Bacterial diversity on wild shrimp post larvae in a mangrove biodiversity hotspot

ABSTRACT

Aims@#This study aims to assess the impact of anthropogenic activities on shrimp microbiome in a biodiverse mangrove forest ecosystem, along the Merbok River, Kedah, Malaysia.@*Methodology and results@#To assess the impacts, a microbiome study of wild post larvae shrimps along the river was conducted as a health indicator of the shrimp hosts which in turn would reflect the river conditions. A 16S rRNA gene amplicon sequencing of the wild post larvae shrimp microbiomes sampled across areas of varying human activities was conducted. Samples were obtained from four sites ranging from upstream river habitat to downstream brackish water towards the marine coast. Individuals detected from the sequence were then counted and their relative abundance of bacterial diversity were compared. All abundances are up to 100% and the diversity indices were calculated using proportions of each species. The Operational Taxonomy Unit (OTUs) were obtained by using USEARCH and UPARSE software. Twenty-eight bacterium phyla were detected, dominated by phyla Proteobacteria, Actinobacteria, Firmicutes and Bacteroidetes at each site. Eighteen families were dominant at each site with Streptomycetaceae being the major abundant. At the genus level, the most abundant genera were Streptomyces sp., Mesorhizobium sp., Rhizobium sp., Bacillus sp. and Pseudomonas sp.@*Conclusion, significance and impact of study@#In general, the diversity of opportunistic and coliform bacteria was low. Thus, despite being exposed to various levels of human activities, the Merbok River and its mangrove surroundings still serve as a good spawning and nursery sites of shrimps and presumably other inhabitants.