Gulf of St. Lawrence explained

Gulf of St. Lawrence
Other Name:	French: Golfe du Saint-Laurent
Image Bathymetry:	Golfe Saint-Laurent Depths fr.svg
Alt Bathymetry:	Bathymetry of the Gulf of St. Lawrence
Caption Bathymetry:	Bathymetry of the Gulf of St. Lawrence
Type:	Gulf
Basin Countries:	Canada Saint Pierre and Miquelon (France)
Area:	226000km2^[1]
Depth:	152m (499feet)
Max-Depth:	530m (1,740feet)
Volume:	34500km3

The Gulf of St. Lawrence 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 North America.^[2]

The Gulf of St. Lawrence connects the Great Lakes to the Atlantic Ocean via the St. Lawrence River.^{[3] [4] [5]}

Geography

At Baie-Trinité, the Pointe-des-Monts Lighthouse, a National historic site of Canada, was built in 1829-1830 on a point that ancient geographers, since Samuel de Champlain (1567-1655) himself, classified as the demarcation point between the St. Lawrence River and the Gulf of St. Lawrence.^{[6] [7]}

The Gulf of St. Lawrence is bounded on the north by the Labrador Peninsula and Quebec, to the east by Saint-Pierre and Newfoundland, to the south by the Nova Scotia peninsula and Cape Breton Island, and to the west by the Gaspé Peninsula, New Brunswick, and Quebec. As for significant islands the Gulf of St. Lawrence contains Anticosti Island, Prince Edward Island, Îles-de-la-Madeleine archipelago, Cape Breton Island, Saint Pierre Island, and Miquelon-Langlade.

Half of the ten provinces of Canada adjoin the Gulf: New Brunswick, Nova Scotia, Prince Edward Island, Newfoundland and Labrador, and Quebec.

Besides the St. Lawrence River itself, significant streams emptying into the Gulf of St. Lawrence include the Miramichi River, Natashquan River, Romaine River, Restigouche River, Margaree River, Humber River, Mingan River and others.

Branches of the Gulf include the Chaleur Bay, Fortune Bay, Miramichi Bay, St. George's Bay, Bay St. George, Bay of Islands, and Northumberland Strait.

According to Commission of Toponymy Quebec, the St. Lawrence River becomes the gulf at Pointe des Monts on the Côte-Nord and Matane Bas-Saint-Laurent or Sainte-Anne-des-Monts La Haute-Gaspésie, the Estuary is upstream, the Gulf of St. Lawrence, much wider, downstream.^{[8] [9]}

Marine mammals

Large marine mammals travel in all the seas of the earth, the research and observations of these giants concern fishermen and shipping industry, exercise a fascination and a keen interest for laymen and, subjects of endless studies for scientists from Quebec, Canada and around the world.^{[10] [11] [12]}

Thirteen species of cetaceans frequent the waters of the estuary and the gulf of the St. Lawrence River.^[13]

1. Hyperoodon ampullatus. — Hypéroodon boreal, Hypéroodon arctique. — (Northern Bottlenose Whale).
2. Delphinapterus leucas. — Béluga, Bélouga, Baleine blanche, Dauphin blanc, Marsouin blanc. — (Beluga Whale).
3. Physeter macrocephalus. — Grand cachalot, Cachalot, Cachalot macrocéphale. — (Sperm whale).
4. Lagenorhynchus acutus. — Lagénorhynque à flancs blancs, Dauphin à flancs blancs. — (Atlantic white-sided dolphin).
5. Lagenorhynchus albirostris. — Dauphin à nez blanc, Dauphin à bec blanc, Lagénorhynque à bec blanc. — (White-beaked dolphin).
6. Orcinus orca. — Orque, Épaulard. — (Killer Whale).
7. Globicephala melas. — Globicéphale commun, Globicéphale noir, Dauphin pilote. — (Long-Finned Pilot Whale).
8. Phocoena Phocoena. — Marsouin commun, Cochon de mer, Dieu des mers. — (Harbour Porpoise).
9. Eubalaena glacialis. — Baleine franche de l'Atlantique nord, Baleine noire de l'Atlantique nord, Baleine de Biscaye. — (North Atlantic Right Whale).
10. Balaenoptera acutorostrata. — Petit rorqual. — (Minke whale).
11. Balaenoptera musculus. — Baleine bleue, Rorqual bleu. — (Blue whale).
12. Megaptera novaeangliae. — Rorqual à bosse, Baleine à bosse. — (Humpback whale).
13. Balaenoptera physalus. — Rorqual commun. — (Fin whale).

Outlets

The gulf flows into the Atlantic Ocean through the following straits:

• Strait of Belle Isle between Labrador and Newfoundland: between 15km (09miles) and 60km (40miles) wide and 60m (200feet) deep at its deepest.
• Cabot Strait, about 56 miles wide, is the entrance to the Gulf of St. Lawrence between Cape Ray, Newfoundland, and Cape North, the NE point of Cape Breton Island.^[14]
• Strait of Canso^[15] is located between Cape Breton Island and mainland Nova Scotia, it originally served as an outlet 1.0 km (0.6 mi) wide and 60 m (200 ft) deep at its deepest.^{[16] [17]} Due to the construction of the Canso Causeway across the strait in 1955, the roadway no longer allows exchange of water between the Gulf of St. Lawrence and the Atlantic Ocean.^[18]

Limits

Since its appearance on maps, there has been no consensus on the demarcation of the St Lawrence River from the Gulf, nor whether it is hydrographically a gulf or an estuary.^{[19] [20]}

According to Fisheries and Oceans Canada 2023, the Estuary and Gulf of St. Lawrence planning area covers most of the Estuary and Gulf of St. Lawrence bioregion, an area with some of the warmest surface waters in Atlantic Canada during summer and the largest amount of sea ice during winter. The planning area is approximately 240,000 km².^[21]

According to Encyclopedia Britannica, the name of Gulf St. Lawrence in a hydrologic context is not accurate, a gulf has to be considered more as a sea bordering the North American continent than as simply a river mouth.^[22]

The International Hydrographic Organization 1953 defines it as follows:^[23]

On the Northeast: A line running from Cape Bauld (North point of Kirpon Island,) to the East extreme of Belle Isle^[24] and on to the Northeast Ledge . Thence a line joining this ledge with the East extreme of Cape St. Charles (52°13'N) in Labrador.

On the Southeast: A line from Cape Canso to Red Point in Cape Breton Island, through this Island to Cape Breton [{{coord|45|57|N|59|47|W|display=inline}}] and on to Pointe Blanche in the Island of St. Pierre, and thence to the southwest point of Morgan Island .

On the West: The meridian of 64°30'W from Pointe-Jaune (49.06°N -64.5°W) to Magpie (50.31°N -64.5°W), but the whole of Anticosti Island is included in the Gulf.

Protected areas and National parks

St. Paul Island in Nova Scotia off the northeastern tip of Cape Breton Island, is known as the "Graveyard of the Gulf" because of its many shipwrecks.^[25] Access to this island is controlled by the Canadian Coast Guard.^[26]

In 1919 the first Migratory Bird Sanctuaries (MBS) in Canada were established under the Migratory Birds Convention Act on Bonaventure Island, on the Bird Rocks of the Magdalen Islands, and on the Percé Rock. These migratory bird sanctuaries are administered by the Canadian Wildlife Service.^[27]

The Federal Government of Canada manages 37 National Parks of Canada,^[28] overview of the parks touching the Gulf of St. Lawrence: Mingan Archipelago National Park Reserve, in Côte-Nord, Forillon National Park on the eastern tip of the Gaspé Peninsula, Prince Edward Island National Park on the northern shore of the island, Kouchibouguac National Park on the northeastern coast of New Brunswick, Cape Breton Highlands National Park on the northern tip of Cape Breton Island, Gros Morne National Park on the west coast of Newfoundland.^[29]

In Quebec, since March 31, 2024, the network of protected areas^{[30] [31]} extends over 274,431 km2 and is established as follows:

• Continental environment (terrestrial and fresh water): 255,377 km2 or 16.89%;
• Marine and coastal environments: 18,991 km2 or 12.21% distributed as follows:
• Marine protected areas and territories set aside in the marine environment: 16,140 km2 or 10.39%;
• Portions of territories in marine and coastal environments associated with protected areas whose conservation objectives do not specifically target the marine environment (national parks, national park reserves of Quebec and Canada, migratory bird sanctuaries, planned aquatic reserves, reserves of projected biodiversity, areas of concentration of aquatic birds, etc.): 2,854 km2 or 1.84%;
• Plan Nord territory: 229,021 km2 or 19.19%.^[32]

The five provinces bordering the Gulf of St. Lawrence have several provincial parks with protected coasts.

Undersea features

The Laurentian Channel is a feature of the floor of the Gulf that was formed during previous ice ages, when the Continental Shelf was eroded by the St. Lawrence River during the periods when the sea level plunged. The Laurentian Channel is about 290m (950feet) deep and about 1250km (780miles) long from the Continental Shelf to the mouth of the St. Lawrence River. Deep waters with temperatures between 2°C6.5°C enter the Gulf at the continental slope and are slowly advected up the channel by estuariane circulation.^[33] Over the 20th century, the bottom waters of the end of the channel (i.e. in the St. Lawrence estuary) have become hypoxic.^[34]

History

The gulf has provided a historically important marine fishery for various First Nations that have lived on its shores for millennia and used its waters for transportation.^{[35] [36] [37]}

The first documented voyage by a European in its waters was by the French explorer Jacques Cartier in the year 1534. Cartier named the shores of the St. Lawrence River "The Country of Canadas", after an indigenous word meaning "village" or "settlement", thus naming the world's second largest country.^[38]

Basque whalers from Saint-Jean-de-Luz sailed into the Gulf of St. Lawrence in 1530 and began whaling at Red Bay.^[39] They established their base on the Strait of Belle Isle and worked closely with the Iroquois in the Gulf of St. Lawrence. In 1579 the English government closed all English ports to Spanish oil imports. As a result, a third of Basque whale oil could not be sold. Basque whaling collapsed in the Gulf of St. Lawrence and never recovered.

See also

• Anticosti Island
• Atlantic Ocean
• Estuary of St. Lawrence
• Maritime Peninsula
• St. Lawrence Seaway

External links

• Species of cetacean, comparison poster, Encyclopedia Britannica 2024
• Integrated Access to Knowledge and Open Data of the St. Lawrence, St. Lawrence Global Observatory (SLGO). (French)
• Atlas of the biodiversity of northern Quebec, Ministère de l’Environnement et de la Lutte contre les changements climatiques (MELCC). (French)
• Rare plants of the Mingan Archipelago Environnement Canada, 2025 (French)
• The lighthouse Trail, Bas-Saint-Laurent, Gaspésie, Côte-Nord, Îles de la Madeleine (French)
• The New Map of Empire. How Britain Imagined America before Independence, Harvard University Press
• Mapping Land Tenure Pluralism in the St. Lawrence River Valley, Julia Lewandoski, essay kicks off a Borealia series on Cartography an Empire
• Légendes du Saint-Laurent, Récits des voyageurs, Jean-Claude Dupont, 1985, 72 pages (French)
• The Gulf of St. Lawrence - a Unique Ecosystem, Government of Canada 2005 [English | French]
• Timing and position of late Wisconsinan ice-margins on the upper slope seaward of Laurentian Channel David J. W. Piper et Adam Macdonald, 2001, 11 page

Notes and References

1. Web site: Atlantic region, Government of Canada, page 86. publications.gc.ca. 14 March 2018.
2. Web site: Claudine Loiselle . Jean Raveneau . The Environmental Atlas of the St. Lawrence . Environnement Canada, Geography department . Université Laval . 21 February 2024 . 34 of 67 . December 1997 . A River, Estuaries, a Gulf: The Great Hydrographic Divisions of the St. Lawrence.
3. Web site: Jean-Claude Therriault . The Gulf od St. Lawrence: Small Ocean or Big Estuary . Fischeries and Oceans Canada . Canadian special Publication of Fischeries and Aquatic Science . 21 February 2024 . 359 . fr, en . 2012 . the Gulf must be considered a complete and coherent systern: for example, what happens in the Gaspé current cannot be completely isolated from the phenomena that occur elsewhere. The degree of interdependence of the various areas remains to be explored..
4. Web site: St. Lawrence River and Seaway . Great Lakes Commission . 22 February 2024 . . . . can be divided into three broad sections: the freshwater river, which extends from Lake Ontario to just outside the city of Quebec; the St. Lawrence estuary, which extends from Quebec to Anticosti Island; and the Gulf of St. Lawrence, which leads into the Atlantic Ocean.
5. Web site: St Lawrence River . The Canadian Encyclopedia . 22 February 2024 . Geography and Geology . According to the Royal Proclamation of 1763, a line from the mouth of Rivière St-Jean on the north shore past the western tip of Île d'Anticosti to Cap des Rosiers on Gaspé marks the end of the river and the beginning of the gulf..
6. Web site: The Pointe-des-Monts Lighthouse . Corporation de Promotion et de Développement du site du Phare historique de Pointe‑des‑Monts . 25 February 2024 . fr . 2024 . Built on a rocky outcrop that forms an islet at high tide, the lighthouse bears witness to a time when navigation in the Gulf of St. Lawrence was perilous..
7. Web site: Edward F. Bush . The Canadian Lighthouse . National Historic Parks and Sites, Branch, Indian and Northern Affairs . 25 February 2024 . 55 of 188 . 1975 . The first lighthouse, completed in 1830, had walls six feet thick at the base, tapering to two feet at the lantern deck.20.
8. Web site: Gulf of St. Lawrence . Commission de toponymie Quebec . Government of Quebec . 23 February 2024 . fr . 1968-12-05 . Sixteenth-century cartographers, historians and memorialists were most often inspired by the Spanish and Italian translations of the Brief récit, and not by the original French published in 1545 to impose the toponym Gulf of St. Lawrence.
9. Web site: Pointe des Monts . Commission de toponymie Quebec . Government of Quebec . 24 February 2024 . fr . 1968-12-05 . These points serve as a boundary between the Estuary of the St. Lawrence River upstream and the much wider Gulf of St. Lawrence downstream.
10. Web site: Saguenay–St. Lawrence Marine Park . Government Quebec - Government of Canada . 19 August 2024 . 2024 . More than 2,200 species frequent these waters, including species at risk such as the beluga whale, the blue whale and the Barrow’s goldeneye..
11. Web site: International Marine Mammal Project (IMMP) . Earth Island Institute . 19 August 2024 . 2024 . We have achieved victories for marine mammals around the world and work to make the oceans safe for whales, dolphins and marine life..
12. Web site: Stéphane Plourde . Right Whales: A Look Back on the Summer of 2017 . Gouvernement of Canada . InfoOceans - New wave . 19 August 2024 . 7 November 2017 . The North Atlantic right whale is an endangered species - Over the coming months, the Government of Canada will meet with representatives of the fishing and shipping industries, Aboriginal communities, whale experts and scientists, as well as the US National Oceanographic and Atmospheric Administration (NOAA)..
13. Web site: The Species of the St. Lawrence . Whales Online, magazine and encyclopedia . Group for Research and Education on Marine Mammals (GREMM) . 10 August 2024 . July 2024 . The different species of seals and whales are all mammal species. © GREMM.
14. Web site: Canadian Hydrographic Service . ATL 104: Cape North to Cape Canso (including Bras d’Or Lake) . Fisheries and Oceans Canada . Canadian Sailing Directions . 16 August 2024 . 9 of 95 . 16 April 2024 . St. Paul Island presents the only danger in the Cabot strait. Mariners are advised to navigate with caution during periods of reduced visibility..
15. Web site: Strait of Canso - Map . Water Resources, Nova Scotia . Strait of Canso Environment Committee . 17 August 2024 . 1975 . From George Bay to Chedabucto Bay.
16. Web site: Strait of Canso Environment Committee . Water Resources . 33 . 1975 . The Strait is relatively narrow, varying in width from 800 m to 2,000 m (2,600 to 6,600 ft.), although it is most commonly 1,600 m (1 mile) wide throughout the 27 km (17 mi.) length..
17. Web site: Gary L. Bugden . Brent A. Law . Edward P.W. Horne . Shawn E. Roach . Flow through the Canso Causeway . Fischeries and Oceans Canada . Canadian Technical Report of Fisheries and Aquatic Sciences . 16 August 2024 . 21 of 55 . en and fr . 2020 . Although blocked in the 1950’s by the Canso Causeway, Canso Strait could potentially be a transport pathway for the spread of Malpeque Disease.
18. Web site: Canso Causeway - Road to the Isles . Canada's Digital collections . 16 August 2024 . The mile long eighty foot wide man-made causeway is known as the deepest in the world.
19. Web site: Lionel Groulx . History of French Canada since the Discovery . Fides, Montreal and Paris . 23 February 2024 . 16 of 404 . fr . 1960 . In the absence of decisive, first-hand documents, historians and cartographers can only assert probabilities..
20. Web site: Jean-Claude Therriault . The Gulf of St. Lawrence: Small Ocean or Big Estuary . Fisheries and Oceans Canada . 23 February 2024 . 359 . en, fr . The Gulf of St. Lawrence contains a wide range of hydrodynamic conditions including seasonal ice cover, polynyas, fronts, gyres, freshwater input and influences, and large seasonal variations in vertical stratification..
21. Web site: Estuary and Gulf of St. Lawrence . Gouvernement of Canada . Fisheries and Oceans Canada . 19 February 2024 . 2023-01-27 . The area represents one of the largest and most productive estuarine/marine ecosystems in Canada and in the world..
22. Web site: Gulf of St. Lawrence . Encyclopedia Britannica . Britannica, The Editors of Encyclopaedia . 23 February 2024 . 2024-02-20 . body of water covering about 60,000 square miles (155,000 square km) at the mouth of the St. Lawrence River. The reefs on these surfaces, coupled with the hazards of fog and ice, have caused a large number of shipwrecks..
23. Web site: Gulf of St. Lawrence . Limits of Oceans and Seas . International Hydrographic organization . 19 February 2024 . 14 of 42 . 1953 . Limits of Oceans and Seas.
24. Web site: Strait of Belle Isle . Gouvernement of Quebec . Commission de Toponymy Quebec . 14 August 2024 . fr . 13 December 1988 . In addition to Grande Bay, this arm of the sea had notably borne the names of Friar Lewis, on maps from 1505, then Gulf of Chasteulx, Charles Streights and Passage du Nord which a cartographer describes as "subject to Glaces” later in the 16th and during the 17th century..
25. Web site: St. Paul Island Southwest Lighthouse . Parks Canada Directory of Federal Heritage Designations . 12 March 2023 . en.
26. Web site: Zydler . Tom . Cruising Canada's Gulf of St. Lawrence . Cruising World . 12 March 2023 . 18 October 2018 . "As I stepped ashore onto a blanket-size piece of sand, I realized I was probably trespassing; landing on the island requires an official permit from the Canadian coast guard.".
27. Web site: Migratory bird sanctuaries across Canada . 22 February 2011 . Government of Canada.
28. Web site: Parks Canada . Government of Canada . 13 August 2024 . 2024 . There are 37 national parks and 11 national park reserves in Canada that represent 31 of Canada's 39 terrestrial natural regions and protect approximately 343,377 square kilometers of lands in Canada..
29. Web site: National Parks of Canada, search by province or territory - Map . Government of Canada . 13 August 2024 . 2024 . National Parks of Canada, search by province or territory.
30. Web site: Protected areas in Quebec . Ministère de l'Environnement, de la Lutte contre les changements climatiques, de la Faune et des Parcs . 13 August 2024 . fr . 2024 . Protected areas are also recognized as an essential tool for adaptation to climate change. In particular, they allow carbon to be stored..
31. Web site: Map of protected areas in Quebec . Environment and Climate Change Canada . 13 August 2024 . fr . March 2024 . Protected areas register database, 2024 Ministry of Environment and Ecological reference framework, 2018 adapted.
32. Web site: Network of protected areas in Quebec . Environment and Climate Change Canada . 13 August 2024 . fr . 2024 . The Register of Protected Areas in Quebec constitutes a unique and integrated reference for Quebec in terms of protected areas, both within the meaning of the Natural Heritage Conservation Act and the recommendations of the International Union for Conservation of Nature (IUCN)..
33. Galbraith, P.S., Pettipas, R.G., Chassé, J., Gilbert, D., Larouche, P., Pettigrew, B., Gosselin, A., Devine, L. and Lafleur, C. 2009. Physical Oceanographic Conditions in the Gulf of St. Lawrence in 2008. DFO Can. Sci. Advis. Sec. Res. Doc. 2009/014. iv + 69 p.
34. Gilbert, D., B. Sundby, C. Gobeil, A. Mucci and G.-H. Tremblay. 2005. A seventy-two-year record of diminishing deep-water oxygen in the St. Lawrence estuary: The northwest Atlantic connection. Limnol. Oceanogr., 50(5): 1654–1666.
35. Web site: A Brief History of the Gulf Region . Fisheries Peches and Ocean Canada . Gulf region . 10 August 2024 . 14 . 1991 . We must manage the Gulf fishery as a biological reality, not as a battlefield for provincial ambitions.
36. Web site: Action River, Discovering the St. Lawrence . Government of Canada . 14 August 2024 . 7 of 32 . 24 November 2015 . The Aboriginal people were the first to benefit from the abundant resources of the Great Lakes and the St. Lawrence: water, game, fish and marine mammals..
37. Web site: Christian Gates St-Pierre . Iroquoians in the St. Lawrence River Valley before European Contact . 14 August 2024 . 18 . 9 July 2017 . At the time of contact with the first Europeans, the St. Lawrence Iroquoians occupied a territory that extended from the mouth of Lake Ontario to the Cap Tourmente area, near Quebec City, with a southward extension to the northern tip of Lake Champlain, as well as seasonal extensions into the estuary and the gulf of St. Lawrence. D.
38. Web site: French navigator Jacques Cartier sails the St. Lawrence River. A&E Television Networks. 14 June 2021.
39. Web site: Red Bay National Historic Site . 9 February 2022 .