The Gully Ecosystem

Long ago, much of the continental shelf off the coast of Nova Scotia was dry land. As the glaciers retreated, the ice and melt-water carved out the Gully - a deep, steep-walled canyon that became submerged with rising sea levels. Today, the Gully is the largest undersea canyon in the western North Atlantic.

The Gully is located 200 kilometres off the coast of Nova Scotia, just east of Sable Island on the edge of the continental shelf. This submarine canyon is 40 kilometres long, up to 16 kilometres wide, and over 2 kilometres deep. The Gully’s size, shape, and location have an effect on currents and local circulation patterns, concentrating nutrients and small organisms within the canyon. This, combined with the diverse habitats found in the Gully, make it an important place for many interesting sea creatures. For these reasons, the Gully is considered a ‘hotspot’ of marine biodiversity.

The Gully is an important habitat for marine mammals on the Scotian Shelf; 16 species of whales and dolphins have been spotted here, including the blue whale - the largest animal on the planet. Some species, like the endangered Scotian Shelf population of northern bottlenose whales, are year-round residents of the Gully that are known to dive from the surface waters to the deepest parts of the canyon, sometimes staying underwater for more than an hour while they search for food.

Endangered blue whale taking a breath of air at the surface in the Gully MPA Coral on the Gully seafloor

Surface waters of the Gully are also home to tiny plankton; a variety of fish such as sharks, tunas and swordfish; and seabirds. Halibut, skates, cusk and lanternfish can be found as deep as 1 kilometre below the surface. The ocean floor community includes crabs, sea pens, anemones, brittle stars, and the largest variety of cold-water corals in Atlantic Canada – approximately 30 different species of coral have been identified in the Gully to date!

Even after decades of research in the Gully, many mysteries remain, making it a place of great interest for continued research, monitoring, and conservation efforts. To learn more about the general ecology of the Gully, see Rutherford & Breeze (2002) and other Gully publications.


Oceans and Coastal Management Division
Fisheries and Oceans Canada (Maritimes Region)
Bedford Institute of Oceanography
PO Box 1006
Dartmouth, Nova Scotia
B2Y 4A2
Phone: (902) 426-9919
Fax: (902) 426-2331