Ecological analysis of the ichthyofaunal community ten years after a diesel oil spill at Serra do Mar, Paraná state, Brazil

In February 2001, an accidental spill dumped 52,000 litres of diesel oil in Serra do Mar, Paraná state, Brazil, contaminating streams. This study aimed to evaluate if fish communities currently inhabiting environments exposed to the oil spill still showing evidence of spill-related impacts. Ichthyofauna communities were monitored in five rivers located in the region of the spill. Two sites exposed to oil (Meio and Sagrado rivers) were considered treatment sites, and three unexposed sites with environmental characteristics similar to the treatment sites (Pinto, Passa Sete and Marumbi rivers) were considered control sites. Analysis of water quality parameters indicated that sites within rivers were more similar than sites among rivers. The diversity and species composition of fish communities differed between the treatment and control groups and among the rivers. The distribution and species composition of ichthyofaunal communities likely reflect the environmental characteristics of each river and not related to the environmental contamination resulting from the oil spill.