Studies on the bioremediation capacity of the adult black clam, Chione fluctifraga, of shrimp culture effluents

The black clam, Chione fluctifraga, can be used to bioremediate discharge effluents produced by shrimp aquaculture. With such purpose we evaluated during 77 days, the effect of two densities of clams (12.5 and 25·specimens m^-2) and a control (0·m^-2) on the water quality of raw effluents from a semi-intensive culture of shrimp (Litopenaeus vannamei; 25 m^-2). Parameters such as total suspended solids (TSS), organic suspended solids (OSS), total ammonium nitrogen (TAN) and total nitrogen (TN) were measured in raw effluents, control, treatments and estuary (water source for shrimp culture). The TSS and OSS diminished in control and treatments, compared with untreated effluents. The TSS and OSS decreased over time with no significant difference observed among the treatments during the first 22 days of trial. However, treatments had a greater decrease of TSS and OSS levels at days 48 and 77 compared with the control. TAN recorded the lowest levels in both treatments, followed by control and effluents respectively; no significant differences were observed for TN. The results indicate that Chione fluctifraga has ability as biorremediator and it does survive well in shrimp pond effluents.