A multi biomarker approach for the assessment of the physiological condition of Solea sp populations in NW Mediterranean fishing

Abstract

The use of biomarkers comprising several levels of biological organization (biochemical, immune and physiological) as indicators of exposure and/or effect to environmental pollutants, allows for a very comprehensive understanding of alterations that might compromise essential physiological processes. This multibiomarker approach was applied to a benthic fish species of great commercial interest. The sampling of sole, Solea solea and Solea senegalensis was carried out using artisanal fishing techniques with the collaboration of local fisherman. Immediately after fishing, biological traits such as total length and weight were recorded for the determination of their condition factor. Blood was taken right after capture and the fish immediately sacrificed and dissected. Tissues and organs including brain, muscle, gills, liver, kidney, gonad and bile were snap frozen in liquid nitrogen for further biochemical analyses. In addition, portions of liver and gonads were preserved in Bouin-hollande fixative for histological analysis. Liver and gonad weight were also recorded for hepatosomatic and gonadosomatic index calculations. The comprehensive set of biomarkers included: vitellogenin (VTG), sex hormone levels, immune markers and cell counts, metallothionein content, activities of the enzymes acetylcholinesterase (AChE), lactate dehydrogenase, carboxylesterase, glutathione S-transferase, ethoxyresorufin O-deethylasa (EROD), antioxidants such as catalase, glutathione peroxidase, glutathione reductase and lipid peroxidation (LP) levels in several target tissues/organs. Five sampling sites along the Northern Mediterranean coast from Costa Brava to Cambrils were studied. The sites were selected according to the possible presence of organic contaminants and metals since some of them could be end points for run offs from local discharges. [...]