Swarm of fish flies returns to Leamington, signalling a healthy lake — and a seasonal headache

CTV News

3 days ago

Residents of Leamington are once again swatting, sweeping and sighing as fish flies make their annual appearance along the Lake Erie shoreline.
The delicate, short-lived insects — also known as mayflies — emerge in large numbers every June, coating cars, sidewalks, and windows across the southern Ontario town.
'If it's good for the environment, I'm happy to see them, but they are kind of a pain in the neck,' said Daphne Steer, a Canada Post letter carrier.
'You just use the mail and swat around you as you're walking.'
Fish flies in Leamington, Ont. 2025
Fish flies swarm Leamington, Ont., seen on June 25, 2025. (Chris Campbell/CTV News Windsor)
While their presence can be overwhelming, scientists and local officials say the arrival of fish flies is actually a positive sign.
'When mayflies are thriving and hatching, that's telling you that you have a lot of oxygen in the water,' said Ken Drouillard, director of the School of the Environment at the University of Windsor.
'And it basically suggests that things are getting pretty good.'
Leamington Mayor Hilda MacDonald agrees.
'This is just what happens. It's a sign the lakes are healthy, and we just get used to it,' she said.
'We turn off the outside lights at night. We hose off our cars. They're not particularly creepy. They're just kind of annoying. And they're on your windows and all of that. It's a regular season, I can't say there's more. The one big thing is they smell bad when they're dead. They smell like fish.'
Fish flies in Leamington, Ont. 2025
Fish flies swarm Leamington, Ont., seen on June 25, 2025. (Chris Campbell/CTV News Windsor)
The smell, the mess, and the sheer volume are what many residents are dealing with this week.
'We get thousands of them,' said Connie Nelson, who has lived in Leamington for five years.
'The good thing is they're only here for a couple of weeks, and we know they're going to come every June. So, we just deal with it and know that July's coming soon.'
Alan Antoniuk, who lives near Seacliff Park, said the latest wave hit hard overnight. He placed a 'Free fish flies' sign on his front yard.
'The fish flies hit hard last night again. About four to six inches in spots,' he said.
'The town's been fabulous cleaning it up. We haven't had any accidents. Some years, it makes such a grease slick that the cars go to stop, and they go right into the fence down here at Seacliff Park. But for the most part, it's been okay.'
He added that they're feeding the environment, and they're needed, but they cause a big mess.
'Free fish flies. Bring your own buckets. Bring your own truck. Truckloads at a time. I'll give you the shovels if you want, you can clean them up on your own first thing in the morning,' Antoniuk said.
Drivers are among those most frustrated, with cars and windshields often coated by the insects, especially if they sat under a light overnight.
'There's a lot of them,' exclaimed Tim Hergott as he washed his car.
'I don't know why they use my car as a target, but they do.'
Hergott said he's been washing his vehicle more often since the insects arrived.
Fish flies in Leamington, Ont. 2025
Fish flies swarm Leamington, Ont., seen on June 25, 2025. (Chris Campbell/CTV News Windsor)
'I'd rather they move on, but they're only here for, like, two or three weeks, and then they're gone,' he explained.
'You'd never know they were here.'
Others are simply avoiding cleanup until the bugs are gone.
'I don't like it. They smell and there's no sense in trying to clean it off until they're all done coming here,' said Susan Bondy.
'It's crazy.'
While short-lived, the mayflies serve a vital role in the ecosystem.
'It's remarkable how many other things in the environment are just waiting for that mayfly emergence to happen,' Drouillard said.
'So, first of all, even when those mayflies are sitting in sediments, they're a prominent component of fish food. Our walleye and yellow perch are consuming these at various stages of their life stages. And then when they emerge and they come out into the air, all kinds of birds and frogs and snakes, you name it. I've even seen skunks having a feeding frenzy on these mayflies.'
As Leamington residents brace for another week or two of buzzing, crunching and sweeping, many are trying to keep their cool — and their sense of humour.
'Free fish flies,' Antoniuk said. 'Truckloads.'