The State of Circumpolar Walrus Populations

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59 study designs (e.g., aerial line surveys versus aerial haulout count surveys) would benefit walrus conservation and management across the species’ range. All populations would also benefit from regular systematic surveys for trend assessment. Amongst Atlantic walruses, abundance trends for the Kara Sea - Southern Barents Sea – Novaya Zemlya (KS-SBS-NZ) population are considered positive (M. Gavrilo, pers. comm.), but no systematic surveys have been conducted. This should be a priority going forward. Recent surveys have been conducted for various parts of the range of the Canadian Central Arctic - West Greenland (CCA-WG) population (Elliott et al. 2013; Heide-Jørgensen et al. 2014; R.E.A. Stewart et al. 2014c; Hammill et al. 2016b), but a lack of understanding of seasonal distribution and potential movements between sub-areas (see above) leads to uncertainty in estimates of population size. Surveys of the entire range could be conducted, using multiple crews to reduce potential biases introduced by animal movement. For Pacific walruses, data on abundance from the Laptev Sea are needed, so trends can be monitored in relation to industrial development, pollution, and climate change. The ability of walruses to re-colonize areas where populations have been depleted or extirpated is not known. Large-scale studies of walrus movements (e.g., satellite-tagging) and population genetics (see below) could provide relevant information. The rarity of Atlantic walruses along the Atlantic coast of Canada since the Nova Scotia-Newfoundland-Gulf of St Lawrence population was extirpated in the 1850s suggests that re-colonization would be exceedingly slow at best, however. Genetic relationships Genetic research can help answer numerous research questions, including those of relevance to other identified categories (e.g., Abundance, distribution, and movements, above). At the species level, research on circumpolar population genetic patterns can provide valuable information on historic diversity, abundance (e.g., effective population size), and the evolution of subspeciesand population-level differentiation. Among Atlantic walruses, there is a lack of genetic data from the Canadian Low Arctic (CLA) population, an important knowledge gap. If these animals are genetically distinct it will be important to retain their genetic adaptive potential as they represent the most southerly remaining population in a period of climatic change (see below). Genetic relationships between walruses in the Svalbard-Franz Josef Land (S-FJL) population and those in Novaya Zemlya and the Pechora and Kara seas in the southeastern Barents Sea (KS-SBS-NZ population) are unknown (Boltunov et al. 2010; Lydersen et al. 2012; Lydersen and Kovacs 2014; Shitova et al.
60 2014a, b; Lindqvist et al. 2016). The genetic placement of these walruses in relation to other Atlantic walruses should be a top research priority. These data should be used to delineate where in the Russian Arctic the separation between the Atlantic and Pacific walrus subspecies occurs. Further research on stock structure in the BCS population of Pacific walruses is also needed (Garlich-Miller et al. 2011; USFWS 2014). Mortality (anthropogenic and natural) Hunting by humans is the greatest known cause of mortality in most areas of walrus range within Canada, Greenland, Russia and the United States. The hunting mortality that the different Atlantic walrus and Pacific walrus populations can sustain is not known. In all areas where walruses are legally harvested, removal rates are uncertain due to uncertainties in the reported harvest. This is due to factors such as reporting bias and lack of systematic data collection effort. Even where extensive data on harvests are available, the proportion of the population being harvested is typically uncertain due to biased population estimates. These uncertainties are further compounded by significant uncertainty in struck and loss rates (animals injured or killed but not secured) (D.B. Stewart et al. 2014a). There are few estimates for loss rates in subsistence hunts, and none are recent. Accurate seasonal and habitat specific (e.g., land-based, and over deep and shallow water) data on struck and lost rates are needed for all hunted populations. For populations that are not legally harvested (e.g., KS-SBS-NZ population of Atlantic walruses; LVS population of Pacific walruses), data on illegal removals (poaching) would be of value. However, the collection of data needed to understand abundance and distribution should take precedence. The natural survival rate of walruses is thought to be high, due to their low reproductive rate and long life span, but this has not been directly estimated (Taylor and Udevitz 2015). Rigorous survival rate estimates do not exist for any population. Lack of this information increases uncertainty in important population management tools used to predict demography, estimate abundance, and calculate total allowable removals. Rates of walrus predation by polar bears and killer whales are not well known, nor are rates of natural mortality from sources such as disturbance, which can stampede walruses causing trampling mortality. Efforts to study and monitor walrus behaviour at haulouts (see below) can provide important data on disturbances. Mortality rates from pathogens and parasites are generally unknown. The susceptibility of walruses to viral and bacterial diseases is poorly understood for both subspecies (e.g., Nielsen et al. 2000, 2001a, 2001b, 2004; Calle et al. 2002; Phillipa et al 2004). Research could improve understanding of potential risk to populations from
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REPORT © Mikhail Cherkasov / WWF-R
Page 3 and 4:
2 ABSTRACT The walrus (Odobenus ros
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4 PURPOSE AND SCOPE The WWF Arctic
Page 7 and 8:
6 beginning ca. 50,000 yBP that lim
Page 9 and 10: 8 Walruses from the Foxe Basin stoc
Page 11 and 12: 10 al. 2003). These differences coi
Page 13 and 14: 12 under favourable environmental c
Page 15 and 16: 14 appeared to be male. Crude measu
Page 17 and 18: 16 comparable data for proper asses
Page 19 and 20: 18 (Fay 1982). The walruses that ar
Page 21 and 22: 20 A joint U.S.-Russia survey, with
Page 23 and 24: 22 for the conservation of walruses
Page 25 and 26: 24 provisions for walrus protection
Page 27 and 28: 26 northwestern and northeastern Gr
Page 29 and 30: 28 Franz Josef Land was discovered
Page 31 and 32: 30 USFWS 2014). The population is c
Page 33 and 34: 32 they return from hunting trips (
Page 35 and 36: 34 The USFWS has also developed gui
Page 37 and 38: 36 how many walruses are represente
Page 39 and 40: 38 (www.iucn.org/about/). The IUCN
Page 41 and 42: 40 Atlantic Walruses In Canada, the
Page 43 and 44: 42 Pacific walruses The primary sou
Page 45 and 46: 44 Foxe Basin (BIMC 2012). It has b
Page 47 and 48: 46 define shipping channels, season
Page 49 and 50: 48 Alaska may be a successful manag
Page 51 and 52: 50 of the population (Born et al. 1
Page 53 and 54: 52 In the Bering and Chukchi seas,
Page 55 and 56: 54 Garlich-Miller et al. (2011) ass
Page 57 and 58: 56 Hamilton et al. (2014) assessed
Page 59: 58 Canadian High Arctic - Northwest
Page 63 and 64: 62 reproduction and survival rates,
Page 65 and 66: 64 Jurisdictions with walrus popula
Page 67 and 68: 66 REFERENCES Allen, J.A. 1880. His
Page 69 and 70: 68 Boertmann, D., A. Mosbech, D. Sc
Page 71 and 72: 70 Chernook, V.I., C. Lydersen, D,M
Page 73 and 74: 72 Durner, G.M., D.C. Douglas, R.M.
Page 75 and 76: 74 Galicia, M.P., G.W. Thiemann, M.
Page 77 and 78: 76 Environmental Ltd., Edmonton AB
Page 79 and 80: 78 Collection of scientific papers
Page 81 and 82: 80 University of Guelph, Ontario, C
Page 83 and 84: 82 Noren S.R., M.S. Udevitz, and C.
Page 85 and 86: 84 Phillipa, J.D.W., F.A. Leighton,
Page 87 and 88: 86 Shitova M., M. Babushkin, A. Bol
Page 89 and 90: 88 Swenson, J.E., A. Bjørge, K. Ko
Page 91 and 92: 90 Witting, L. and E. Born. 2014. P
Page 93 and 94: 92 Figure 2. Atlantic walruses in F
Page 95 and 96: Figure 4. Map of Atlantic walrus po
Page 97 and 98: TABLES Table 1. Assessment of Atlan
Page 99 and 100: 98 Population 1 Stock or area 2 Sto
Page 101 and 102: 100 Table 2. Assessment of Pacific
Page 103 and 104: 102 Table 3. Conservation status of
Page 105 and 106: 104 Table 4. Summary of primary wal
Page 107 and 108: 106 Country Subspecies Hunt managem
Page 109 and 110: 108 Country Subspecies Hunt managem
Page 111 and 112:
110 Country Subspecies Hunt managem
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112 Subspecies Population 1 Knowled
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114 Subspecies Population 1 Knowled
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The State of Circumpolar Walrus Populations

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