Mud mappers: Drones return to Penobscot to study clam flats
Stefan Claesson pilots one of two drones he flew over Northern Bay in Penobscot. Photo by John Boit.
By John Boit
PENOBSCOT–Drones carrying high-tech sensors flew once again over Northern Bay on Nov. 14, part of an ongoing effort to understand how the mud is shifting in the 1,000-acre stretch of once-productive clam flats.
Stefan Claesson of the New Hampshire-based company Nearview operated two drones throughout the day. One mapped the mudflats using LIDAR, a form of laser technology, while another used spectral photography, which can see just light bands that are invisible to the human eye. Spectral photography is useful for mapping algae, of which “there is a lot of that on the mudflat now, whereas there was none in June,” Claesson said.
“You can use different combinations of bands to look at plant health, soil conditions, habitat types, and water quality,” Claesson said. “We are researching what spectral signatures in the mudflats, along with elevation data from LIDAR, may correlate with shellfish habitats and abundances. We are also hoping to see how extreme weather events may impact the soils and substrates of mudflats, and how shellfish abundances are impacted by such events.”
While Claesson maneuvered the drones, a colleague searched the mudflats on foot conducting biological surveys to assess clam populations.
Clams have almost completely disappeared from the bay, in part due to invasive green crabs. But Bailey Bowden, the town’s shellfish warden, has also suggested a theory that the mud is disappearing because winter ice sheets no longer form as regularly over the bay due to climate change. That leaves the mud susceptible to powerful wave action from winter storms, Bowden has theorized.
“Ideally we look at it pre-storm and post-storm and see what elevation or sediment changes have occurred,” Claesson said.
The research, which began in 2024, is a collaborative effort by the town’s shellfish committee, Nearview, the Schoodic Institute in Winter Harbor, and Manomet Conservation Sciences in Massachusetts.
