The state says that eelgrass meadows in Casco Bay declined by more than half between 2018 and 2022.
The report from the Department of Environmental Protection calls the loss of 54% of eelgrass abundance "staggering."
Eelgrass provides important habitat for many species. And Casco Baykeeper Ivy Frignoca says it also stores carbon efficiently, and buffers against storm surges. She says the fast-warming waters of Casco Bay are creating many challenges.
"The temperatures we are getting in the nearshore are above the temperature range where the eelgrass that we have can remain healthy," Frignoca says. "The warmer temperatures also have a bunch of secondary impacts. And one is that it allows the invasive green crab to be more prolific."
Frignoca says warmer waters also enhance algae blooms, which can block light from the eelgrass beds. The survey was conducted in July using aerial photos taken at low tide, followed by field verification.
