Humpback whales share a simplistic skin bacterial community across populations, according to results published March 26, 2014, in the open access journal PLOS ONE by Amy Apprill from the Woods Hole Oceanographic Institution and colleagues. The overall bacterial communities differ by geographic area and by metabolic state, such as feeding versus starving during migration and breeding.
Bacterial communities living on mammal skin may play a role in their health; for humans, there is a relationship between skin bacteria and allergic or inflammatory conditions. While skin bacteria are frequently studied in humans, less is known about the composition of skin bacteria in other mammals. Whales move thousands of miles through the ocean and come in contact with numerous bacteria. Scientists studied the bacterial species on the skin of humpbacks from different geographical areas, as well as their health conditions to better understand the role these microbes play in their health. They genetically sequenced over 500,000 genes from bacteria obtained from humpback whale skin collected in various geographic locations in the Pacific and Atlantic and during various stages of the life cycle, including during breeding and feeding. These data were also compared to bacterial sequences found on the skin of deceased whales and whales with injuries and compromised health from entanglement in fishing line.
The authors found that the general bacterial community of the healthy individuals consisted mainly of Tenacibaculum and Psychrobacter spp., sequences that were specific to humpbacks, but the overall composition of the bacterial populations differed by geographical location and metabolic state, as well as in stressed and deceased individuals. The latter contained less core bacteria (Tenacibaculum and Psychrobacter spp.) and more potential pathogens. These results may indicate, according to the authors, that the bacterial skin community may act as an indicator of whales' health and the status of the environment. Though more work needs to be done, this study may help researchers monitoring the population health and conservation status of threatened or endangered marine mammals.
"It is astonishing that we find Tenacibaculum and Psychrobacter spp. bacteria on whale skin regardless of animal age, sex, metabolic state, geographic region or population. These bacteria may be involved in an important interaction with the whales," Amy Apprill added. "With further development, we might be able to gain insight into the health of whales by examining their skin-bacteria."
Citation: Apprill A, Robbins J, Eren AM, Pack AA, Reveillaud J, et al. (2014) Humpback Whale Populations Share a Core Skin Bacterial Community: Towards a Health Index for Marine Mammals? PLoS ONE 9(3): e90785. doi:10.1371/journal.pone.0090785
Financial Disclosure: A.A. was funded by a WHOI Ocean Life Institute post-doctoral scholar award, and this research was supported by a grant to A.A. and T.J.M. from Woods Hole Oceanographic Institution's (WHOI) Marine Mammal Center. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interest Statement: The authors have declared that no competing interests exist.
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