Acute and long-term biological effects of mechanically and chemically dispersed oil on lumpsucker (Cyclopterus lumpus)

• Acute and long-term effects of dispersed oil were assessed on juvenile lumpsucker.
• Dynamic exposure conditions simulating sub-Arctic coastal oil spills were utilized.
• No mortality was observed at oil concentrations reported after real oil spills.
• Equal toxicity was observed for chemically and mechanically dispersed oil.

Concentration dependent differences in acute and long-term effects of a 48 h exposure to mechanically or chemically dispersed crude oil were assessed on juvenile lumpsucker (Cyclopterus lumpus). Acute or post-exposure mortality was only observed at oil concentrations representing higher concentrations than reported after real oil spills. Acute mortality was more apparent in chemically than mechanically dispersed oil treatments whereas comparable EC50s were observed for narcosis. There was a positive correlation between EROD activity and muscle PAH concentration for the lower oil concentrations whereas higher concentrations inhibited the enzyme activity. The incidence of gill tissue lesions was low with no difference between dispersion methods or oil concentrations. A concentration dependent decrease in swimming- and feeding behavior and in SGR was observed at the start of the post-exposure period, but with no differences between corresponding oil treatments. Three weeks post-exposure, fish from all treatments showed as high SGR as the control fish.