The fish in Lake Erie are certainly eating well right now.
Every year in late June or early July billions of may flies hatch and swarm over lake eerie. According to The Ohio State University these swarms have been common since 1995 when pollution levels in the lake began to fall. The Mayflies come from the deep beneath the waters of Lake Erie. The mayflies start out as an egg and after hatching int a nymph they burrow into lake sediment. The nymph continues to grow larger until the skin molts, presenting a pair of ready-to-fly wings.
Here’s another GIF from the National Weather Service in Cleveland
The mayflies are completely harmless, but they can be a little annoying especially if you are out on the water.
Fly fishermen often replicate mayflies when tying their own flies. They are one of the main sources of food for trout and other game fish.