Invasive mussels causing massive ecological changes in Great Lakes

University of Michigan News Service: The ongoing spread of non-native mussels in the Great Lakes has caused "massive, ecosystem-wide changes" throughout lakes Michigan and Huron, two of the planet's largest freshwater lakes, according to a new University of Michigan-led study. The blitzkrieg advance of two closely related species of mussels—the zebra and quagga—is stripping the lakes of their life-supporting algae, resulting in a remarkable ecological transformation and threatening the multibillion-dollar U.S. commercial and recreational Great Lakes fisheries.

Previous studies have linked the mussels to far-reaching changes in Lake Michigan's southern basin. Now a paper by two University of Michigan ecologists and a colleague shows that the same dramatic changes are occurring in northern Lake Michigan and throughout Lake Huron, as well.

"These are astounding changes, a tremendous shifting of the very base of the food web in those lakes into a state that has not been seen in the recorded history of the lakes," said Mary Anne Evans, lead author of a paper scheduled for publication in the April 15 edition of the journal Environmental Science & Technology. "We're talking about massive, ecosystem-wide changes."

Evans is a research fellow at the U-M School of Natural Resources and Environment. The other authors are Donald Scavia, director of U-M's Graham Environmental Sustainability Institute, and Gary Fahnenstiel, senior ecologist at the National Oceanic and Atmospheric Administration's Great Lakes Environmental Research Laboratory.

Because the changes are so profound and are happening so rapidly, the authors recommend that Great Lakes management agencies review and perhaps revise their policies so they can respond more quickly. "New strategies for managing the lakes are urgently needed. Ecological changes that formerly occurred over decades are now happening in just a few years, so we need to adapt our management policies to this new reality," Scavia said….

Quagga mussels in Lake Michigan sediment sample from Lake Michigan taken during whole lake benthic survey, June 2005. From NOAA