Marine Mammals and Underwater Mountains: More Evidence for Protecting Habitats with Diverse Wildlife

The deep-water canyons, seamounts, and underwater mountain ranges in the coastal waters of New England are gaining recognition for their importance to the health of fish populations like the struggling Atlantic cod. But these unique geological formations are also critical for the marine mammals that call the North Atlantic home.

Hail the WhalesNorth Atlantic Right Whale mother and calf

The Atlantic coast is a veritable highway for migrating whales, which travel from breeding grounds in the south to feeding grounds in the north each year. But with many species facing reduced habitat, diminished populations, and increased boat traffic, this annual journey has become more and more difficult. These growing threats make areas of food abundance and shelter, such as Cashes Ledge and the New England Canyons and Seamounts, ever more critical to the success of migrating whales’ journeys.

Cashes Ledge and the canyons and seamounts are unique in the Atlantic because their topography creates ideal conditions for plankton, zooplankton, and copepods – the main food for migrating minke, right, and humpback whales – to thrive. They also serve as spawning ground for larger food sources – including many squish, fish, and crustaceans. Altogether, this rich abundance of species adds up to a bountiful buffet for whales and other marine mammals.

Sperm whales have often been spotted in the waters of seamounts, taking advantage of the reliable food, and Cashes Ledge serves as an oasis for hungry whales on their journey north.

The healthy kelp domino effect

These areas are not only crucial to whales; other marine mammals depend on them as well. Cashes Ledge boasts the largest coldwater kelp forest on the Atlantic seaboard, a habitat that creates ideal spawning grounds for cod, herring, and hake. The abundance of fish in turn feeds seals and porpoises, as well as whales.

Scientists have noted a positive correlation between the size of an undersea kelp forest and populations of marine mammals, suggesting that more, healthy kelp means more marine mammals. That makes protecting areas with large kelp forests such as Cashes Ledge even more important.

Even marine mammals that don’t visit Cashes Ledge itself still benefit from the protection of the area’s kelp forest, thanks to the “spillover effect:” Fish spawned in the shelter of the rocky crevasses and havens of the kelp forests disperse beyond Cashes Ledge and feed sea animals throughout the Gulf of Maine.

Across the globe, underwater mountain and canyon habitats have proved to be important areas where marine mammals congregate to feed – and the canyons, seamounts, and ledges off the coast of New England are no different. Unfortunately, these important ecosystems are delicate and facing threats from harmful fishing gear and climate change.

With so much at stake, it is vital to protect these places – not only for their inherent ecological value, but also so that they may sustain the mammals that depend on them.