The Laurentian ChannelGeographical Names of Canada - Laurentian Channel
/ref> is a deep

submarine A submarine (or sub) is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term is also sometimes used historically or colloquially to refer to remotely op ...

valley off the coast of eastern

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

in the

Gulf of Saint Lawrence , image = Baie de la Tour.jpg , alt = , caption = Gulf of St. Lawrence from Anticosti National Park, Quebec , image_bathymetry = Golfe Saint-Laurent Depths fr.svg , alt_bathymetry = Bathymetry ...

The channel is of glacial origin and is the submerged valley of the historic

Saint Lawrence River The St. Lawrence River (french: Fleuve Saint-Laurent, ) is a large river in the middle latitudes of North America. Its headwaters begin flowing from Lake Ontario in a (roughly) northeasterly direction, into the Gulf of St. Lawrence, connectin ...

, running from a sharp escarpment downstream from the confluence of the St. Lawrence with the

Saguenay River __NOTOC__ The Saguenay River () is a major river of Quebec, Canada. It drains Lac Saint-Jean in the Laurentian Highlands, leaving at Alma and running east; the city of Saguenay is located on the river. It drains into the Saint Lawrence River. T ...

, past

Anticosti Island ; moe, Notiskuan; mic, Natigostec , sobriquet = , image_name = RiviereHuileAnticosti.jpg , image_caption = Salmon fisherman on Rivière à l'Huile , image_map ...

and through the Gulf of St. Lawrence to the edge of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

off the island of

Newfoundland Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

. Its depth ranges from with sub-tidal shelves on each side of the channel ranging in depths of less than . The channel ranges from a minimum width of to as much as at the

Laurentian fan The Laurentian Fan or Laurentian Abyss is an underwater depression off the eastern coast of Canada in the Atlantic Ocean. Not a trench, but more of an "underwater valley", it is estimated to be at most ~19,685 feet (3.7 miles; 6.0 km) in depth. The ...

which is located at the edge of the continental shelf. Deep waters with temperatures between enter the Gulf at the continental slope and are slowly advected up the channel by estuariane circulation. Over the 20th century, the bottom waters of the end of the channel (i.e. in the Saint Lawrence estuary) have become

hypoxic Hypoxia means a lower than normal level of oxygen, and may refer to: Reduced or insufficient oxygen * Hypoxia (environmental), abnormally low oxygen content of the specific environment * Hypoxia (medical), abnormally low level of oxygen in the t ...

Ecological importance

The Laurentian Channel is an ecologically important area, providing critical habitat for a variety of marine species, some of which are fished commercially and others that are not. Non-commercial species are part of the marine ecosystem in the area. The Laurentian Channel contains the highest concentration of

black dogfish The black dogfish (''Centroscyllium fabricii'') is a species of dogfish shark in the family Etmopteridae. It is common over the outer continental shelf and continental slope at depths of . Females generally inhabit deeper water than males, and ...

in Canadian waters and is the only place where pupping occurs. It is an important spawning, nursery, and feeding area for a variety of species including

porbeagle shark The porbeagle (''Lamna nasus'') is a species of mackerel shark in the family Lamnidae, distributed widely in the cold and temperate marine waters of the North Atlantic and Southern Hemisphere. In the North Pacific, its ecological equivalent is ...

and

smooth skate The Anacanthobatidae, the smooth skates or leg skates, are a family of skates found at depths below in the Indian, Pacific and Atlantic Oceans. They lack the dorsal denticles (sharp, tooth-like scales) of other rays, hence their name, from G ...

. Porbeagle sharks and basking sharks move into the area in the spring and reside there throughout the summer. One of only two known porbeagle shark mating grounds occurs within the channel. Two species at risk, the

northern wolffish The northern wolffish (''Anarhichas denticulatus''), also known as the blue sea cat or jelly cat, is a species of marine ray-finned fish belonging to the family Anarhichadidae, the wolf fishes. This species is found in the North Atlantic Ocean an ...

and the

leatherback sea turtle The leatherback sea turtle (''Dermochelys coriacea''), sometimes called the lute turtle or leathery turtle or simply the luth, is the largest of all living turtles and the heaviest non-crocodilian reptile, reaching lengths of up to and weights ...

, have been found in the area. In addition, at least 20 species of whales and dolphins have been observed in the area, as it is a critical feeding area and migration route into and out of the Gulf of St. Lawrence. The Laurentian Channel contains significant

coral Corals are marine invertebrates within the class Anthozoa of the phylum Cnidaria. They typically form compact colonies of many identical individual polyps. Coral species include the important reef builders that inhabit tropical oceans and sec ...

and

sea pen Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. There are 14 families within the order; 35 extant genera, and it is estimated that of 450 described species, around 200 are valid. Sea pens have a co ...

populations, representing sensitive

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "t ...

habitats. Coral and sea pens are important to the ecosystem and depend on the integrity of the sands and muds in the area for their survival. Of the variety of coral species found in the area, sea pens have been recorded in the greatest numbers and diversity, with the Laurentian Channel being described as having the highest sea pen concentrations within the entire Newfoundland and Labrador Shelves Bioregion.

Laurentian Channel Marine Protected Area

A portion of the Laurentian Channel was identified as an Ecologically and Biologically Significant Area (EBSA) in 2007. On June 8, 2010, the Minister of Fisheries and Oceans Canada announced the Laurentian Channel as an Area of Interest (AOI). The AOI encompasses a portion of Laurentian Channel located off the southwest coast of Newfoundland and Labrador, an area of . In June 2017 Fisheries and Oceans Canada (DFO) has proposed the Laurentian Channel AOI as a Marine Protected Area (MPA) under the Oceans Act. In April 2019 Fisheries and Oceans Canada designated the Laurentian Channel Marine Protected Area (MPA). The main purpose of the Laurentian Channel Marine Protected Area is to protect the biodiversity of the region. This MPA explicitly protects porbeagle sharks, smooth sakes, basking sharks, black dogfishes, northern wolffish, and leatherback sea turtles, along with sea pens and other cold water coral. Atlantic cod is not officially protected, the Laurentian Channel MPA could encompass a possible spawning ground. Much is still to be discovered regarding the life cycle of Atlantic cod which makes it a difficult species to protect using smaller, specific MPAs (

SLOSS Debate The SLOSS debate was a debate in ecology and conservation biology during the 1970's and 1980's as to whether a single large or several small (SLOSS) reserves were a superior means of conserving biodiversity in a habitat fragmentation, fragmented hab ...

). Thus, due to the large, undivided size of the Laurentian Channel MPA, the chance of protecting the region where Atlantic cod spawn is significantly higher.

References

External links

Will "Dead Zones" Spread in the St. Lawrence River? - Department of Fisheries and Oceans
{{Authority control Valleys of Canada Marine Protected Areas of Canada

Ecological importance

Laurentian Channel Marine Protected Area

See also

References

External links