Water quality tested after midge flies invade areas of Lee County

After swarms of midge flies invaded areas of Lee County, water quality was cited as a possible reason.

The bugs covered walls and lanai screens, traveled in swarms, and caused quite a commotion, especially in areas along the Caloosahatchee River.

“They seek out light, they congregate around light. And by the way, they’re not going to bite you, sting you, cause diseases, they’re just a nuisance,” said Stephen Brown, a horticulture extension agent with UF/IFAS Extension Lee County.

Once we learned midge flies could be a reflection of poor water quality, WINK News had Sanders Laboratories take water samples for us from around Lee County, including Billy Creek, from Shady Oaks Park and the Caloosahatchee in downtown Fort Myers.

“There’s concern that water quality is changing, and the amount of sedimentation or muck that builds up in the river that, you know, the juvenile stage of this fly likes to be in that part of the habitat or the environment. So that’s changing through time,” said John Cassani, Calusa Waterkeeper.

He said juvenile midge flies can live in a low-oxygen environment. “And since they don’t have a lot of competitors there, they can get very abundant in that kind of habitat.”

We shared the testing results with Cassani. On the day of testing at that given time, he explained dissolved oxygen in Billy Creek was low and on the cusp of being low in the Caloosahatchee. Total nitrogen, a nutrient that can contribute to algal blooms, was high in the Caloosahatchee.

“With the total nitrogen, those were very high values. And again, a single sample on a single day isn’t going to tell you very much. But they were relatively high levels,” Cassani said.

Cassani said the water’s always changing, so while our test results are important, they’re also just a snapshot of what our water quality is.