The effectiveness of Sargassum polycystum C.Agardh (1824) density to reduce nitrate and phosphate in vannamei shrimp aquaculture

The current development of aquaculture raises problems in the form of pollution of liquid waste generated during the production process. Aquaculture wastewater contains very high concentrations of inorganic nutrient. This study aims to determine the effectiveness of Sargassum polycystum density as a biofilter to reduce nitrate and phosphate in whiteleg shrimp pond. The study was conducted experimentally at indoor tank culture using a Completely Randomized Design (CRD) consisting of 3 density treatments with 3 replications, which were 1 gL-1, 2 gL-1, and 3 gL-1. The parameters observed were water quality such as nitrate, phosphate, temperature, salinity, pH, DO (Dissolved Oxygen), TSS (Total Suspended Solid), and TDS (Total Dissolved Solid); and also Saragassum's growth. The results showed that the density of 3 gL-1 able to reduce nitrate 80 and phosphate 86,30. The growth of S. polycystum for the three treatments decreased due to several factors, such as low nitrogen availability, environmental conditions, predators, and differences in stocking density. The average water quality measured during the study was temperature 27.84 °C; salinity 31.31 ppt; DO 4.72 mgL-1; pH 7.69; TDS 34.94 mgL-1; and TSS 4807.63 mgL-1. S. polycystum has the ability as biofilter for white shrimp culture because able to reduce nitrate and phosphate concentration. S. polycystum has potential benefits as alternative comodity candidate for polyculture and Integrated Multi Throphic Aquaculture (IMTA).