Published March 22, 2021 at 1:11 PM EDT Listen • 5:02
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John Janssen remembers the moment he realized Lake Michigan was about to change.
It was a September day in 1990 and he was diving looking for sculpin an ugly fish with big lips that likes to hide under rocks.
“I wasn’t paying much attention to anything else it was my dive partner who suddenly grabbed me and pointed out that first zebra mussel,” he says.
“I just lay on the bottom for like five minutes, trying to imagine what the lake was going to look like in a year.”
Janssen is a fisheries biologist at the University of Wisconsin, Milwaukee, and he knew what was coming. Zebra mussels had already invaded Lake Erie.