The Walrus, Odobenus rosmarus, was in the past divided into three subspecies: the Atlantic Walrus (O. r. rosmarus), the Pacific Walrus (O. r. divergens), and the Laptev Walrus (O. r. laptevi) (Rice 1998). However, the status of the Laptev Walrus has always been somewhat uncertain, animals from that region are described as being intermediate in size between the Pacific and Atlantic forms, with skull morphology most similar to the Pacific subspecies (Fay 1982). Recent analyses of mitochondrial DNA and morphometric data suggest that the taxon O. r. laptevi should be abandoned (Lindqvist et al. 2009). The walruses found in the Laptev Sea are in all probability the westernmost part of the Pacific Walrus population.

European regional assessment: Near Threatened (NT)

Walruses occur within the European marine assessment area (EMAA) from its westernmost borders in East Greenland (north of Scoresbysund) to its easternmost borders along the west coast of Novaya Zemlya, in Arctic waters of the Barents Sea south to the mainland coast of Russia in the Pechora Sea, with hotspots in both the Svalbard and Frans Josef Land archipelagos in the north. Sea ice in the Barents region is declining rapidly (>30%), reducing Walrus breeding sites and foraging habitats significantly. Walruses depend on rich beds of molluscs to support their individual and population food requirements, and global warming is also likely reducing productivity of benthic communities in shallow Arctic seas that are tightly coupled to sea ice community production. A reduction of 20-30% population is suspected to occur over the future three generation length period (3GL = 45.3 years, decline period 2024-2068) in future due to these threats. Population trends within the EMAA area are mixed (decreasing, increasing and unknown), and data are lacking on the abundance of Walruses for several important regions. Thus, the European populations of Walruses are assessed as Near Threatened under criteria A3c.

All Walruses within the European marine assessment area (EMAA) are Atlantic Walrus (O. r. rosmarus). It is likely that the EMAA contains three populations; one in East Greenland (Witting and Born 2005), one comprising animals that haul-out in Svalbard and Frans Joseph Land (and on the ice between the archipelagos; Wiig et al. 1996, Hamilton et al. 2021), and another population (or subpopulation) in the southern Barents Region (Andersen et al. 2017; Pechora Sea and Kara Sea animals likely belong to the same population, but no genetics studies are available).

Walruses have a discontinuous circumpolar Arctic and sub-Arctic distribution. They are primarily found in relatively shallow continental shelf areas (Rice 1998, Lydersen 2018). The Pacific Walrus (O. r. divergens) ranges from the Bering and Chukchi Seas, which constitute the centre of its range, to the Laptev Sea in the west and the Beaufort Sea in the east, with vagrants recorded south into the North Pacific Ocean to southcentral Alaska and Japan (Fay 1981, 1982). The Atlantic Walrus occurs from the eastern Canadian Arctic to the western Kara Sea (Keighley et al. 2021), north to the North Pole (Lydersen et al. 2022), in areas that can be over 90% ice cover (Freitas et al. 2009). The Walrus has been extirpated from some areas of its historical range by excessive hunting i.e. Gulf of St Lawrence (McLeod et al. 2014) and a local population just north of Scoresby Sound, (Born et al. 1997) and Iceland (Keighley et al. 2019). In the east, Atlantic Walruses occur south of the mainland Russian coast within the Pechora and Kara Seas. Vagrants have been reported from New England, Iceland, and from Norway south to the Bay of Biscay in France/Spain. They are rare, but do also occur on occasion, in the White Sea in Russia.

All Walrus populations were drastically historically reduced by overharvesting to serve the Walrus ivory trade (Barrett et al. 2020), and some populations in Greenland and in Canada have been reduced further in recent times by unsustainable subsistence hunting (Wiig et al. 2014, Garde and Hansen 2021), though it is thought that sustainable harvest levels have been achieved since 2006 (NAMMCO 2018).

The Atlantic Walrus has been extirpated from some areas of its historical range (i.e. Gulf of St Lawrence; McLeod et al. 2014), a local subpopulation just north of Scoresby Sound (Born et al. 1997) and in Iceland (Keighley et al. 2019), but extant subpopulations in combination number 45,000+ animals. The Pacific Walrus is approximately five times as abundant as the Atlantic Walrus, with numbers recently estimated to be ca 250,000 (Fischback et al. 2021, Beatty et al. 2022); this number does not include the Laptev population, which has not been surveyed. In Canada and West Greenland (where several populations are bilateral), there are some 25,000 animals (Heide-Jørgensen et al. 2013, Stewart et al. 2014, Hammill et al. 2016a,b; NAMMCO 2018).

Within the EMAA, the East Greenland population is the smallest; it totals some 279 (CI 226-345) animals (NAMMCO 2018). The next largest is the Pechora Sea population, which holds at least 4,000 animals (Lydersen et al. 2012, Semyonova et al. 2015); the west side of Novaya Zemlya has never been surveyed, but animals in this area are likely in the same population as Pechora/Kara Sea Walruses. Finally, the largest population – the Svalbard-Franz Josef population has only been surveyed in Svalbard, where the most recent estimate, conducted in 2018, was 5,503 (CI 5,031-6,636) animals residing in the archipelago in late summer. No scientific surveys have been conducted in Franz Josef Land, but Gavrilo (2017) suggested that some 3,000-3,500 Walrus were counted (at an unknown number/proportion of haul-out sites). Adjacent to the EMAA, the Kara Sea also has Walrus; no full estimate is available for this area, but a summer direct count was 1,062 individuals (Boltunov et al. 2021); these animals are likely members of the same population as the Pechora Sea animals and those that summer on Novaya Zemlya (both coasts).

The population in East Greenland is in decline - but this is a tiny population to start with, so has little impact on the overall species status for Europe. A population reduction of 20-30% is suspected to occur in Europe over the future three generations due to habitat (see 'Threats' section).

Walruses are one of the largest pinnipeds and the only one that bears tusks. The tusks can grow to be a meter long and can weigh 5 kg in large bulls; females have thinner tusks than males. Males can reach 3.6 m in length and weigh up to 1,500 kg, while females are somewhat smaller, reaching lengths of about 3 m and weighing up to 1,000 kg. Newborns are 1-1.4 m long and weigh 33-85 kg (Fay 1981, Lydersen 2018, Keighley et al. 2021). Males have specialised integumentary nodes on their neck and shoulders that probably function as an optical signal of maturity, and they might also have a shielding function (Miller and Kochnev 2021). Although some females can ovulate at four years of age, the majority do not give birth until they are seven to eight years old and usually produce one calf every three years. Gestation lasts 15 months, including a period of delayed implantation that lasts 3-3.5 months. Calves are born in May in drift ice areas, some close to land. The period of calf dependency is long, they are often attended to by their mothers for two or more years. Males become sexually mature between 7–10 years of age, but are not physically and socially mature enough to successfully compete for breeding opportunities until they are approximately 15 years old. Longevity is approximately 40 years (Fay 1981). Walruses normally feed quite close to where they haul out throughout the year.

Walruses are extremely social animals, and when on land or ice Atlantic Walruses are normally found in tight groups ranging in size from a few individuals up to hundreds. Walruses seek extensive body contact with conspecifics, which might in part serve to conserve heat, but clearly also has a social function, and may also serve to reduce the risk of predation by bears (A. Fischbach pers. comm.). At sea, they usually travel in groups as well, and mothers and calves maintain close physical contact. Walruses are able to nurse their pups at sea, holding the pup upside-down against the mother’s body (Kryukova 2016); being adapted to suction feeding plays a role in this unique behaviour. There is significant sexual segregation outside the breeding season, with males often being found in areas away from females and their calves. Courtship and mating occur during the winter within loose and sparse ice polynyas of the pack ice. Walruses are believed to be polygynous, with males forming a type of lek and displaying vigorously, while vocalising, adjacent to females hauled-out on ice floes (Sjare and Stirling 1996, Sjare et al. 2003). Males produce bell-like sounds underwater using a pair of elastic pharyngeal pouches in the neck that can be inflated with air to serve as resonance chambers that make this unique sound. Male Walruses also sleep at sea with these pouches inflated. There is intense male-male fighting during mating and the tusks are used in these encounters both to signal strength and intent as well as using them as weapons. The tusks are also used during interspecific aggression against potential predators such as Polar Bears and Killer Whales (Miller and Kochnev 2021); Walruses will defend members of the group against predators (Stirling 1984). They also use their tusks to help get up onto ice floes. Walrus societies are complex, which is facilitated in part by a rich vocal repertoire (Miller and Kochnev 2021).

Walruses have a narrow ecological niche. They depend on: 1) the availability of large areas of shallow water with suitable bottom substrate to support a productive bivalve community, 2) the presence of reliable open water areas over rich feeding areas, particularly in winter when access to feeding areas is limited by ice cover, and 3) the presence of haul-out areas in reasonably close proximity to feeding areas (Lydersen 2018). The preferred haul-out platform is sea ice, although Walruses routinely use terrestrial haul-out sites in the summer and autumn (Lydersen et al. 2008, Kovacs et al. 2014, Hamilton et al. 2015). Walruses are primarily bottom feeders and shallow divers (Lowther et al. 2015). Most prey taken is found in the upper few centimetres of sediment, or on or just above the bottom. A wide variety of benthic invertebrates, with several species of clams, make up the majority of food for most animals (Fay 1982, Skoglund et al. 2010). Walrus whiskers are the texture of strong plastic (stiff but bendable), and they are highly innervated and are extremely sensitive (Kastelein and van Gaalen 1988). They are used to search for prey in soft substrates (Marshall and Pyenson 2019). The diet of the Walrus also includes a range of other prey, including many species of worms, snails, soft-shell crabs, amphipods, shrimp, sea cucumbers, tunicates, and slow-moving fish. Some individuals also prey on seals, small whales, and seabirds (Lowry and Fay 1984, Sheffield and Grebemeyer 2009, Seymour et al. 2014), and occasionally they scavenge marine mammal carcasses (Fay 1982). Because they feed in shallow, coastal areas Walruses usually perform only relatively shallow, short dives (Hamilton et al. 2015, Lowther et al. 2015); Garde et al. (2018) found Atlantic Walruses in the NW Artic to mostly dive to less than 100 m depth, but also recorded dives to depths >500 m. Trips at sea can last several days, but typically last well less than half a day (A. Fischbach pers. comm.).

Haul-out patterns follow both diel and strongly seasonal patterns (Hamilton et al. 2015). During the winter, walruses spend 15-20 % of their time hauled-out. This increases to 30% during the summer months. Much of the year, males haul out for a day to two and then spend several days at sea (Lydersen et al. 2008). Diving patterns change markedly during the mating period, when males dive to the bottom rarely, spending much of their time doing shallow dives, near ice edges (Lowther et al. 2015). On average, Walruses are in the water 75% of the time. The primary predators of Walrus are Polar Bears and Killer Whales (Killian and Stirling 1978, Fay 1981).

Sea ice in the Barents region is declining rapidly, reducing Walrus breeding and foraging habitats significantly.

All three Walrus populations were severely depleted by episodic commercial hunting that was heaviest from the 18th through the mid-20^th centuries. Native people of the Arctic have depended on Walruses for food, hides, ivory, and bones, and subsistence harvests of both subspecies continue today in most parts of their ranges. Based on hindcasts of the original population size, Walruses in the EMAA currently number less than half of the original population sizes combined (Gjertz et al. 1998, Weslawski et al. 2000, Witting and Born 2014). Harvests are close to sustainable limits in Greenland and some low level of poaching takes place in the Pechora Sea despite Walruses being protected in this region.

Levels of direct conflicts with fisheries are low; however, trawl fisheries can disturb important benthic feeding areas (Born et al. 2003, COSEWIC 2017, Born et al. 2021a). Similarly, oil and gas development or marine mining can disrupt benthic habitats and oil spills can have serious negative impacts on Walruses via impacts on their food. Human disturbance at land-based haul-out sites, low-level aircraft over-flights, transport ships, drilling activities and near-shore passage of vessels can have serious effects on Walruses when they are hauled out, as they are susceptible to disturbance, and are easily panicked into stampedes (Born et al. 2021a). In Svalbard, where protection has been in place since 1952, Walruses are very robust to human visitation if approaches are made carefully (Øren et al. 2018).

Walruses in Svalbard have dramatically variable contaminant levels from individual to individual, which are perhaps related to their diets (Wolkers et al. 2006, Scotter et al. 2019) and individual variability in foraging; while most Walruses eat benthic bivalves, some eat seals and birds. Some animals have such high contaminant burdens that they might suffer from immune depression (Routti et al. 2019). In the Pacific, where herd size is increasing in association with climate warming, stampedes are thought to already be a significant source of mortality (Udevitz et al. 2013); the regular occurrence of large herds with females and young at coastal haulouts is a novel phenomena that only occurs when sea ice is regionally absent (A. Fischbach pers. comm.).

Global warming and associated reductions in the extent and seasonal period of sea ice cover are expected to have negative effects on Walrus populations (Kovacs et al. 2016, but also see Born et al. 2021b). Declining sea ice reduces suitable pupping and breeding habitats and limits access to offshore feeding areas (Tynan and DeMaster 1997, Moore 2005; Kovacs et al. 2011, 2012, 2021; Laidre et al. 2015). Reductions in sea ice could also lead to the addition of commercial shipping and development in areas previously protected by extensive ice with increased risk of spills and discharge of pollutants, disturbance, and coastal development (Tynan and DeMaster 1997, Semyonova et al. 2015, NAMMCO 2018). Walrus prey is also likely to be negatively impacted by reductions in sea ice and the associated reduction of sympagic community fall-out (Grebmeier et al. 2018, Mueter et al. 2021).

Walruses have been historically used for human and dog food. This species has also been subject to both subsidence and commercial hunting. Additionally, the ivory has been an important item in trade from most of the species range in the past, and it was used to create carvings, sculptures, and traditional handicrafts in various Arctic cultures. Their hides have been used in the past as covering for boats.

Commercial hunting of Walruses is forbidden world-wide, but most populations are harvested by indigenous people. Within the EMAA, legal hunting of Walruses only takes place in Greenland, where subsistence quotas were put in place in 2006 (NAMMCO 2018). Hunting at terrestrial haul-outs is banned in Greenland and adult females are not supposed to be taken. Both in Norway and in Russia, Walruses are Red Listed in the Barents Region. Gavrilo (2017) considered that Walruses have recovered to near their original stock size in Frans Josef Land, though surveys are lacking. In Svalbard, Walruses are also increasing in number following protection being put in place in 1952. They have now reached 25% of original stock size, but the sex ratio remains heavily skewed toward males, although females with calves are increasingly observed (Wiig et al. 2007, Kovacs et al. 2014). Many protected areas in Svalbard are relevant for Walrus conservation (Kovacs and Lydersen 2006). The species is included in Appendix III of Cites and in Annex B of the EU wildlife trade Regulation (Commission Regulation 2023/966 of 15 May 2023).

Resource and habitat protection measures are required, as well as monitoring of population trends.