Metabolic and physiological responses of a coastal fish in highly and lightly impacted habitats

Coastal and estuarine zones are used by fish as nursery, spawning and feeding grounds. However, these essential habitats are characterized by the presence of both natural and anthropogenic stressors that may represent potential threats for the wellbeing of aquatic organisms, particularly fish. The main objective of this study was to evaluate and understand the effects of environmental stressors, both natural and anthropogenic, on coastal fish species using Ramnogaster arcuata as bioindicator. Fish were captured in two zones with different human activity levels: a highly impacted zone in Bahía Blanca Estuary (BBE) and a lightly impacted zone in the adjacent coastal zone (ACZ). Various indicators were used to determine fish responses to environmental stress. Main differences found between fishes from the two zones were in the condition index, trophic ecology (including feeding activity and diet composition) and liver metabolic biomarkers (ALT/AST enzymes, protein levels and lipid peroxidation). On the other hand, metal concentration levels analyzed in muscle did not show important differences between both environments. Physiological responses of R. arcuata from both zones were strongly correlated with natural stressors.