Avaliação de efluentes provenientes do cultivo de camarão marinho Litopeneaus vannamei (Bonne,1931), utilizando a ostra nativa Crassostrea rhizophorae (Guilding,1828) como biofiltro

Abstract

The bivalve mollusks are filter feeders that have been used as natural biofilter with the purpose of minimizing the excess of nutritious coming of the liberation of effluent’s of the sea shrimp culture, considering that such a nutrients ones can cause serious problems to the aquatic environment. The native oyster Crassostrea rhizophorae has been used as natural biofilter in cultivations of sea shrimps. The present work, used the native oyster C. rhizophorae as natural biofilter, has the purpose to verify the efficiency of C. rhizophorae in the reduction of the tenors of Ammonia, Nitrite, Nitrate, Orthophosphate and Chlorophyll the one of the effluent’s in the cultivation of shrimps sea the (10, 20 and 30) meters of distance of the beds in relation to the drainage of effluent’s of the shrimp culture. The experiment was accomplished in the period of March to December of 2003, in the farm of sea shrimp (New Field), in the Municipal district of (Rio Formoso), coast South of Pernambuco. They were certain the tenors of nutrients through the collection of samples of water in three points of the farm: in the channel of provisioning-AB, nursery 1 (V1), drainage-D and (bed I, II and III, respectively. These were analyzed at the Laboratory of Limnology of the Department of Fishing of Universidade Federal Rural de Pernambuco - UFRPE. The maximum and minimum value registered for Ammonia corresponded to 113.267 and 0.000μg/L; for Nitrate 41.055μg/L and 0.008μg/L; for Nitrite 3.435μg/L and 0.297μg/L; for Orthophosphate 104.411μg/L and 1.339μg/L and for Chlorophyll to 105.035μg/L and 1.860μg/L respectively. The experiment randomic was used entirely, being the treatments represented by three different distances of the beds in relation to drainage floodgate the (10m, 20m and 30m), with densities of stock of 1500 semen/cam. Theused statistical analysis was the one of analysis of simple variance (ANOVA), associated to the test of grouping of averages (Test of Tukey) being this applied to the analyses of compositions nitrogen and Chlorophyll-a. With base in the results is possible to affirm that the native oyster reduces the chlorophyll tenors the, and the orthophosphate.