No Simple Answer to Lake Whitefish Decline

Ann Arbor, MI — The decline of lake whitefish in the Great Lakes may be due to several factors including the number of lake whitefish present in a given area.

Research at Michigan State University (MSU) is helping to shed some light on the lake whitefish mystery.

"We wanted to determine whether lake whitefish density or the amount of food available to them is more important in determining the number and fat content of eggs in lake whitefish of the Great Lakes," said Jud Kratzer.

Kratzer, an MSU graduate student, used data from two time periods (1986-1987 and 2003-2005) from seven locations in the Great Lakes to solve the mystery. The seven locations studied were Big Bay de Noc, Naubinway, and Grand Traverse Bay in Lake Michigan; Cheboygan, Alpena, and Bayport in Lake Huron; and Whitefish Bay in Lake Superior.

Kratzer found that the amount of energy that lake whitefish invested in egg production was more closely associated with lake whitefish abundance than with the amount of food available.

"These findings are important because many people have placed the blame for recent declines in the growth and plumpness of Great Lakes whitefish solely on changes in the food web, but this study shows that the number of lake whitefish present in a given area could actually be a more critical factor," Kratzer said.

Lake whitefish is an important commercial food fish in the Great Lakes.

Original Publication Information

Results of this study, "Changes in Fecundity and Egg Lipid Content of Lake Whitefish (Coregonus clupeaformis) in the Upper Laurentian Great Lakes between 1986–87 and 2003–05," are reported by Jud F. Kratzer, William W. Taylor and Mark Turner in the latest issue (Volume 33, No. 4, pp. 922-929) of the Journal of Great Lakes Research, published by the International Association for Great Lakes Research, 2007.

Contacts

For more information about the study, contact Jud Kratzer, Vermont Fish and Wildlife Department, 1229 Portland St., Suite 201, St. Johnsbury, VT 05819, jud.kratzer@state.vt.us, (802) 751-0486.

For information about the Journal of Great Lakes Research, contact Marlene Evans, Editor, National Water Research Institute, 11 Innovation Boulevard, Saskatoon, SK, S7N 3H5, Canada; editor@iaglr.org; (608) 692-1076.

Links

Since 1967, IAGLR has served as the focal point for compiling and disseminating multidisciplinary knowledge on North America's Laurentian Great Lakes and other large lakes of the world and their watersheds. In part, IAGLR communicates this knowledge through publication of the Journal of Great Lakes Research, available to members in print and electronic form. A searchable archive of the journal is available online and includes the abstracts of articles from the journal's inception in 1975 through the most recent issue. In addition, complete articles are available to members who have signed up for an electronic subscription.