Skin Microbiome as a Tool to Determine Whale Health Status: A Comparison of Stranded Versus Hunted Bowhead Whales (Balaena mysticetus) from Nunavut, Canada
Abstract
Climate change impacts oceans through fluctuations in temperature, oxygenation, and salinity.1 When paired with increasing human activity, these effects impair the immune system, enhance pathogen exposure and susceptibility, and boost diseases,2,3 threatening the health and survival of marine organisms, including whales.
The microbiome is a highly complex and dynamic community that participates in biogeochemical cycles in all ecosystems and performs functions that impact the health of living organisms.5 It is well-recognized that the dynamics of these communities are influenced by both intrinsic factors, such as the interactions between the diverse taxa, and extrinsic factors, such as host health status.6
Between October 2020 and April 2021, 11 bowhead whales (Balaena mysticetus), mostly juveniles, were stranded in the Gulf of Boothia near Kugaaruk, Nunavut, Canada. In partnership with local Inuit, we collected skin samples and analyzed the carcasses of stranded individuals. To gain additional insight into the causes of strandings, we analyzed and compared the skin microbiome composition of eight stranded individuals compared to ten healthy whales harvested during permitted subsistence hunts from the Eastern Canada and West Greenland populations.
Comprehending the bacterial microbiome’s structure and how it differs between hunted and stranded whales could be a valuable tool for determining the health status of bowhead whale populations. While we anticipate detection of a stable core microbiome in healthy animals, we may be able to identify a typical dysbiosis microbiome from stranded whales. Changes in the richness of microorganisms from the addition or deletion of community members are expected in stranded individuals.6 Given these alterations in the microbiome, an organic imbalance is generated, generally resulting in the detriment of the host’s health.7
Understanding the microbiome composition of healthy animals is critical to determining a baseline of animal health to which changes in composition may reflect disease processes. Analyzing the fungal and bacterial microbiomes can provide preemptive information that can be used to supplement stranded findings in cases where a definitive cause of death could not be determined. This study is the first approach to characterize and determine the core skin microbiome as a health/disease indicator in bowhead whales, allowing a much broader understanding of the health status of marine mammals in a changing ocean world.
Acknowledgments
The authors wish to thank the local Inuit from the community of Kugaaruk for their contributions to the study, collecting the bowhead whales’ skin samples.
*Presenting author
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