Diversity, composition and abundance of the gut microbiome of the mesopelagic fish revealed by 16S rRNA metabarcoding.
Supervisors: Laura Alonso, Raquel Liébana (AZTI)
The composition, abundance and diversity of the gut microbiome in 34 mesopelagic fish species (i.e., Nostocopelus kroyeri (NK), Benthosema glaciale (BG), Protomyctophum articum (PA), Cyclothone microdon (CM), Maurolicus muelleri (MM), Myctophum punctatum (MP), Scopelogadus beanii (SB) and Xenodermichthys copei (XC)) sampled from the Irminger Sea, North Atlantic Ocean were revealed by 16S rRNA metabarcoding. The results of alpha diversity of the gut microbiomes of the mesopelagic fish samples showed heterogenous patterns in the microbial diversity indices (i.e., Observed Amplicon Sequence Variants (Observed ASVs), Shannon and Inverse Simpson) suggesting a high variability in the diversity among different gut microbiome samples. The three diversity indices were significantly different (p-value < 0.05) among mesopelagic species overall, but no individual pairwise differences were statistically significant (p-value > 0.05) after accounting for multiple comparisons. A notable variation in the gut microbiome composition and abundance was observed, and certain bacterial taxa exhibited high abundances across the host-associated microbiomes. Analysis of beta diversity showed that most of the samples from the same fish species or the same sampling area clustered together and separated from the other clusters meaning that the gut microbiome from the same fish species or the same environmental conditions were similar at some level. Our findings reveal marked differences in the gut microbiome of different mesopelagic fishes, potentially due to different environmental conditions or diets.