Scientists at Cornell University said the seaweed, Heterosiphonia japonica, is native to Japan and has not been reported elsewhere in Maine to date.
After growing in water along the shoreline, the algae detaches and creates vast, decaying piles in the intertidal zone along the shore, biologists said, creating concern the seaweed may out-compete native plants and overwhelm local ecosystems, and the commercial fisheries they support.
Experts at the Shoals Marine Lab, jointly supported by Cornell University and the University of New Hampshire, say the impact of the red algae on Appledore Island -- farther north than the algae has previously been seen -- has yet to be fully measured.
"It is currently present in large enough amounts in limited areas of Appledore's shoreline to impact the intertidal zone. We don't know what those impacts will be," Robin Hadlock Seeley, Shoals senior research associate, said in a Cornell release Thursday. "Other than reports from lobster fishermen about clogged traps and troublesome piles of the seaweed on swimming beaches, we don't yet know the impacts of this seaweed invasion on the coast. But it's moving fast."
Researchers said they believe the algae, first discovered in southern New England on Rhode Island's eastern seaboard in 2009, was transported to the Atlantic coast on boat hulls or by shellfish aquaculture.