Hematology and Plasma Chemistry as Indicators of Health and Ecological Status In Beluga Whales, Delphinapterus Leucas

Abstract

ABSTRACT. The capture of beluga whales, Delphinapterus leucas, for instrumentation or tagging afforded the opportunity to collect blood, which was analyzed to evaluate the animals' health and gain information on basic physiological systems. Here, we report on hematological and plasma chemical constituents in samples obtained from 183 belugas, 55 of which were handled during attempts to apply tracking instruments. The other 128 samples were either drawn from live belugas captured for exhibit in zoological parks or research or obtained from the fresh carcasses of whales taken by Inuit hunters. The data span a 15-year period beginning in 1983 and represent various beluga stocks in the Canadian Arctic. The majority of the specimens were collected during the summer or estuarine phase of the belugas' annual cycle. Comparisons by age group, sex, stock, season, and year revealed significant differences in most of the cellular and chemical constituents examined. These results demonstrate some of the variability that might be encountered when examining a "random" selection of belugas at a particular location and time. Immaturesized whales had higher leucocyte counts, electrolyte concentrations, enzyme activity, total protein, albumin, hemoglobin, and some metabolites than older animals. Sex alone was associated with few hematological and plasma chemical differences. Seasonal variation in thyroid hormone activity was linked to marked environmental changes associated with the transition from cold oceanic waters to relatively warm estuaries. Two belugas recaptured 19 and 24 days after instrumentation showed changes in leucocyte counts, hematocrit, and a variety of plasma chemical constituents, some of which indicate inflammation and a likely physiological response to handling and tagging stresses.Key words: beluga, blood analysis, diagnostics, health, hematology, physiology, plasma chemistry, stress RÉSUMÉ. On a profité du fait qu'on capturait des bélougas, Delphinapterus leucas, en vue de les équiper d'instruments ou de les marquer, pour prélever des échantillons de sang qu'on a ensuite analysés afin d'évaluer l'état de santé des individus et de collecter de l'information sur leurs grands systèmes physiologiques. Nous présentons ici un rapport sur les constituants hématologiques et chimiques du plasma dans des échantillons provenant de 183 bélougas, dont 55 ont été manipulés au cours de tentatives visant à les équiper d'instruments de poursuite. Les 128 autres échantillons ont été obtenus soit de bélougas vivants capturés en vue d'être placés dans des zoos ou pour la recherche, soit de carcasses fraîches de baleines prises par les chasseurs inuits. Les données couvrent une période de 15 ans, commençant en 1983, et représentent divers stocks de bélougas de l'océan Arctique canadien. La plupart des spécimens ont été recueillis durant l'été ou durant la phase estuarienne du cycle annuel du bélouga. Des comparaisons par groupe d'âge, sexe, stock, saison et année ont révélé des différences marquées dans la plupart des constituan...

Cortisol levels in beluga whales (Delphinapterus leucas): Setting a benchmark for Marine Protected Area monitoring

“…This is in accordance with previous findings where plasma cortisol measurements were not ideal for monitoring the general state of beluga health due to reactivity to acute stress (St. Aubin et al 2001). Middle and outer blubber tissues are also ideal tissue when considering storage degradation factors of heat, light, and oxygen exposure that the inner blubber and sample edges are readily exposed to (Trana et al 2015); the use of the outer layer would allow for live biopsy collections.…”

“…Plasma cortisol levels in live captured, wild belugas (Beaufort Sea, Hudson Bay, High Arctic) were double the measurements in our study, but lower than the induced stressful event in the captive belugas (St. Aubin and Geraci 1989;St. Aubin et al 2001) (Table 3).…”

“…Aubin et al (2001) reported standard deviation. The authors noted a lack of size and age effects on cortisol levels (St. Aubin et al 2001). Additional studies are needed to enable robust comparisons between live sampled to hunted sampled beluga cortisol levels.…”

“…Cortisol has been used as an indicator of stress response and overall population health for a wide range of mammals (Sheriff et al 2011;Atkinson et al 2015). It has been quantified in many matrices such as blood (serum/plasma), urine, feces and hair, as well as in blubber and the blow from cetaceans (St. Aubin et al 2001;Schmitt et al 2010;Macbeth et al 2012;Palme et al 2013;Thompson et al 2014;Kellar et al 2015;Trana et al 2015). Cortisol has also provided insight into stress associated with contaminants, such as persistent organic pollutants (POPs) that include PCBs and PBDEs (Verboven et al 2010;Bechshoft et al 2012b).…”

Hematology and Serum Biochemistry Values in Five Captive Finless Porpoises (<i>Neophocaena phocaenoides</i>)

“…Seasonal differences in hematological and serum biochemical parameters have been reported in wild beluga whales and bottlenose dolphins [7,14]. A study on captive bottlenose dolphins also showed significantly higher creatinine levels in adult animals in summer than in winter [7,17].…”