Fisheries and Trophic Change
Understanding Great Lakes ecosystems is critical for successful fisheries management. New Sea Grant research employs state-of-the-art statistical modeling and genetic structuring techniques to enhance knowledge of Great Lakes fish communities. These projects complement work by extension staff to assist Michigan’s fishing industries and to broaden fisheries knowledge and leadership among Michigan citizens.

A New Perspective on Saginaw Bay
Lake Huron’s Saginaw Bay, the largest bay in Michigan, is ecologically productive and provides an important nursery area for many species of fish. Surrounded by agricultural and urban areas, the Bay has withstood a barrage of impacts ranging from industrial pollution and urban runoff to excessive nutrients and invasive species.

The Bay is also remarkable, according to University of Michigan researcher Sara Adlerstein, because long-term data are plentiful—from information on zooplankton and phytoplankton that make up the lower aquatic food levels to annual surveys of top predators such as walleye and yellow perch.

With Sea Grant funding, Adlerstein and University of Michigan researcher Ed Rutherford are employing statistical modeling techniques to analyze disparate data and create a complete ecosystem view. This broad perspective will shed light on the impact of exotic species on the Saginaw Bay fish community, especially walleye and yellow perch.

The researchers will look specifically at the factors that control fish community structure and population, feeding habits, and variation in spatial distribution and abundance.

“The project really looks at the ecosystem from basic environmental conditions to the whole food web,” says Adlerstein. “The data are there and waiting to be analyzed... It’s a matter of putting the whole picture together.”

With assistance from Ph.D. student Brian Chilcott, project researchers have begun gathering environmental data, fish survey data and data on the lower food web levels. While project results will be relevant to Saginaw Bay, an understanding of ecological processes will be significant to similar ecosystems in the Great Lakes. For more information contact adlerste@umich.edu or (734) 764-4491.

The Life of the Lakes: A Guide to the Great Lakes Fishery
Michigan Sea Grant Communications produced the revised edition of The Life
of the Lakes: A Guide to the Great Lakes Fishery in September 2003. The publication was used as the primary curriculum for fisheries leadership institute workshops and is also marketed to the public. More than 600 copies of the booklet have been distributed.

The Life of the Lakes, which features more than 30 photos and illustrations, employs an ecosystem approach to show how social, environmental and technological changes have influenced Great Lakes recreational and commercial fisheries over time. The publication was authored by Michigan State University’s Shari Dann and Brandon Schroeder, now Michigan Sea Grant extension agent for Northeast Michigan. For more information contact Elizabeth LaPorte at elzblap@umich.edu or (734) 647-0767.