Measurement of cortisol in blow samples collected from free‐swimming beluga whales (Delphinapterus leucas)

Abstract

Blow or respiratory vapor collection is a noninvasive technique for monitoring the physiology of cetaceans and although this technique shows promise, a major challenge of blow collection is difficulty quantifying samples due to variable amounts of seawater contamination. Here, we aimed to (1) determine whether blow samples could be collected from free‐swimming belugas, (2) assess whether urea could be used as a dilution marker to normalize blow samples, and (3) determine which factors influenced cortisol and urea concentrations. We collected a total of 252 blow samples from free‐swimming belugas in the Churchill River in Manitoba, Canada. Cortisol, an indicator of individual stress and health, was detected in 65.87% of samples with concentrations ranging from 6.73 to 963.17 pg/ml of extract volume, while urea was detected in 90.48% of samples with concentrations ranging from 0.21 to 20.30 mg/L. We were unable to verify the efficacy of urea as a dilution marker to normalize blow samples from free‐swimming belugas; however, absolute cortisol concentrations varied based on sample device and quantity rating. Although we demonstrated that blow can be successfully collected from free‐swimming belugas, further refinement of this technique is needed before it can be used as a reliable method for physiological assessments.

Evaluating beluga (Delphinapterus leucas) blow samples as a potential diagnostic for immune function gene expression within the respiratory system

“…Further research on aquarium belugas can refine sampling and extraction methods and provide the necessary physiological validation for this developing diagnostic tool. For wild belugas specifically, this approach could be utilized during health assessments of temporarily restrained belugas, in populations where close-proximity boat-based sampling is feasible ( Hudson et al, 2021 ), or while they are temporarily mass-stranded, as occurs occasionally in the endangered population of Cook Inlet, Alaska ( National Marine Fisheries Service, 2015 ). Utilizing blow samples for gene expression studies also has the distinct advantage of providing information specific to the respiratory system, which is likely to be increasingly affected by anthropogenic disturbances.…”

Selection of appropriate biomatrices for studies of chronic stress in animals: a review

“…Cow Blood [14], saliva [14,15], urine [16], milk [17], feces [18] Sheep Blood [19], saliva [19], urine [20], feces [19] Pig Blood [21], saliva [22,23], urine [24], feces [25] Fish Blood [26], respiratory vapor [27] Chronic Cow Hair [28], hooves and claws [29] Sheep Wool [30] Pig Hair [31] Fish Scales [32], fins [33] Table 2. Use of corticosterone as a biomarker in previous studies of stress in animals…”