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.

scholarly journals Health reference intervals and values for common bottlenose dolphins (Tursiops truncatus), Indo-Pacific bottlenose dolphins (Tursiops aduncus), Pacific white-sided dolphins (Lagenorhynchus obliquidens), and beluga whales (Delphinapterus leucas)

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0250332
Author(s):  
Lisa K. Lauderdale ◽  
Michael T. Walsh ◽  
Kevin A. Mitchell ◽  
Douglas A. Granger ◽  
Jill D. Mellen ◽  
...  
Keyword(s):  
Tursiops Truncatus ◽  
Bottlenose Dolphins ◽  
Reference Intervals ◽  
Least Square ◽  
Delphinapterus Leucas ◽  
Blood Samples ◽  
Tursiops Aduncus ◽  
Beluga Whales ◽  
Biochemical Variables ◽  
Lagenorhynchus Obliquidens

This study reports comprehensive clinical pathology data for hematology, serum, and plasma biochemistry reference intervals for 174 apparently healthy common bottlenose dolphins (Tursiops truncatus) and reference values for 27 Indo-Pacific bottlenose dolphins (Tursiops aduncus), 13 beluga whales (Delphinapterus leucas), and 6 Pacific white-sided dolphins (Lagenorhynchus obliquidens) in zoos and aquariums accredited by the Alliance for Marine Mammal Parks and Aquariums and the Association of Zoos & Aquariums. Blood samples were collected as part of a larger study titled “Towards understanding the welfare of cetaceans in zoos and aquariums” (colloquially called the Cetacean Welfare Study). Two blood samples were collected following a standardized protocol, and two veterinarian examinations were conducted approximately six months apart between July to November 2018 and January to April 2019. Least square means, standard deviations, and 95% confidence intervals were calculated for hematology, serum, and plasma biochemical variables. Comparisons by age, gender, and month revealed statistically significant differences (p < 0.01) for several variables. Reference intervals and values were generated for samples tested at two laboratories for up to 56 hematologic, serum, and plasma biochemical variables. To apply these data, ZooPhysioTrak, an iOS mobile software application, was developed to provide a new resource for cetacean management. ZooPhysioTrak provides species-specific reference intervals and values based on user inputs of individual demographic and sample information. These data provide a baseline from which to compare hematological, serum, and plasma biochemical values in cetaceans in zoos and aquariums.

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 Reference intervals and values for fecal cortisol, aldosterone, and the ratio of cortisol to dehydroepiandrosterone metabolites in four species of cetaceans

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0250331
Author(s):  
Lance J. Miller ◽  
Lisa K. Lauderdale ◽  
Michael T. Walsh ◽  
Jocelyn L. Bryant ◽  
Kevin A. Mitchell ◽  
...  
Keyword(s):  
Bottlenose Dolphins ◽  
Time Factors ◽  
Reference Intervals ◽  
Easy Access ◽  
Delphinapterus Leucas ◽  
Specific Reference ◽  
Beluga Whales ◽  
Physiological Indicators ◽  
Fecal Cortisol ◽  
Additional Reference

The goal of the current study was to create reference intervals and values for several common and one potential novel physiological indicators of animal welfare for four species of cetaceans. The subjects included 189 bottlenose dolphins (Tursiops truncatus), 27 Indo-Pacific bottlenose dolphins (Tursiops aduncus), eight Pacific white-sided dolphins (Lagenorhynchus obliquidens), and 13 beluga whales (Delphinapterus leucas) at Alliance of Marine Mammal Parks and Aquariums and/or Association of Zoos and Aquariums accredited facilities. During two sampling time periods between July and November of 2018 and between January and April of 2019, fecal samples were collected weekly for five weeks from all animals. Samples were processed and analyzed using enzyme immunoassay for fecal cortisol, aldosterone, and dehydroepiandrosterone (DHEA) metabolites. Linear mixed models were used to examine demographic and time factors impacting hormone metabolite concentrations. Age, sex, and time of year were all significant predictors for some of the models (p < 0.01). An iOS mobile application ZooPhysioTrak was created for easy access to species-specific reference intervals and values accounting for significant predictors. For facilities without access to this application, additional reference intervals and values were constructed without accounting for significant predictors. Information gained from this study and the use of the application can provide reference intervals and values to make informed management decisions for cetaceans in zoological facilities.

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 Towards understanding the welfare of cetaceans in accredited zoos and aquariums

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255506
Author(s):  
Lisa K. Lauderdale ◽  
Jill D. Mellen ◽  
Michael T. Walsh ◽  
Douglas A. Granger ◽  
Lance J. Miller
Keyword(s):  
Environmental Enrichment ◽  
Research Effort ◽  
Clinical Care ◽  
Bottlenose Dolphins ◽  
Reference Intervals ◽  
Habitat Characteristics ◽  
Delphinapterus Leucas ◽  
Specific Reference ◽  
Conservation Action ◽  
Beluga Whales

Cetaceans are long-lived, social species that are valued as ambassadors inspiring the public to engage in conservation action. Under professional care, they are critical partners with the scientific community to understanding the biology, behavior, physiology, health, and welfare requirements of this taxonomic group. The Cetacean Welfare Study was a highly collaborative research effort among zoos and aquariums accredited by the Alliance for Marine Mammal Parks and Aquariums and/or the Association of Zoos & Aquariums that provided important empirical and comparative information on the care and management of cetaceans. The goal was to identify factors that were related to the welfare of bottlenose dolphins and to develop reference intervals and values for common and novel indicators of health and welfare for common bottlenose dolphins (Tursiops truncatus), Indo-Pacific bottlenose dolphins (Tursiops aduncus), beluga whales (Delphinapterus leucas), and Pacific white-sided dolphins (Lagenorhynchus obliquidens). Data were collected from cetaceans at 43 accredited zoos and aquariums in seven countries in 2018 and 2019. This overview presents a summary of findings from the initial research articles that resulted from the study titled “Towards understanding the welfare of cetaceans in zoos and aquariums.” With multiple related objectives, animal-based metrics were used to advance frameworks of clinical care and target key conditions that were associated with good welfare of cetaceans in zoo and aquarium environments. As a result of this collaboration, species-specific reference intervals and values for blood variables and fecal hormone metabolites were developed and are freely available in an iOS application called ZooPhysioTrak. The results suggested that environmental enrichment programs and social management factors were more strongly related to behaviors likely indicative of positive welfare than habitat characteristics for common and Indo-Pacific bottlenose dolphins. These findings can be widely applied to optimize care and future science-based welfare practice.

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.

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 Cardiorespiratory coupling in cetaceans; a physiological strategy to improve gas exchange?

2020 ◽  
Vol 223 (17) ◽  
pp. jeb226365 ◽  
Author(s):  
Andreas Fahlman ◽  
Stefan Miedler ◽  
Luis Marti-Bonmati ◽  
Diana Ferrero Fernandez ◽  
Paola Muñoz Caballero ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Killer Whale ◽  
Bottlenose Dolphins ◽  
Beluga Whale ◽  
Cardiac Response ◽  
Delphinapterus Leucas ◽  
Pilot Whale ◽  
Terrestrial Mammals ◽  
False Killer Whale ◽  
Cardiorespiratory Coupling

ABSTRACTIn the current study we used transthoracic echocardiography to measure stroke volume (SV), heart rate (fH) and cardiac output (CO) in adult bottlenose dolphins (Tursiops truncatus), a male beluga whale calf [Delphinapterus leucas, body mass (Mb) range: 151–175 kg] and an adult female false killer whale (Pseudorca crassidens, estimated Mb: 500–550 kg) housed in managed care. We also recorded continuous electrocardiogram (ECG) in the beluga whale, bottlenose dolphin, false killer whale, killer whale (Orcinus orca) and pilot whale (Globicephala macrorhynchus) to evaluate cardiorespiratory coupling while breathing spontaneously under voluntary control. The results show that cetaceans have a strong respiratory sinus arrythmia (RSA), during which both fH and SV vary within the interbreath interval, making average values dependent on the breathing frequency (fR). The RSA-corrected fH was lower for all cetaceans compared with that of similarly sized terrestrial mammals breathing continuously. As compared with terrestrial mammals, the RSA-corrected SV and CO were either lower or the same for the dolphin and false killer whale, while both were elevated in the beluga whale. When plotting fR against fH for an inactive mammal, cetaceans had a greater cardiac response to changes in fR as compared with terrestrial mammals. We propose that these data indicate an important coupling between respiration and cardiac function that enhances gas exchange, and that this RSA is important to maximize gas exchange during surface intervals, similar to that reported in the elephant seal.

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