A study of the microbiome present in faeces sampled from 47 dugongs between tropical Cleveland Bay (19.2 °S, 146.9 °E) and sub-tropical Moreton Bay (27.3 oS, 153.3 oE), Queensland, Australia.. Queensland Dugong Faecal Microbiome

Gut microbial composition of herbivores may be related to diet and may reflect host health. Dugongs are obligate seagrass grazers with an expanded hindgut and associated microbiome. This study aimed to characterise and compare the faecal (hindgut) microbiota of dugongs from genetic populations along the east coast of Australia between subtropical Moreton Bay and tropical Townsville. Since seagrass diversity and community composition vary latitudinally, we hypothesised that the hindgut microbiome would also vary. Fresh dugong faecal samples (n = 47) were examined by 16S rRNA gene amplicon sequencing. Firmicutes (62 %) dominated the hindgut microbiome across all populations, followed by Bacteroidetes (30 %), Actinobacteria (5 %) and Proteobacteria (2 %). Several bacterial families (Clostridiaceae_1, Lachnospiraceae, Peptostreptococcaceae, Ruminococcaceae, Bacteroidaceae and Flavobacteriaceae) were detected in samples from all locations, suggesting their importance in seagrass digestion. Principal Coordinate Analysis showed that the three southern-most dugong populations had different microbiota compositions from northern populations, suggesting potential adaptive changes associated with location. This study contributes to our knowledge of the hindgut microbiota of dugongs inhabiting Australian coastal waters. Future studies of diet selection will help to advance our understanding of the roles that seagrass species may play in affecting the dugong’s microbiota community composition.