Invasive Scud Is Threatening the Great Lakes. Pollution Might Be Helping to Keep It Back.

Through the murky waters of the Illinois River, scud have been moving steadily toward Lake Michigan. Scientists suggest the tiny crustaceans, an invasive species known as Apocorophium lacustre , pose a big threat to the lake’s ecosystem—but so far, pollution has hindered their spread.

As water quality in the area improves, following decades of work to clean up the Illinois River and other bodies of water near Chicago, authors of a recent study analyzing barriers preventing the invasion of A. lacustre, published in the journal Biological Invasions, suggest additional techniques for managing the species might be necessary.

“For us as biologists, obviously, water quality getting better is the best thing we could possibly hear,” said John Bieber, co-author of the study and a biologist at Loy