|Scientific Name:||Balaena mysticetus Linnaeus, 1758|
|Infra-specific Taxa Assessed:|
|Taxonomic Notes:||The taxonomy of the Bowhead Whale is not in doubt. There are four identified subpopulations two of which (Okhotsk Sea and East Greenland-Svalbard-Barents Sea) have separate IUCN Red List assessments.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Cooke, J.G. & Reeves, R.|
|Reviewer(s):||George, C., Moore, S., Taylor, B.L. & Lowry, L.|
The global (pan-arctic) population of the Bowhead Whale appears to be increasing, due primarily to the well-documented increase in the large Bering – Chukchi – Beaufort Seas subpopulation (also known as the Western Arctic population or stock). The global population size, at over 25,000 animals, is well above the IUCN Red List Vulnerable threshold for a non-declining population. The Bering – Chukchi – Beaufort subpopulation (estimated to be over 16,000 and increasing at 3% per year or more) may have recovered to near or even above its level prior to commercial whaling. The East Canada – West Greenland subpopulation is estimated to exceed 4,000, and has probably been increasing but is still below its pre-whaling level. Bowhead Whale numbers in the East Greenland – Svalbard – Barents Sea subpopulation remain at a small fraction of pre-whaling abundance with no estimate of trend. The main reduction in the global population occurred before the three-generation time window that would trigger the Red List population reduction (A) criterion. The East Greenland – Svalbard – Barents Sea and Okhotsk Sea subpopulations have separate Red List assessments, in addition to being included in this global assessment.
|Previously published Red List assessments:|
Bowhead Whales are found only in Arctic and subarctic regions. Until recently they have spent much of their lives in and near sea ice and they migrate seasonally to avoid ice entrapment and to take advantage of food concentrations (Moore and Reeves 1993). With the reduction of sea ice cover, Bowhead Whales now occur increasingly in open water during the summer (Moore 2016).
With the exception of the Okhotsk Sea, genetic divergence between Bowhead Whales in different parts of their range appears to be low, and there is some evidence of movement between the main areas of occurrence (IWC 2013). The Okhotsk Sea subpopulation appears to be genetically and geographically isolated.
Based on direct observations and telemetry, the summer range of the Bering – Chukchi – Beaufort Seas subpopulation extends from Chaunskaya Guba (Russian Federation) in the western Chukchi Sea through the Beaufort Sea and east to Amundsen Gulf (Canada) and Viscount Melville Sound (Heide-Jørgensen et al. 2012). Most of the whales appear to migrate into the Bering Sea in winter (IWC 2013, Quakenbush et al. 2012, Citta et al. 2015). In the 19th century, substantial catches were also taken in summer in the Bering Sea, but the climatic conditions were quite different then than at the present (IWC 2013)
Bowhead Whales belonging to the East Canada – West Greenland subpopulation are observed in Hudson Bay, Foxe Basin, Hudson Strait, Davis Strait, Baffin Bay, Gulf of Boothia, Prince Regent Inlet, and other waters of the Canadian Arctic Archipelago. Tracking of satellite-tagged whales has confirmed movements from Foxe Basin through Fury and Hecla Strait into the Gulf of Boothia and Prince Regent Inlet, and from Cumberland Sound into Prince Regent Inlet, Gulf of Boothia, Foxe Basin, and Hudson Strait, while animals tagged in West Greenland moved to Prince Regent Inlet and Hudson Strait (Heide-Jørgensen et al. 2012). The whales move out of the summering areas as ice forms in autumn to wintering areas in polynyas (Holst and Stirling 1999), unconsolidated pack ice, and open water near the ice edge off West Greenland (Reeves and Heide-Jørgensen 1996) and eastern Baffin Island. Sightings and strandings have occurred in recent years in the western North Atlantic as far south as Newfoundland (Ledwell et al. 2007) and the Gulf of Maine (Accardo et al. in press).The East Greenland – Svalbard – Barents Sea subpopulation occurs from the east coast of Greenland across the Greenland Sea, including the Northeast Water polynya off northeastern Greenland, in the Barents Sea, in the Franz Josef Land Archipelago, and in the Kara Sea at least as far as far as Severnaya Zemlya. There have also been sightings further south, exceptionally reaching Iceland and the coast of Finnmark. Vagrants have been observed as far south as the western British Isles and France (de Boer et al. 2017).
The Okhotsk Sea subpopulation occurs in the northern and western Sea of Okhotsk from Shantarskiye Zaliv east to Zaliv Shelikova, Gizhiginskaya Guba, and Penzhinskaya Guba (Moore and Reeves 1993, Shpak et al. 2014). There is no evidence of migration into or out of the Okhotsk Sea.
Native:Canada; Greenland; Iceland; Norway; Russian Federation; Svalbard and Jan Mayen; United States (Alaska)
Vagrant:France; Ireland; United Kingdom
|FAO Marine Fishing Areas:|
Arctic Sea; Atlantic – northeast; Atlantic – northwest; Pacific – northeast; Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Current Population sizes|
The Bering – Chukchi – Beaufort Seas subpopulation is estimated to have numbered 16,900 (15,700-18,900) in 2011 from shore/ice-based counts (Givens et al. 2016) or 19,000 (12,400-28,500) from photo-identification capture-recapture (Givens et al. 2017). Numbers in the East Canada – West Greenland subpopulation are estimated at 4,000-10,500 in 2013 from aerial surveys (Doniol-Valcroze et al. 2015) or 4,500-11,000 in 2008-12 from genetic mark-recapture (Frasier et al. 2015). Given the increasing trend in the large Bering – Chukchi – Beaufort subpopulation, the total range-wide population likely exceeds 25,000 individuals. The Okhotsk Sea subpopulation is estimated to be only about 200, and the East Greenland – Svalbard – Barents Sea subpopulation probably also numbers in the hundreds (see separate listings).
The Bering – Chukchi – Beaufort Seas subpopulation has been monitored for more than 30 years and has been increasing over that period at an estimated annual rate of 3.7% (range 2.8–5.4%) in the presence of subsistence hunting (Givens et al. 2016). The East Canada – West Greenland subpopulation has probably also been increasing. Based on aerial surveys and genetic capture-recapture, Rekdal et al. (2015) concluded that the number of Bowhead Whales using West Greenland waters in the winter-spring period increased from 1998 to 2006 and has levelled off since then. The Okhotsk Sea subpopulation may be declining (Cooke et al. 2017). No estimates of trend are available for the East Greenland – Svalbard – Barents Sea subpopulation.
Pre-whaling population sizes
Commercial whaling for Bowhead Whales in the Bering Sea began in 1848 and expanded rapidly, depleting the worldwide population (Bockstoce and Burns 1993). Brandon and Wade (2006) estimated the initial abundance of the Bering – Chukchi – Beaufort subpopulation at 10–20,000. Using a different kind of population model, Witting (2013) estimated pre-whaling abundance to be 13-24,000. Therefore, the Bering – Chukchi – Beaufort subpopulation appears to have reached or exceeded estimates of its size prior to commercial whaling. All models indicate that the population reached a minimum size around 1914.
Basque whalers took Bowhead Whales in the northwestern Atlantic in the 16th century, but ambiguities over the species identity of whales taken in early commercial whaling have made interpretation of old catch records difficult. Genetic analysis of bones from 16th and 17th century shore stations in the Strait of Belle Isle and Gulf of St Lawrence found that, contrary to previous assumptions, almost all bones were from Bowhead Whales rather than North Atlantic Right Whales (Eubalaena glacialis) (Macleod et al. 2008). This suggests that 25-40,000 Bowhead Whales were taken in the eastern Canadian Arctic by Basque whalers during 1530-1610, followed by approximately 28,000 during the pelagic whaling phase during 1719-1915 (Ross, 1993).
The pre-whaling size of the East Canada – West Greenland population was thus probably at least 25,000, well above the likely current level.The pre-whaling size of the East Greenland – Svalbard – Barents Sea population has been estimated to be 33,000-65,000 using a simple population model (Allen and Keay 2006) applied to historical catch data from Dutch, German, and British sources compiled by de Jong (1983). The current population size, therefore, is a small fraction of the pre-whaling size. The pre-whaling population size in the Okhtosk Sea has been variously estimated as between 3,000 and 20,000 depending on assumptions about past catches (Ivashchenko and Clapham 2010). The current population size is a small fraction of those estimates.
|Current Population Trend:||Increasing|
|Habitat and Ecology:||Small to medium-sized crustaceans, especially krill and copepods, form the bulk of the Bowhead Whale diet (Lowry et al. 2004, Pomerleau et al. 2011). Bowheads also commonly feed on mysids and gammarid amphipods, and the diet includes at least 60 species (Lowry 1993).|
The seasonal distribution of Bowhead Whales is strongly influenced by prey availability and pack ice conditions (Moore and Reeves 1993). During the winter, they occur within areas of sea ice (Stafford et al. 2012) and appear to feed mainly near the bottom (Citta et al. 2015). During the spring, they use leads and cracks in the ice to penetrate areas that were inaccessible during the winter due to heavy ice coverage. During the summer and autumn, they concentrate in areas where zooplankton production is high or where large-scale biophysical processes create local concentrations of calanoid copepods (Finley 1990, Finley et al. 2000) and appear to feed mainly in mid-water and near the surface (Citta et al. 2015). In the Pacific Arctic, six feeding hotspots have been identified including two in the Bering Sea and one in the Chukchi Sea along the northern coast of Chukotka where there is evidence of winter feeding, and three in the Beaufort Sea where most of the feeding occurs in summer and autumn (Citta et al. 2015).
The Bowhead Whale may be the longest-living mammal, possibly capable of living for over 200 years (George et al. 1999, Keane et al. 2015, Wetzel et al. 2017). Nearly all life history data come from the Bering – Chukchi – Beaufort Seas population. Female age at sexual maturity is estimated at 18-33 years (Rosa et al. 2013). Taylor et al. (2007) estimated the mean generation time for Bowhead Whales to be about 52 years, assuming an age at first reproduction of 20 years. Females give birth every 3-7 years (Rugh et al. 1992) and calves are weaned at 9-12 months of age (Koski et al. 1993).
|Continuing decline in area, extent and/or quality of habitat:||Unknown|
|Generation Length (years):||52|
|Movement patterns:||Full Migrant|
|Use and Trade:||
Limited subsistence whaling on the Bering – Chukchi – Beaufort subpopulation by indigenous people of Alaska and Chukotka is permitted by the IWC on the basis of advice from its Scientific Committee (under its aboriginal subsistence whaling management procedure). Small hunts are also authorized in Canadian waters under co-management agreements between federal agencies and indigenous communities, and in West Greenland under the IWC management procedure. The reported average annual take in Alaska and Chukotka during 2006-15 was about 55 animals struck of which about 75% were successfully landed (Allison 2017, Suydam et al. 2017).
Extensive commercial hunting, beginning in the 1500s, depleted Bowhead Whales throughout their range. Commercial whaling for the species has been prohibited under international conventions since the 1930s. The limited subsistence whaling by indigenous communities mentioned above has not impeded the recovery of the affected populations.
Accidental human-caused deaths are relatively few. During 2010-15, two dead-stranded and one live Bowhead were observed to be entangled with fishing gear but it was unclear whether the entanglement was the cause of death. Of the Bowhead Whales taken in Alaskan hunts during 1990-2012, 12% showed scars or wounds from fishing gear and 2% showed scars or wounds from ship strikes (George et al. 2017a).
There has been concern since the 1970s that disturbance from oil and gas exploration and extraction activities in the Arctic region would affect Bowhead Whales. Effects on diving behavior (Robertson et al. 2013) and calling rates (Blackwell et al. 2015) in the vicinity of seismic surveys have been observed, but to date there has been no discernible population-level impact. Examination of whales taken in subsistence hunts off Alaska since 1980 found relatively low levels of morbidity, which would be consistent with an increasing population and good individual animal health (George et al. 2017b).
During this century, a profound reduction in the extent and thickness of sea ice in the Arctic has occurred and this reduction is predicted to continue, possibly leading eventually to the complete disappearance of sea ice in summer as mean Arctic temperatures rise faster than the global average (Frey et al. 2015). The short-term effects of reduced ice cover on Bowhead Whales in the western Arctic appear to be positive, due to increased feeding opportunities (George et al. 2015, Moore 2016). However, the long-term effects are less clear. The emergence of Bowheads as a separate, ice-adapted species may have coincided with the appearance of sea ice in the late Pliocene, and Bowheads could lose out to non-ice-adapted species in the long term, but no projections of the time scale of such an eventuality are available (Harington 2008, IWC 2016).
There is also concern that, as the sea ice diminishes, the opening up of the Arctic to increased vessel traffic, fishing activities, and extractive industries will increase human-caused impacts on Bowhead Whales (Reeves et al. 2012, 2014).
Bowhead Whales were legally protected from commercial whaling under the International Convention for the Regulation of Whaling (ICRW) since its entry into force in 1948, and by its predecessor the Convention on the Regulation of Whaling since the 1930s. All range states except Canada are parties to the ICRW. Limited aboriginal subsistence whaling of Bowhead Whales is allowed by the IWC (the regulatory body established under the ICRW) from the Bering-Chukchi-Beaufort Seas stock and off West Greenland on the basis of scientific advice (see Threats section). Hunting by indigenous people in Canada is co-managed by the federal government and regional bodies created under land-claim agreements. The Bowhead Whale has been included in the Convention on International Trade in Endangered Species Appendix I since 1975 and it is listed on the Convention on the Conservation of Migratory Species of Wild Animals Appendix I. Bowhead Whales are managed under national threatened species legislation in the U.S.A., Canada, and the Russian Federation.
|Citation:||Cooke, J.G. & Reeves, R. 2018. Balaena mysticetus. The IUCN Red List of Threatened Species 2018: e.T2467A50347659.Downloaded on 17 July 2018.|
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