Narwhal (Monodon monoceros) COSEWIC assessment and status report: chapter 4

Distribution

Global range

Narwhals inhabit Arctic waters and are seldom seen south of 61°N (Figures 2 and figure3). They are common in the waters of Nunavut, west Greenland and the European Arctic but are rare in the East Siberian, Bering, Chukchi and Beaufort seas. This distribution appears to be unchanged from historical reports.

Two populations of narwhals have been recognized for the purpose of hunt management in Canada (Fisheries and Oceans Canada 1998a, 1998b). This tentative separation into Baffin Bay and Hudson Bay populations is based largely on summering distribution and may not reflect the degree of interchange between populations Narwhals from the Baffin Bay population summer in the waters of West Greenland and the Canadian High Arctic and winter in Baffin Bay and Davis Strait (Koski and Davis 1994; Dietz et al. 2001; Heide-Jørgensen et al. 2003). They range over an area of at least 1.25 million km². The degree of site fidelity within this shared population is unknown and it may in fact consist of several populations (JCNB/NAMMCO 2001). Narwhals that summer in northwest Hudson Bay are believed to winter in eastern Hudson Strait (Richard 1991). They range over an area of roughly 250,000 km². Animals that summer in East Greenland waters are believed to winter in the pack ice between eastern Greenland and Svalbard (Dietz et al. 1994). They are not thought to enter Canadian waters.

Physical and behavioural observations suggest that different narwhal populations exist within the Baffin Region. Hunters from Qikiqtarjuaq, Clyde River, and Resolute recognize two different types of narwhals -- one that is relatively large and dark with a long tusk and another that is smaller and lighter in colour with a smaller and more twisted tusk (Remnant and Thomas 1992). Narwhals in the Jones Sound area are more likely to seek deep water when threatened by hunters than those in the Pond Inlet area (Reeves 1992a), and are not alarmed by the sight of hunters at the ice edge (Stewart et al. 1995).

Studies of molecular genetics from narwhals taken in Canada and Greenland have yet to find strong, consistent differences that would lead to better population definition (Palsbøll et al. 1997; de March et al. 2001, 2003). Genetic differences were observed by these studies, but their interpretation is confounded by the fact that samples from a particular area are typically small and non-random. However, narwhals from Repulse Bay were significantly differentiated from most high Arctic locations for both microsatellite alleles and mitochondrial DNA (de March et al. 2003). Comparison of contaminant composition may be more useful for the delineation of narwhal populations (JCNB/NAMMCO 2001; de March et al. 2003). Whales taken from the Repulse Bay, Pond Inlet, Grise Fiord, and Broughton Island areas have different organochlorine contaminant profiles, with those from Repulse Bay being the most distinct (de March and Stern 2003).

Figure 2. Map referencing the names of locations used within the report.

Figure 2. Map referencing the names of locations used within the report.

Figure 3. Narwhal distribution as modified from Reeves (1992a) using reference material cited in text. Stippling indicates the species’ general distribution and the dots indicate extralimital reports.

Figure 3. Narwhal distribution as modified from Reeves (1992a)using reference material cited in text. Stippling indicates the species’ general distribution and the dots indicate extralimital reports.

Canadian range

The seasonal range of narwhals in Canada extends throughout the eastern Canadian Arctic south to northwest Hudson Bay, west to Viscount Melville Sound and north to the northern tip of Ellesmere Island (Figure 4). Animals from the Baffin Bay population occupy the northern portion of this range; those from the Hudson Bay population occupy the south. The population affinity of animals that may summer north of Baffin Bay and along the eastern and southern coasts of Baffin Island is unknown. Inuit have described changes in the species’ seasonal distribution.

Baffin BayPopulation

In summer, narwhals from the Baffin Bay population probably move into waters of the Canadian Arctic Archipelago as far north and west as ice conditions permit (Figure 4). Their range certainly extends from southern Baffin Island north into Hall Basin (Greeley 1886; Peary 1907; Borup 1911; Vibe 1950), and probably into the Lincoln Sea, and it extends west into Viscount Melville Sound (Strong 1988; Richard et al. 2001). Lancaster Sound is an important migration route in the spring and fall for Baffin Bay narwhals moving to and from summering grounds in Barrow Strait, Peel Sound, Prince Regent Inlet, Admiralty Inlet and the Eclipse Sound area (Read and Stephansson 1976; Richard et al. 1994). The area of these summering grounds could be close to 300,000 km². Many animals spend the summer in these areas, but some may enter northern Foxe Basin via Fury and Hecla Strait (Stewart et al. 1995). Little is known of their distribution in the interior channels of Queen Elizabeth Islands, but narwhals have been seen in Queens Channel and in McLean Strait between King Christian and Lougheed islands (Roe and Stephen 1977). They are rare to the southwest in waters surrounding Victoria and Banks Islands but there are incidental reports of their occurrence in the Beaufort and Bering seas (Huey 1952; Geist et al. 1960; Smith 1977) and at Bell Island, Newfoundland (Mercer 1973). In summer, concentrations of narwhals from the Baffin Bay population are also found at Melville and Inglefield bays in West Greenland (Born 1986, Born et al. 1994; Heide-Jørgensen 1994).

Narwhals from the Baffin Bay population that summer in Canada and Greenland winter together in Baffin Bay and Davis Strait (Dietz et al. 2001). Observations from aerial surveys in the late winter and early spring (mid-March to late May) suggest that they are distributed throughout the close pack ice in Davis Strait and southern Baffin Bay south to 64°N (Turl 1987; Heide-Jørgensen et al. 1993; Koski and Davis 1994). Narwhals are more numerous in winter south of 64°N, and are found at least as far north as Smith Sound in winter. Recent satellite tracking studies suggest that they may tend to concentrate along the edges of the continental shelf near the southern tip of the deep trough that extends down the middle of Baffin Bay and Davis Strait, midway between Canada and Greenland (Dietz et al. 2001; Heide-Jørgensen et al. 2002). Narwhals also overwinter in leads and polynyas of the “North Water” of Baffin Bay (Finley and Renaud 1980; Richard et al. 1998).

Figure 4. Distribution of narwhals in Canada. Modified from Strong (1988) to include material from literature cited in text. Summer concentrations in solid black include: A. Eclipse Sound/Navy Board Inlet, B. Admiralty Inlet, C. Prince Regent Inlet, D. Peel Sound, E. Foxe Channel, F. Melville Bay, and G. Inglefield Bredning. Wintering concentrations are shown in medium grey and known range in pale grey. Question marks indicate areas where the extent of the narwhal’s distribution is uncertain.

Figure 4. Distribution of narwhals inCanada. Modified from Strong (1988) to include material from literature cited in text.

Hudson Bay Population

The summer range of the Hudson Bay narwhal population includes the waters surrounding Southampton Island, with the largest aggregations in Repulse Bay, Frozen Strait, western Foxe Channel and Lyon Inlet (Richard 1991; Gaston and Ouellet 1997; DFO 1998a; Gonzalez 2001; P. Richard, pers. comm. 2002). The area of these summering grounds is roughly 17,000 km².  Whales from this population also summer, typically in smaller numbers, in Wager Bay or Duke of York Bay. There are no indications of large summer aggregations elsewhere in Hudson Bay or in James Bay, Hudson Strait or southern Foxe Basin. Sightings of narwhals to the south near Arviat and east near Cape Dorset are unusual and have been attributed to the presence of killer whales (Orcinus orca) (Higgins 1968; W. Angalik, pers comm. in Stewart et al. 1991). Narwhals were not seen in central or eastern Foxe Channel during a visual aerial reconnaissance survey of Foxe Channel on 8 August 2000 (P. Richard, pers. comm. 2002). Thorough searches of the historical literature for the Quebec coast of Hudson Bay and James Bay have not found reports of narwhals (Reeves and Mitchell 1987). Three narwhal carcasses have been found along the Ontario coast of Hudson Bay (Johnston 1961).

Hudson Strait appears to be an important migration route for this population in the spring and fall, but there is no evidence of movement northward into Foxe Basin (Richard 1991; Gonzalez 2001). Most animals follow the east coast of Southampton Island on their way to and from Hudson Strait, but some occasionally visit Coral Harbour. The population is believed to winter mainly in eastern Hudson Strait where hundreds of narwhals were seen during aerial surveys in March 1981 (McLaren and Davis 1982; Richard 1991; Koski and Davis 1994). Some animals also winter in open leads and polynyas of northern Hudson Bay and western Hudson Strait (Sutton and Hamilton 1932; Richard 1991). Narwhals are only seen during late spring or early summer, May or June, in the Kangiqsujuaq area (Fleming 2002).

Narwhals of unknown population affinity

Narwhals may also summer north of Baffin Bay, in the Smith Sound-Kane Basin area, and in the fiords of eastern and southern Baffin Island. The population affinity of these whales is unknown. On 5 July 1979, 1216 narwhals were counted at the ice edge in northern Smith Sound (Koski and Davis 1994) before they dispersed to their summering grounds (Born 1986). The presence of narwhals in Hall Basin (81°30’N, 63°00’W) suggests that these whales may move northward as the ice deteriorates. Studies have not been conducted to confirm their summer destination.

Summer use of the Home Bay area of eastern Baffin Island is supported by the observations of Inuit hunters (Haller 1967; Brody 1976; Remnant and Thomas 1992), and by the sighting of 300 narwhals east of Kekertal Island on 1 August 1985 (68°38’N, 67°36’W; Guinn and Stewart 1988). These animals were moving northward and no correction was made for submerged animals. Narwhals may also summer in the fiords of southern Baffin Island where over 400 animals were seen in Totnes Road (66°22’N, 62°20’W) on 18 July 1985, 50 on 22 July in Sunneshine Fiord (66°34’N, 61°39’W), and >100 in Totnes Road on 23 July (Guinn and Stewart 1988). On the 23 of July, hunters also harvested 3 narwhals at Delight Harbour (67°02’N, 62°44’W). These sightings are well past the typical entry date of narwhals from the Baffin Bay population into Lancaster Sound (Greendale and Brousseau-Greendale 1976; Koski 1980a) or from the Hudson Bay population into the Repulse Bay area (Gonzalez 2001).

Changes in Seasonal Distribution

Scientific studies have not identified any large-scale changes in the seasonal distribution of narwhals, but Inuit have observed local changes. In the late 1970s, narwhals stopped frequenting the areas around Kivitoo and Padloping Island, but began to appear near Qikiqtarjuaq and Canso Channel (67°15’N, 63°35’W) and in the fiords in between (Remnant and Thomas 1992). Until the 1970s, narwhals in the Clyde River area were mainly transients migrating south in the fall. Since then they have remained in the area from spring to fall. Since the 1970s, narwhals have been seen more often in the sounds and bays south of Eclipse Sound. They have been seen since the 1980s in the Coutts Inlet area and further south towards Clyde River. Since the 1960s, narwhals have become less common near Pond Inlet and tend to travel down the middle of the inlet. Hunters attribute this change to an increase in the number of people hunting and traveling with motorboats and snowmobiles near the community. Hunters at Resolute, Arctic Bay, and Repulse Bay have made similar observations (Remnant and Thomas 1992; Stewart et al. 1995; Gonzalez 2001). In the Arctic Bay area, some hunters report that narwhals now make less use of the inlets off Admiralty Inlet and arrive later in the year when the ice is unsafe for travel (Stewart et al. 1995).

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