Bacterial Community Composition and Succession During Larval Ontogeny of Cultured Tropical Rock Lobster ( Panulirus ornatus )

The dynamics within bacterial communities play a significant role in the health, nutrition and disease resistance of tropical rock lobster ( Panulirus ornatus ) larvae in aquaculture. However, studies on bacterial succession throughout P. ornatus larval development remain limited. Therefore, this study investigated bacterial community composition and succession from newly hatched phyllosoma (0‐day post‐hatching, 0 dph) to the puerulus stage, using Oxford Nanopore 16S rRNA gene sequencing. Alpha and beta diversity metrics were used to assess patterns of diversity and shifts in community composition. Indicator species analysis was applied to identify taxa associated with specific developmental stages. Larval bacterial diversity showed a trend aligned with larvae developing to the puerulus stage. Early phyllosoma stages were enriched in bacterial families, such as Alteromonadaceae and Roseobacteraceae, whereas Pseudoalteromonadaceae dominated later stages. The key bacterial taxa identified as stage‐specific indicators were Alteromonas , Ruegeria , Shimia , Thalassotalea and Pseudoalteromonas . Several intrinsic cues, such as maternal effect, moulting and immune status, were considered factors influencing bacterial composition throughout larval development. This study provides the first comprehensive analysis of bacterial succession during the larval ontogeny of P. ornatus , revealing that bacteriome dynamics are closely associated with developmental physiology and environmental inputs. The identification of bacterial indicators specific to lobster developmental stages enhances our understanding of host–bacteria interactions during lobster larval rearing. It also strongly supports the development of strategies to improve larval survival and mitigate disease in aquaculture systems.