Feasibility of implantation of net tanks in the SHP reservoir in the state of Tocantins, Brazil

Abstract

For the sustainable development of intensive pisciculture activities in reservoirs, it is essential to have information on the limnological characteristics of their contributing water bodies, its peculiarities and support capacity. Therefore, the study aimed to verify the feasibility of implementing intensive pisciculture adopting net cages in the reservoir of the Small Hydroelectric Plant (PCH) Boa Sorte, Tocantins, evaluating the favorable locations for installation of net cages, the limnological characteristics and the support capacity of the water bodies. The reservoir is located on the Palmeiras River, which belongs to Palma River basin and integrates the Paranã River basin, which is an important tributary of the Tocantins River. To identify areas favorable to the establishment of the aquaculture park, the entire reservoir area was analyzed, making up an area of 232 ha of water depth, where the majority, 141 ha, were considered favorable. After that, the limnological parameters were analyzed, namely: Temperature, pH, dissolved oxygen, transparency, chlorophyll-a, total phosphorus, ammonia, nitrite and nitrate. All parameters, except for total phosphorus, met the values recommended in CONAMA (2005) nº 357 resolution. The average concentration of total phosphorus during the study period was 0.13 mg.L-1, which demonstrates that the support capacity of the reservoir has already been exceeded. In view of the data presented in this study, it was concluded that fish farming in net cages is not recommended in PCH Boa Sorte reservoir, as such activity can aggravate the eutrophication process existing in the water body under study.