Effect of Landscape Changes on Water Quality and Health Status of Heptapterus mustelinus (Siluriformes, Heptapteridae).

Substances derived from anthropogenic activities induce changes in the physical and chemical characteristics of the aquatic environment. Physicochemical and biological studies are necessary to understand how changes in landscape affect the health of the aquatic environment. The main goal of this study was to evaluate how the landscape at different spatial scales affects (1) water quality and (2) the health status of Heptapterus mustelinus, based on several biomarkers. During the dry season, individuals were caught in three sites with different degrees of anthropogenic activity. The quality of the terrestrial environment was assessed using the Riparian Quality and Land Use Indices. The water quality condition was evaluated using a water quality index, and pesticides and pharmaceuticals were measured in water. The following biomarkers were analyzed in the fish: general health status (Condition Factor, Hepatosomatic index and energetic costs), enzymatic activity (GST, CAT, AchE), carbonyl content in proteins and histopathological responses in liver and gills. The most impacted sites by the presence of pesticides showed more alterations in the surrounding landscape; specially, changes in the riparian area. In this area, biomarkers denoted more damage than in sites with protected riparian zone. Conservation status of riparian ecosystems is crucial in the determination of rivers ecological quality. Our results demonstrate the importance of monitoring the environmental quality through an integrated analysis, using native fish to understand the effects of human activities on the biota.