Evaluation of Size-Based Performance of Blood Cockles Anadara granosa as a Biofiltration Agent in Whiteleg Shrimp Litopenaeus vannamei Aquaculture Systems

Effluent from intensive whiteleg shrimp ponds can promote excessive phytoplankton growth in natural aquatic ecosystems. One potential mitigation strategy is the use of blood cockles, which can assimilate excess nutrients present in the effluent. Cockle size is an important consideration, as it may affect their nutrient uptake capacity. This study evaluated the performance of blood cockles from different size groups in improving the quality of effluent from intensive shrimp farming. The 90-day experiment was conducted at a semi-outdoor scale using shrimp pond effluent as the culture medium. Four treatments were applied: blood cockles with shell sizes of 25– 30, 30– 35 & 35–40mm, and a control without cockles. Each treatment was replicated three times. Results showed that cockles in all size groups reduced phytoplankton abundance as well as concentrations of inorganic and organic nutrients in the medium. The 30– 35mm size group achieved the highest efficiency and overall performance. Survival rates exceeded 90% across all treatments, and steady growth was observed throughout the culture period. In conclusion, blood cockles in the 30– 35mm size group provided the most efficient and optimal reduction of nutrient levels in shrimp pond effluent, while maintaining high survival and consistent growth over the 90-day period.