One morning we woke up to discover the deck of Diesel Duck strewn with large insects. These were fish flies that are not common to the Toronto area and totally new to us. Washing them off only helped somewhat, as there were more of them all around. Out on the parking lot the white cars and trucks had it worse and the ground was covered all over with these critters. I photographed one that held on to the window of our van while we were driving. The good part is, they do not sting or pester you other than being there by the billions!
A quick research on the net revealed the following excerpt:
A 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!