Sexual differences in the foraging ecology of 19th century beluga whales ( Delphinapterus leucas ) from the Canadian High Arctic

2020 ◽  
Vol 36 (2) ◽  
pp. 451-471 ◽  
Author(s):  
Paul Szpak ◽  
Marie‐Hélène Julien ◽  
Thomas C. A. Royle ◽  
James M. Savelle ◽  
Dongya Y. Yang ◽  
...  
Keyword(s):  
19Th Century ◽  
Foraging Ecology ◽  
High Arctic ◽  
Sexual Differences ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
Beluga Whales

Deep Diving in Wild, Free-Ranging Beluga Whales, Delphinapterus leucas

1992 ◽  
Vol 49 (3) ◽  
pp. 462-466 ◽  
Author(s):  
A. R. Martin ◽  
T. G. Smith
Keyword(s):  
Upper Bound ◽  
Ambient Pressure ◽  
High Arctic ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
Near Surface ◽  
Beluga Whales ◽  
Deep Diving ◽  
Radio Transmitters ◽  
Free Ranging

Three adult female beluga whales, Delphinapterus leucas, were captured during summer in the Canadian high Arctic and equipped with satellite-linked radio transmitters that measured and recorded ambient pressure every 20 s. Diving behaviour was divisible into three distinct categories: (1) near-surface, (2) "spike" dives to 20–150 m depth, and (3) prolonged, flat-bottomed dives to a maximum depth of 350 m. The duration of these prolonged dives was 9.3–13.7 min, but the upper bound is known to be underestimated. Average descent rates varied between dives in the range 1.43–2.20 m/s and ascent rates between 1.23 and 1.84 m/s. Within periods of 20 s duration, maximum descent and ascent rates were 2.55 and 2.35 m/s, respectively. After most prolonged dives the rate of ascent declined progressively as the surface was approached, particularly in the final 100 m. Such dives were usually to, or near to, the seabed and were probably for foraging. Up to 42% of an animal's time could be spent at depths of 8 m or more.

scholarly journals Larger body size leads to greater female beluga fitness at the southern periphery of their range

2020 ◽  
Author(s):  
Steven Ferguson ◽  
David Yurkowski ◽  
Justine Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  
Keyword(s):  
Body Size ◽  
Body Length ◽  
High Arctic ◽  
Delphinapterus Leucas ◽  
Causal Mechanism ◽  
Hudson Bay ◽  
Peripheral Populations ◽  
Beluga Whales ◽  
Future Challenges ◽  
Variation Explained

Identifying phenotypic characteristics of evolutionarily fit individuals provides important insight into the evolutionary processes that cause range shifts with climate warming. Female beluga whales (Delphinapterus leucas) from the Canadian high Arctic (BB) residing in the core region of the species’ geographic range are 14% larger than their conspecifics at the southern periphery in Hudson Bay (HB). We investigated the causal mechanism for this north (core)-south (periphery) difference as it relates to fitness by combining morphometric data with ovarian corpora counted in female reproductive tracts. We found evidence for reproductive senescence in older HB females from the southern peripheral population but not for BB whales. Female beluga whale fitness in the more-northern BB increased faster with age (48% partial variation explained) versus a more gradual slope (25%) in HB. In contrast, body length in HB female beluga accounted for five times more of the total variation in fitness compared to BB whales. We speculate that female HB beluga fitness was more strongly linked with body length due to higher density, as larger body size provides survival advantages during seasonal food limitations. Understanding the evolutionary mechanism of how fitness changes will assist conservation efforts in anticipating and mitigating future challenges to peripheral populations.

An estimate of the fraction of belugas (Delphinapterus leucas) in the Canadian high Arctic that winter in West Greenland

Polar Biology ◽  
2003 ◽  
Vol 26 (5) ◽  
pp. 318-326 ◽  
Author(s):  
M. P. Heide-Jørgensen ◽  
P. Richard ◽  
R. Dietz ◽  
K. L. Laidre ◽  
J. Orr ◽  
...  
Keyword(s):  
High Arctic ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
West Greenland

scholarly journals Surveys of belugas and narwhals in the Canadian High Arctic in 1996

2002 ◽  
Vol 4 ◽  
pp. 169 ◽  
Author(s):  
Stuart Innes ◽  
MP Heide-Jørgensen ◽  
Jeff L Laake ◽  
Kristin L Laidre ◽  
Holly J Cleator ◽  
...  
Keyword(s):  
High Arctic ◽  
Aerial Survey ◽  
Delphinapterus Leucas ◽  
Line Transect ◽  
Canadian High Arctic ◽  
Distance Measurements ◽  
Distance Information ◽  
Surface Time ◽  
Summer Range ◽  
Using Data

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).

Distribution and Movements of Belugas, Delphinapterus leucas, in the Canadian High Arctic

1994 ◽  
Vol 51 (7) ◽  
pp. 1653-1663 ◽  
Author(s):  
Thomas G. Smith ◽  
A. R. Martin
Keyword(s):  
Coastal Waters ◽  
High Arctic ◽  
Delphinapterus Leucas ◽  
Canadian High Arctic ◽  
Directed Movement ◽  
Seasonal Movements ◽  
Devon Island ◽  
Aerial Surveys ◽  
Fast Ice ◽  
Somerset Island

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.

scholarly journals Seasonal distribution and foraging occurrence of Cook Inlet beluga whales based on passive acoustic monitoring

2020 ◽  
Vol 41 ◽  
pp. 225-243 ◽  
Author(s):  
M Castellote ◽  
RJ Small ◽  
MO Lammers ◽  
J Jenniges ◽  
J Mondragon ◽  
...  
Keyword(s):  
Foraging Ecology ◽  
Acoustic Monitoring ◽  
Seasonal Distribution ◽  
Substantial Contribution ◽  
Delphinapterus Leucas ◽  
Passive Acoustic Monitoring ◽  
Cook Inlet ◽  
Beluga Whales ◽  
Endangered Population ◽  
Passive Acoustic

A paucity of information on the basic biology and ecology of Cook Inlet beluga whales Delphinapterus leucas remains a decade after the species was listed as endangered in 2008. The causes of its continued decline remain unclear. This lack of knowledge limits our understanding of, and ability to manage, potential threats impeding the recovery of this endangered population. Seasonal distribution and foraging ecology, particularly during winter, are currently among the most basic gaps in knowledge. Therefore, we conducted a year-round passive acoustic monitoring program from 2008-2013, monitoring 13 locations within the belugas’ critical habitat. We identified seasonal occurrence patterns across years at most locations. Detections were higher in the upper inlet during summer, peaking in known concentration areas. The occurrence of whales in the upper inlet when ice coverage peaked during winter was more prevalent than previously suggested. We documented seasonal differences in foraging habitat preference, with foraging behavior more prevalent during summer, particularly near upper inlet rivers, than during winter. Foraging peaks coincided with the presence of different anadromous fish runs from spring to fall. Low levels of feeding activity in winter suggest a lack of feeding aggregation areas, feeding in non-monitored offshore waters, or increased effort on benthic prey. These results represent a substantial contribution to our knowledge of Cook Inlet beluga seasonal distribution and foraging ecology, which will strengthen conservation and management strategies and thus more effectively promote recovery of this endangered population.

scholarly journals Distribution and abundance of Canadian High Arctic belugas, 1974-1979

2002 ◽  
Vol 4 ◽  
pp. 87 ◽  
Author(s):  
William R Koski ◽  
Kerwin J Finley
Keyword(s):  
Late Summer ◽  
High Arctic ◽  
Delphinapterus Leucas ◽  
Polar Cod ◽  
Canadian High Arctic ◽  
Devon Island ◽  
The North ◽  
Polar Cod Boreogadus Saida ◽  
North Water ◽  
Somerset Island

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.

scholarly journals Three recent ice entrapments of Arctic cetaceans in West Greenland and the eastern Canadian High Arctic

2002 ◽  
Vol 4 ◽  
pp. 143 ◽  
Author(s):  
MP Heide-Jørgensen ◽  
P Richard ◽  
M Ramsay ◽  
S Akeeagok
Keyword(s):  
North Atlantic ◽  
Polar Bear ◽  
Canadian Arctic ◽  
High Arctic ◽  
Bowhead Whale ◽  
Delphinapterus Leucas ◽  
Polar Bears ◽  
Canadian High Arctic ◽  
West Greenland ◽  
The One

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.

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