October 13, 2026 — The massive algae bloom along the Maine coast is starting to dissipate, at least in some areas, but the severe impacts continue to grow.
The Friends of Casco Bay says it, along with several other groups and the state, has been monitoring the Karenia mikimotoi bloom, commonly known as red tide, in Casco Bay for over a month.
The dense blooms that were present throughout September discolored the water, lowered dissolved oxygen levels, and caused die-offs of marine organisms, particularly soft-shell clams and marine worms.
In late September, testing found high-density blooms near Harpswell. High-density blooms are generally considered those having a density of more than one million cells per liter. Testing in Maine at the time found a density of 20 million cells per liter. Video shared by Harpswell Marine Resources & Harbor Management showed very brown and murky water.