Estado trófico e bioacumulação do fósforo total no cultivo de peixes em tanques-rede na área aqüícola do reservatório de Itaipu

Abstract

The intense production of fishes and the use of water resources can compromise the quality and availability of water, in addition to its effects on environmental carrying capacity, causing eutrophication and consequently water pollution. Therefore, the objective of this study was to monitor the physical-chemical water variables and to measure the total phosphorus (total-P) in sediment, feed and fish in cage culture in an aquaculture area situated at the Itaipu reservoir in Santa Helena - Paraná State, observing water quality and determining the total eutrophic level on the aquaculture area, in addition to analyzing total-P bioaccumulation in fish and sediment. The physical-chemical water variables presented normal values as indicated by Conama. The mean concentration of total-P for the aquaculture area was 28.41 IET and Secchi disc transparency of 2.74 m, giving it an oligotrophic classification. There was a correlation of 0.55 (p < 0.01) between these two variables. The bioaccumulation of total-P in sediments decreased from 0.76 to 0.35 g kg-1 during this period. Mean fish accumulation ranged from 0.30 to 2.82 g kg-1. This activity can be used in the biomanipulation of total-P in similar reservoirs.