Assessing and monitoring local and long-range-transported hydrocarbons as potential stressors to fish stocks

The Arctic is poorly described and understood compared to the North Sea and other boreal areas. We need to learn how knowledge obtained at boreal conditions may be applied at Arctic conditions. Increasing activity of the hydrocarbon industry may cause exposure stress from discharges. Within a joint industry research programme (Biosea) we studied how responses in fish from oil exposure may differ at North Sea boreal and Barents Sea Arctic conditions. Hydrocarbon uptake, metabolites, and enzymatic and genotoxic biomarker type of effect responses were measured in cod (Gadus morhua L.). Hydrocarbon metabolites remain longer in fish bile than original hydrocarbons, which are eliminated fast from tissues. The metabolites may be measured to background concentrations. They describe exposure and they constitute a link to other effects. Body burden, biliary polyaromatic hydrocarbon (PAH) metabolite concentration, and quantities of Cytochrome P-450 1A (CYP1A) and DNA adducts increased with oil in water concentration. The extent of biomarker expression was lower for some biomarkers and elimination was slower at the lowest temperature. The results show that several factors have to be accounted for if warm-water biomarker data are to be applied in cold water.