The nasal microbiota of two marine fish species: diversity, community structure, variability and first insights into the impacts of climate change-related stressors

Abstract

Vertebrate nasal microbiota (NM) plays a key role in regulating host olfaction, immunity, neuronal differentiation, and structuring the epithelium. However, little is known in fish. This study provides the first comprehensive analysis of the NM in two marine fish species, the European seabass and the Atlantic cod. Given its direct contact with the environment, fish NM is likely influenced by seawater. We analysed the community structure, specificity regarding seawater, and interindividual variability of 32 to 38 fish reared under ambient conditions. Additionally, we conducted a simulated laboratory experiment to investigate the influence of acidification and a simplified heatwave on cod NM (3 fish per replicate). High-throughput 16S rRNA sequencing revealed species-specific NM communities at the genus level with Stenotrophomonas and Ralstonia dominating seabass and cod NM, respectively. This suggests potential habitat- or physiology-related adaptations. The most abundant bacterial genera in seabass NM were al

The nasal microbiota of two marine fish species: diversity, community structure, variability and first insights into the impacts of climate change-related stressors