Gulf of Maine Algal Bloom Shows Signs of Decline
Gulf of Maine Algal Bloom Shows Signs of Decline
US · Published Oct 28, 2026
• A harmful algal bloom in the Gulf of Maine, caused by the phytoplankton Karenia mikimotoi, has been closely monitored by researchers using the SeaTrac autonomous vessel.
• The bloom, which led to low oxygen levels in nearshore waters, posed risks to marine life, including fish, shellfish, and marine worms.

Impact & Risks

The algal bloom has caused low oxygen conditions that threaten marine ecosystems, particularly in areas with high cell concentrations. Commercial fisheries and aquaculture operations in affected regions, such as Muscongus and Penobscot bays, remain at risk. While the bloom is declining overall, localized impacts on soft-shell clams and marine worms persist, requiring continued monitoring.

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