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Øystein Wiig - One of the best experts on this subject based on the ideXlab platform.
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MOESM3 of Genetic diversity of historical Atlantic Walruses (Odobenus rosmarus rosmarus) from Bjørnøya and Håøya (Tusenøyane), Svalbard, Norway
2016Co-Authors: Charlotte Lindqvist, Øystein Wiig, Christian Lydersen, Tilottama Roy, Kit Kovacs, Jon Aars, Lutz BachmannAbstract:Additional file 3. Aligned nucleotide sequences of the mitochondrial control region (CR) obtained from historical Walrus samples. Reference sequences from other Atlantic Walrus samples obtained from GenBank are included
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MOESM2 of Genetic diversity of historical Atlantic Walruses (Odobenus rosmarus rosmarus) from Bjørnøya and Håøya (Tusenøyane), Svalbard, Norway
2016Co-Authors: Charlotte Lindqvist, Øystein Wiig, Christian Lydersen, Tilottama Roy, Kit Kovacs, Jon Aars, Lutz BachmannAbstract:Additional file 2. Aligned nucleotide sequences of the mitochondrial NADH dehydrogenase 1 (ND1) obtained from historical Walrus samples. Reference sequences from other Atlantic Walrus samples obtained from GenBank are included
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MOESM1 of Genetic diversity of historical Atlantic Walruses (Odobenus rosmarus rosmarus) from Bjørnøya and Håøya (Tusenøyane), Svalbard, Norway
2016Co-Authors: Charlotte Lindqvist, Øystein Wiig, Christian Lydersen, Tilottama Roy, Kit Kovacs, Jon Aars, Lutz BachmannAbstract:Additional file 1. Aligned nucleotide sequences of the mitochondrial cytochrome c oxidase 1 (COI) obtained from historical Walrus samples. Reference sequences from other Atlantic Walrus samples obtained from GenBank are included
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MOESM4 of Genetic diversity of historical Atlantic Walruses (Odobenus rosmarus rosmarus) from Bjørnøya and Håøya (Tusenøyane), Svalbard, Norway
2016Co-Authors: Charlotte Lindqvist, Øystein Wiig, Christian Lydersen, Tilottama Roy, Kit Kovacs, Jon Aars, Lutz BachmannAbstract:Additional file 4: Table S1. List of Walrus mitochondrial control region (CR) sequences downloaded from GenBank
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Management of Atlantic Walrus (Odobenus rosmarus rosmarus) in the arctic Atlantic
NAMMCO Scientific Publications, 2014Co-Authors: Øystein Wiig, Erik W. Born, Robert E. A. StewartAbstract:We review the management of Atlantic Walruses ( Odobenus rosmarus rosmarus ) past and present in the four range states—Canada, Greenland, Norway and Russia—which have permanent populations of Atlantic Walruses. Populations in all four countries have been depleted, although the extent of depletion is not well known. Inuit in Arctic Canada and Greenland hunt Atlantic Walruses for subsistence while they have been protected at Svalbard (Norway) since 1952 and in the western Russian Arctic since 1956. Since the second half of the 20 th Century Canada and Greenland have increased protection of their Walrus. Generally the number of Walruses landed in Canada is governed by the number of hunters and/or people in the settlement and not by stock-specific quotas. Although quotas have been set in few communities, it is not known if they are adequate to prevent overhunting. A quota system for Walrus hunting in Greenland began in 2006. The current control system is largely effective in ensuring the quotas are applied and that reporting is correct. Greenland currently sets quotas based on recommendations from scientific assessments using recent population estimates to allow population growth from a depleted population. A challenge with respect to managing Walrus hunting remains the variable and sometimes high rates of lost animals. Since the 1960s changes in socio-economics in hunting areas of Arctic Canada and Greenland (and the use of snowmobiles instead of dog sleds in Canada) have led to a general decrease in interest in hunting of Walruses and reduced harvest on Walrus stocks in these countries. Although there is an active ongoing cooperation between Canada and Greenland scientists regarding assessments of shared populations of Walruses currently there is no formal agreement between the two range states on co-management of shared stocks. Protection of Walrus from other anthropogenic impacts generally focusses on large-scale industrial activity. The level of protection afforded to Walrus habitat in many areas depends entirely on the rigor with which the Environmental Impact Assessments are conducted. Basic information on Walrus such as numbers and stock discreteness is often lacking and sufficient lead-time is required to collect baseline data. Moreover, although most environmental protection legislation considers ‘cumulative impacts’, practical application remains problematic. The effectiveness of environmental protection regulations depends on industry compliance and the management authorities’ ability to enforce compliance. Because Walrus are found in remote locations, enforcement remains a challenge. Increased human activity allowed by the current change in distribution and quality of arctic sea ice poses new threats to Walrus if not well regulated. International agreements have varying importance for management within and among member states. Regulations governing international trade serve to identify illegally obtained products and to encourage range states to have a sustainable quota system. International cooperation in information sharing has had clear benefits for management of Walruses in the past. The maintenance and expansion of these international efforts will improve the management of Atlantic Walruses in the future.
R E A Stewart - One of the best experts on this subject based on the ideXlab platform.
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Stock discrimination of Atlantic Walrus (Odobenus rosmarus rosmarus) in the eastern Canadian Arctic using lead isotope and element signatures in teeth
Canadian Journal of Fisheries and Aquatic Sciences, 1999Co-Authors: P. M. Outridge, R E A StewartAbstract:Atlantic Walrus (Odobenus rosmarus rosmarus) harvested from three regions of the Canadian Arctic, and by different communities within two of those regions, were distinguished using the stable Pb isotope or trace element composition of their tooth cementum. Walrus from Foxe Basin (Igloolik, Hall Beach), the High Arctic (Grise Fiord, Resolute Bay), and eastern Hudson Bay (Akulivik, Inukjuak) were each characterized by specific combinations of Pb isotope ratios and Co concentrations, and we conclude that they represent different regional stocks. Walrus landed at Akulivik and Inukjuak were further discriminated by significant differences in 208Pb/207Pb, even though the communities are only 250 km apart. There was more overlap between Walrus from Igloolik and Hall Beach, which are 80 km apart, but significant differences between sites in Pb isotope ratios and in concentrations of V, Zn, and Mo suggested that more than one Foxe Basin stock was being harvested. Particularly at Hall Beach, the herds contained a f...
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summer foods of atlantic Walrus odobenus rosmarus rosmarus in northern foxe basin northwest territories
Canadian Journal of Zoology, 1997Co-Authors: K. I. Fisher, R E A StewartAbstract:Stomach contents of Atlantic Walrus, Odobenus rosmarus rosmarus, taken by Inuit hunters in northern Foxe Basin in July 1987 and 1988 (n = 105) and September 1988 (n = 2) were examined. In July, 20 of 94 stomachs from immature and adult Walrus contained > 5 g of food representing 17 prey taxa, including bivalves, gastropods, holothurians, polychaetes, and brachiopods. The bivalve Mya truncata contributed 81.4% of the total gross energy in the diet, with the bivalve Hiatella arctica, holothurians, and the polychaete Nereis sp. contributing 7.5, 3.5, and 2.8%, respectively. The diets of male and female Walrus were similar except that females received a significantly (P < 0.05) greater percentage of gross energy in their diet from H. arctica than did males. Walrus less than 3 years old (n = 11) consumed mostly milk, although some benthic invertebrates were eaten. Analysis of the contents of two stomachs collected in September suggested that Walrus may feed more intensively in the fall. Mya truncata was again ...
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can seal eating explain elevated levels of pcbs and organochlorine pesticides in Walrus blubber from eastern hudson bay canada
Environmental Pollution, 1995Co-Authors: Derek C G Muir, Mark D Segstro, Keith A Hobson, C A Ford, R E A Stewart, S OlpinskiAbstract:Walrus (Odobenus rosmarus) blubber samples from Inukjuak and Akulivik (East Hudson Bay), Foxe Basin (Igloolik and Hall Beach) and Loks Land (East Baffin Island) were analysed for PCB congeners (ortho and non-ortho substituted) and other persistent organochlorines (DDT, toxaphene, chlordanes, dieldrin, mirex), as well as chlorinated dioxins/furans, to document spatial trends in contaminants in Canadian Arctic marine biota. Samples from 19 of 53 individuals had concentrations of ΣPCBs greater than 1000 ng g−1 (wet wt); the remaining individuals had much lower concentrations (50–600 ng g−1). Highest concentrations were found in samples from Inukjuak where average concentrations in blubber of females (N = 9) were 1450 ± 954 ng g−1 toxaphene, 2750 ± 1780 ng g−1 ΣCHLOR, 2160 ± 925 ng g−1 ΣDDT and 4790 ± 2380 ng g−1 ΣPCB. ΣPCB and ΣDDT concentrations greater than 1000 ng g−1 were unexpected based on previous studies of Walrus from Greenland and Alaska. Local contamination was ruled out because levels of all organochlorines were elevated in each animal from Inukjuak, and elevated levels were also found in animals from Akulivik and Loks Land. Walrus from Inukjuak had δ13C and δ15N values in muscle intermediate between those of ringed seals (Phoca hispida) and those of Walrus from Akulivik with low organochlorine levels. There was a weak but significant correlation between and δ15N and (log)ΣPCB. The Inukjuak Walrus also had higher proportions of highly chlorinated PCB congeners, and higher DDE/ΣDDT ratios than Walrus from Igloolik or Akulivik. The results suggest that the Walrus with elevated organochlorines are feeding at a higher trophic level than those with low levels and are probably utilizing ringed seals for a portion of their diet.
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Concentrations of Heavy Metals and Selenium in Tissues and Some Foods of Walrus (Odobenus rosmarus rosmarus) from the Eastern Canadian Arctic and Sub-Arctic, and Associations between Metals, Age, and Gender
Canadian Journal of Fisheries and Aquatic Sciences, 1994Co-Authors: R. Wagemann, R E A StewartAbstract:Atlantic Walrus (Odobenus rosmarus rosmarus) harvested at Igloolik and Hall Beach (Foxe Basin) and Inukjuak and Akulivik (eastern coast of Hudson Bay) and clams (Mya truncata) and cockles (Serripes groenlandicus) collected at Igloolik were analyzed for heavy metals and Se. Pb was high in Walrus from both Hudson Bay and Foxe Basin compared with other marine mammals, but levels were higher in animals from Hudson Bay than Foxe Basin, showing a geographic trend of increasing concentration from north to south. In some tissues of clams, Pb was also high, up to 3 μg/g (wet weight). Hg levels in Walrus were low compared with those in other Arctic marine mammals; in liver, Hg showed a geographic trend similar to Pb. Cd in liver and particularly in kidney of Walrus was high compared with other Arctic marine mammals and was higher in those from Foxe Basin than Hudson Bay. Associations among metals and between metals and age were found in Walrus that were also reported for other marine mammals, namely between Hg and ...
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Comparison of mandibular with cemental growth-layer counts for ageing Atlantic Walrus (Odobenus rosmarus rosmarus)
Canadian Journal of Zoology, 1993Co-Authors: J. L. Garlich-miller, R E A Stewart, B. E. Stewart, E. A. HiltzAbstract:The relationship between the numbers of growth layers counted in the mandible and in the cementum of lower canines from 87 Walrus (Odobenus rosmarus rosmarus) was examined. A 1:1 correlation between counts of growth layers in the two tissues was found in males ≤ 19 years old and females ≤ 9 years old. No correlation was found in males with ≥ 21 or in females with ≥ 10 cemental growth layers. In physically mature Walrus, mandibular layering was unreliable for age analysis. Resorption and a reduced mandibular growth rate appear to be the main factors limiting mandibular age estimates in mature Walrus.
Ian Gjertz - One of the best experts on this subject based on the ideXlab platform.
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historical sex specific distribution of atlantic Walrus odobenus rosmarus rosmarus in svalbard assessed by mandible measurements
Polar Biology, 2007Co-Authors: Øystein Wiig, Erik W. Born, Ian Gjertz, Christian Lydersen, R StewartAbstract:We developed a discriminant function based on measurements of known-sex mandibles of Walrus from the Canadian Arctic collected between 1983 and 1998 and used it to explore the sex ratio in the catches of Walrus in Tusenoyane, south-eastern Svalbard, during the nineteenth century. Canadian mandibles older than 5 years of age of known sex were classified into correct sex with 100% accuracy by using two measurements. Applying the same discriminant function to 80 mandibles from Svalbard older than 5 years of age classified 48 (60%) as males and 32 (40%) as females. It also classified 584 aged and un-aged mandibles from Svalbard 67% (390) as males and 33% (194) as females. Eight of the aged jaws (10%) and 41 (7%) of the un-aged jaws had probabilities of classification into sex <80%. We stress the importance of being cautious in applying a discriminant function developed from Canadian mandibles to classify the sex of old weathered mandibles from Svalbard. However, we believe our results indicate that female Walrus were once more common in south-eastern Svalbard than they are now.
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Backcalculation of original population size for Walruses Odobenus rosmarus in Franz Josef Land
Wildlife Biology, 1998Co-Authors: Ian Gjertz, Øystein Wiig, Nils Are ØritslandAbstract:Walrus Odobenus rosmarus hunting was conducted for hundreds of years in large parts of the European Arctic. Catch statistics are incomplete, or non-existent, and it is therefore difficult to determine the original population numbers for the different geographical areas. One exception is the Russian archipelago Franz Josef Land. These islands were discovered in 1873, and large-scale Walrus hunting started there in the late 1890s and continued for four decades. It is therefore possible to estimate the minimum original population size based on catch statistics from Franz Josef Land for the last century. Using a simple population model backcalculation of the Franz Josef Land population to 1897 produces an estimate of 6,000–12,500 Walruses.
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Population structure and gene flow of the Atlantic Walrus (Odobenus rosmarus rosmarus) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation
Molecular ecology, 1998Co-Authors: Liselotte Wesley Andersen, Erik W. Born, Øystein Wiig, Ian Gjertz, Lars-erik Holm, Christian BendixenAbstract:The population structure of the Atlantic Walrus, Odobenus rosmarus rosmarus, was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 Walrus samples were analysed from northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of Walruses in this area is evolutionary distinct from Walruses in the other three areas. One individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific Walrus and Walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene flow (Nm) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land-Svalbard population, which were connected by moderate gene flow.
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Migration of Walruses (Odobenus rosmarus) in the Svalbard and Franz Josef Land area
Journal of Zoology, 1996Co-Authors: Øystein Wiig, Ian Gjertz, David GriffithsAbstract:Thirty-four Walruses (Odobenus rosmarus) were fitted with satellite transmitters (PTTs) from 1990 to 1993 in order to study the distribution of the population in the Svalbard area. Twenty-eight were caught at Svalbard and six at Franz Josef Land. All were males except one female caught at Franz Josef Land. At Svalbard, one Walrus was caught on the west coast of Spitsbergen, while the others were caught at southern Edgeoya. All Walruses were caught in the period from mid-July to early September. The PTTs provided information on location for periods ranging from 0 to 212 days. The results of the satellite trackings show that there is a migration of male Walruses between most of the Walrus areas at Svalbard and Franz Josef Land. In particular, it seems that migration of males from southern Edgeoya to Kvitoya, Viktoria Island, and Franz Josef Land is common. The Walruses winter in the southern parts of Svalbard, as well as within the winter pack-ice of north-eastern Svalbard, which contains numerous open leads. The only Walrus at Franz Josef Land that was followed to mid-winter stayed in the area and therefore supports the view that Walruses also winter in that area. It is assumed that the majority of Walruses at Svalbard are males from one common Svalbard-Franz Josef Land stock. The Walrus in the Svalbard-Franz Josef Land area today belong to a recovering population. Their current distribution and behaviour may therefore differ from that found in Svalbard in former times.
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IMMOBILIZATION OF Walrus WITH ETORPHINE HYDROCHLORIDE AND ZOLETIL
Marine Mammal Science, 1993Co-Authors: David Griffiths, Øystein Wiig, Ian GjertzAbstract:The Norwegian Polar Research Institute, Rolfstangveien 12, N-1330 Oslo Lufthavn, Norway IAN GJERTZ The Norwegian Polar Research Institute, N-9170 Longyearbyen, Norway ABSTRACT The paper describes the use of the drugs Zoletil@ and etorphine for the immobilization of Walrus (Odobenus rosmarus rosmarus) for attachment of satellite telemetry equipment. Three animals weighing approximately 1,500 kg each were injected intramuscularly with Zoletil@ at a dose between 1.4 and 2.2 mg/ kg. One Walrus died while the two others were adequately restrained. The induction time was between 14 and 29 minutes and the effect lasted for 75- 220 min. Thirty-eight animals of weight 900-1,500 kg were darted intramuscularly with etorphine at a dose between 3.3 and 8 mg/kg. Thirty-six were immobilized although one died later. The induction time for etorphine was two to ten minutes. The action of this drug was terminated with an injection of the antidote di- prenorphine. The use of etorphine was accompanied by convulsive movements and apnoea while Zoletil@ produced a gradual and smooth entry into and withdrawal from immobilization. Key words: Walrus, Odobenus rosmarus rosmarus immobilization, etorphine, Zo- letil @ , marine mammal, seal. Etorphine
Erik W. Born - One of the best experts on this subject based on the ideXlab platform.
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supplemented
2016Co-Authors: David Griffiths, Erik W. Born, Mario AcquaroneAbstract:Prolonged chemical restraint of Walrus (Odobenus rosmarus) with etorphin
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Creative Commons License
2016Co-Authors: David Griffiths, Erik W. Born, Mario AcquaroneAbstract:Prolonged chemical restraint of Walrus (Odobenus rosmarus) with etorphine supplemented with medetomidin
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Management of Atlantic Walrus (Odobenus rosmarus rosmarus) in the arctic Atlantic
NAMMCO Scientific Publications, 2014Co-Authors: Øystein Wiig, Erik W. Born, Robert E. A. StewartAbstract:We review the management of Atlantic Walruses ( Odobenus rosmarus rosmarus ) past and present in the four range states—Canada, Greenland, Norway and Russia—which have permanent populations of Atlantic Walruses. Populations in all four countries have been depleted, although the extent of depletion is not well known. Inuit in Arctic Canada and Greenland hunt Atlantic Walruses for subsistence while they have been protected at Svalbard (Norway) since 1952 and in the western Russian Arctic since 1956. Since the second half of the 20 th Century Canada and Greenland have increased protection of their Walrus. Generally the number of Walruses landed in Canada is governed by the number of hunters and/or people in the settlement and not by stock-specific quotas. Although quotas have been set in few communities, it is not known if they are adequate to prevent overhunting. A quota system for Walrus hunting in Greenland began in 2006. The current control system is largely effective in ensuring the quotas are applied and that reporting is correct. Greenland currently sets quotas based on recommendations from scientific assessments using recent population estimates to allow population growth from a depleted population. A challenge with respect to managing Walrus hunting remains the variable and sometimes high rates of lost animals. Since the 1960s changes in socio-economics in hunting areas of Arctic Canada and Greenland (and the use of snowmobiles instead of dog sleds in Canada) have led to a general decrease in interest in hunting of Walruses and reduced harvest on Walrus stocks in these countries. Although there is an active ongoing cooperation between Canada and Greenland scientists regarding assessments of shared populations of Walruses currently there is no formal agreement between the two range states on co-management of shared stocks. Protection of Walrus from other anthropogenic impacts generally focusses on large-scale industrial activity. The level of protection afforded to Walrus habitat in many areas depends entirely on the rigor with which the Environmental Impact Assessments are conducted. Basic information on Walrus such as numbers and stock discreteness is often lacking and sufficient lead-time is required to collect baseline data. Moreover, although most environmental protection legislation considers ‘cumulative impacts’, practical application remains problematic. The effectiveness of environmental protection regulations depends on industry compliance and the management authorities’ ability to enforce compliance. Because Walrus are found in remote locations, enforcement remains a challenge. Increased human activity allowed by the current change in distribution and quality of arctic sea ice poses new threats to Walrus if not well regulated. International agreements have varying importance for management within and among member states. Regulations governing international trade serve to identify illegally obtained products and to encourage range states to have a sustainable quota system. International cooperation in information sharing has had clear benefits for management of Walruses in the past. The maintenance and expansion of these international efforts will improve the management of Atlantic Walruses in the future.
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Estimates of Minimum Population Size for Walrus near Southeast Baffin Island, Nunavut
Septentrio Academic Publishing, 2014Co-Authors: Robert E. A. Stewart, Erik W. Born, Rune Dietz, Anna K RyanAbstract:To support management objectives in Canada and Greenland, joint research between the Department of Fisheries and Oceans and Greenland Institute of Natural Resources was begun in 2005. Direct counts were used to determine the Minimum Counted Population (MCP) in summer around SE Baffin Island. Aerial surveys examined the coast from roughly the Saddleback Island in northern Hudson Strait to Isabella Bay on eastern Baffin Island but concentrated on the area between Loks Land and Cape Dyer. The maximum count was obtained on 3–4 September 2007 during boat surveys. The MCP ranged from 716 (in 2006) to 1,056 (2007). Using the largest MCP adjusted with published maximum estimates of the proportion of Walrus hauled out concurrently, we estimated 1,420 (95% CI: 1,219–1,622) Walrus were present. In addition, four Walrus had been fitted with satellite relayed data logger tags prior to the maximum counts in 2007. Using the simple proportion of ‘tags dry’ on 3 September to adjust counts on 3 and 4 September 2007 provided an estimate of 2,102 (CI = MCP-4,482). Using the proportion of time dry immediately preceding the survey to adjust the maximum count produced an estimate of 2,502 (CI = 1,660–3,345) Walrus were present in Hoare Bay. We conclude approximately 2,100–2,500 Walrus were present in Hoare Bay in late summer 2007. This number is a negatively biased estimator of the population of Walrus around SE Baffin Island and in the Hudson Bay–Davis Strait stock as a whole. Broader survey coverage in a short period and more detailed information on the movement of Walrus between Greenland and Canada and the summer dispersal of these animals within Canada are required to improve population estimates
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use of multiple methods to estimate Walrus odobenus rosmarus rosmarus abundance in the penny strait lancaster sound and west jones sound stocks canada
Nammco Scientific Publications, 2013Co-Authors: Robert E. A. Stewart, Erik W. Born, Blair J Dunn, William R Koski, Anna K RyanAbstract:Surveys to estimate Walrus abundance at terrestrial haulout sites in the Penny Strait-Lancaster Sound (PS-LS) and West Jones Sound (WJS) stocks were conducted in 1977 and 1998-2009. The Minimum Counted Population (MCP) was similar in 1977 (565) to recent years (557) for the PS-LS stock. The MCP for the WJS stock was higher in recent surveys (404) than in 1977 (290). Regression analysis of MCP and density (number of Walrus divided by number of haulouts surveyed) showed no significant trends over time. We also calculated bounded count estimates for comparison. Finally, we used broad-scale behavioural data to estimate the proportion of the total stock that could be considered countable, to produce two adjusted estimates. We selected recent surveys with good coverage and ignored adjusted estimates that were lower than MCP. For the PS-LS stock, the adjusted MCP (with 95% CL) was 672 (575-768) and 727 (623-831) Walrus in 2007 and 2009, respectively. For WJS, the best estimates were the adjusted MCP of 503 (473-534) in 2008 and the adjusted bounded count of 470 (297-1732) in 2009. While both stocks appear to have remained stable over three decades, differences in survey coverage and possible differences in Walrus distribution make precise population estimation difficult.
Imran M Chaudry - One of the best experts on this subject based on the ideXlab platform.
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Walrus large bore guide catheter impact on recanalization first pass effect and outcomes the wicked study
Journal of NeuroInterventional Surgery, 2021Co-Authors: Gustavo M Cortez, Shahram Majidi, Raymond D Turner, Andre Monteiro, Ajit S Puri, Adnan H Siddiqui, J Mocco, Jan Vargas, Anna Luisa Kuhn, Imran M ChaudryAbstract:Background The use of a balloon-guide catheter (BGC) in acute stroke treatment has been widely adopted after demonstrating optimized procedure metrics and outcomes. Initial technical constraints of previous devices included catheter stiffness and smaller inner diameters. We aim to evaluate the performance and safety of the Walrus BGC, a variable stiffness catheter with a large bore 0.087 inch inner diameter (ID), via the the WICkED study (Walrus Large Bore guide Catheter Impact on reCanalization first pass Effect anD outcomes). Methods This is a retrospective, site adjudicated, multicenter study on consecutive patients with large vessel occlusion treated with the Walrus BGC. Baseline characteristics, procedural outcomes and functional outcomes were analyzed. Results A total of 338 patients met the inclusion criteria. The Walrus was successfully tracked into distal vasculature and allowed therapeutic device delivery in all but 3 cases (0.9%). Large aspiration catheters ≥0.070 inch ID were used in 71.9% of cases. Stent retriever thrombectomy was used as the first-line modality in 59.2% and thromboaspiration in 40.8% of cases. The successful recanalization rate (modified treatment in cerebral ischemia (mTICI) 2b/3) was 94.4%, with 64.8% of the patients achieving mTICI 2b/3 after the first pass. The Walrus-related adverse event rate was 0.6%, corresponding to two vessel dissections. Functional independence was 50% (126/252) and mortality 25% (63/252). Unfavorable outcomes were more likely in older patients, who had unsuccessful reperfusion, longer procedure times, and a higher mean number of passes. Conclusion In acute ischemic stroke patients presenting with large vessel occlusion, the Walrus BGC demonstrated excellent navigability and safety profile, allowed the accommodation of leading large bore aspiration catheters, and demonstrated high vessel recanalization rates.
