Walrus <i>Odobenus rosmarus</i> research in Svalbard, Norway, 2000-2010

Abstract

<p class="MsoNormal" style="text-align: justify;"><span style="font-size: 10.0pt;" lang="EN-US">Herein we report results from studies on walruses in Svalbard conducted in 2000-2010.</span><span style="font-size: 10.0pt; mso-ansi-language: EN-GB;"> Data from newly developed satellite relay data loggers (SRDLs) </span><span style="font-size: 10.0pt;" lang="EN-US">revealed seasonal differences in habitat use of adult male walruses. During winter, </span><span style="font-size: 10.0pt; mso-ansi-language: EN-GB;">they</span><span style="font-size: 10.0pt;" lang="EN-US"> moved into areas of >90% ice concentration, traveling as far as 600 km from ice-free water. Breeding areas deep into the pack ice were identified based on timing of the occupancy and diving behaviour. When the breeding season was over, walruses with SRDLs that were still transmitting locations returned to the coast, showing high site fidelity to the previous year&rsquo;s summering area. Haul-out data from the SRDLs provided correction factors for an aerial survey of walruses that covered all known haul-out sites within the Svalbard Archipelago. This survey estimated 2,629 (95 % CI; 2,318 &ndash; 2,998) walruses to be in Svalbard during August 2006. Blubber biopsies from adult male walruses analyzed for fatty acids (FAs) showed vertical stratification similar to that observed in many other marine mammals. However, differences between layers were less pronounced, possibly because the thick dermis of walruses provides an insulating shield, affecting the FA composition of the outer blubber. The FA composition of the inner blubber most closely resembled the lipids in <em>Mya truncata </em>and <em>Buccinum</em> spp., which are considered the most important walrus prey in Svalbard. A study investigating the use of skin biopsies for assessing levels of organochlorines (OCs) in walruses found a significant relationship between OC levels in skin and blubber. Another contaminant study found a significant decrease in levels of PCBs and DDE in walruses in Svalbard from 1993 to 2002-04. Large inter-individual variation in OC levels was found, although all of the study animals were adult males from roughly the same location. In FA analyses of the inner blubber this variation appeared to be diet-related, with high OC levels having FA compositions in the inner blubber that closely matched seal tissues, while those with low levels matched typical invertebrate prey. Various enzymes, proteins, metabolites, minerals, and hormones were measured in blood samples to serve as baseline data for future health-related studies of both wild and captive walruses. Historical sex-distribution of walruses in southern Svalbard was investigated based on mandible measurements of individuals hunted during the 19^th century.</span><span style="font-size: 10.0pt; mso-ansi-language: EN-GB;">The analyses showed that female walruses were once more common in south-eastern Svalbard than they are today.</span></p

Genetic diversity of historical Atlantic walruses (Odobenus rosmarus rosmarus) from Bjørnøya and Håøya (Tusenøyane), Svalbard, Norway

“…Various studies on the distribution [ 8 , 13 ], and movement patterns [ 14 – 16 ], as well as population structure [ 17 – 19 ] have shown that the walruses in Svalbard and Franz Josef Land belong to the same population. In the summer months most males stay in Svalbard and most females and calves remain in the northeastern parts of Svalbard and in Franz Josef Land.…”

“…Migration between the Svalbard–Franz Josef Land population and the neighboring population in East Greenland is thought to be rare. The relationship between the Svalbard–Franz Josef Land population and walruses in Novaya Zemlya and the Pechora and Kara Seas in the southeastern Barents Sea remains unknown [ 1 , 16 , 20 , 21 ].…”

Conservation of rare species of marine flora and fauna of the Russian Arctic National Park, included in the Red Data Book of the Russian Federation and in the IUCN Red List

“…4, 5), относятся к восточно-атлантической метапопуляции, распространенной от Шпицбергена до Новой Земли и юго-востока Баренцева моря, а также, очевидно, доходящей на восток до Северной Земли . Моржи ЗФИ и Шпицбергена образуют единое стадо Lydersen & Kovacs, 2013), причем на Шпицбергене летом сосредотачиваются преимущественно самцы, в то время как самки и молодые животные держатся восточнее, основная масса -в районе ЗФИ и о. Виктория . Единство группировки было доказано спутниковым мечением �reitas et al, 2010).…”

“…Исследования моржей на территории ЗФИ в 1990-х гг. проводили норвежские специалисты (Gjertz et al, , 1998Knutsen, 1992), ряд сведений о распределении моржей на ООПТ было получено от животных, меченых на Шпицбергене (Lydersen & Kovacs, 2013). В настоящее время парк сотрудничает с Советом по морским млекопитающим, специалисты которого выполнили на ООПТ в 2016 г. ряд работ по мечению моржей, изучению их кормовой базы, популяционной экологии.…”

“…Здесь сосредоточена значительная часть восточно-атлантической метапопуляции подвида. Показаны широкие миграционные связи моржей, обитающих на ООПТ, со Шпицбергеном и Печорским морем �reitas et al, 2010;Lydersen & Kovacs, 2013;Семенова и др., 2015). По полученным предварительным оценкам численность моржей в районе кластера ЗФИ восстанавливается и приближается к предпромысловой.…”