Water quality and microbial interactions in aerofloc systems for whiteleg shrimp aquaculture in round ponds in east Java, Indonesia

Intensive shrimp aquaculture in tropical regions is increasingly challenged by recurrent bacterial disease outbreaks, particularly vibriosis and acute hepatopancreatic necrosis disease (AHPND), alongside growing pressure to reduce antibiotic use while maintaining high productivity. In this context, production systems capable of stabilizing water quality and microbial balance are critical for sustainable intensification. East Java represents a typical tropical intensive shrimp-farming environment characterized by high stocking densities and elevated disease risks. This study investigated microbial and water quality dynamics in an aerofloc-based intensive white shrimp (Litopenaeus vannamei) culture system using a round-tank configuration under tropical conditions. The aerofloc system, which integrates continuous aeration and enhanced water circulation, was evaluated as an alternative to conventional biofloc, recirculating aquaculture systems, and traditional pond systems in terms of its capacity to support microbial balance under intensive culture conditions. Shrimp were cultured at different stocking densities (11-44 individuals m⁻²), and key water quality parameters, organic matter proxies, microbial populations (total bacteria and presumptive Vibrio), and plankton communities were monitored. The results indicated stable water quality conditions and a predominance of non-Vibrio bacterial populations across treatments, with microbial and planktonic patterns closely associated with organic matter dynamics. These findings highlight the relevance of aerofloc-based systems in managing microbial balance under high-intensity tropical shrimp culture, with important implications for disease risk mitigation, reduced reliance on antibiotics, and the sustainable intensification of shrimp aquaculture.