Estudo da qualidade da água durante a criação de peixes em tanques-rede no reservatório de Salto Caxias

Abstract

The control of abiotic parameters in fish farming in ponds network is difficult because the structures are distributed over large areas, these sites are subject to the weather forecast and the actual environment in which they are located. Thus, knowledge of the behavior of physical and chemical factors is of paramount importance to the activity occurring fish in a sustainable and environmentally friendly. Thus, this study aimed to carry out a monitoring of limnological characteristics during the period of one year and see if there are changes in time, longitudinal and vertical water quality in the catchment area of fish farming in ponds in the reservoir of Salto Network Caxias in Rio Iguaçu and the results determine the carrying capacity of the site. The study was conducted during the months of August 2010 to July 2011 and made a collection every month. The parameters evaluated were: water temperature, hydrogen potential (pH), dissolved oxygen, water transparency, chlorophyll, total phosphorus and orthophosphate. To evaluate the longitudinal dynamics of six stations are established in a sample covering the entire area of influence of the tanks network. To determine the dynamic vertical, the samples were collected with the aid of a Van Dorn bottle at three layers: epilimnion (surface layer), Metalímnio (middle layer) and hypolimnion (deep layer). The estimated carrying capacity was performed using the method developed by Dillon and Rigler (1974). There were temporal variations (except for the pH and chlorophyll) and no changes spatial and vertical (except for dissolved oxygen). Overall, the site presents characteristics favorable for breeding fish, nor is there evidence of deterioration of water quality. Months of the Dec/10 mar/11 water temperatures were more favorable for the growth of fish. The production capacity of the site can be increased by 44 tons, without exceeding the recommended limit of phosphorus in the resolution n. 357/05 of CONAMA.