Mayflies' return to Ohio isn't just a nuisance — it's a good sign for Lake Erie

Today from the Ohio Newsroom, the return of the Mayflies. Support comes from Ohio CASA. Ohio CASA's mission is to ensure children experiencing abuse and neglect have a caring, trained adult in their corner. Information about CASA volunteer work is at Ohio's C-A.org. Support comes from the James at Ohio State. Cancer. For some, it's one of life's fiercest foes, but not at the James. where a team of nearly 300 specialists and over 1,500 researchers are working together to create a cancer-free world. Today from the Ohio Newsroom takes you around the state. Connecting you with news and neighbors from all over Ohio, I'm Kendall Crawford. In 2014, toxic alcohol blooms caused a water crisis in Toledo. Since then, Lake Erie has been at the forefront of the conversation about preserving freshwater resources. Advocates across the state track its health through water sampling. But as midstories, Yaffa Segal reports for the Ohio Newsroom, A tiny bug can also reveal a lot about the lake. Summers near Lake Erie bring company. Swarms of mayflies cling to your windshield and blanket your driveway. These little guys are an iconic harbinger of Midwest Summer and an important indicator species. Mayfly swarms have been observed across Northwest Ohio this season, and experts say that is a good sign for the region's freshwater. So when we're seeing them, we have the indication that they emerge from a healthy ecosystem. That's Autumn Moore, the Northwest Ohio Stream Quality Monitoring Coordinator for the Ohio Scenic Rivers program. She says the life cycle of the mayfly relies on specific freshwater conditions, but maintaining a healthy lake isn't easy. As industrialization ramped up after World War II, Lake Erie was a dumping ground for industrial and agricultural waste from cities like Toledo, Cleveland, and Buffalo. By the mid-century, it was a toxic swamp, overflowing with nutrients that triggered harmful algal blooms and spelled disaster for mayflies. That's because the first two years of the mayflies' life cycle are spent underwater as nymphs. According to Mayfly expert Moore, in order to survive to winged adulthood, the nymphs habitat has to meet certain conditions. The mayflies are one of the more sensitive indicator species that we work with. We work with all sorts of critters. The mayflies are... quite particular. They require a lot of oxygen. They also are not very tolerant of pollution. So they need pretty clean water to be able to survive. Algal blooms create pockets without oxygen called dead zones that are uninhabitable for mayfly nymphs. So by 1953, mayflies were considered locally extinct in the western basin of Lake Erie. At the time, the loss went largely unrecorded.

Around the 60s and 70s, the U.S. EPA was established, and with it came the 1972 Great Lakes Water Quality Agreement between the U.S. and Canada. This was one of the first major international agreements explicitly designed to tackle ecosystem pollution, and heavily degraded Lake Erie was at the top of the list. By the 90s, the lake had recovered, and so had the mayflies. But an entire generation had grown up without these insects, and the sudden, massive swarms caught people off guard. People didn't really know what they were when these big hatches started happening again. They had to ask the old timers because they were the only ones that remembered it. And so from that time in the 90s to now, those hatches have increased quite a bit compared to what they were. Giant swarms of bugs emerging from the lake might seem less like an environmental victory and more like something out of a Hitchcock movie. But Dr. Christine Péter Magyar, a professor of ecology at the University of Toledo, wants people to know that these creatures are completely harmless. Embodying a live-fast die-young philosophy, the mayflies only live for around two days, during which their only responsibility is to mate. They have no need to eat, so they don't even have mouths. They can't harm you. All they can do is pile up and be stinky in your driveway. And when the 48-hour party is over, the mayflies start to die off in unison. As piles of them carpet the pavement, it can be easy to be annoyed. But to chase Fleece, an environmental historian at Bowling Green State University, this abundance of mayflies is something to be thankful for. We should be grateful to the mayflies. They're more than simply a nuisance, but instead an ally in the struggle for cleaner water. Fleece said that this year's mayfly swarms are a visible reminder of the progress we've made for the health of the Great Lakes. Today, mayfly populations are strong, but if the environmental history of the Great Lakes tells us anything, it's that we cannot be complacent in the notion that these improved conditions will prevail forever. So the next time you find yourself sweeping thousands of tiny bugs off your porch, try not to complain too much. It means the lake is going strong. For Midstory in the Ohio Newsroom, I'm Yafa Siegel. That's all today from the Ohio Newsroom. We'll talk with you tomorrow.