Dive form and function in belugas Delphinapterus leucas of the eastern Canadian High Arctic

Polar Biology ◽  
1998 ◽  
Vol 20 (3) ◽  
pp. 218-228 ◽  
Author(s):  
A. R. Martin ◽  
T. G. Smith ◽  
O. P. Cox
2020 ◽  
Vol 36 (2) ◽  
pp. 451-471 ◽  
Author(s):  
Paul Szpak ◽  
Marie‐Hélène Julien ◽  
Thomas C. A. Royle ◽  
James M. Savelle ◽  
Dongya Y. Yang ◽  
...  

Polar Biology ◽  
2003 ◽  
Vol 26 (5) ◽  
pp. 318-326 ◽  
Author(s):  
M. P. Heide-Jørgensen ◽  
P. Richard ◽  
R. Dietz ◽  
K. L. Laidre ◽  
J. Orr ◽  
...  

2002 ◽  
Vol 4 ◽  
pp. 169 ◽  
Author(s):  
Stuart Innes ◽  
MP Heide-Jørgensen ◽  
Jeff L Laake ◽  
Kristin L Laidre ◽  
Holly J Cleator ◽  
...  

The summer range of belugas (Delphinapterus leucas) and narwhals (Monodon monoceros) in Prince Regent Inlet, Barrow Strait and Peel Sound in the Canadian High Arctic was surveyed from 31 July to 3 August 1996 with a visual aerial survey of offshore areas and photographic aerial surveys of concentration areas. The visual survey estimate based on the number of belugas visible to the observers using systematic line transect methods was 10,347 (cv = 0.28). This included corrections for whales that were missed by the observers, observations without distance measurements and an estimate of 1,949 (cv=0.22) belugas from a photographic survey in southern Peel Sound. Using data from belugas tagged with satellite-linked time-depth recorders, the estimate was adjusted for individuals that were diving during the survey which resulted in an estimate of 18,930 belugas (cv = 0.28). Finally, counts of belugas in estuaries, corrected for estuarine surface time, were added to provide a complete estimate of 21,213 belugas (95% CI 10,985 to 32,619). The estimated number of narwhals corrected for sightings that were missed by observers was 16,364 (cv = 0.24). Adjusting this for sightings without distance information and correcting for whales that were submerged produced an estimate of 45,358 narwhals (95% CI 23,397 to 87,932).


1994 ◽  
Vol 51 (7) ◽  
pp. 1653-1663 ◽  
Author(s):  
Thomas G. Smith ◽  
A. R. Martin

Belugas, Delphinapterus leucas, move into the coastal waters of Somerset Island as soon as the annual land-fast ice breaks up in late June – early July. Six bays or inlets which receive the outflow of rivers are the major areas of summer aggregation. Belugas captured and equipped with satellite-linked UHF transmitters in Cunningham Inlet (Barrow Strait), Elwin Bay (Prince Regent Inlet), and Creswell Bay moved west into Peel Sound where they frequented two other estuaries. Rapid and directed movement out of Peel Sound occurred in late August. All of the animals which transmitted locations into September or October moved to eastern Devon Island and Jones Sound. The longest period of transmission was 75 d, lasting until mid-October. Belugas tagged in three different locations around Somerset Island in the summers of 1988–93 showed a well-defined and consistent pattern of behaviour. Aerial surveys done during this period confirm that the vast majority of belugas in this region are involved in these seasonal movements.


2002 ◽  
Vol 4 ◽  
pp. 87 ◽  
Author(s):  
William R Koski ◽  
Kerwin J Finley

We conducted >236,000 km of aerial surveys and some supplementary studies of belugas (Delphinapterus leucas) in the central and eastern Canadian High Arctic in 974-79. Belugas that wintered in the “North Water” in Baffin Bay moved southwest into Lancaster Sound in April and early May. The main westward migration into Lancaster Sound occurred over a 2 to 3 week period during late June to late July. Estuaries along Somerset Island were occupied for <3 weeks from mid-July to mid-August. Little feeding occurred in estuaries. From mid-August until fall migration began in mid-September belugas occupied estuaries and offshore waters in Peel Sound. Fall migration eastward through Lancaster Sound was exclusively along the south coast of Devon Island, highly co-ordinated, and rapid; most of the population passed through the sound in <1 week. The whales then moved north along the east coast of Devon Island; some entered Jones Sound while others crossed directly to SE Ellesmere Island. Most calving occurred in July and early August; calving was not seen in estuaries and probably occurred offshore. Excluding calves, adults and yearlings formed 77% and 8.4%, respectively, of the population. The proportion of calves during mid-August was consistent with a triennial calving cycle. During late summer, belugas fed on coastal concentrations of polar cod (Boreogadus saida), under pan ice offshore (probably on cod), and in deep offshore waters. The size of the Canadian High Arctic population in the late 1970s was estimated to be at least 10,250 to 12,000 animals without allowing for animals that may have passed between surveys or that were below the surface at the time of the counts.


2002 ◽  
Vol 4 ◽  
pp. 143 ◽  
Author(s):  
MP Heide-Jørgensen ◽  
P Richard ◽  
M Ramsay ◽  
S Akeeagok

Three ice entrapments of Monodontids have been reported in the western North Atlantic since 1993. Hunters in Disko Bay, West Greenland, discovered one in March 1994 that included about 150 narwhals (Monodon monoceros). The entrapment occurred during a sudden cold period which caused ice to form rapidly. The trapped whales were subject to hunting, but about 50 of the killed whales could not be retrieved in the ice. The whales were trapped in a small opening in the ice and because of that they would probably have succumbed even if not discovered by hunters. Two entrapments involving white whales or belugas (Delphinapterus leucas) occurred in the eastern Canadian Arctic in May 1999; one in Lancaster Sound discovered by polar bear (Ursus maritimus) researchers and one in Jones Sound discovered by hunters. The first included one bowhead whale (Balaena mysticetus) and about 40 belugas that were being preyed upon by polar bears. The second involved at least 170 belugas, of which about 100 were killed by polar bears and 17 were taken by hunters. The entrapments in Disko Bay and Jones Sound both occurred in areas where entrapments have previously been reported, whereas the one in Lancaster Sound was in a new area.


1985 ◽  
Vol 42 (4) ◽  
pp. 676-684 ◽  
Author(s):  
T. G. Smith ◽  
M. O. Hammsll ◽  
D. J. Burrage ◽  
G. A. Sleno

Opportunistic reconnaissance aerial surveys of Lancaster Sound, Barrow Strait, Peel Sound, and Prince Regent Inlet were conducted between 1974 and 1982 to determine the distribution and abundance of belugas, Delphinapterus leucas, and narwhals, Monodon monoceros. In 1981, two stratified strip-transect surveys were flown. From these we estimate that a total of 6300 – 18 600 belugas and approximately 13 200 –18 000 narwhals summer in Lancaster Sound and adjoining waterways. Improvement in the precision of these estimates would require a substantial increase in survey coverage and may not be justified considering the significant increase in costs. Our review of the results of surveys conducted since 1975 in the same study area, of which most of the information is not yet available in the scientific literature, shows much duplication of effort, little increase in information, and a lack of confidence limits for the estimated numbers.


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