PORT CLINTON, Ohio - Lake Erie's mayfly population is surviving and showing no signs of trouble despite water quality problems over the last few years that have caused alarm.
The pesky but harmless winged insects are starting again to rise out of the lake along Ohio's northern shore.
One researcher said the annual invasion is a good sign because mayflies are an indication of a healthier Lake Erie.
"Back in the '60s and '70s, the mayflies basically were gone from Lake Erie," said Tory Gabriel, fisheries outreach coordinator for Ohio State University's Sea Grant program.
"The fact that we have (mayflies) still tells us it's not as bad as it was when they disappeared," he told the Port Clinton News-Herald.
Each year around the middle of June, millions of mayflies hatch and sprout wings and then blanket street lamps, store windows, screen doors and just about anything they can cling to in places that include Sandusky, Port Clinton and parts of the Toledo area.
They're an annoyance because they stick to clothes and sometimes land in hair.
Many residents along the lake dim their house lights so that they don't attract the bugs. In many years, the swarms are so thick in the city of Port Clinton that business owners use leaf blowers to remove them from buildings and sidewalks.
Lately, toxic algae blooms have been more frequent on Lake Erie and are believed to be causing the return of a "dead zone" in the lake's central basin with so little oxygen that fish can't survive.
Eventually, dead zones could affect mayfly populations, but they do not appear to have done so at this point, Gabriel said.
Mayflies typically live for a day or two before dying. But the life cycle actually lasts two years.
They begin as eggs on the water's surface, Gabriel said, before the eggs sink to the bottom of the lake. The larvae hatch and burrow in the mud and later wiggle out of their burrows, hatch and take off from the water.
They are an important part of the lake's food chain because both fish and birds feed on them, Gabriel said.
"Really anything that can fit them in their mouth depends on that explosion of protein," he said.