Impacts of the Deepwater Horizon Oil Spill on the Ontogeny of Resident Killifish

The gulf killifish, Fundulus grandis, is one of the most abundant fish species in coastal marsh ecosystems of the northern Gulf of Mexico. Peak oiling of these marsh habitats during the summer of 2010 coincided with the most reproductively active period for this species, putting it at high risk of crude oil exposure during early development. Since F. grandis is non-migratory and has high home range fidelity, impacts during development may be predictive of longer-term population-level effects. To test the effects of oiled waters on killifish development, embryos fertilized in vitro were exposed throughout development to water collected from various sites along the northern Gulf of Mexico before and after oiling. Three different developmental stages were selected for comparison; 3 days post-fertilization (3 DPF), just after hatch (10 DPF), and as larvae (24 DPF). No alterations in development or morphological differences were observed in these fish despite a difference in CYP1A expression in the kidney, gills, liver, intestine, and muscles. These studies have provided a critical foundation for future endeavors to monitor fish health in affected areas. Ongoing efforts are focused on examining tissue and developmental stage-specific expression of proteins indicative of crude oil exposure and effect, including CYP1A, glutathione S-transferase, and other biomarkers of exposure and effect following exposure to hydrocarbons. Presently, we are conducting an ongoing comprehensive health assessment of early-life stage fish exposed to oiled water, both in vitro, and in situ to examine effects of exposure to crude oil.