Predicting chronic effects in Fish from sublethal markers

Offshore activities input large volumes of moderately contaminated effluents into the North Sea. There is uncertainty as to the biological effects of the effluents, although there are signs that some biological systems are affected. The current methods to assess effects in the pelagic zone mainly depend on health assessments of fish or mussels, i.e. biomarkers. The methods currently available are not optimal for offshore-relevant contaminants and there is limited knowledge of whether responses change over time (adaptation). This project aims to use state-of-the-art methods both to identify effects at an early point in a deleterious process and to identify changes in responses over time. The project will use zebrafish as a model to identify early responses using microarray technology. Results from the zebrafish studies will be carried over to a one-year study in which Atlantic cod will be exposed through water to selected offshore effluent (produced water) components, i.e. alkylphenols and PAHs. In additio n to screening by microarray analyses, fish will be analysed for a range of contaminant-specific, contaminant-related and health related endpoints at regular intervals during long-term exposures. At the end of the exposures of both fish, hatching success will be determined. The project will produce new knowledge of responses to long-term low level and intermittent exposure to contaminants. It will further identify endpoints that are suitable for monitoring and enable an improved assessment of methods curr ently in use.