Mud crab aquaculture is expanding rapidly, but its potential is undermined by high mortality rates associated with post-transport stress and suboptimal rearing systems. The industry’s reliance on prolonged transport and clear-water recirculating aquaculture systems (RAS) is fundamentally misaligned with the physiology of Scylla serrata, the Indo-Pacific’s most farmed crab species. This study evaluated a habitat-enhanced RAS that mimicked estuarine conditions using a mud substrate, turbid water, and shelters to mitigate these challenges. Crabs subjected to transport durations of 0 h, 24 h, and 48 h were reared in conventional clearwater or naturalized RAS. Results demonstrated that extended transport significantly increased Vibrio spp. loads in haemolymph and tissues, induced gill damage, and suppressed immune function. In contrast, naturalized RAS markedly improved outcomes, enabling 80% survival even after 48h transport. These systems also improved key health metrics including immune (THC, PO) and antioxidant (SOD, GPx) capacity while simultaneously increasing moulting frequency and growth rates compared to clear-water controls. Kaplan-Meier analysis confirmed a significantly lower mortality risk in naturalized systems. These findings establish that adopting naturalized, species-specific RAS designs is a viable and critical strategy for mitigating transport stress, improving animal welfare, and securing the commercial sustainability of mud crab aquaculture.
Keywords: Scylla serrata, transport stress, RAS, Vibrio.