The amazing mayfly mess

The amazing mayfly mess

The reality television show “Dirty Jobs” could have done a segment at the McKinley Park Campground this week. If you think your job is bad, just be thankful you’re not a summer youth worker in Breitung Township this year. This week, the three young workers have had the unenviable task of raking and shoveling up the millions (maybe billions?) of dead mayflies that washed up on the campground’s beach in the wake of an exceptionally prolific hatch of these aquatic insects.

Raking a few dead mayflies isn’t unusual at the campground, but this year’s mess is reminiscent of a horror movie, one that required the use of a front end loader to haul it all away each morning. Campground manager Jerry Chiabotti figures the clean-up crew has raked and shoveled about thirty-five cubic yards of dead mayflies, equal to about three full gravel trucks.

“It’s the worst I’ve ever seen,” said Chiabotti, who grew up on Lake Vermilion. “They’ve been coming in large rafts.”

A strong north wind for the last seven days has apparently funneled a large portion of the lake’s mayfly population into the lakefront portion of McKinley Park Campground.

“It must be all the mayflies in Big Bay,” speculated Chiabotti.

The swarms of mayflies at night have been so thick it looks like black snow, according to area residents. A group of campers was shooting off fireworks on July 5, and the mayflies were so thick it was hard to see the explosions. One camper reported the swarm lasted at least 45 minutes.

“I was sitting on the beach and couldn’t see the water,” he said, “it was that thick.”

“People are being pretty good-natured,” said Susie Chiabotti, who has been fielding lots of questions at the campground store. She said the mayflies haven’t affected business at the campground, which has been running pretty full this summer. Kids are still swimming in the lake. The mayflies come in after dark, so once the mess is cleaned up in the morning, the beach is fine for swimming.

The township has been hauling the dead mayfies to an old gravel pit and township officials advise you don’t want to anywhere near the place because it, well, stinks to high heaven.


Mayflies belong to the Order Ephemeroptera, named for their short lives, at least while on land. Their immature form is called a nymph or naiad, which usually lives for a year in fresh water before emerging to breed. Depending on the species, adult mayflies live anywhere from a few minutes to a few days.

Females lay their eggs on the surface of lakes and streams, and die moments later. The eggs then sink to the bottom. The naiads live primarily under rocks or in the lake sediments, with most species feeding primarily on algae. Mayflies are unique among the winged insects because they molt one extra time after acquiring functional wings. This second-to-last stage is usually very short, often only a few hours, and this stage is a favorite food of many fish, including the walleye. The male mayflies generally form giant swarms.

Mayflies are not considered pests, but when they emerge all at once, they can create a nuisance. Just ask the folks at McKinley Park.

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