Integrated multi-trophic aquaculture (IMTA) enhances growth, water quality, and sustainable productivity in pond systems

Integrated multi-trophic aquaculture (IMTA) systems can enhance pond performance by combining fed and extractive species, yet evidence from brackish water earthen ponds in South Asia remains limited. This study evaluated how adding aquatic macrophytes and mud-flat snails alongside black tiger shrimp and goldspot mullet affects growth, survival, water quality, and economic outcomes. A 120-day experiment was conducted using four systems: a Control, and three IMTA treatments incorporating aquatic macrophytes (T1), snails (T2), or both components (T3), each with three replicate ponds. Growth was sampled every 15 days, harvest yield and survival were recorded at the end, and water quality was monitored throughout. All analyses followed linear models with Tukey comparisons and Pearson correlations. Across all taxa, T3 produced the strongest improvements in growth, daily weight gain, and production. Both shrimp and mullet showed higher specific growth rates, lower feed conversion ratios, and improved survival in IMTA systems, with the greatest gains in T3. Snail and macrophyte production increased significantly, consistent with their extractive roles. Water quality remained stable and within acceptable limits. Temperature and hardness were positive predictors of growth, survival, and production, whereas dissolved oxygen and pH showed negative correlations during periods of high biological activity. Economic returns improved across all IMTA treatments, with T3 yielding the highest net return and benefit–cost ratio. These results show that IMTA enhances growth, stabilizes water quality, and increases farm profitability. By promoting nutrient recycling and reducing waste, the system supports sustainable production, circular resource use, and low-waste aquaculture in coastal farming.