The Influence of crude oil and oil dispersant in the physiology of adult Gulf Killifish

The fish gill epithelium is a sensitive site of interaction between a fish and its environment partially due to its role in ion regulation. Addition of dispersant to crude oil can result in increased bioavailability of aromatic and aliphatic hydrocarbons. Treatment waters were generated at nominal salinities of 4, 12, and 18 g/L. Control water was left undisturbed. Dispersant water was mixed at 22 mL of Corexit-9500 to 80 L of treatment water. Oiled water was initially mixed at an approximate 1:4 oil:water ratio by volume and the dispersant was used at a 10:1 oil:dispersant ratio to generate oil/dispersant water. Treatment waters at the previously mentioned nominal salinities were weathered for 1, 4, and 16 weeks in treatment mesocosms. Gulf killifish were sampled for plasma after 48 and 96 hours of exposure to treatment waters. Impacts of treatment water on adult Gulf killifish physiology were determined through measurements of hematocrit and plasma ion concentrations of sodium, potassium, and chloride.