The Physiological Effects of Resident Killifish Impacted by the Deepwater Horizon Oil Spill

The gulf killifish, Fundulus grandis, is one of the most abundant and ecologically important fish inhabiting coastal marsh habitats of the Gulf of Mexico; a region severely contaminated with oil from the BP Deepwater Horizon oil spill. Unlike most fish species in these habitats, killifish have high home range fidelity, making them a useful model organism to study the site-specific effects of environmental contamination. We have initiated two separate projects aimed at characterizing the integrated effects of crude oil exposure in situ to gulf killifish. In one study, six populations ranging from Grande Terre, LA to Fort Morgan, AL were sampled pre-oil, and at two times post exposure to oil. This study involves a detailed integrated assessment of effects from the level of the whole animal to genomic-level effects, and includes detailed water chemistry analyses and satellite imagery to document the magnitude of exposure. The second study provides a detailed assessment of in situ effects on fish physiology in 6 reference and 6 heavily-oiled sites within Barataria Bay, Louisiana following the oil spill. Tissues from these fish are being analyzed for various indicators of oil exposure and effect, including the documentation of protein-level effects at the gills, intestines, livers, and kidneys. Results to date demonstrate severe histological damage coincident with dramatic up-regulation of cytochrome P450 1A (CYP 1A) protein expression in the gills and intestines of fish sampled from the most heavily-oiled sites. These results are consistent with previous studies describing the effects of polyaromatic hydrocarbon exposure in teleost fish, including killifish.