scholarly journals Population dynamics of walruses in Greenland

2014 ◽  
Vol 9 ◽  
pp. 191 ◽  
Author(s):  
Lars Witting ◽  
Erik Born
Keyword(s):  
Baffin Island ◽  
Continuous Increase ◽  
East Greenland ◽  
Baffin Bay ◽  
West Greenland ◽  
Structure Information ◽  
Abundance Estimate ◽  
Structured Population Models ◽  
Abundance Estimates ◽  
The 1960S

The historical and current dynamics of the three Atlantic walrus (Odobenus rosmarus rosmarus) populations that occur in Greenland are estimated using age- and sex-structured population models with exponential growth, density-regulated growth and selection-delayed dynamics. These models are integrated with data in a Bayesian framework, where the likelihood of the simulated population trajectories are evaluated from recent abundance estimates and age-structure information from a selective hunt. The overall decline in the Baffin Bay population caused by historical catches is unclear due to incomplete catch reporting prior to 1950s. However, it is estimated that the population declined by 40% from the 1960s to 2005; decreased catches (≈ 140 to ≈ 70) have subsequently allowed this population to increase. The 2012 abundance estimate is 1,400 (95% CI: 1,000-2,000) individuals, and the annual natural growth rate in this population is now 7.7% (95% CI: 6.7-8.9%). Averaging across models, it is estimated that West Greenland/Baffin Island walruses declined by 80% from 7,000 (95% CI: 5,400-10,000) in 1900 to 1,350 (CI: 950-1,950) in 1960. Hereafter they increased to 3,100 (95% CI: 2,500-4,400) in 1993, and owing to increased catches they have experienced a minor decline between 1994 and the early 2000s. Annual catches where then cut from 190 to the current quota of 61, and the population is again increasing with a 2012 estimate of 3,900 (95% CI: 2,500-5,300) individuals. A 2012 estimate of 1,400 (95% CI: 700-3,100) walruses in East Greenland is recovered relative to 1888; the year prior to our first historical catches by European sealers. The historical trajectory, however, is uncertain: Density regulation estimates a relatively flat trajectory, with a maximal depletion in 1890 to 80% of the initial abundance, and a slow continuous increase to almost no current growth. A recovered population is also estimated by selection-delayed dynamics. However, this model estimates a continued increase, and a historical depletion to 2% in 1957. These results are only partially comparable with an earlier assessment for East Greenland. Updated abundance estimates for West Greenland, and modelling with age-structured data from Baffin Bay, have greatly improved our status estimates for Baffin Bay and West Greenland/Baffin Island.

scholarly journals An assessment of Greenland walrus populations

2005 ◽  
Vol 62 (2) ◽  
pp. 266-284 ◽  
Author(s):  
Lars Witting ◽  
Erik W. Born
Keyword(s):  
Protective Measures ◽  
East Greenland ◽  
Baffin Bay ◽  
West Greenland ◽  
Population Dynamic Model ◽  
The North ◽  
Structured Population ◽  
Abundance Estimates ◽  
North Water ◽  
A Current

AbstractRecent abundance estimates were combined with historical catches and an age- and sex-structured population dynamic model to perform Bayesian assessments of the walrus (Odobenus rosmarus) populations in West Greenland, the North Water in northern Baffin Bay, and East Greenland. The model assumed density-regulated dynamics and pre-harvest populations in population-dynamical equilibrium. It projected the populations under the influence of the catches to estimate the historical trajectories and the current population status. It was found that the West Greenland and North Water populations have been heavily exploited during the last century with the current abundance being at best only a few per cent of the historical abundance. Apparently these populations are still being exploited above sustainable level. The East Greenland population was heavily exploited after 1889 and during the first half of the 20th century and was depleted to approximately 50% of pristine population size in 1933. After protective measures were introduced in the 1950s this population has increased to a current level close to the abundance in 1889, and the present exploitation appears to be sustainable.

An Index of the Relative Abundance of Wintering Belugas, Delphinapterus leucas, and Narwhals, Monodon monoceros, off West Greenland

1993 ◽  
Vol 50 (11) ◽  
pp. 2323-2335 ◽  
Author(s):  
M. P. Heide-Jørgensen ◽  
H. Lassen ◽  
J. Teilmann ◽  
R. A. Davis
Keyword(s):  
Relative Abundance ◽  
Delphinapterus Leucas ◽  
Late Winter ◽  
The West ◽  
Baffin Bay ◽  
West Greenland ◽  
Abundance Estimate ◽  
Monodon Monoceros ◽  
Pack Ice ◽  
Ice Conditions

Systematic aerial surveys of the wintering grounds of belugas, Delphinapterus leucas, and narwhals, Monodon monoceros, in southern Baffin Bay and northern Davis Strait were conducted in late winter of 1981, 1982, 1990, and 1991. Most belugas were found between 67°N and 69°N and none were seen more than 80 km off the coast of West Greenland. Compared with the surveys in 1981 and 1982, a decline in relative abundance of belugas along West Greenland was evident in 1991. This decline was significant at a probability level of 0.13 of the bootstrapped distribution of the combined abundance estimate. Pod sizes declined significantly between the 1981–82 and 1990–91 surveys. The variations in ice conditions between years did not seem to affect the distribution, clumping, or pod sizes of the belugas. Narwhals were widely distributed in the close pack ice offshore between 65°N and 72°N. Along the West Greenland coast, narwhals were primarily seen at the mouth of Disko Bay. No change in relative abundance or pod sizes could be detected for narwhals.

scholarly journals Early Tertiary, low-potassium tholeiites from exploration wells on the West Greenland shelf

1987 ◽  
Vol 136 ◽  
pp. 1-25
Author(s):  
N Hald ◽  
J.G Larsen
Keyword(s):  
Baffin Island ◽  
Quaternary Sediments ◽  
The South ◽  
The West ◽  
Baffin Bay ◽  
West Greenland ◽  
Early Tertiary ◽  
Davis Strait ◽  
Low Potassium

Data on the Tertiary basalts in the Davis Strait region are reported from two exploration wells drilled by Arco and Mobil on the West Greenland shelf. Hellefisk 1 (67°53 'N, 56°44'W), situated only 60 km east of the mid-line in Davis Strait, penetrated the upper 690 m of a subaeriallava sequence continuous with the onshore volcanics of Disko and situated beneath 2.3 km of Paleocene to Quaternary sediments. The lavas are feldspar microporphyritic tholeiites and mostly unmetamorphosed despite the presence of laumontite and prehnite in the vesicular top zones. Nukik 2 (65°38'N, 54°46'W) penetrated 150 m of hyaloclastites and tholeiitic olivine dolerite sheets, presumably sills, some 200 km further to the south. These vo1canics are also deeply buried and are of unknown extension. The drilled rocks, except for the much altered hyaloclastites in the Nukik 2 well, have low contents of Ti02 (0.99-2.03%), K2O (0.09-0.18%) and P2O5 (0.08-0.21%), La/Sm ratios less than one and 87Sr/86Sr ratios of 0.7032 to 0.7044. Chemically they are related to the MORB-like picrites of Baffin Island rather than the less depleted tholeiites of West Greenland. In both areas the MORB affinity may be related to eruptions through a strongly attenuated lithosphere associated with the opening of Baffin Bay and Davis Strait.

scholarly journals Abundance of whales in West and East Greenland in summer 2015

2019 ◽  
Vol 11 ◽  
Author(s):  
Rikke Guldborg Hansen ◽  
Tenna K. Boye ◽  
Rasmus S. Larsen ◽  
Nynne H. Nielsen ◽  
Outi Tervo ◽  
...  
Keyword(s):  
Shelf Break ◽  
Estimation Methods ◽  
Baleen Whale ◽  
Pilot Whale ◽  
East Greenland ◽  
West Greenland ◽  
Minke Whales ◽  
Abundance Estimates ◽  
Recent Climate ◽  
Pilot Whales

An aerial line transect survey of whales in West and East Greenland was conducted in August-September 2015. The survey covered the area between the coast of West Greenland and offshore (up to 100 km) to the shelf break. In East Greenland, the survey lines covered the area from the coast up to 50 km offshore crossing the shelf break. A total of 423 sightings of 12 cetacean species were obtained and abundance estimates were developed for common minke whale, (Balaenoptera acutorostrata) (32 sightings), fin whale (Balaenoptera physalus) (129 sightings), humpback whale (Megaptera novaeangliae) (84 sightings), harbour porpoise (Phocoena phocoena) (55 sightings), long-finned pilot whale, (Globicephala melas) (42 sightings) and white-beaked dolphin (Lagenorhynchus albirostri) (50 sightings). The developed at-surface abundance estimates were corrected for both perception bias and availability bias if possible. Data on surface corrections for minke whales and harbour porpoises were collected from whales instrumented with satellite-linked time-depth-recorders. Options for estimation methods are presented and the preferred estimates are: minke whales: 5,095 (95% CI: 2,171-11,961) in West Greenland and 2,762 (95% CI: 1,160-6,574) in East Greenland, fin whales: 2,215 (95% CI: 1,017-4,823) in West Greenland and 6,440 (95% CI: 3,901-10,632) in East Greenland, humpback whales: 993 (95% CI: 434-2,272) in West Greenland and 4,223 (95% CI: 1,845-9,666) in East Greenland, harbour porpoises: 83,321 (95% CI: 43,377-160,047) in West Greenland and 1,642 (95% CI: 319-8,464) in East Greenland, pilot whales: 9,190 (95% CI: 3,635-23,234) in West Greenland and 258 (95% CI: 50-1,354) in East Greenland, white-beaked dolphins 15,261 (95% CI: 7,048-33,046) in West Greenland and 11,889 (95% CI: 4,710-30,008) in East Greenland. The abundance of cetaceans in coastal areas of East Greenland has not been estimated before, but the limited historical information from the area indicates that the achieved abundance estimates were remarkably high. When comparing the abundance estimates from 2015 in West Greenland with a similar survey conducted in 2007, there is a clear trend towards lower densities in 2015 for the three baleen whale species and white-beaked dolphins. Harbour porpoises and pilot whales, however, did not show a similar decline. The decline in baleen whale and white-beaked dolphin abundance is likely due to emigration to the East Greenland shelf areas where recent climate driven changes in pelagic productivity may have accelerated favourable conditions for these species.

Paleomagnetic Results on Early Tertiary Lava Flows from West Greenland and their bearing on the Evolution History of the Baffin Bay–Labrador Sea Region

1975 ◽  
Vol 12 (1) ◽  
pp. 1-18 ◽  
Author(s):  
R. N. Athavale ◽  
P. V. Sharma
Keyword(s):  
Pole Position ◽  
Ocean Basin ◽  
Lava Flows ◽  
Labrador Sea ◽  
Baffin Island ◽  
Baffin Bay ◽  
West Greenland ◽  
Early Tertiary ◽  
History Of ◽  
The One

Paleomagnetic investigations have been carried out on about 250 oriented block samples collected from Early Tertiary lava flows representing an altitude span of about 1200 m on the Disko Island and 600 m on the Nûgssuaq Peninsula of West Greenland. The results reveal a record of two polarity transitions on the Disko Island and the existence of normal (N) and reverse (R) groups of lava flows on the Nûgssuaq Peninsula. A tentative correlation of the lava sequences from the two areas, on the basis of polarity of magnetization, has been suggested. Subject to the assumption of relatively uniform extrusion rates in northern Disko, a correlation of the comparatively thick sequence of reverse (R) polarity flows with the relatively long reverse epoch between the anomaly no. 25 (ca. 63 m.y.) and anomaly no. 24 (ca. 60.5 m.y.B.P.), has been attempted and an age estimate of the lava flows has been obtained.The Early Tertiary paleomagnetic pole for Greenland, computed from stable remanent magnetic directions of the Disko lavas is located at 67.5 °N and 165 °W. This pole position and the one for contemporaneous lava flows on the Baffin Island of Canada have been used in testing the models proposed by various workers for a paleogeographic reconstruction of Greenland and Canada, involving a closure of the Baffin Bay – Labrador Sea. The results of this paleomagnetic test suggest the existence of an ocean basin in the area, prior to the eruption of Early Tertiary lava sequences on Baffin Island and West Greenland, and also that this ocean basin had a much wider extent in Pre-Tertiary times.A model for the evolution of Baffin Bay – Labrador Sea has been suggested in the light of available geological/geophysical information about the region. It involves the opening of this sea in the Mesozoic and its partial closure during the Cenozoic as a consequence of the drift of Greenland in the northwesterly direction.

scholarly journals A genetic comparison of West Greenland and Baffin Island (Canada) walruses: Management implications

2014 ◽  
Vol 9 ◽  
pp. 33 ◽  
Author(s):  
Liselotte Wesley Andersen ◽  
Erik W Born ◽  
Robert EA Stewart ◽  
Rune Dietz ◽  
DW Doidge ◽  
...  
Keyword(s):  
Baffin Island ◽  
Sustainable Harvest ◽  
Baffin Bay ◽  
West Greenland ◽  
Odobenus Rosmarus ◽  
Davis Strait ◽  
Intense Exploitation ◽  
The Relationship ◽  
Genetic Comparison

Until recently Atlantic walruses (Odobenus rosmarus rosmarus) have been subject to relatively intense exploitation in West Greenland. Animals in this stock have also been hunted in Nunavut/Canada. However, the demographic identity of these animals and their connection with walruses in neighbouring areas is poorly resolved, hampering the determination of sustainable harvest levels. It has been suggested that walruses in West Greenland are genetically linked with walruses at SE Baffin Island (Canada) where they are also hunted for subsistence purposes. To determine the relationship(s) between walruses in these areas we conducted a genetic analysis including recent samples from West Greenland, Southeast Baffin Island in western Davis Strait, Hudson Strait in Canada and Northwest Greenland in northern Baffin Bay. Seventeen microsatellite markers were applied to all samples. Walruses in West Greenland and at Southeast Baffin Island did not differ from each other and therefore may be regarded as belonging to the same stock. However, walruses in these two areas differed genetically from both Northwest Greenland and Hudson Strait walruses. These findings support (1) that there are subunits within the range of walruses in the Hudson Strait-Davis Strait-Baffin Bay region and (2) that walruses along E Baffin Island and W Greenland constitute a common population that receive some influx from Hudson Strait. Thus, sustainable catch levels in Southeast Baffin Island (Nunavut) and in West Greenland must be set in light of the finding that they belong to the same stock, which is exploited in these two areas. This requires Canadian-Greenlandic co-management of the W Greenland-SE Baffin Island walrus stock.

scholarly journals An overview of genetic relationships of Canadian and adjacent populations of belugas (Delphinapterus leucas) with emphasis on Baffin Bay and Canadian eastern Arctic populations

2002 ◽  
Vol 4 ◽  
pp. 17 ◽  
Author(s):  
BGE De March ◽  
L D Maiers ◽  
M K Friesen
Keyword(s):  
Current Knowledge ◽  
Genetic Relationships ◽  
High Arctic ◽  
Small Sample ◽  
Delphinapterus Leucas ◽  
Baffin Island ◽  
Genetic Characteristics ◽  
Baffin Bay ◽  
West Greenland ◽  
Small Sample Sizes

Our current knowledge of the molecular genetics of High Arctic beluga (Delphinapterus leucas) populations (West Greenland, Lancaster Sound/Barrow Strait, Grise Fiord) and populations that are related (southeast Baffin, Beaufort Sea), is presented. In general, genetic analyses confirm the designation of putative stocks and suggest the existence of more stocks than previously described. Comparisons based on mitochondrial DNA haplotypes show that West Greenland (1992) belugas were significantly differentiated from Lancaster Sound/Barrow Strait, Kimmirut, Iqaluit, and/or Pangnirtung but not from Grise Fiord. Grise Fiord haplotypes were not significantly differentiated from Lancaster Sound/Barrow Strait and not from southeast Baffin locations in some years. Lancaster Sound and southeast Baffin collections were not significantly differentiated from each other. These patterns existed for most years within locations, however a few yearly collections within major locations had different patterns. The collections that differed were small groups with few haplotypes, most likely relatives. Patterns in microsatellite differentiation were slightly different than those for haplotypes. This may be due to the fact that individuals in sampled summering populations breed with individuals in other populations during migration or in overwintering areas. West Greenland and Grise Fiord microsatellites were not significantly differentiated from each other. However, Greenland differed from Lancaster Sound and southeast Baffin Island, while Grise Fiord did not. In southeast Baffin Island, Pangnirtung samples differed from Kimmirut using both haplotypes and microsatellites. Iqaluit samples had intermediate genetic characteristics between Pangnirtung and Kimmirut. Patterns of significant differentiation among collections within locations was believed to be due to a combination of temporal patterns, sampling of relatives, chance, seasonal hunting, small sample sizes, and actual differences among populations.

scholarly journals Abundance of Whales in West and East Greenland in Summer 2015

2018 ◽  
Author(s):  
Rikke G. Hansen ◽  
Tenna K. Boye ◽  
Rasmus S. Larsen ◽  
Nynne H. Nielsen ◽  
Outi Tervo ◽  
...  
Keyword(s):  
Shelf Break ◽  
Minke Whale ◽  
Harbour Porpoise ◽  
Baleen Whale ◽  
Pilot Whale ◽  
East Greenland ◽  
West Greenland ◽  
Minke Whales ◽  
Abundance Estimates ◽  
Pilot Whales

ABSTRACTAn aerial line transect survey of whales in West and East Greenland was conducted in August-September 2015. The survey covered the area between the coast of West Greenland and offshore (up to 100 km) to the shelf break. In East Greenland, the survey lines covered the area from the coast up to 50 km offshore crossing the shelf break. A total of 423 sightings of 12 cetacean species were obtained and abundance estimates were developed for common minke whale, from now on called minke whale, (Balaenoptera acutorostrata)(32 sightings), fin whale (Balaenoptera physalus) (129 sightings), humpback whale (Megaptera novaeangliae)(84 sightings), harbour porpoise (Phocoena phocoena)(55 sightings), long-finned pilot whale, from now on called pilot whale, (Globicephala melas)(42 sightings) and white-beaked dolphins (Lagenorhynchus albirostri)(50 sightings). The developed at-surface abundance estimates were corrected for both perception bias and availability bias if possible. Data on surface corrections for minke whales and harbour porpoises were collected from whales instrumented with satellite-linked time-depth-recorders. Options for estimation methods are presented and the preferred estimates are: Minke whales: 5,095 (95% CI: 2,171-11,961) in West Greenland and 2,762 (95% CI: 1,160-6,574) in East Greenland, fin whales: 2,215 (95% CI: 1,017-4,823) in West Greenland and 6,440 (95% CI: 3,901-10,632) in East Greenland, humpback whales: 993 (95% CI: 434-2,272) in West Greenland and 4,223 (95%CI: 1,845-9,666) in East Greenland, harbour porpoise: 83,321 (95% CI: 43,377-160,047) in West Greenland and 1,642 (95% CI: 319-8,464) in East Greenland, pilot whales: 9,190 (95% CI: 3,635-23,234) in West Greenland and 258 (95% CI: 50-1,354) in East Greenland, white-beaked dolphins 15,261 (95% CI: 7,048-33,046) in West Greenland and 11,889 (95% CI: 4,710-30,008) in East Greenland. The abundance of cetaceans in coastal areas of East Greenland has not been estimated before, but the limited historical information from the area indicate that the achieved abundance estimates were remarkably high. When comparing the abundance estimates from 2015 in West Greenland with a similar survey conducted in 2007 there is a clear trend towards lower densities in 2015 for the three baleen whale species and white-beaked dolphins. Harbour porpoises and pilot whales however, did not show a similar decline. The decline in baleen whale and white-beaked dolphin abundance is likely due to emigration to the East Greenland shelf areas where recent climate driven changes in pelagic productivity may have accelerated favourable conditions for these species.

scholarly journals The variability of Baffin Bay seafloor sediment mineralogy: the identification of discrete glacial sediment sources and application to Late Quaternary downcore analysis

2018 ◽  
Vol 55 (6) ◽  
pp. 620-639 ◽  
Author(s):  
John T. Andrews ◽  
Anna J. Klein ◽  
Kimberly A. Jenner ◽  
Anne E. Jennings ◽  
Calvin Campbell
Keyword(s):  
Grain Size ◽  
Late Quaternary ◽  
Baffin Island ◽  
Sediment Sources ◽  
The West ◽  
Regional Patterns ◽  
Size Spectra ◽  
Baffin Bay ◽  
West Greenland ◽  
Mineral Assemblages

Quantitative X-ray diffraction (qXRD) mineralogy of bedrock, ice-rafted, and fluvial clasts, 239 seafloor samples (<2 mm), and samples from two long piston cores were used to (i) define regional patterns and sources within Baffin Bay, (ii) evaluate two areas from west Greenland and east Baffin Island in more detail, and (iii) apply these findings to the interpretation of downcore variations in sediment sources. A sediment-unmixing program is used to define surface regional mineral assemblages and to examine changes in sediment sources in cores HU2013029-77PC (southern Baffin Island slope) and HU2008029-8PC (Davis Strait) during Marine Isotope Stages 1 through 3. Distinct regional patterns are observed in the association between the mineralogy of surface sediments and carbonate and basalt bedrock outcrops. Detailed analysis of seafloor samples from the west Greenland troughs and Baffin Island fjords show regional differences in mineralogy, with sediments derived from the Foxe Fold Belt (north-central Baffin Island) being mineralogically distinct from sediments to the north and south. Grain-size spectra from the west Greenland troughs suggested an association between grain-size spectra and mineral assemblages. Sediment unmixing of qXRD data from the two piston cores shows discrete intervals where one or more mineral sources were dominant. However, chronological control is such that it is unclear whether the various ice streams draining into Baffin Bay behaved synchronously.

Tertiary Basalts of Baffin Island: Field Relations and Tectonic Setting

1971 ◽  
Vol 8 (2) ◽  
pp. 248-258 ◽  
Author(s):  
D. B. Clarke ◽  
B. G. J. Upton
Keyword(s):  
Tectonic Setting ◽  
Continental Drift ◽  
Labrador Sea ◽  
Baffin Island ◽  
Precambrian Basement ◽  
Baffin Bay ◽  
West Greenland ◽  
Magma Type ◽  
Terrestrial Sediments ◽  
Stratigraphic Position

This paper describes the field relations of Tertiary basalts which are preserved as small patches intermittently along the coast for 90 km northwest from Cape Dyer, Baffin Island. The flat-lying, subaerial lavas generally rest directly on the Precambrian basement but in some localities a thin sequence of terrestrial sediments intervenes between the basement and the volcanics. Where the sediments occur, the overlying volcanics tend to be divisible into a lower unit of subaqueous volcanic breccia and an upper sequence of subaerial flows. In age, stratigraphic position and magma-type, these volcanics strongly resemble those of the basalt province of west Greenland. A model is presented for the generation of both provinces in a single volcanic episode, related to the opening of Labrador Sea – Baffin Bay by continental drift.

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