Novel Diversity of Bacterial Communities Associated with Bottlenose Dolphin Upper Respiratory Tracts

Respiratory illness is thought to be most the common cause of death in both wild and captive populations of bottlenose dolphins (Tursiops truncatus). The suspected pathogens that have been isolated from diseased animals have also been isolated from healthy individuals, suggesting they may be part of the normal flora.

Our current understanding of the bacteria associated with the upper respiratory tract (URT) of bottlenose dolphins is based exclusively upon culture-based isolation and identification. Because < 1% of naturally occurring bacteria are culturable, a substantial fraction of the bacterial community associated with the dolphin URT remains to be described.

The dolphin URT microbiota revealed by sequencing of bacterial 16S rDNA exhibits almost no overlap with the taxa indicated in culture-based studies. The most abundant sequences in our libraries were similar among all of our study animals and shared the greatest homology to sequences of bacteria belonging to the genera CardiobacteriumSuttonellaPsychrobacterTenacibaculumFluviicola, and Flavobacterium; however, they were sufficiently different from database sequences from both cultured and uncultured organisms to suggest they represent novel genera and species.

Our findings also demonstrate the dominance of three of the four bacterial phyla that dominate other mammalian microbiomes, including those of humans, and show tremendous diversity at the species/strain level, suggesting tight coevolution of the dolphin host and its URT bacterial community.


Microbial ecology. 2018-02-01; 75.2: 303-309.
Bacterial Species Identified on the Skin of Bottlenose Dolphins Off Southern California via Next Generation Sequencing Techniques
Russo CD, Weller DW, Nelson KE, Chivers SJ, Torralba M, Grimes DJ
PMID: 29080910
Environmental microbiology reports. 2009-12-01; 1.6: 555-62.
Novel diversity of bacterial communities associated with bottlenose dolphin upper respiratory tracts
Johnson WR, Torralba M, Fair PA, Bossart GD, Nelson KE, Morris PJ
PMID: 23765934


Funding provided through the National Science Foundation Biodiversity Surveys and Inventories, grant DEB0516347.


Pamela Morris
Hollings Marine Laboratory

Related Research