Fish fly takes Caledonia by storm during breeding season

Last week Caledonia witnessed blizzard-like conditions when an insect called the fish fly insect created large swarms during the course of its annual breeding period.

It's like a blizzard in summer as adult fish flies come out for just a couple of days to mate, then die

Local resident and photographer, Gail MacLellan was out to take photos of the fish flies mating in Caledonia. (Gail MacLellan)

It was only around for days last week, but it stormed the small town of Caledonia, Ont., by the tens of thousands in a fast and furious way.

The fish fly, an insect named after the horrid smell created when crushed underfoot, breeds in large swarms over the course of a few days after emerging from the water, creating a spectacle in the town along the Grand River southwest of Hamilton, Ont.

For residents of Caledonia, it was like a blizzard in the middle of the summer when they witnessed the annual phenomenon last week.

Heather Hibbs and her family jumped in the car late last Thursday night to go see the insects.

She says it's a big event in the town and broader Haldimand County.

McMaster insect physiologist, Rosa da Silva says the presence of the fish flies are a sign of a healthy environment. (Gail MacLellan)

"It's a gross thing, but it is a phenomenon right? It's quite interesting," said Hibbs.

A video Hibbs' 15-year-old son took while on the family outing has garnered over 80,000 views on social media.

In the video you can hear the crunching of the bodies under the wheels of their car.

A big mess

Neat yes, but the aftermath creates a large mess. 

After the insects mate, the males die and blanket the ground with their carcasses.

This can create very dangerous road conditions as Haldimand County's Roads and Operations Manager, Brent Hammond explains.

"They are slippery, they are greasy. In at times they come in heavy," said Hammond.

Because the area is used to the occurrence, Hammond says crews get out with sweepers and leaf blowers, but it's never an extensive cleanup.

Once they know of the insect's activities, crews are usually out early in the morning to address the mess.

It was fitting to see shovels come out with the way local resident and photographer, Gail MacLellan described the scene.

"Basically it looked like we were in the middle of a snowstorm," said MacLellan.

According to Haldimand Manager of Roads and Operations, Brent Hammond, the roads can become very slippery and dangerous with the carcasses covering the roads. (Gail MacLellan )

MacLellan covered herself up and went out to witness the spectacle because she takes photos of insects.

She says it was interesting to see the reactions of people who didn't know what was going on.

"It took them by surprise. All of a sudden arms started flailing or they're running faster or they're just couldn't understand what they're running into," said MacLellan.  

Unusual life cycle

According to McMaster University insect physiologist, Rosa da Silva, the fish fly has a distinct life.

Most of their lives they're larvae under water, living in the sediments of lakes and streams, feeding off of small plants.

Da Silva says they can live down there for years.  

Once they start maturing they'll emerge from the water as a cream colour and then shed their skin. 

What makes these insects unique is their mating process, the blizzard-like mess. 

The carcasses are horribly smelly, which is why they're given their name, the fish fly. (Gail MacLellan)

"They have an interesting mating strategy where a male and female swarm mate and shortly thereafter die, so what you see is a lot of carcasses lying around," said da Silva.

Before expiring, the females return to the water to lay their eggs.

A sad life, says da Silva, because essentially its life purpose is to just mate for a few days.

A sign of a healthy environment 

One good thing about the fish fly is what its presence represents.

According to da Silva, the insects are a sign of a healthy ecosystem, so you actually want them around.

"If we're looking at what they need to survive, they need a really good environment that has good oxygen in the water," said da Silva. "That's pretty much a healthy habitat, so having them in your lakes is probably a good sign that the lake is healthy or in the stream, because these guys are just thriving in there."

Fish flies are found in various locations.

Da Silva says Lake Erie tends to get them and some areas in Michigan.