NOAA Ocean Outlook Projects Cooler Deep Waters for Gulf of Maine

The Gulf of Maine, historically one of the fastest-warming ocean regions in the world, is predicted to experience cooler bottom-water temperatures this spring and summer, according to a new experimental outlook developed by NOAA scientists.

Initial signs of this shift were reported by NOAA’s Northeast Fisheries Science Centeroffsite link and documented in the NOAA Fisheries 2025 New England State of the Ecosystem Report.offsite link

Data shows that since late 2023, the Northwest Atlantic has seen cooler bottom-water temperatures due to the southward movement of the eastern portion of the Gulf Stream and possibly an increased influx of Labrador Slope and Scotian Shelf water into the system. Researchers expect the Gulf of Maine to be 0.9-1.8 degrees Fahrenheit (0.5-1 degree Celsius) cooler this summer compared to the average summer temperature.

“The cooling trend from the Labrador Shelf region is significant and could have important effects on local marine ecosystems and fisheries,” said Vincent Saba, a research fishery biologist at NOAA’s Northeast Fisheries Science Center.

Bottom-water temperatures influence the productivity of groundfishoffsite link, like cod, haddock, pollock, and several species of flounder, which prefer cooler water. Lobster, the most valuable fishery in the northeast, are also temperature-sensitive. Warming waters along the New England coast in recent decades have contributed to the collapse of the southern New England lobster population while the Gulf of Maine population has boomed. Researchers expect that cooler waters will impact this economically and culturally important species.