Many of the most productive shellfishing areas in Casco Bay have been shut down due to the presence of a rare late-season toxic algae bloom.
The closure stretches from Portland Harbor to the west side of Harpswell. The Portland Press Herald reports that the ban affects hundreds of acres of productive clam flats in Freeport and Brunswick, as well as mussel and oyster farms in those locales and around Chebeague Island.
Maine Department of Marine Resources spokesman Jeff Nichols says this is a precautionary closure and that toxin levels haven’t yet reached the 20-part-per-million threshold that would trigger a mandatory closure.
“We got very close in some areas. In fact we were at 17 parts per million, so the director of our bureau decided let’s make this a precautionary closure, just to get ahead of it and to avoid the possibility of recalls,” he says.
Nichols says marine scientists are still trying to understand the biotoxin involved, which he says becomes toxic much more rapidly than other biotoxins.