Cashes Ledge Is the Last Bastion of Biodiversity in the Gulf of Maine

DOWN EAST magazine • March 1, 2026

Ammen Rock is the highest point in Cashes Ledge, a 32-mile-long submarine mountain range that supports the largest, densest kelp forest in the northwestern Atlantic and gathers together in one place a number of other habitat types found throughout the Gulf of Maine: granite ledges, boulders and steep talus slopes, cobble and scree, patches of sand and gravel, and in the deep basins surrounding the mountains, mud. These habitats have long supported an array of species that are adapted to their nuances, and today, Cashes Ledge is the last bastion of biodiversity in the Gulf of Maine, making it an important area for the recovery of depleted species and for scientific study. Researchers believe it is a glimpse into what this part of the ocean was like many hundreds of years ago.