Bluntnose sixgill shark (Hexanchus griseus) COSEWIC assessment and status report: chapter 4

Distribution

Global range

Bluntnose sixgill sharks are widely distributed throughout temperate and tropical seas around the world. In the north Pacific they can be found from Japan, south of the Aleutian Islands, to California and Mexico as well as the Hawaiian Islands (Figure 2) (Compagno 1984; Mecklenburg et al. 2002). In the south Pacific they are reported from Australia and New Zealand.  In the western Atlantic Ocean, their range is considered to be from North Carolina to Florida and from the northern Gulf of Mexico to northern Argentina including Nicaragua, Costa Rica, and Cuba; however, two immature individuals were captured off Nova Scotia in 1989 and 1990 (Proceedings Nova Scotia Institute of Sciences (Proc. N.S. Inst. Sci.) 1989). In the eastern Atlantic, this shark is found from Iceland and Norway south to Namibia, including the Mediterranean Sea. Its range in the Indian Ocean includes waters off Madagascar and Mozambique.

Figure 2. Global distribution of bluntnose sixgill sharks. Source: Compagno 1984.

Figure 2. Global distribution of bluntnose sixgill sharks. Source: Compagno 1984. (See long description below)
Long description of Figure 2

Figure 2 is an illustration of the Tope Shark, showing the colouring being dark bluish gray on its dorsal side which shades to white on the underside. The Tope Shark has two dorsal fins, and the caudal fin has a large subterminal lobe nearly as long as the lower lobe. The snout is long and pointed. A line representing the maximum recorded length of 175 centimetres (cm) (male) and 195 cm (female) is provided at the bottom of the illustration.

Canadian range

Bluntnose sixgill sharks are likely well distributed throughout much of Canada’s Pacific waters including inlets, continental shelf and slope, and the Strait of Georgia (Figure 3).  Recorded observations available in databases are limited to recent commercial catch records (1996-2005) and research surveys and therefore do not provide a full understanding of their Canadian range (Figure 3). The trawl fleet captures this species over a wide range of depths (20-1000 metres [m]) (Figure 4). The hook and line fleet has encountered this species between 20 and 440 m with most observations less than 200 m (Figure 5). They are reported in the literature to exist to at least 2500 m (Ebert 2003). In the absence of better information, for this report the extent of occurrence is considered to be all Canadian waters between 20-2000 m, which represents an area of 133,139 square kilometres (km²) (Figure 6). A record of two immature individuals from Nova Scotia in 1989 and 1990 indicates that this species also occurs in Atlantic Canadian waters, although it is likely very rare there or present only as a vagrant (Proc. N.S. Inst. Sci. 1989).

Figure 3. Canadian range of bluntnose sixgill shark based on observations in the commercial hook and line and trawl fisheries between 1996 and 2005. Note that records up inlets appear to be on land. Source: PacHarv database.

Figure 3.  Canadian range of bluntnose sixgill shark based on observations in the commercial hook and line and trawl fisheries between 1996 and 2005. (See long description below)
Long description of Figure 3

Figure 3 is a map highlighting the wide distribution of Bluntnose Sixgill Sharks throughout temperate and tropical seas around the world. Distribution is highlighted in red, showing strong representation in the North Pacific from Japan, south of Aleutian Islands to California and Mexico as well as the Hawaiian Islands. In the South Pacific, it is found in Australia and New Zealand. In the western Atlantic Ocean, it is found from North Carolina and from the northern Gulf of Mexico to Nicaragua, Costa Rica, Cuba and Argentina In eastern Atlantic, it is found from Iceland and Norway to South Africa, including the Mediterranean Sea. In the Indian Ocean, it is found near Madagascar and Mozambique.

Figure 4. Depth distribution of commercial trawl tows coastwide between 1996-2005 with records of bluntnose sixgill shark (clear bars) compared with the total trawl effort by depth (solid grey bars). Records between the vertical lines represent the depth interval accounting for 95% of the sightings. Source: PacHarvTrawl database.

Figure 4. Depth distribution of commercial trawl tows coastwide between 1996-2005 with records of bluntnose sixgill shark (clear bars) compared with the total trawl effort by depth (solid grey bars) (See long description below)
Long description of Figure 4

Figure 4 is a detailed image of the distribution of catches of Bluntnose Sixgill Shark occurrence in Canadian Pacific waters, showing it is likely well distributed throughout much of the area, including inlets, continental shelf and slope, and the Straight of Georgia. The image includes small black dots that represent a record of species catch (may be more than one individual per record) for each location, showing concentration around Haida Gwaii, Queen Charlotte Sound, and the continental shelf along the west coast of Vancouver Island, as well as a few location in Georgia Strait.

Figure 5. Depth distribution of commercial hook and line sets capturing bluntnose sixgill shark along the coast of British Columbiabetween 1996 and 2004. Source PacHarvHL database.

Figure 5. Depth distribution of commercial hook and line sets capturing bluntnose sixgill shark along the coast of British Columbiabetween 1996 and 2004. Source PacHarvHL database. (See long description below)
Long description of Figure 5

Figure 5 is a map highlighting the distribution of Tope Shark throughout temperate and subtropical areas between 68°N - 55°S latitude. Distribution is highlighted in red, showing strong representation in the Northeastern Pacific from British Columbia through Baja California. In the South Pacific, it is found in Australia and New Zealand as well as along most of the Pacific coastline in South America. In the western Atlantic Ocean, it is found along the southern end of South America from southern Brazil to Argentina. In eastern Atlantic, it is found throughout the European coastline including the Mediterranean Sea, as well as along the west coast of Africa.

Figure 6. Probable distribution of bluntnose sixgill shark in Canada’s Pacific waters (grey shaded area) based on preferred depth range (20-2000 m).

Figure 6. Probable distribution of bluntnose sixgill shark inCanada’s Pacific waters (grey shaded area) based on preferred depth range (20-2000 metres). (See long description below)
Long description of Figure 6

Figure 6 is a detailed image of the distribution of catches of Tope Shark occurrence in Canadian Pacific waters. The image includes small black dots that represent a record of species catch (may be more than one individual per record) for each location, showing it primarily occurs in continental shelf waters along Vancouver Island, Queen Charlotte Sound, and Hecate Strait.

Page details

Date modified: