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 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.

Variation in the diet of beluga whales in response to changes in prey availability: insights on changes in the Beaufort Sea ecosystem

2020 ◽  
Vol 647 ◽  
pp. 195-210 ◽  
Author(s):  
ES Choy ◽  
C Giraldo ◽  
B Rosenberg ◽  
JD Roth ◽  
AD Ehrman ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Prey Availability ◽  
Beaufort Sea ◽  
Delphinapterus Leucas ◽  
Fatty Acid Signature ◽  
Arctic Cod ◽  
Beluga Whales ◽  
Highly Sensitive ◽  
Condition Indices

The eastern Beaufort Sea (EBS) beluga whale Delphinapterus leucas population has experienced a 20 yr decline in inferred growth rates of individuals, which is hypothesized to have resulted from changes in prey availability. We used fatty acid signatures and stable isotope ratios to reconstruct the proportional contributions of 14 prey species to the diets of 178 beluga whales from 2011 to 2014. Prey estimates using quantitative fatty acid signature analysis suggest that EBS beluga whales primarily consume Arctic cod Boreogadus saida, a species highly sensitive to climate change. Prey estimates varied with year and sex and size class of the whales, with large males consuming the highest proportions of Arctic cod, and females consuming the highest proportions of capelin Mallotus villosus. Estimated proportional contributions of Arctic cod to beluga diet decreased from 2011 to 2014, coinciding with an increase in capelin. Belugas consumed the highest proportions of capelin and the lowest proportions of cod in 2014, the same year in which body condition indices were lowest in the whales. We hypothesize that changing conditions in the Beaufort Sea ecosystem may result in a decreased consumption of Arctic cod by belugas and increased consumption of capelin, which may result in a decline in condition. This may predominately affect females and juveniles since they consume the highest proportions of capelin; however, long-term monitoring is needed for confirmation. Understanding inter-annual variation in prey, and the longer-term nutritional implications of shifting from an Arctic cod- to a capelin-dominated diet should be a priority for monitoring EBS predators.

Anthropogenic Scarring in Long-term Photo-identification Records of Cook Inlet Beluga Whales, Delphinapterus leucas

2021 ◽  
pp. 20-40
Author(s):  
Tamara L. McGuire ◽  
Amber D. Stephens ◽  
John R. McClung ◽  
Christopher Garner ◽  
Kathleen A. Burek-Huntington ◽  
...  
Keyword(s):  
Delphinapterus Leucas ◽  
Cook Inlet ◽  
Beluga Whales ◽  
Photo Identification

scholarly journals Straight as an arrow: humpback whales swim constant course tracks during long-distance migration

2011 ◽  
Vol 7 (5) ◽  
pp. 674-679 ◽  
Author(s):  
Travis W. Horton ◽  
Richard N. Holdaway ◽  
Alexandre N. Zerbini ◽  
Nan Hauser ◽  
Claire Garrigue ◽  
...  
Keyword(s):  
Humpback Whale ◽  
Open Ocean ◽  
Sea Surface ◽  
Humpback Whales ◽  
Surface Currents ◽  
Migration Routes ◽  
Long Distance ◽  
Seasonal Migrations ◽  
Compass Mechanisms ◽  
Better Than

Humpback whale seasonal migrations, spanning greater than 6500 km of open ocean, demonstrate remarkable navigational precision despite following spatially and temporally distinct migration routes. Satellite-monitored radio tag-derived humpback whale migration tracks in both the South Atlantic and South Pacific include constant course segments of greater than 200 km, each spanning several days of continuous movement. The whales studied here maintain these directed movements, often with better than 1° precision, despite the effects of variable sea-surface currents. Such remarkable directional precision is difficult to explain by established models of directional orientation, suggesting that alternative compass mechanisms should be explored.

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.

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

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 migrations of Sea of Okhotsk beluga whales (Delphinapterus leucas) of the Sakhalin-Amur summer aggregation

2010 ◽  
Vol 36 (1) ◽  
pp. 56-62 ◽  
Author(s):  
O. V. Shpak ◽  
R. D. Andrews ◽  
D. M. Glazov ◽  
D. I. Litovka ◽  
R. C. Hobbs ◽  
...  
Keyword(s):  
Sea Of Okhotsk ◽  
Delphinapterus Leucas ◽  
Beluga Whales ◽  
Seasonal Migrations

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.

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