title: Humpback whale populations share a core skin bacterial community: towards a health index for marine mammals?
abstract: Microbes are now well regarded for their important role in mammalian health. The microbiology of skin--a unique interface between the host and environment--is a major research focus in human health and skin disorders, but is less explored in other mammals. Here, we report on a cross-population study of the skin-associated bacterial community of humpback whales (Megaptera novaeangliae), and examine the potential for a core bacterial community and its variability with host (endogenous) or geographic/environmental (exogenous) specific factors. Skin biopsies or freshly sloughed skin from 56 individuals were sampled from populations in the North Atlantic, North Pacific and South Pacific oceans and bacteria were characterized using 454 pyrosequencing of SSU rRNA genes. Phylogenetic and statistical analyses revealed the ubiquity and abundance of bacteria belonging to the Flavobacteria genus Tenacibaculum and the Gammaproteobacteria genus Psychrobacter across the whale populations. Scanning electron microscopy of skin indicated that microbial cells colonize the skin surface. Despite the ubiquity of Tenacibaculum and Psychrobater spp., the relative composition of the skin-bacterial community differed significantly by geographic area as well as metabolic state of the animals (feeding versus starving during migration and breeding), suggesting that both exogenous and endogenous factors may play a role in influencing the skin-bacteria. Further, characteristics of the skin bacterial community from these free-swimming individuals were assembled and compared to two entangled and three dead individuals, revealing a decrease in the central or core bacterial community members (Tenacibaculum and Psychrobater spp.), as well as the emergence of potential pathogens in the latter cases. This is the first discovery of a cross-population, shared skin bacterial community. This research suggests that the skin bacteria may be connected to humpback health and immunity and could possibly serve as a useful index for health and skin disorder monitoring of threatened and endangered marine mammals.
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America.
authors.forename: Amy
authors.initials: A
authors.lastname: Apprill
authors.affiliation: Center for Coastal Studies, Provincetown, Massachusetts, United States of America.
authors.forename: Jooke
authors.initials: J
authors.lastname: Robbins
authors.affiliation: Josephine Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America.
authors.forename: A Murat
authors.initials: AM
authors.lastname: Eren
authors.affiliation: University of Hawaii at Hilo, Hilo, Hawaii, United States of America; The Dolphin Institute, Honolulu, Hawaii, United States of America.
authors.forename: Adam A
authors.initials: AA
authors.lastname: Pack
authors.affiliation: Josephine Bay Paul Center, Marine Biological Laboratory, Woods Hole, Massachusetts, United States of America.
authors.forename: Julie
authors.initials: J
authors.lastname: Reveillaud
authors.affiliation: Hawaiian Islands Humpback Whale National Marine Sanctuary, Kihei, Hawaii, United States of America.
authors.forename: David
authors.initials: D
authors.lastname: Mattila
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America.
authors.forename: Michael
authors.initials: M
authors.lastname: Moore
authors.affiliation: International Fund for Animal Welfare, Yarmouth Port, Massachusetts, United States of America.
authors.forename: Misty
authors.initials: M
authors.lastname: Niemeyer
authors.affiliation: International Fund for Animal Welfare, Yarmouth Port, Massachusetts, United States of America.
authors.forename: Kathleen M T
authors.initials: KM
authors.lastname: Moore
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, United States of America.
authors.forename: Tracy J
authors.initials: TJ
authors.lastname: Mincer
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D059001:Aquatic Organisms / Q000382:microbiology*; D001419:Bacteria / Q000145:classification / Q000235:genetics; D001483:Base Sequence; D044822:Biodiversity; D005260:Female; D005843:Geography; D006262:Health; D050640:Humpback Whale / Q000382:microbiology*; D008297:Male; D064307:Microbiota / Q000235:genetics; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012867:Skin / Q000382:microbiology* / Q000648:ultrastructure
chemical_list: D012335:RNA, Ribosomal