Clamshell (Anomalocardia brasiliana) use as biofilter substrate in the treatment of heterotrophic shrimp culture in laboratory

The purpose of this research was to compare the efficiency of clamshell and ceramic ring biofilters in the treatment of aquaculture effluents. The experiment was carried out in the Laboratory of Mariculture Development - LAMARSU at the Federal Rural University of Pernambuco - UFRPE. The completely randomized design considered three treatments with three replicates each, in a total of nine experimental units, divided in natural clamshell substrates (NCS), ceramic ring commercial substrates (CRCS), and without any type of substrate (control). The comparison between treatments was made using ANOVA and Duncan test (P < 0.05). Results showed that the NCS and CRCS treatments presented different levels of ammonia reduction only on the first day; ammonia levels were the same for both treatments in the remainder of the trial period, coming to a reduction to zero. These figures were better than those found in the control treatment, where there was a reduction of ammonia from 0.60 mg/L to 0.39 mg/L. Thus, it was possible to conclude that the natural clamshell substrate (NCS) can replace or be used in conjunction with the ceramic ring commercial substrate (CRCS) aiming at ammonia reduction in the medium.