Microbial community profiles in water and biofilm of a bioball-based reactor for Litopenaeus Vannamei aquaculture

Microbial communities are integral to recirculating aquaculture systems (RAS), yet differences between planktonic and carrier-associated communities in early Litopenaeus vannamei culture remain poorly characterised. Water and bioball-biofilm bacterial communities were descriptively compared at Day of Culture 30, ending the blind-feeding phase, when feed follows a predetermined schedule before biomass and response-based adjustment. Water and pooled biofilm samples from a single RAS were sequenced (V3–V4 16S rRNA; 146,718 and 156,152 tags; Good's coverage = 1.000). Numerically greater richness and diversity were recorded in biofilm (472 versus 360 observed species; Shannon 3.888 versus 2.950). Shared OTUs totalled 316, whereas 156 and 44 were unique to biofilm and water, respectively. Pseudomonas was prominent in water, and Exiguobacterium and Psychrobacter in biofilm. Water-quality data characterised only the environmental context. Without biological replication, these findings represent system-specific descriptive patterns, not statistically demonstrated compartment effects, providing a preliminary baseline for replicated, longitudinal compartmentalisation studies.