LIMNOLOGICAL CHARACTERIZATION IN A TILAPIA CULTIVATION SYSTEM IN CAGES AT THE ESTEVAM MARINHO DAM IN COREMAS-PB

Abstract

The study evaluated the limnological characteristics of a tilapia cultivation system in cages at the Coremas-PB dam, one of the largest reservoirs in the Brazilian Northeast. The samples were collected at 7 sampling points, including 5 cages, one point is called by the author, arm of the dam and another in the catchment, during the months of July to November 2005, a period characterized as drought in the region. Physicochemical parameters such as temperature, transparency, pH, electrical conductivity, dissolved oxygen, BOD and nitrogen series were analyzed. The results indicated high water transparency (average of 1.43m in the cages), with a euphotic zone of approximately 3.86m, demonstrating a low amount of suspended material and good light penetration. The average temperature remained at 26.47°C, within the ideal range for cultivation, and the dissolved oxygen values were adequate for production (average of 6.4 mg/L in the cages). The levels of ammonium ion were high in the cages (maximum of 0.76 mg/L), but the slightly acidic pH (mean 6.9) favored the non-toxic form of the compound. The analysis of the parameters allowed to classify the water as Class 1 according to CONAMA Resolution 357/2005, indicating suitability for cultivation. Continuous monitoring of these parameters is essential to ensure the sustainability of production and the preservation of the aquatic environment.