A study led by University of Michigan scientists says the spread of two closely relates species of invasive mussels, the zebra and the quagga, are displacing life-supporting algae and threatening the multibillion-dollar U.S. commercial and recreational fisheries in Both Lake Michigan and Lake Huron.
By filtering out and feeding on the algae, the mussels are robbing other organisms of the food they need to survive, researchers said.
"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 to be published in the journal Environmental Science & Technology.
The changes are so significant and occurring so quickly, researchers say, that Great Lakes management agencies should review and revise their policies to respond more quickly.
"New strategies for managing the lakes are urgently needed," said researcher Donald Scavia, director of U-M's Graham Environmental Sustainability Institute.
"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.