Determining oxidative stress and EROD activity in dab (Limanda limanda) in the North and Baltic Seas

The North and Baltic Seas are heavily trafficked marine areas with extensive anthropogenic activities, including cargo and fishing vessels, waste dumping, oil platforms, industrial activities and contamination from coastal runoff. In order to evaluate the environmental health of these regions, we used the demersal fish dab (Limanda limanda) as a sentinel species. The current study used well-established biomarkers for PAH exposure and oxidative stress, measuring EROD activity, the acute antioxidant response as well as oxidation of proteins detected as protein carbonyl levels. Results show the strongest biomarker results in an area with extensive oil drilling, where dab displayed high levels of EROD activities. This was also seen in dab captured in the Baltic Sea where elevated levels of oxidized glutathione and a trend towards higher EROD activity were observed. The obtained results did, however, not indicate a coherent biomarker response. The study was conducted off shore where many areas have presumably low levels of pollutants, and we could detect minor effects using the biomarker approach.