|Scientific Name:||Monodon monoceros Linnaeus, 1758|
|Taxonomic Notes:||The Narwhal (Monodon monoceros) and the Beluga Whale (Delphinapterus leucas) are the only two species in the cetacean family Monodontidae (Rice 1998). While these are well-defined taxa, Heide-Jørgensen and Reeves (1993) described a skull from West Greenland of what apparently was a Narwhal-Beluga hybrid.
While Narwhals occur broadly in Arctic waters, their distribution, movements, and genetic characteristics suggest the existence of about 12 discrete or semi-discrete subpopulations or management stocks (Palsbøll et al. 1997, Richard 2010, NAMMCO in prep).
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Lowry, L., Laidre, K. & Reeves, R.|
|Reviewer(s):||Moore, S., Brownell, R., Ferguson, S. & Hansen, R.|
|Facilitator/Compiler(s):||Taylor, B.L., Chiozza, F., Pollock, C.M.|
The Narwhal is widely distributed in a number of distinct subpopulations. Combining the most current abundance estimates for the known and surveyed subpopulations results in a total global abundance of more than 170,000 whales, however this does not include Northeast Greenland or the Russian Arctic for which no estimates are available. Ten subpopulations number more than 10,000 individuals, and two subpopulations number more than 35,000. One subpopulation is thought to be increasing, five are considered stable, and for five the trend is unknown. As a species, the Narwhal does not meet any IUCN criteria for threatened categories and is listed as Least Concern
Across the global range of the Narwhal, subpopulations are of various sizes and subject to differing levels of threats. Due to this variability, some of the subpopulations warrant Red List assessment.
|Previously published Red List assessments:|
|Range Description:||Narwhals primarily inhabit the Arctic, including northeastern Canada, northern Greenland, Svalbard, and waters of northern Russia as far east as the East Siberian Sea. Their principal distribution is from the central Canadian Arctic (Peel Sound – Prince Regent Inlet and northern Hudson Bay) eastward to Greenland (Rice 1998). In the Canada-Greenland region in summer, Narwhals spend approximately two months in the high Arctic, largely in bays and fjords; they overwinter in offshore, deep, partially ice-covered habitat along the continental slope (Heide-Jørgensen and Dietz 1995). Narwhals migrate annually between these disjunct seasonal concentration areas, with the migratory periods lasting approximately two months (Koski and Davis 1994, Innes et al. 2002, Heide-Jørgensen et al. 2002, Dietz et al. 2001). Vagrants have been recorded at Newfoundland, the British Isles, Germany, and the Netherlands in the east, and in the Chukchi and Bering seas as far south as the Alaska Peninsula and Commander Islands (Rice 1998).|
Native:Canada (Newfoundland I - Vagrant); Greenland; Russian Federation; Svalbard and Jan Mayen
Vagrant:Germany; Iceland; Netherlands; Norway; United Kingdom; United States
|FAO Marine Fishing Areas:|
Arctic Sea; Atlantic – northwest; Atlantic – northeast
|Range Map:||Click here to open the map viewer and explore range.|
The global Narwhal population consists of about 12 subpopulations with varying degrees of genetic differentiation and geographical isolation (hereafter the terms subpopulation and stock are used interchangeably). Due to incomplete sampling in parts of the range, particularly in Russia, the total number of subpopulations is not precisely known. In 1999, the International Whaling Commission’s (IWC) Scientific Committee recognized two stocks of Narwhal but noted that there were probably more that were not yet recognized (IWC 2000). A recent (March 2017) Global Review of Monodontids (GROM) hosted by the North Atlantic Marine Mammal Commission (NAMMCO) developed a list of 12 Narwhal stocks (NAMMCO in prep.).
Discrimination and definition of subpopulations are based mostly on nearshore areas (principally fjords and bays) where Narwhals congregate during summer. Genetic studies, satellite telemetry, traditional ecological knowledge, stable isotope values, and contaminant analyses have shown that Narwhals have strong matrilineally driven fidelity to those areas (e.g., Palsbøll et al. 1997, Riget et al. 2002, de March et al. 2003, Westdal et al. 2010, Watt et al. 2013).
Available information on sizes of Narwhal subpopulations is summarized below.
Northern Hudson Bay
Narwhals from the Northern Hudson Bay subpopulation summer in northwestern Hudson Bay, particularly in Repulse Bay and in waters around Southampton Island. They winter in eastern Hudson Strait (Richard 1991, Westdal et al. 2010). The abundance of Northern Hudson Bay Narwhals in 2011, corrected for perception bias (animals that were at the surface but not seen by observers) and availability bias (animals too deep to be seen by observers), was estimated as 12,485 (CV 0.21; Asselin et al. 2012). Richard (1991) reported results of surveys conducted in 1982, 1983, and 1984 that were limited to areas with less than 20% ice cover and his estimates were not corrected for availability. Abundance estimates from Richard (1991) ranged from 1,038 to 1,517 but were certainly biased negatively. A similar survey in 2000 estimated uncorrected abundance as 1,780 (Bourassa 2003). Abundance of this subpopulation is believed to be fairly stable (NAMMCO in prep.).
Narwhal from the Somerset Island subpopulation range over a large area in the eastern Canadian Arctic. During summer, satellite-tagged animals were mostly concentrated around Somerset Island and they spent winter in Baffin Bay (Heide-Jørgensen et al. 2003). The abundance of Somerset Island Narwhals in 2013, corrected for both perception and availability biases, was estimated as 49,768 (CV 0.20; Doniol-Valcroze et al. 2015). Previous abundance surveys were flown in 1982, 1996, and 2002. The corrected estimate for 1982 was 27,656 (CV 0.54; Richard et al. 2010). Analysis of those data by Witting (2016) suggests that abundance has been increasing.
Narwhals from the Admiralty Inlet subpopulation remain in and near the Inlet during summer, and spend winter in the Baffin Bay region (Dietz et al. 2008, Watt et al. 2012). The most recent abundance estimate for Admiralty Inlet Narwhals comes from aerial line-transect surveys flown in 2013 (Doniol-Valcroze et al. 2015). When corrected for perception and availability biases the abundance estimate for this stock was 35,043 (CV 0.42). Four previous surveys in 1975, 1985, 2003, and 2010 yielded lower mean abundance estimates with wide confidence intervals. Analysis of those data by Witting (2016) suggested that abundance has been stable.
Narwhal from the Eclipse Sound subpopulation generally stay in and near the Sound in the summer, and winter in Baffin Bay (Dietz et al. 2001). The abundance of Eclipse Sound Narwhals in 2013, corrected for both perception and availability biases, was estimated as 10,489 (CV 0.24; Doniol-Valcroze et al. 2015). A previous survey in 2004 produced a higher corrected estimate of 20,225 with wide confidence limits (95% CL 9,471-37,096; Richard et al. 2010). Available data are insufficient to detect any trend in abundance for this subpopulation (Witting 2016).
Eastern Baffin Island
The Eastern Baffin Island Narwhal subpopulation summers in Cumberland Sound and along the Baffin Island coast to the north, and winters in northern Davis Strait (Heide-Jørgensen et al. 2002). Abundance in 2013, corrected for both perception and availability biases, was estimated as 17,555 (CV 0.35; Doniol-Valcroze et al. 2015). Surveys in 2003 that had similar coverage of the eastern Baffin Island fiord area produced a corrected estimate of 10,073 (SE 3,123) Narwhals in the surveyed region (Richard et al. 2010). Available data are insufficient to detect any trend in abundance for this subpopulation (Witting 2016).
The Jones Sound subpopulation of Narwhals summers between Devon Island and Ellesmere Island and in fiords of western Ellesmere Island. Jones Sound Narwhals have not been tagged and tracked, and their distribution at times of year other than summer is unknown (NAMMCO in prep.). The abundance of Jones Sound Narwhals in 2013, corrected for both perception and availability biases, was estimated as 12,694 (CV 0.33; Doniol-Valcroze et al. 2015). That is the only abundance survey conducted in Jones Sound so there is no information on trend for this subpopulation.
The Smith Sound Narwhal subpopulation summers along the southeastern coast of Ellesmere Island (Richard 2010); its wintering area is unknown. Abundance of Smith Sound Narwhals in 2013, corrected for both perception and availability biases, was estimated as 16,360 (CV 0.65; Doniol-Valcroze et al. 2015). That is the only abundance estimate for Smith Sound so there is no information on trend for this subpopulation.
This subpopulation of Narwhals summers in Inglefield Bredning which is its major concentration area in northwestern Greenland (Born et al. 1994). Little is known about distribution at other times of year. Abundance of Inglefield Bredning Narwhals in 2007, corrected for both perception and availability biases, was estimated as 8,368 (CV 0.25; Heide-Jørgensen et al. 2010). Previous surveys of this subpopulation were conducted in 1985-86 (Born et al. 1994) and 2001-02 (Heide‐Jørgensen et al. 2004) with generally similar results, and abundance appears to be stable (Witting 2016).
The Melville Bay Narwhal subpopulation spends the ice-free season in and near Melville Bay, and may spend significant time at the fronts of coastal glaciers that are important habitats for them (Laidre et al. 2016). With freeze-up they move south to the southern part of Baffin Bay for overwintering (Dietz and Heide-Jørgensen 1995). Heide-Jørgensen et al. (2014) reported that the range of Narwhals in Melville Bay contracted over the period from 2007 to 2014. Abundance in 2014, corrected for both perception and availability biases, was estimated as 3,091 (95% CI 1,228-7,783). Previous surveys resulted in estimates of 5,605 whales (95% CI 1,319-23,815) in 2007 and 2,983 (95% CI 1,452-6,127) in 2012 (Heide-Jørgensen et al. 2014). Confidence limits for all three surveys overlap broadly and abundance appears fairly stable (Witting 2016).
Narwhals assigned to the Northeast Greenland subpopulation are frequently seen during May-August in Young Sound (74°N) and along the coast as far north as Nordost Rundingen (82°N; Boertmann et al. 2009). There has been no attempt to estimate abundance of Narwhals in north-eastern Greenland, but surveys of the area were planned for 2017 (NAMMCO in prep.).
In summer Narwhals occur along the east coast of Greenland mostly from about 64° to 72° N, but they have been reported at more than 81° (Dietz et al. 1994), which means the distinction between Northeast and East Greenland Narwhals is uncertain. Narwhals are relatively common in Scoresby Sound and the Kangerlussuaq fjord (Heide-Jørgensen et al. 2010). They winter in sea ice in the Greenland Sea and Fram Strait, but winter observations are sparse (Dietz et al. 1994, Heide-Jørgensen et al. 2015). Aerial surveys conducted in Scoresby Sound in 1983-84 and from Tasiilaq to Scoresby Sound in 2008 and 2016 resulted in conflicting results, leading to the conclusion (as of summer 2017) that Narwhals off East Greenland are widely scattered and may number fewer than 1,000 individuals (NAMMCO in prep.).
Narwhals that occur around Svalbard and in the northwestern Russian High Arctic have been little studied but they are thought to be widely distributed in low numbers throughout this region (Heide-Jørgensen 2009). Gjertz (1991) described previous observations and catches that were largely west and north of Svalbard. In August 1998, Lydersen et al. (2007) tagged three subadult Narwhals at Svalbard with satellite-relay data loggers and tracked them for up to 46 days. The whales spent time in fiords in western Svalbard, then moved north and east to deep offshore waters north of 80°N. A survey in the marginal ice zone north of Svalbard in August 2015 produced a corrected estimate of 837 (CV 0.50) Narwhals, but this estimate is negatively biased because the study area did not include the whole range used by Narwhals around Svalbard (Vacquie-Garcia et al. 2017). There are no estimates of abundance for other areas and overall abundance and trend for this subpopulation are unknown (NAMMCO in prep.).
The sum of the abundance estimates for the 12 Narwhal subpopulations listed above is 173,134. There is no estimate for Northeast Greenland and the figure for the Svalbard-Russia region is known to be an underestimate because only a portion of the known range was surveyed. If 71% of the overall Narwhal population consists of mature animals (Taylor et al. 2007), the minimum number of mature individuals would be 122,925. The number of mature individuals in the largest subpopulation (Somerset Island) is estimated as 35,335. For the six subpopulations for which there is some information on trend, one is thought to be increasing and five are likely stable.
The generation length for the Narwhal was estimated as 21.9 years by Taylor et al. (2007) and as 30 and 33 years in East and West Greenland, respectively, by Garde et al. (2015) using aspartic acid ageing. Using these estimates, three generations is 66-99 years. For most subpopulations, abundance estimates for years prior to 2000 do not exist, so trends in abundance over a three-generation period cannot be calculated.
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
Narwhals spend approximately two months each summer in ice-free bays and fjords of the Canadian Arctic, eastern Baffin Island, western and eastern Greenland, and Svalbard (Innes et al. 2002, Richard et al. 2010, Heide-Jørgensen et al. 2010). In some parts of this range during summer they may aggregate at tidewater glacier fronts (Lydersen et al. 2014, Laidre et al. 2016). In autumn, Narwhals migrate with the forming fast ice to wintering areas that tend to be deep, offshore, ice-covered habitats along the continental slope (Innes et al. 2002, Laidre et al. 2003, Laidre and Heide-Jørgensen 2011, Heide-Jørgensen et al. 2015). Narwhals are highly adapted to winter habitats with limited open water (Laidre et al. 2004, Laidre and Heide-Jørgensen 2011). Few other cetaceans use areas with such dense sea ice cover, and Narwhals have remarkable site fidelity to these areas. They may dive to depths of over 1,500 m multiple times per day and spend over 3 h per day at depths of 800 m (Laidre et al. 2003, 2010). A double-platform visual aerial survey over a Narwhal wintering ground in West Greenland found high densities of whales in the leads and cracks of the Baffin Bay pack ice, up to an average density of about 77 Narwhals/km² (Laidre and Heide-Jørgensen 2011).
In the winter, Narwhals feed intensively at the sea floor (Laidre et al. 2003, 2004; Laidre and Heide-Jørgensen 2005a) but some subpopulations may also feed on pelagic prey (Watt and Ferguson 2014). A major portion of the annual energy intake is obtained during the winter. Although there seems to be relatively little feeding activity during the summer, Narwhals apparently feed opportunistically during this time. Narwhal sighting probability in winter in habitats with <50% open water is significantly higher than sighting probability in habitats with >50% open water, suggesting that the animals select for optimal foraging areas in dense pack ice regardless of the availability of open water (Laidre and Heide-Jørgensen 2011). In the autumn and winter Narwhals are vulnerable to ice entrapments, or sassats, when rapidly changing conditions cause open-water areas used by the whales to freeze over and trap them, sometimes leading to suffocation (Laidre et al. 2012). Calving occurs in spring during the northbound (or in some populations inshore) migration that coincides with the receding sea ice. There is remarkable consistency across Narwhal subpopulations in the types of habitat used, in site fidelity to migration routes and summering and wintering areas, and in feeding patterns (Heide-Jørgensen et al. 2015). Fish, squid, and shrimp make up the Narwhal’s diet (Hay and Mansfield 1989, Heide-Jørgensen 2009), especially Arctic fish species, such as Greenland Halibut (Reinhardtius hippoglossoides), Arctic Cod (Boreogadus saida), and Polar Cod (Arctogadus glacialis) (Laidre and Heide-Jørgensen 2005a).
|Continuing decline in area, extent and/or quality of habitat:||Yes|
|Generation Length (years):||21.9-33.0|
|Movement patterns:||Full Migrant|
|Congregatory:||Congregatory (and dispersive)|
|Use and Trade:||
Narwhals are hunted in Canada and Greenland for human and animal food and for tusk ivory. They supply various staples in the traditional subsistence economy. Today the main products are mattak (skin with some blubber attached) and ivory (Reeves 1993, Reeves and Heide-Jørgensen 1994, Heide-Jørgensen 1994). Narwhal tusks from Canada and Greenland are sold in specialty souvenir markets domestically and are also exported, either as whole tusks or as carved items.
In the 2008 IUCN Red List assessment (Jefferson et al. 2012), intense hunting of Narwhals (including associated loss due to wounding and sinking) in Greenland and Canada was described as a cause for concern, particularly given the lack of reliable data on hidden mortality and serious injury (see Finley and Miller 1982). Statistics on the number of Narwhals reported as landed by the hunting communities are available starting in the 1950s for Greenland and the 1970s for Canada (NAMMCO in prep.). Data summarized by Shadbolt et al. (2015) for the period 2007-2011 show a mean annual retrieved catch of 358 in Greenland and 621 in Canada. The Canadian catch was unusually large due to 624 Narwhals being taken from an ice entrapment event in 2008. Watt and Hall (2016) presented Canadian harvest data that had been corrected for estimated struck and lost. Those data indicate that the total number of Narwhals killed in Canada averaged 620/year (range 515-768) during 2011-2015.
The Conservation of Arctic Flora and Fauna (CAFF) Arctic Biodiversity Assessment (CAFF 2013) lists threats to arctic marine mammals as harvest, loss of sea ice, human activities, pollution, and disease (see also Laidre et al. 2015). Narwhals are susceptible to all those threats, but their importance among the many Narwhal subpopulations varies.
Narwhals were never the targets of large-scale commercial hunting except for a brief period of several decades of the early 20th century in the eastern Canadian Arctic (Mitchell and Reeves 1981). They were hunted opportunistically by commercial whalers, explorers and adventurers in many parts of their range. At present, Narwhals are hunted only in some indigenous communities in Canada and Greenland – for both human consumption and for ivory (see Use and Trade). In some communities Narwhal carcasses are at least partially used as dog food. The strong fidelity of Narwhals, which causes them to return to the same nearshore areas each summer, makes them highly vulnerable to overexploitation. In nearly all parts of their range, hunting is now controlled by limits on harvest levels that are judged to be sustainable (NAMMCO in prep.) (also see the Conservation Actions section)
Ongoing climate change is resulting in substantial loss of sea ice in the Arctic (Comiso 2012, Stroeve et al. 2012), including changes in the timing of sea ice formation and breakup (Laidre et al. 2015, Frey et al. 2015). The effects of climate change on Narwhals are uncertain. Broad changes in the ecosystem may influence the distribution of their prey. Narwhals are well adapted to a life in the pack ice as indicated by the fact that there is very little open water in their winter habitat (Laidre and Heide-Jørgensen 2005b), and they can be found in high densities in areas with more than 98% ice coverage (Laidre and Heide-Jørgensen 2011). They spend much of their time in heavy ice and in some areas are vulnerable to ice entrapments where hundreds can become trapped in a small opening in the sea ice and die (Heide-Jørgensen et al. 2002). This occurs when sudden changes in weather conditions (such as shifts in wind or rapid drops in temperature) freeze shut leads and cracks that the Narwhals were using, and such entrapment may be occurring more often as autumn freeze-up occurs later in the year and on an unpredictable schedule (Laidre et al. 2012). When entrapped whales are discovered by hunters, they normally are harvested. Killer Whales (Orcinus orca) are known to prey on Narwhal in summering areas (Ferguson et al. 2012) and the presence Killer Whales in such areas can greatly affect Narwhal behavior (Breed et al. 2017). Sea ice normally inhibits movements of Killer Whales, and Higdon and Ferguson (2009) documented substantial increases in Killer Whale presence in Hudson Bay when sea ice reduction allowed them to pass through Hudson Strait. An assessment of the sensitivity of all arctic marine mammals to climate change ranked the Narwhal as one of the three most sensitive species, primarily due to its narrow geographic distribution, specialized feeding and habitat choice, and high site fidelity (Laidre et al. 2008).
Known or potential threats to Narwhals include a variety of commercial human activities in addition to hunting, and climate change is facilitating increases in the scale and distribution of those activities. Oil and gas development is ongoing and expanding, and along with commercial shipping is likely to modify and degrade habitat used by Narwhals (Reeves et al. 2014). Areas in Greenland and arctic Russia are subject to oil and gas exploration and development, which often includes seismic surveys, offshore drilling, and artificial island construction, accompanied by ice breaking and shipping. Finley et al. (1990) found that Narwhals at an ice edge reacted strongly to ice-breaking ships, and Cosens and Duek (1993) concluded that Narwhals would likely be able to detect the high-frequency components of icebreaker noise 25-30 km from the source. Heide-Jørgensen et al. (2013) speculated that noise from seismic surveys, at least in some contexts, could enhance the susceptibility of Narwhals to ice-entrapment.
Pollution from industrial and other sources is pervasive in the world’s oceans and marine mammals are known to accumulate levels of contaminants that are high enough to cause impacts on health and reproductive performance (Ross 2000). Organochlorine and heavy metal contaminants have been found in Narwhals in several areas (Dietz et al. 2004). At Svalbard, Wolkers et al. (2006) found that levels of contaminants in Narwhals were higher than those in Beluga Whales (Delphinapterus leucas).
Commercial fisheries for Greenland Halibut operate in both the Canada and Greenland sides of Baffin Bay/Davis Strait and have done so on the inshore Greenland side for several decades (Treble and Bowering 2002). This fishing overlaps spatially with where Narwhals winter and feed extensively on the target species, Greenland Halibut (Laidre et al. 2004, Laidre and Heide-Jørgensen 2005a).Like other marine mammals, Narwhals are exposed to a number of diseases that may influence their population status (Gulland and Hall 2006), but significant epizootics have not been recorded. Nielsen et al. (2001) found a low prevalence of exposure to Brucella spp. in Narwhals sampled in arctic Canada. Nielsen et al. (2000) found no serological evidence of exposure to morbilliviruses, and speculated that because they are immunologically naïve, Narwhals are at considerable risk of a serious epidemic if they become exposed. Burek et al. (2008) described ways in which climate change could influence disease exposure for arctic marine mammals.
The Narwhal is listed in Appendix II of the Convention on International Trade in Endangered Species (CITES). As a result, a non-detriment finding (NDF; analysis showing that the taking and trade is not detrimental to the species’ survival or to maintenance of the species “throughout its range at a level consistent with its role in the ecosystems in which it occurs”) by the Scientific Authority of the exporting country is required for export. This requirement has had the effect of forcing both Canada and Greenland to document catch and trade levels and to provide data on abundance and trends of hunted Narwhal stocks. Negative NDFs were issued for both countries (Greenland in 2005, Canada in 2010; Shadbolt et al. 2015) making exports of Narwhal ivory from several stocks in Canada illegal for a brief period in 2010-11 and leading to a temporary export ban in Greenland in 2006. This ban remained in effect through at least February 2014 despite the fact that new information reported in 2009 indicated that removal levels for at least some stocks in Greenland were sustainable (Shadbolt et al. 2015). The NAMMCO Scientific Committee Working Group on the Population Status of Narwhal and Beluga in the North Atlantic and the JCNB [Canada/Greenland Joint Commission on Conservation and Management of Narwhal and Beluga] Scientific Working Group meet jointly every other year to review new information on the biology of Narwhals and Belugas, update assessments, and provide advice to the Canada and Greenland governments based, in part, on a catch allocation model designed to ensure the long-term sustainability of removals from the various stocks (NAMMCO 2016, in prep.). Greenland’s annual report to NAMMCO in 2016 (NAMMCO 2017) noted that the NDF for 2016 compared catches and advice for 2013, 2014, and 2015, concluding that, “as a whole, in the period 2013-2015, catches … followed the advice from NAMMCO, JCNB or IWC for all stocks, except Narwhals in Inglefield Bredning, Melville Bay, Ittoqqortormiit and Tasiilaq.”
Particularly in the context of NAMMCO (NAMMCO, in prep.) and among non-governmental organizations (Shadbolt et al. 2015), there is increasing recognition of the need to improve understanding of the impacts – direct and indirect, individual and cumulative – on Narwhals from climate change and associated changes in human activity in the Arctic (e.g., mining, oil and gas development, shipping, fisheries, tourism).
|Citation:||Lowry, L., Laidre, K. & Reeves, R. 2017. Monodon monoceros. The IUCN Red List of Threatened Species 2017: e.T13704A50367651.Downloaded on 20 September 2018.|
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