Environmental impact of semi-intensive shrimp farming on benthic fauna in southern Brazil - DOI: 10.4025/actascibiolsci.v31i4.3601

Abstract

The increase in aquaculture activity in costal areas has raised concerns about the discharge of effluents in the aquatic environment. The aim of this study was to determine the impact of effluents from the cultivation in Patos Lagoon – Brazil, using benthic macroinvertebrates as indicators. This research was conducted in a farm of Litopenaeus vannamei shrimp. Water parameters such as pH, diluted oxygen, oxygen consumption and total suspended solids were checked every 15 days. The sampling sites were a controlled region, the farm outflow channel and the settling ponds. The sediment for analysis of the benthic was sampled in the farm outflow channel and in the control area. One sampling occurred before the cultivation was started, and then every 15 days during the cultivation. The results show that the settling pond in shrimp cultivation was efficient. The pH and oxygen concentrations decreased, and oxygen consumption increased in the farm outflow channel. Furthermore, a change was observed in the macrofaunal structure in the environment adjacent to the cultivation. A decrease was also observed in the density of species sensitive to disturbance, such as Nephtys fluviatilis, Heleobia australis and fluctuations in the abundance of Kalliapseudes schubartii