scholarly journals Abundance of walruses in Eastern Baffin Bay and Davis Strait

2014 ◽  
Vol 9 ◽  
pp. 159 ◽  
Author(s):  
Mads Peter Heide-Jørgensen ◽  
Kristin Laidre ◽  
Sabrina Fossette ◽  
Marianne H Rasmussen ◽  
Nynne Hjort Nielsen ◽  
...  
Keyword(s):  
Correction Factor ◽  
Pressure Transducer ◽  
Detection Threshold ◽  
Wintering Grounds ◽  
Baffin Bay ◽  
Current Information ◽  
Aerial Surveys ◽  
Odobenus Rosmarus ◽  
Abundance Estimates ◽  
Davis Strait

Walruses (Odobenus rosmarus) are exploited for subsistence purposes in West Greenland. However, current information about the abundance of walruses subject to harvest in eastern Baffin Bay subject to harvest has been unavailable despite being critical for maintaining sustainable catch levels. Three visual aerial surveys were conducted in 2006 (21 March to 19 April 2006), 2008 (3 to 12 April) and 2012 (24 March to 14 April) to estimate the number of walruses on the wintering grounds in eastern Baffin Bay and Davis Strait. Data on the fraction of walruses that were submerged below a 2m detection threshold during the surveys were obtained from 24 walruses instrumented with satellite-linked-time-depth-recorders in northern Baffin Bay in May-June 2010-2012. An availability correction factor was estimated at 36.5% (cv=0.08) after filtering of data for an observed drift of the pressure transducer of more than 2.5 m. The surveys resulted in walrus abundance estimates that were corrected for walruses submerged below a detection threshold and for walruses that were missed by the observers. The estimates of abundance were 1,105 (cv=0.31, 95% CI 610-2,002) in 2006, 1,137 (0.48, 468-2,758) in 2008 and 1,408 (0.22, 922-2,150) in 2012. 

Abundance and Distribution of Narwhals (Monodon monoceros) in Northern Hudson Bay

1991 ◽  
Vol 48 (2) ◽  
pp. 276-283 ◽  
Author(s):  
Pierre R. Richard
Keyword(s):  
Hudson Bay ◽  
Baffin Bay ◽  
Bay Area ◽  
Monodon Monoceros ◽  
Aerial Surveys ◽  
Davis Strait ◽  
Abundance And Distribution ◽  
Reconnaissance Surveys

Aerial surveys for narwhals (Monodon monoceros) were conducted in August 1981, in July 1982, 1983, and 1984, and in March 1983 in the Repulse Bay area between Roes Welcome Sound and Lyon Inlet, north of Southampton Island. About 1300 narwhals were estimated to occupy waters between northern Roes Welcome Sound and Lyon Inlet in July 1982, 1983, and 1984. Narwhals were found throughout the study area but were more concentrated in three areas: northern Roes Welcome Sound, southern Frozen Strait, and, in 1984, Lyon Inlet. Only four narwhals were observed during August 1981 reconnaissance surveys of these areas. No narwhals were seen during the March 1983 survey of Roes Welcome Sound and leads of Frozen Strait. A winter concentration of narwhals observed by others in eastern Hudson Strait was of similar size to that which we observed in July, suggesting that they could be the same stock. If this is so, the northern Hudson Bay narwhals could be distinct from the stock that inhabits Davis Strait and Baffin Bay.

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.

Trends and variability of sea ice in Baffin Bay and Davis Strait, 1953–2001

2003 ◽  
Vol 22 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Harry L. Stern ◽  
Mads Peter Heide-Jørgensen
Keyword(s):  
Sea Ice ◽  
Baffin Bay ◽  
Davis Strait

scholarly journals Full-fit reconstruction of the Labrador Sea and Baffin Bay

2013 ◽  
Vol 5 (2) ◽  
pp. 917-962 ◽  
Author(s):  
M. Hosseinpour ◽  
R. D. Müller ◽  
S. E. Williams ◽  
J. M. Whittaker
Keyword(s):  
North America ◽  
Continental Crust ◽  
Seafloor Spreading ◽  
Labrador Sea ◽  
Gravity Inversion ◽  
Seismic Profiles ◽  
Baffin Bay ◽  
Davis Strait ◽  
Break Up ◽  
Magnetic Lineations

Abstract. Reconstructing the opening of the Labrador Sea and Baffin Bay between Greenland and North America remains controversial. Recent seismic data suggest that magnetic lineations along the margins of the Labrador Sea, originally interpreted as seafloor spreading anomalies, may lie within the crust of the continent–ocean transition. These data also suggest a more seaward extent of continental crust within the Greenland margin near the Davis Strait than assumed in previous full-fit reconstructions. Our study focuses on reconstructing the full-fit configuration of Greenland and North America using an approach that considers continental deformation in a quantitative manner. We use gravity inversion to map crustal thickness across the conjugate margins, and assimilate observations from available seismic profiles and potential field data to constrain the likely extent of different crustal types. We derive end-member continental margin restorations following alternative interpretations of published seismic profiles. The boundaries between continental and oceanic crust (COB) are restored to their pre-stretching locations along small circle motion paths across the region of Cretaceous extension. Restored COBs are fitted quantitatively to compute alternative total-fit reconstructions. A preferred full-fit model is chosen based on the strongest compatibility with geological and geophysical data. Our preferred model suggests that (i) the COB lies oceanward of magnetic lineations interpreted as magnetic anomaly 31 (70 Ma) in the Labrador Sea, (ii) all previously identified magnetic lineations landward of anomaly 27 reflect intrusions into continental crust, and (iii) the Ungava fault zone in Davis Strait acted as a leaky transform fault during rifting. This robust plate reconstruction reduces gaps and overlaps in the Davis Strait and suggests that there is no need for alternative models proposed for reconstructions of this area including additional plate boundaries in North America or Greenland. Our favored model implies that break up and formation of continent–ocean transition (COT) first started in the southern Labrador Sea and Davis Strait around 88 Ma and then propagated north and southwards up to onset of real seafloor spreading at 63 Ma in the Labrador Sea. In the Baffin Bay, continental stretching lasted longer and actual break up and seafloor spreading started around 61 Ma (Chron 26).

Trends and variability of sea ice in Baffin Bay and Davis Strait, 1953?2001

2003 ◽  
Vol 22 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Harry L. Stern ◽  
Mads Peter Heide-Jørgensen
Keyword(s):  
Sea Ice ◽  
Baffin Bay ◽  
Davis Strait
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