scholarly journals Anisakidae in beluga whales Delphinapterus leucas from Hudson Bay and Hudson Strait

2015 ◽  
Vol 115 (1) ◽  
pp. 9-14 ◽  
Author(s):  
K Najda ◽  
M Simard ◽  
J Osewska ◽  
J Dziekońska-Rynko ◽  
J Dzido ◽  
...  
Keyword(s):  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Beluga Whales

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.

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

2021 ◽  
Author(s):  
Steven Ferguson ◽  
David Yurkowski ◽  
Justine Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  
Keyword(s):  
Body Size ◽  
Body Length ◽  
Reproductive Activity ◽  
Food Competition ◽  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Beluga Whales ◽  
Future Challenges ◽  
Variation Explained

Identification of phenotypic characteristics in reproductively successful individuals provides important insights into the evolutionary processes that cause range shifts due to environmental change. Female beluga whales (Delphinapterus leucas) from the Baffin Bay region (BB) of the Canadian Arctic in the core area of the species’ geographic range have larger body size than their conspecifics at the southern range periphery in Hudson Bay (HB). We investigated the mechanism for this north and south divergence as it relates to reproductive activity (RA = total corpora) that combines morphometric data with ovarian corpora counted from female reproductive tracts. Based on the previous finding of reproductive senescence in older HB females, but not for BB whales, we compared RA patterns the of the two populations’ with age and body length. Female beluga whale RA increased more quickly with age (63% partial variation explained) in BB than in HB (41%). In contrast, body length in HB female beluga whale accounted for considerably more of the total variation (12 vs 1%) in RA compared to BB whales. We speculate that female HB beluga whale RA was more strongly linked with body length due to higher population density resulting in food competition that favors the energetic advantages of larger body size during seasonal food limitations. Understanding the evolutionary mechanism of how RA, and potentially fitness, varies across a species’ range will assist conservation efforts in anticipating and mitigating future challenges associated with a warming planet.

Systematic Review and Critique of the Contributions of Traditional Ecological Knowledge of Beluga Whales in the Marine Mammal Literature + Supplementary Appendix Table (See Article Tools)

ARCTIC ◽  
2016 ◽  
Vol 69 (1) ◽  
pp. 37 ◽  
Author(s):  
Kaitlin Breton-Honeyman ◽  
Chris M. Furgal ◽  
Michael O. Hammill
Keyword(s):  
Traditional Ecological Knowledge ◽  
Marine Mammal ◽  
Grey Literature ◽  
Final Analysis ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Ecological Knowledge ◽  
Beluga Whales ◽  
Online Databases

In this study we systematically review and critique literature containing Traditional Ecological Knowledge (TEK) of the beluga (<em>Delphinapterus leucas</em>) as a case study to gain insights into TEK’s contributions to the marine mammal literature over the past four decades. We reviewed multiple searchable online databases, collected both academic and grey literature, and categorized it by geographic and disciplinary focus, as well as by the contribution of TEK to the source. Of the total 137 papers retained in the final analysis, 67% referred to the Canadian North, particularly the Hudson Bay subregion. Articles that included informal or anecdotal representations of TEK of belugas were the most prevalent. The number of papers containing TEK of belugas increased rapidly between 1975 and 2004 but appears to have leveled off since then. Biological papers represented the largest disciplinary focus (72%), followed by papers on management or co-management. This review showed that although knowledge of Indigenous peoples has made substantial contributions to the understanding of beluga, there is a lack of explicit collection, documentation, and use of TEK in the literature on belugas and particularly in the literature on beluga management.

Seasonal epidermal molt in beluga whales, Delphinapterus leucas

1990 ◽  
Vol 68 (2) ◽  
pp. 359-367 ◽  
Author(s):  
D. J. St. Aubin ◽  
T. G. Smith ◽  
J. R. Geraci
Keyword(s):  
Tritiated Thymidine ◽  
Bottlenose Dolphins ◽  
Superficial Layer ◽  
Turnover Time ◽  
Spring Migration ◽  
Proliferation Rate ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Beluga Whales ◽  
Terrestrial Mammals

Epidermal morphology and proliferation were examined in beluga whales during three phases of their annual cycle: spring migration from oceanic wintering grounds, summer occupation of estuaries in Hudson Bay, and return migration in fall. Incursion into relatively warm brackish water was associated with decreased thickness of the stratum externum and sloughing of a superficial layer of degenerative epidermal cells, changes that resulted in the loss of a distinctive yellow hue apparent over the dorsal body surface of whales examined during spring migration. Proliferation rate, determined by incorporation of tritiated thymidine in germinal cells, averaged 13.8–16.6% in all three seasons, but exceeded 20% in 7 of 16 whales examined in the estuaries; similarly high values were not observed during spring migration, and in only one of nine animals sampled in the fall. Average proliferation rate in 13 captive belugas was 14.2–16.6%, two to three times higher than any reported value for other cetaceans or terrestrial mammals. Epidermal turnover time in a single whale studied over a 6-week period was estimated to be 70–75 days, comparable to that in bottlenose dolphins, but indicating a much higher rate of cell migration. In estuaries, elevated temperature and low salinity are presumably responsible for accelerating turnover of superficial cells, and may contribute to elevated proliferation rates by stimulating blood flow to the germinal layer.

Adaptive Changes in Hematologic and Plasma Chemical Constituents in Captive Beluga Whales, Delphinapterus leucas

1989 ◽  
Vol 46 (5) ◽  
pp. 796-803 ◽  
Author(s):  
D. J. St. Aubin ◽  
J. R. Geraci
Keyword(s):  
Chemical Constituents ◽  
Cell Mass ◽  
Caloric Intake ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Blood Samples ◽  
Beluga Whales ◽  
In Captivity ◽  
Acute Changes ◽  
Oxygen Carrying Capacity

Forty-two beluga whales, Delphinapterus leucas, were captured in the Seal and Churchill River estuaries in western Hudson Bay during July, 1985 and 1987. Blood samples were drawn from each whale, and analyzed for cellular elements, electrolytes, metabolites, enzymes, proteins, and adrenocortical hormones. Most of the whales were released immediately after sampling; six were maintained in holding facilities for 10 k during 1985. Blood samples drawn during the early stages of acclimation to captivity, and at irregular intervals thereafter, revealed the variety of metabolic adjustments that accompanied the transition to captivity. The stress and exertion of capture resulted in increased levels of aldosterone, Cortisol, glucose, iron, potassium, and the enzymes creatine kinase, aspartate aminotransferase, alanine aminotransferase, and γ-glutamyltranspeptidase. Acute changes in leucocytes included lymphopenia, eosinopenia, and mild neutrophilia. Most of these indices normalized within the first week in captivity. Progressive changes were noted in triglycerides and creatinine, reflecting the whales' altered diet and caloric intake. A steady decline in red cell mass was indicative of reduced demands on oxygen carrying capacity, and provided a clue to the significance of low hematocrits reported for whales sampled after several weeks in shallow estuaries.

scholarly journals Groups of related belugas ( Delphinapterus leucas ) travel together during their seasonal migrations in and around Hudson Bay

2013 ◽  
Vol 280 (1752) ◽  
pp. 20122552 ◽  
Author(s):  
Gabriel J. Colbeck ◽  
Pierre Duchesne ◽  
Lianne D. Postma ◽  
Véronique Lesage ◽  
Mike O. Hammill ◽  
...  
Keyword(s):  
Social Structure ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Migration Routes ◽  
Long Distance ◽  
Beluga Whales ◽  
Seasonal Migrations ◽  
Cultural Conservatism ◽  
Migratory Cycle

Social structure involving long-term associations with relatives should facilitate the learning of complex behaviours such as long-distance migration. In and around Hudson Bay (Canada), three stocks of beluga whales form a panmictic unit, but have different migratory behaviours associated with different summering areas. We analysed genetic variation at 13 microsatellite loci among 1524 belugas, to test hypotheses about social structure in belugas. We found significant proportions of mother–offspring pairs throughout the migratory cycle, but average relatedness extended beyond close kinship only during migration. Average relatedness was significantly above random expectations for pairs caught at the same site but on different days or months of a year, suggesting that belugas maintain associations with a network of relatives during migration. Pairs involving a female (female–female or male–female) were on average more related than pairs of males, and males seemed to disperse from their matrilineal group to associate with other mature males. Altogether, our results indicate that relatives other than strictly parents, and especially females, play a role in maintaining a social structure that could facilitate the learning of migration routes. Cultural conservatism may limit contributions from nearby summer stocks to endangered stocks such as the Eastern Hudson Bay beluga.

scholarly journals Reproductive Parameters for Female Beluga Whales (Delphinapterus leucas) of Baffin Bay and Hudson Bay, Canada

ARCTIC ◽  
2020 ◽  
Vol 73 (4) ◽  
pp. 405-420
Author(s):  
Steven H. Ferguson ◽  
Cornelia Willing ◽  
Trish C. Kelley ◽  
David A. Boguski ◽  
David J. Yurkowski ◽  
...  
Keyword(s):  
Sexual Maturity ◽  
Growth Patterns ◽  
Beluga Whale ◽  
The Arctic ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Reproductive Parameters ◽  
Baffin Bay ◽  
Beluga Whales ◽  
Reproductive Patterns

Monitoring marine mammal populations and their habitats is crucial for assessing population status and defining realistic management and conservation goals. Environmental and anthropogenic changes in the Arctic have prompted the pursuit for improved understanding of female beluga whale (Delphinapterus leucas) spatial and temporal reproductive patterns. There are relatively few estimates for female reproductive parameters of beluga whale populations across the Arctic, and those few that are available are outdated. Here we summarize female reproductive data from samples collected through Inuit subsistence hunts of three eastern Canadian Arctic beluga populations: High Arctic/Baffin Bay (HA), Western Hudson Bay (HB), and Cumberland Sound (CS) from 1989 to 2014. We grouped the CS and HA populations into a Baffin Bay region (BB) population based on similar body growth patterns and genetic similarity. Asymptotic body length of BB beluga whales (370.9 cm) was greater than HB whales (354.4 cm) as established from Gompertz growth curves fitted for whales ranging in age from 1 – 89 y. We did not detect a significant difference in average number of pseudocervices (8.6) between regions. Differences in average age of sexual maturity (ASM) and length at sexual maturity (LSM) were identified, with evidence of BB females maturing earlier than females from HB (probability method BB = 9.9 y versus HB = 11.0 and logistic method ASM50% HB = 9.99 and BB unresolved). BB females were also longer than HB females at maturing age (logistic LSM50%: BB = 314.5 cm vs HB = 290.3). Total corpora counts were strongly correlated with age, although the number of corpora (≥ 10 mm) suggests reproductive senescence between 40 and 50 y. Improved understanding of female reproductive patterns and knowledge of changes in the spatial and temporal timing of reproductive processes are fundamental for effective conservation and sustainable management of beluga whale populations.

scholarly journals Larger body size leads to greater female beluga whale ovarian reproductive activity at the southern periphery of their range

2021 ◽  
Author(s):  
Steven Ferguson ◽  
David Yurkowski ◽  
Justine Hudson ◽  
Tera Edkins ◽  
Cornelia Willing ◽  
...  
Keyword(s):  
Body Size ◽  
Body Length ◽  
Reproductive Activity ◽  
Food Competition ◽  
Beluga Whale ◽  
Delphinapterus Leucas ◽  
Hudson Bay ◽  
Beluga Whales ◽  
Future Challenges ◽  
Variation Explained

Identification of phenotypic characteristics in reproductively successful individuals provides important insights into the evolutionary processes that cause range shifts due to environmental change. Female beluga whales (Delphinapterus leucas) from the Baffin Bay region (BB) of the Canadian Arctic in the core area of the species’ geographic range have larger body size than their conspecifics at the southern range periphery in Hudson Bay (HB). We investigated the mechanism for this north and south divergence as it relates to ovarian reproductive activity (ORA = total corpora) that combines morphometric data with ovarian corpora counted from female reproductive tracts. Based on the previous finding of reproductive senescence in older HB females, but not for BB whales, we compared ORA patterns of the two populations with age and body length. Female beluga whale ORA increased more quickly with age (63% partial variation explained) in BB than in HB (41%). In contrast, body length in HB female beluga whales accounted for considerably more of the total variation (12 vs 1%) in ORA compared to BB whales. We speculate that female HB beluga whale ORA was more strongly linked with body length due to higher population density resulting in food competition that favors the energetic advantages of larger body size during seasonal food limitations. Understanding the evolutionary mechanism of how ORA varies across a species’ range will assist conservation efforts in anticipating and mitigating future challenges associated with a warming planet.

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.

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