Optimizing trichloroisocyanuric acid disinfection in industrialized Litopenaeus vannamei culture: A system dynamics approach

Trichloroisocyanuric acid (TCCA) is widely used as a disinfectant in shrimp aquaculture, but inappropriate dosing can lead to ineffective pathogen control or toxicity to cultured organisms. This study developed a quantitative framework to optimize disinfection in industrialized Pacific white shrimp ( Litopenaeus vannamei ) culture. The approach integrates pathogen inactivation, disinfectant decay, and shrimp safety. Laboratory experiments quantified the inactivation kinetics of TCCA against pathogenic Vibrio species. Additionally, we assessed residual chlorine decay under varying water-quality conditions and acute toxicity to juvenile shrimp. TCCA at 0.3–0.5 mg/L achieved 96–99% inactivation of Vibrio within 3 h; however, bacterial regrowth occurred during the later exposure period as residual chlorine declined, particularly at lower concentrations. Residual chlorine followed first-order decay kinetics and was strongly influenced by temperature, total suspended solids, chemical oxygen demand, pH, and dissolved oxygen. The 96-h median lethal concentration (LC 50 ) for juvenile shrimp was 1.319 mg/L. This corresponds to a calculated safe concentration (SC) of 0.1319 mg/L. These datasets were integrated into a system dynamics model that coupled Vibrio growth, disinfectant decay, and bactericidal efficacy, enabling dynamic simulation of pathogen suppression and post-disinfection rebound. Model predictions agreed well with independent experimental observations. This study provides a practical decision-support tool to balance Vibrio control with shrimp safety. These results support precision disinfection management for sustainable aquaculture.