birds because they offer isolation from mainland predators and human disturbance and proximity

to aquatic food sources. Although the present remnant of Cat Island has become dominated by double-crested cormorants in recent years, the islands have supported at least thirteen different species of colonial nesting birds--one of the highest biodiversities of any Great Lakes island.

Sea Grant Researchers's Graduate Class Lends a Hand

Students in Joy Zedler’s UW–Madison Adaptive Restoration class are lending a hand in restoring the Cat Island chain.

Project partners have spent nearly a decade working with the U.S. Army Corps of Engineers, Brown County Port Authority, U.S. Fish and Wildlife Service (USFWS), Wisconsin Department of Natural Resources, and coastal engineers W.F. Baird & Associates to design a restoration plan for the island chain using navigation channel dredged materials.

With those blueprints nearly completed, Victoria Harris and Janet Smith, Biota & Habitat Work Group Chair, sought the help of Zedler and her students to draft a habitat restoration plan for the islands. The students found that the island chain provides an excellent opportunity for adaptive restoration, testing a variety of restoration strategies on one island and using the most effective techniques on others. Because the islands will be barren after construction with dredged sediments, the students gave highest priority to improving soil quality to support vegetation and using rocks, logs,

and trees to reduce wind and water induced erosion.  The student's report may be accessed below.

Cat Island Chain Presentations, Links and Reports

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