The Northwest Atlantic Marine Ecozone, as defined by the

Commission for Environmental Cooperation The Commission for Environmental Cooperation (CEC; ; ) is an intergovernmental organization established by Canada, Mexico, and the United States to implement the North American Agreement on Environmental Cooperation (NAAEC), the environmental si ...

(CEC), is a Canadian marine

ecozone An ecozone may refer to: * Biogeographic realm, the broadest biogeographic division of Earth's land surface (referred to as ''ecozone'' by BBC) * Biome, a large collection of flora and fauna occupying a major habitat * Bioregion, an ecologically ...

forming a transitional region between the cold northern waters of the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...

and the more temperate waters in its southern extent.

Geography

Stretching in a narrow strip offshore from

Ellesmere Island Ellesmere Island (; ) is Canada's northernmost and List of Canadian islands by area, third largest island, and the List of islands by area, tenth largest in the world. It comprises an area of , slightly smaller than Great Britain, and the total ...

and

Devon Island Devon Island (, ) is an island in Canada and the largest desert island, uninhabited island (no permanent residents) in the world. It is located in Baffin Bay, Qikiqtaaluk Region, Nunavut, Canada. It is one of the largest members of the Arctic Ar ...

Baffin Bay Baffin Bay (Inuktitut: ''Saknirutiak Imanga''; ; ; ), located between Baffin Island and the west coast of Greenland, is defined by the International Hydrographic Organization as a marginal sea of the Arctic Ocean. It is sometimes considered a s ...

, it runs parallel to the coast of

Bylot Island Bylot Island lies off the northern end of Baffin Island in Nunavut Territory, Canada. Eclipse Sound to the southeast and Navy Board Inlet to the southwest separate it from Baffin Island. Parry Channel lies to its northwest. At it is ranked 7 ...

and

Baffin Island Baffin Island (formerly Baffin Land), in the Canadian territory of Nunavut, is the largest island in Canada, the second-largest island in the Americas (behind Greenland), and the fifth-largest island in the world. Its area is (slightly smal ...

until meeting it at the

Cumberland Peninsula Cumberland Peninsula is a peninsula in the southeastern part of Baffin Island in Nunavut, Canada. It is located between 64°56' and 67°57' north latitude, and 61°56' to 68° west longitude. The Arctic Circle crosses the peninsula, with the Labr ...

. It covers the waters of the

Davis Strait The Davis Strait (Danish language, Danish: ''Davisstrædet'') is a southern arm of the Arctic Ocean that lies north of the Labrador Sea. It lies between mid-western Greenland and Baffin Island in Nunavut, Canada. To the north is Baffin Bay. The ...

and the

Hudson Strait Hudson Strait () in Nunavut links the Atlantic Ocean and the Labrador Sea to Hudson Bay in Canada. This strait lies between Baffin Island and Nunavik, with its eastern entrance marked by Cape Chidley in Newfoundland and Labrador and Nunavut ...

Ungava Bay Ungava Bay (; , ; /) is a bay in Nunavut, Canada separating Nunavik (far northern Quebec) from Baffin Island. Although not geographically apparent, it is a marginal sea of the Arctic Ocean. The bay is roughly oval-shaped, about at its widest p ...

and portions of the

Labrador Sea The Labrador Sea (; ) is an arm of the North Atlantic Ocean between the Labrador Peninsula and Greenland. The sea is flanked by continental shelf, continental shelves to the southwest, northwest, and northeast. It connects to the north with Baffi ...

, including all coastal areas of

Labrador Labrador () is a geographic and cultural region within the Canadian province of Newfoundland and Labrador. It is the primarily continental portion of the province and constitutes 71% of the province's area but is home to only 6% of its populatio ...

and the northern coast of

Newfoundland Newfoundland and Labrador is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region of Labrador, having a total size of . As of 2025 the population ...

. It also includes the

Gulf of Saint Lawrence The Gulf of St. Lawrence is a gulf that fringes the shores of the provinces of Quebec, New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, in Canada, plus the islands Saint-Pierre and Miquelon, possessions of France, in ...

to the mouth of the

Saint Lawrence River The St. Lawrence River (, ) is a large international river in the middle latitudes of North America connecting the Great Lakes to the North Atlantic Ocean. Its waters flow in a northeasterly direction from Lake Ontario to the Gulf of St. Lawrenc ...

. The cold, highly saline

North Atlantic Deep Water North Atlantic Deep Water (NADW) is a deep water mass formed in the North Atlantic Ocean. Thermohaline circulation (properly described as meridional overturning circulation) of the world's oceans involves the flow of warm surface waters from the ...

forms in the Labrador Sea and flows at great depth along the western edge of the

North Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for ...

. Moreover, in this ecozone the cold Labrador Current meets the

Gulf Stream The Gulf Stream is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States, then veers east near 36°N latitude (North Carolin ...

at the

Grand Banks The Grand Banks of Newfoundland are a series of underwater plateaus south-east of the island of Newfoundland on the North American continental shelf. The Grand Banks are one of the world's richest fishing grounds, supporting Atlantic cod, swordfi ...

, and together with the

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

discharge from the Saint Lawrence River, moderate the climate of the coastal areas of the

Maritimes The Maritimes, also called the Maritime provinces, is a region of Eastern Canada consisting of three provinces: New Brunswick, Nova Scotia, and Prince Edward Island. The Maritimes had a population of 1,899,324 in 2021, which makes up 5.1% of ...

. There are more than 440,000 islands in this zone.

Regions

This ecozone consists of eight regions, namely: *

Labrador Shelf Labrador () is a geographic and cultural region within the Canadian province of Newfoundland and Labrador. It is the primarily continental portion of the province and constitutes 71% of the province's area but is home to only 6% of its populatio ...

* Newfoundland Shelf * North Gulf Shelf * Saint Lawrence River Estuary * Magdalen Shallows *

Laurentian Channel The Laurentian Channel is a deep submarine valley off the coast of eastern Canada in the Gulf of Saint Lawrence. The channel is of glacial origin and is the submerged valley of the historic Saint Lawrence River, running from a sharp escarpment ...

Scotian Shelf The Scotian Shelf is a geological formation that is part of the continental shelf southwest of Nova Scotia, Canada. It covers an area of , is long, and has a width from . It has an average depth of . The Scotian Shelf contains the ecologically imp ...

(only a small portion near

Cape Breton Island Cape Breton Island (, formerly '; or '; ) is a rugged and irregularly shaped island on the Atlantic coast of North America and part of the province of Nova Scotia, Canada. The island accounts for 18.7% of Nova Scotia's total area. Although ...

)

Climate

Newfoundland Iceberg just off Exploits Island

This ecozone's climate varies throughout its extent, with temperatures differing by 20 °C between the arctic waters in the north and the Gulf Stream in the south. Sub-surface temperatures are always below the

freezing point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

, but the salinity of the waters prevents them from freezing. Surface

sea ice Sea ice arises as seawater freezes. Because ice is less density, dense than water, it floats on the ocean's surface (as does fresh water ice). Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world' ...

forms throughout this region, and thousands of

iceberg An iceberg is a piece of fresh water ice more than long that has broken off a glacier or an ice shelf and is floating freely in open water. Smaller chunks of floating glacially derived ice are called "growlers" or "bergy bits". Much of an i ...

s may be observed between the northeast coast of Newfoundland and the Grand Banks. The Saint Lawrence River freezes over during the winter, closing the important

shipping channel In physical geography and hydrology, a channel is a landform on which a relatively narrow body of water is situated, such as a river, river delta or strait. While ''channel'' typically refers to a natural formation, the cognate term ''canal'' de ...

until the ice clears in the summer. Summer

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

s may reach 9 to 12 m, though they tend to be exaggerated in Ungava Bay and more subdued in the Gulf of Saint Lawrence.

References

{{Reflist Ecozones and ecoregions of Nunavut Ecozones and ecoregions of Quebec Ecozones and ecoregions of Newfoundland and Labrador Ecozones and ecoregions of New Brunswick Ecozones and ecoregions of Nova Scotia Ecozones and ecoregions of Prince Edward Island