Morse

Walruses were hunted at industrial levels historically, resulting in the depletion of all populations (Scammon 1878, Stewart et al. 2013, Drew et al. 2016, Barrett et al. 2020). In the Pacific Arctic, industrial scale harvests also took place from the 1950's up through 1991 by Soviet collectives as well as offshore marine harvesting vessels to supply fox-food to the fur industry (Fay et al. 1989, Fay et al. 1997, Kerttula 2000, Demuth 2019). The size of the Pacific walrus population was thought to have increased rapidly in the 1960s due to a release from hunting pressure, probably reaching or exceeding the size that could be supported by the environment between the late 1970s and early 1980s (Fay et al. 1989). Density-dependent food limitation is thought to have limited the rate of growth after some decades (given that harvested animals were leaner in the early 1980s compared to previous decades) via an older age of first reproduction (Fay et al. 1989) and lower reproductive rates (Fay et al. 1997). High harvest levels in the 1980s in combination with ecological changes in the North Pacific Arctic led to a significant long-term population decline (ca 50%) (Fay et al. 1989). Increased reproduction and calf survival is thought to have led to recovery and a population that is now approaching a new equilibrium (Taylor et al. 2018).

Indigenous people of the Arctic have depended on walruses for food, hides, ivory, and bones. Subsistence harvests of both subspecies throughout much of the species’ range continues today, except in some few protected areas (Norwegian and Russian Barents Region). Based on hindcasts of original population size, walruses in the Northeast Atlantic Arctic number less than half of the original population sizes combined (Gjertz et al. 1998, Weslawski et al. 2000, Witting and Born 2014). Harvests are currently thought to be at sustainable levels and the only illegal harvest (poaching) is thought to take place in the Pechora Sea at very low levels (where Walruses are protected).

Levels of direct conflicts with fisheries are low; however, trawl fisheries can disturb important benthic feeding areas (McConnaughey et al. 2000, Born et al. 2003, Mecum 2009, Born et al. 2021a, COSEWIC 2021, USFWS 2023). Northward shifts in some Russian fisheries in the Bering Sea are a current concern, particularly when the fishing effort gets close to haulout sites (Datsky et al. 2022, Buslov and Ovsyannikov 2023). IK (Indigenous knowledge) holders are concerned about potential impacts of commercial fisheries (Gadamus and Raymond-Yakoubian 2015).
Oil and gas development and marine mining can disrupt benthic habitats and oil spills can have serious negative impacts on walruses via impacts on their food (Harwood et al. 2019). Additionally, exploration phases can produce high levels of underwater noise that can interfere with communication and also cause temporary of permanent hearing damage if blasts occur at close range (Hermannsen et al. 2015).

Human disturbance at land-based haul-out sites, low-level aircraft over-flights, transport ships, and near-shore passage of vessels can have serious effects on Walruses when they are hauled out, as most populations are susceptible to disturbance, and are easily panicked into stampedes (Born et al. 2021a, USFWS 2016). In Svalbard, where protection has been in place since 1952, Walruses are very robust to human visitation if approaches are done carefully (Øren et al. 2018). In the Pacific, where herds size is increasing in association with climate warming, stampedes are thought to already be a significant source of mortality (Udevitz et al. 2013, Goertz et al. 2017).

Walruses in Svalbard have dramatically variable contaminant levels from individual to individual, that are perhaps related to their diets (Wolkers et al. 2006, Scotter et al. 2019); while most Walruses eat benthic bivalves, some eat seals and birds. Some animals have high enough contaminant burdens that they might suffer immune depression (Routti et al. 2019) but this is not the norm for the Barents population or the species more generally. The Walrus’s low trophic feeding habits means that contaminant levels are generally low (e.g. Quakenbush et al. 2016). Their filter-feeding prey are at risk from effects from harmful algal blooms (HABs), which are expected to increase in a warming Arctic (Lefebvre et al. 2022).

Global warming and associated reductions in the extent and seasonal period of sea ice cover is the most serious current and future threat to Walruses (Kovacs et al. 2011, 2012, 2016, 2021, Laidre et al. 2008, 2015, MacCracken 2012, MacCracken et al. 2017 - but also see Born et al. 2021b). Declining sea ice reduces suitable resting, pupping and breeding habitat and limits access to offshore feeding areas. Sea ice reductions in the North Pacific have resulted in vast herds forming on land in summer, some in excess of 100,000 animals (Fischbach and Douglas 2021, Altukhov et al. 2024) that include many mothers and calves that previously remained associated with ice year-round with resultant high levels of mortality, particularly of calves (e.g. Udevitz et al. 2013). Reductions in sea ice are also likely to lead to other indirect effects such as more commercial fishing, 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, Huntington et al. 2013, 2015, Semyonova et al. 2015, Kovacs et al. 2016, NAMMCO 2018, and references above). 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 depend on rich beds of molluscs to support their individual and population food requirements (Born et al. 2003). Warming in association with increased acidification is likely to have negative impacts on calcifying organisms that are prey for Walruses (Renaud et al. 2015, Waldbusser et al. 2015). Warmer temperatures are also likely to be associated with increased risk of diseases (Burek et al. 2008, VanWormer et al. 2019, Barraclough et al. 2023) and perhaps also changing predator pressures when polar bears do more terrestrial hunting. Avian influenza was documented in Walrus in the North Atlantic in 2023 (Lydersen and Kovacs, unpubl. data) and this virus is a concern for wildlife in Alaska (Reed et al. 2014).

Commercial hunting of Walruses is forbidden world-wide, but most populations are subject to subsistence harvests by indigenous people. Sustainable harvests are thought to have been recently achieved in Greenland following implementation of quotas in 2006 (Wiig et al. 2014, NAMMCO 2018). Hunting at terrestrial haul-outs is banned in Greenland and adult females are not supposed to be taken, though this issue is not yet completely solved. Harvests in the Pacific and in Canada are small compared to population sizes. In Canada Walruses are listed as a Species of Special Concern, largely because of the threat posed by climate change (COSEWIC 2021).

Walruses are in the Russian Red Book, and they are classified as VU (Vulnerable) on the Norwegian Red List because of overharvesting in the past and the threat posed by habitat losses due to climate change. In the Barents Sea Region Walruses are completely protected from harvesting in both Russian and Norway (Boltunov et al. 2010, Eldegard et al. 2021). Many protected areas in Svalbard are relevant for Walrus conservation (Kovacs and Lydersen 2006).

Pacific Walruses became federally protected from commercial harvesting in 1941 in the U.S. and they became further protected under the Marine Mammal Protection Act in 1972. The U.S. Fish and Wildlife Service monitors hunts, which are managed by subsistence walrus-hunting communities in Alaska. Annual quotas are set for Pacific Walrus harvests by local communities in the Russia Arctic (Kryukova 2019).

Transportation of walrus products has been regulated by CITIES import and export controls since 1975.