Ed Smith has walked Wells Beach for years but has never seen anything like it: A mysterious black substance that settles on the sand near the shoreline and stains the feet of anyone who ventures too close.

He first noticed it Sunday night. When he went back out Monday, it was there again. He talked to about a dozen beachgoers who all said they noticed it too.

“I sat on the edge of my tub with blue Dawn (dishwashing soap) and a scrub pad, and I still couldn’t remove the stain from my feet,” Smith said.

It took a few inquiries to local and state officials, and some help from a retired scientist who lives nearby, but Smith got his answer Tuesday. It only raised more questions.

Linda Stathoplos and John Lillibridge look for remnants of bugs that washed ashore on Wells Beach. Ben McCanna/Staff Photographer

According to Steve Dickson, a marine geologist with Maine Geological Survey, the black substance was the collective carcasses of dead insects. Millions of them. The bugs float in the ocean but when waves wash ashore, they settle on the beach and stay there when the tide goes back out.

“This is the first time I’ve seen or heard of this in my 35 years,” Dickson said. “Normally this time of year we get calls about too much seaweed (wrack) on the beach and the swarming flies that hang around the decaying seaweed. This wasn’t that.”


Dickson said he’s still working with entomologists on figuring out what the bugs are, where they came from – and why – but he doesn’t expect it to be a recurring phenomenon. He said once the winds shift, it’s likely that whatever bug debris is left behind will wash back out to sea.

The tip of a sewing pin is included for scale in this photo of an insect, at 20 times magnification, taken with a phone through a microscope. Courtesy photo by Linda Stathoplos

It was Smith’s curiosity that led to the unraveling of the mystery. He took some pictures and sent them to an official at the Department of Environmental Protection out of concern the substance might be toxic. DEP officials then sent the photos around to several others, including Dickson, who was intrigued.

Once he realized the pictures were of Wells Beach, he contacted Linda Stathoplos and John Lillibridge, a married couple who live nearby and who are both retired oceanographers. They also participate in the state’s beach monitoring program.

The couple offered to go down to the beach and get a sample. Stathoplos said they had never seen anything like it either.

She even went one step further.

“I collected some of the stuff, brought it back and put them under my microscope,” she said. Retired scientists still keep their tools handy. “It was clearly little bugs.”


Stathoplos sent magnified photos to Dickson, who agreed.

After Smith was told what was covering the beach and staining his feet, he said it made sense.

Sand at Wells Beach shows the remains of insects left by waves. The insects float in the ocean so waves coming ashore concentrate them on a rising tide. As the tide falls, the bugs are stranded in lines on the beach where the last wave washed ashore. Photo by John Lillibridge

“When I was walking again on Monday, I said to my friend who was with me, ‘I wonder if this is residue from flying black bugs that were all over the beach a week ago,’” he said.

Dickson said there were other reports of a similar substance at York Beach and in Ogunquit as well, but he hadn’t heard of anything anywhere else.

Emma Bouthillette, who regularly walks on Fortunes Rock Beach in Biddeford, posted a photo on Facebook this week of her blackened feet. She doesn’t know if she, too, stepped in a pile of bug carcasses or not, but said she’s always referred to the black substance as “beach tar.” What she encountered is not unusual, she said.

“I think it was from oil deposits that washed up and mixed with sand and just stuck to your feet,” she said.

Asked why the bugs might be staining people’s feet, Dickson said bugs often eat plants that have pigments. In fact, in some countries bugs are still used to dye garments.

“You never know what nature is going to bring next,” he said.

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