From North Bay on Lake Nipissing, to Cornwall on the St. Lawrence River, to Leamington on Lake Erie and many places in between, folks who live near the water welcome a pesky winged creature to their shores each spring when the fish fly makes its grand appearance.

Living on the waterfront has its rewards and its drawbacks
- with the pesky fish fly, you get a taste (and smell) of both

From the ooze beneath the waters of Ontario’s lakes and rivers, they emerge each spring, mate indiscriminately and then die, leaving their decaying corpses stuck to house siding and street lights, or just littering the streets and walkways. There, they emit disgusting popping sounds beneath car tires and human feet.  

The tiny creature in question is the fish fly, a simple insect that has been known to make strong men and women squeamish, and turn stomachs with the stench of fish they emit when squashed.  

The annual invasion is heaviest in Ontario’s Lake St. Clair and western Lake Erie region. But pockets of equally horrifying winged creatures, known locally as everything from mayflies, to shadflies, sand flies and June bugs, have been known to pop up in other areas.  

In North Bay on Lake Nipissing, and in Cornwall on the St. Lawrence River, residents speak in hushed tones of the coming of the shadflies. They know it as a time when no one dares to open their mouths while riding their bikes, for fear of choking on the ghastly creatures.  

Turn off the lights!

There are thousands of similar species worldwide, and many hundreds across North America. So if you decide to move to the waterfront, beware!  

Annually in Ontario, there are reports from the fish fly and shadfly hotspots of neighbours gathering with big green garbage bags and shovels to scoop the insects off the streets before they turn to a mucky grease and become a hazard to vehicular traffic and pedestrians alike.  

Depending on where you live and the precise species that afflicts you, the invasion could be for just a few days, or it could be for a week or two.  

My first experience with the little pests came in the spring of 2009 at my home in Leamington on Lake Erie. It wasn’t a pleasant one. I especially didn’t enjoy sitting in the dark all evening, for fear my lights would attract a bigger swarm of the winged aquatic insects, each about three centimetres long. They can cover a garage door or tree trunk in two minutes flat.  

But as annoying as fish flies can be, they are indeed interesting creatures. On a mating dance, no less!  

Female fish fly lays about 4,000 eggs

In an interview with the Windsor Star, University of Windsor biology graduate student Ellen Green said the fish fly mating season is in full swing when you spot big blobs of brownish stuff on the surface of the water near shorelines. Those blobs are the fish fly eggs. After mating by travelling through a swarm of males hovering in the air, the females head to the water to lay about 4,000 eggs each.  

The eggs then sink to the bottom, where they hatch. The first evolution of the newly hatched fish fly will camp out in the sediment for up to two years before beginning its journey to the surface and out of the water for its own in-air mating dance.  

The fact is, fish flies exist solely to mate. Alas for the fly, the lifespan of a single adult specimen is anywhere from 30 minutes to one day, depending on the species. Dead or alive, they stick to decks and houses and patio furniture like Velcro.  

Many people power-wash the fish flies off their houses and storefronts. Doing that, however, will release a powerful dead fish smell. It’s best to either gently sweep them off with a broom, or simply leave them there until they dry up and blow away on a spring wind.  

The good news for the waterfront is that a heavy infestation of fish flies can be a sign of a healthy marine ecosystem. According to Green, since the prehistoric water-dwelling insects are sensitive to pollution, they need lots of oxygen to survive until they hatch. A healthier lake, with less algae for example, will hold more oxygen.  

Fish flies have been called “an indicator species” of a less polluted ecosystem. And healthy fish flies are much better for the fish that feed on them. Which means the fish we catch will be much better for us, too.  

Bring on the fish flies!