Effects of mechanically and chemically dispersed oil on the osmo- and ion-regulatory capacity of juvenile lumpsucker (Cyclopterus lumpus)

Abstract

The effects of 48 hours exposure to mechanically and chemically dispersed oil on juvenile lumpsuckers, as well as the use of gill EROD activity and bile PAH metabolites as potential biomarkers were assessed in this study. This was done by measuring the gill EROD activity, bile PAH metabolites, plasma osmolality, plasma chloride concentration, and gill Na+/K+ATPase activity. The mechanical and chemical dispersion did not differ significantly in terms of gill EROD induction, PAHs metabolisation, plasma osmolality and chloride concentration, and gill Na+/K+ATPase activity. The oil exposure and metabolisation of PAHs were confirmed by the presence of PAH metabolites in the bile. Thus, this study can recommend the use of juvenile lumpsucker’s bile metabolites as a biomarker in detecting oil exposure. The gill EROD activity showed a lack of response upon exposure to oil. Further investigation is recommended to be able to determine the suitability of its use as a biomarker. A significant relationship was seen between crude oil concentration and plasma osmolality and plasma chloride concentration, i.e. as the oil concentration increases, the plasma osmolality and plasma chloride concentration also increases. The mechanistic link between oil exposure and gill Na+/K+ ATPase activity was not clear, thus warrants further investigation. This study has shown that the acute exposure to crude oil was not fatal to the fish but caused impairment on hypo-osmoregulation mechanism.