Is the Marine Environment of the Black Sea Stressful for Organisms: A Pilot Assessment of Oxidative Stress in Bulgarian Coastal Fish Species

The present study is the first assessment of oxidative stress (OS) in fish species inhabiting the Bulgarian Black Sea coastal zone. The fish were caught during trawl selectivity experiments from different localities of the northern and southern coastal regions. The pro/antioxidant status of fish individuals was assessed by measuring standard OS biomarkers (lipid peroxidation, glutathione concentration, activities of superoxide dismutase and catalase) in gills and liver. Differences in the concentration and activity of OS biomarkers in the studied organs were clearly demonstrated. It was found that the level of OS in the studied fish species differed depending both on the species and on the coastal region they inhabit. Our results demonstrated for the first time the presence of OS in fish inhabiting coastal ecosystems of the Bulgarian Black sea sector with different quality of the marine environment. Obviously, further studies are needed for the assessment of multiple stressor effects on the ecology of Bulgarian Black Sea fish populations.