It has prompted the closure of mussel beds from Machiasport to the Canadian border.
State officials say a large plume of toxic algae blew in from the Bay of Fundy.
The red tide closure bans the harvesting of mussels, european oysters, and carnivorous snails.
The Red Tide closure is not affecting clams…yet, but officials say some clam beds within the area could be closed this week because of the intensity of the bloom.
Officials say there is a strict monitoring system in place so consumers can still safely eat mussels in restaurants and stores.
This comes amidst the time of year when the demand for mussels is traditionally the highest, and harvesters make the most money.
State officials say there’s no way to predict how long the Red Tide closure will last.