Effect of exposure to petroleum hydrocarbons upon cardio-respiratory function in the common sole (Solea solea).

The long term consequences of oil exposure upon marine populations are still poorly evaluated. One particular missing piece of information relates to the link between oil exposure, individuals' ability to face environmental contingencies and populations' production and dynamics. In that context, the present paper investigates the impact of oil exposure upon fish cardio-respiratory performance, this performance being viewed as a key determinant of individual fitness. Experimental conditions replicated the contamination conditions observed during the weeks that immediately followed the Erika oil spill (west coast of France; December 1999). Sole (Solea solea), were exposed to number-2 oil for 5 days and were then challenged with an acute rise in temperature (from 15 to 30 degrees C at 1.5 degrees Ch(-1)). Oxygen consumption, cardiac output, heart rate and stroke volume were monitored throughout. Experimental results showed that compared to uncontaminated control animals, oil-exposed sole displayed impaired cardio-respiratory responses and were unable to meet the temperature-driven increase in tissues oxygen demand. The relationship between oxygen consumption and cardiac output indicated that oil-exposed fish had recourse to venous oxygen stores very early in the thermal challenge (20 degrees C). In control fish there was no evidence for depletion of venous oxygen store until above 25 degrees C.