When mayflies swarm your front porch, crunch under your feet or fly into your hair it is difficult to tell if they are in one of their less abundant years.
But they likely are in a cyclical decline, mayfly researcher Don Schloesser said Tuesday.
“The overall abundance out in the lake is probably 10 to 15 per cent lower than it was last year,” said Schloesser who works as a research fisheries biologist at the U.S. Geological Survey’s Great Lakes Science Center in Ann Arbor, Michigan.
Researchers used to think a cycle lasted about four years but now are wondering if it could be a five year cycle in the western basin of Lake Erie. There isn’t enough data for a pattern in Lake St. Clair, he said.
“The last high peak was 2009 so we’re likely to get a boom in 2014, possibly 2015.”
Lynda Corkum is a University of Windsor professor and author of Fishes of Essex County and Surrounding Waters. (Courtesy of Lynda Corkum)
University of Windsor biology professor Lynda Corkum who has studied mayflies for decades said she didn’t see as many mayflies last year or so far this summer and knows fewer nymphs were being found in early June in research done by her husband at the university. She said lower numbers of mayflies would be concerning because they are food for fish and the decline could be linked to algal blooms in Lake Erie which would rob nymphs in the sediment of oxygen.
Average number of nymphs per square metre at bottom of Lake Erie
- 289 in 2009
- 301 in 2010
- 161 in 2011
- 103 in 2012
Based on research by Don Schloesser
Nightmarish
A fishfly hangs on a window in Windsor. (Tyler Brownbridge/The Windsor Star files)
There were reports on Twitter of swarms of mayflies visible on radar over Lake Erie, a photo showing piles at a Subway restaurant door in Leamington and pictures of them blanketing the ground in Ohio.
“They say mayflies indicate a healthy environment. I must live in a totally pristine place then! Unbelievable!” Leslie Huffman posted on Twitter Monday.
Huffman lives next to a County Road 50 orchard by Lake Erie in southern Essex County and isn’t a fish fly fan.
“They’re the things that nightmares are made of if you live near the lake,” Huffman said Tuesday.
This time of year she turns off all the lights at night but they are still attracted to the yellow house. No one wants to cut the grass, she’s vacuuming them out of the cars and they no longer hold a Father’s Day barbecue because it would fall in mayfly season. She sweeps them away from her porch but gets so many they smell as they rot. The only good thing is birds eat the mayflies instead of the cherries which are ripening at their fruit farm.
Many aliases
Mayflies, fish flies, Canadian/American soldiers, June bugs (incorrect since those are beetles)
Burrowing mayflies are part of the family of Ephemeridae which, like the word ephemeral, comes from the Greek meaning lasts a day. Corkum said there are 1,500 species of mayflies and we have three kinds here: Hexagenia limbata, Hexagenia rigida and Ephemera in Lake St. Clair that have spots on their wings.
Mate and die
Mayflies hang on a wall in Windsor. (Windsor Star files)
Mayflies spend two years in the mud at the bottom of the lake. They emerge, shed their skin, mate and die in about two days or up to 72 hours while on land. They don’t eat as adults. The swarming is all about finding a mate and females fall in the water and die after laying their eggs. The emergence usually lasts from May to October with a peak in mid June to the end of June.
Coping skills for people
Other than turning off lights, you could hope for winds to carry them to the American side. Mayflies are lousy flyers and need wind to get them to shore. They can get killed when it’s rainy and they can’t make it on shore. They like clear calm nights that are a bit on the cool side, Schloesser said.
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