Tagging White Whales in the Canadian Arctic

1969 ◽  
Vol 26 (8) ◽  
pp. 2201-2205 ◽  
Author(s):  
D. E. Sergeant ◽  
P. F. Brodie
Keyword(s):  
Shallow Water ◽  
Canadian Arctic ◽  
The Body ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Western Coast ◽  
Dorsal Part ◽  
Dorsal Ridge ◽  
Western Hudson Bay

White whales, Delphinapterus leucas Pallas, were tagged in the estuary of Seal River, Man., in western Hudson Bay in the summers of 1967 and 1968. Seven hundred harpoon tags were applied to the dorsal part of the body while chasing the animals, and 118 Petersen disc tags through the dorsal ridge after stranding the animals in shallow water on a falling tide. Three recovered harpoon tags include one observed on a living whale at the same site after a year, and two taken from netted whales at fisheries northward along the western coast of Hudson Bay, 300–800 km from the site of tagging and 5–7 weeks after tagging.

Biology of White Whales (Delphinapterus leucas) in Western Hudson Bay

1973 ◽  
Vol 30 (8) ◽  
pp. 1065-1090 ◽  
Author(s):  
D. E. Sergeant
Keyword(s):  
Crude Birth Rate ◽  
Late Summer ◽  
Reproductive Rate ◽  
Delphinapterus Leucas ◽  
Corpora Lutea ◽  
Hudson Bay ◽  
Decapod Crustacea ◽  
The Mean ◽  
Western Hudson Bay ◽  
Frequent Presence

The number of white whales inhabiting western Hudson Bay is about 10,000. In July and early August the herds are concentrated in river estuaries at 57° to 60° N, but a migration in mid-August through September takes them to between 62° and 66°N. Wintering occurs in the western part of the Bay. In the estuary of the Churchill River feeding, mainly on fish, is not heavy and the herds are believed to enter the river estuaries in this region for reproduction as much as feeding. Further north in late summer feeding is heavier and changes towards a diet of decapod Crustacea. It is believed that two dentinal layers are laid down in the teeth each year, each layer consisting of one opaque and one translucent zone of dentine, with the translucent material laid down during periods of reduced feeding. These may occur either at an autumn and a spring migration or during a summer fast at calving time and during winter deprivation. Females attain sexual maturity at 8–13 (mean 10) growth layers and males at 16–18 layers, i.e. at supposed mean ages of 4–7 (5) and 8–9 years. The skin loses all trace of grey color at 18–22 layers. Maximal duration of life is about 50 layers or a supposed age of 25 years in both sexes. The sexes are probably about equal in numbers. Gestation lasts 14 months and lactation about 20 months. Overlap of pregnancy and the previous lactation is infrequent so that calving occurs about once in 3 years. The annual crude birth rate is estimated at 0.12. Estimation of the maximal number of births from counts of corpora luteal scars is complicated by the frequent presence of accessory corpora lutea and luteinized follicles, estimated at about 32% of the total. The mean maximal number of scars retained in the ovaries during a female’s reproductive lifetime is 14.5. The full reproductive lifetime, on the basis of two growth layers per annum, is 20 years. Thus the mean ovulation rate is about 0.7 per annum. Reducing the number of scars by 32% gives 0.5 true (fertile) ovulations per annum, which would indicate a reproductive rate of one pregnancy in 2 years, and a maximal number of 10 pregnancies in a full reproductive lifetime

scholarly journals Assessing spatial segregation of beluga whales (Delphinapterus leucas) in Western Hudson Bay estuaries

2021 ◽  
Author(s):  
Kristin H Westdal ◽  
Jeremy Davies ◽  
Steve Ferguson
Keyword(s):  
Environmental Data ◽  
Beluga Whale ◽  
Habitat Characteristics ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Adult Males ◽  
Coastal Habitat ◽  
Age Classes ◽  
Age Class ◽  
Western Hudson Bay

Segregation of older adult males from females and immature males is known to occur in some beluga whale populations, but it is unclear if adults accompanied by calves segregate in Hudson Bay, where the largest summering population is found. Using imagery from a photographic aerial survey conducted in August 2015, we considered a number of environmental variables that might explain distribution by age class of beluga near two of three main estuaries (Churchill and Seal River) used by Western Hudson Bay belugas in the summer season. Belugas were identified and classified by age manually using an identification decision tree and GPS coordinates were plotted in ArcGIS.  Distribution by age class was examined in relation to distance to coastal habitat and bathymetry to test the predation risk hypothesis, sea surface temperature (thermal advantage hypothesis), and extent of river plume (forge-selection hypothesis). Habitat characteristics and the proportion of age classes in both estuaries were similar between age class groups (with and without calves) indicating no segregation and suggesting the environmental data assessed were not driving patterns of distribution and density of age classes at the spatial and temporal scale being investigated. Results provide a greaterunderstanding of spatial patterns of beluga whale habitat use in western Hudson Bay and information useful in conservation and management advice.

Population genetic structure of beluga whales (Delphinapterus leucas): mitochondrial DNA sequence variation within and among North American populations

1997 ◽  
Vol 75 (5) ◽  
pp. 795-802 ◽  
Author(s):  
Ree Brennin ◽  
Brent W. Murray ◽  
Bradley N. White ◽  
James W. Clayton ◽  
Margaret K. Friesen ◽  
...  
Keyword(s):  
Mitochondrial Dna ◽  
Genetic Structure ◽  
North American ◽  
The Arctic ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Genetic Structuring ◽  
Lawrence Estuary ◽  
Beluga Whales ◽  
Western Hudson Bay

Beluga whales (Delphinapterus leucas) are migratory over much of their range, congregating in small groups around shallow river estuaries in summer and overwintering in areas of broken pack ice. To investigate the potential genetic structuring within North American beluga, we analyzed variation in mitochondrial DNA (mtDNA). Using 10 restriction enzymes, eight haplotypes were identified among 95 beluga from 12 sampling locations. The haplotypes formed two lineages, one occurring primarily in whales from the St. Lawrence estuary and eastern Hudson Bay and the other primarily in beluga sampled in the waters of western Hudson Bay, southern Baffin Island, western Greenland, the Canadian High Arctic, and the eastern Beaufort Sea. The genetic difference between these lineages and the high-level genetic structure among the sample locations, [Formula: see text] (p ≤ 0.0001), indicate that these lineages may represent the original Pacific and Atlantic "refugial" stocks that colonized the Arctic after deglaciation. Further, the present segregation of these lineages between populations summering in eastern and western Hudson Bay (p ≤ 0.005) is consistent with the hypothesis that the mitochondria of the beluga summering in western Hudson Bay are descended from those of a Pacific "refugial" stock and those of beluga summering in eastern Hudson Bay are descended from those of an Atlantic "refugial" stock. The clear differentiation of beluga from different summering locations provides evidence for strong maternally directed philopatry to the summering locations.

Distribution and abundance of ringed (Phoca hispida) and bearded seals (Erignathus barbatus) in western Hudson Bay

1997 ◽  
Vol 54 (4) ◽  
pp. 914-921 ◽  
Author(s):  
N J Lunn ◽  
I Stirling ◽  
S N Nowicki
Keyword(s):  
Polar Bear ◽  
Hudson Bay ◽  
Phoca Hispida ◽  
Current Estimate ◽  
Ringed Seals ◽  
Erignathus Barbatus ◽  
The Mean ◽  
Western Hudson Bay ◽  
The Relationship ◽  
Bearded Seals

We flew a medium-altitude, systematic, strip-transect survey for ringed (Phoca hispida) and bearded seals (Erignathus barbatus) over western Hudson Bay in early June 1994 and 1995. The mean density (per square kilometre) of ringed seals hauled out on the ice was four times higher in 1995 (1.690) than in 1994 (0.380). The 1994 survey appeared to underestimate seal abundance because it was flown too late. Ringed seals preferred high ice cover habitat (6 + /8 ice) and, within this habitat, favoured cracking ice and large floes. We found no consistent effect of either wind or cloud cover on habitat preference. We estimated a total of 1980 bearded seals and 140<|>880 ringed seals hauled out on the sea ice in June 1995. A recent review of the relationship between ringed seal and polar bear (Ursus maritimus) populations suggests that a visible population of this size should support a population of up to 1300 polar bears, which is in general agreement with the current estimate of 1250-1300 bears in western Hudson Bay.

scholarly journals On the tides and resonances of Hudson Bay and Hudson Strait

Ocean Science ◽  
2014 ◽  
Vol 10 (3) ◽  
pp. 411-426 ◽  
Author(s):  
D. J. Webb
Keyword(s):  
Numerical Model ◽  
Shallow Water ◽  
World Ocean ◽  
Tidal Energy ◽  
Tidal Range ◽  
Hudson Bay ◽  
Foxe Basin ◽  
Important Region ◽  
The World ◽  
Diurnal Tides

Abstract. The resonances of Hudson Bay, Foxe Basin and Hudson Strait are investigated using a linear shallow water numerical model. The region is of particular interest because it is the most important region of the world ocean for dissipating tidal energy. The model shows that the semi-diurnal tides of the region are dominated by four nearby overlapping resonances. It shows that these not only affect Ungava Bay, a region of extreme tidal range, but they also extend far into Foxe Basin and Hudson Bay and appear to be affected by the geometry of those regions. The results also indicate that it is the four resonances acting together which make the region such an important area for dissipating tidal energy.

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