Fish in Gulf of Mexico showing long-term oil spill effects

Crude oil from the Deepwater Horizon spill sickened an important fish species in the Gulf of Mexico for at least a year after the disaster, researchers say. Scientists said gulf killifish embryos exposed to sediments in from oiled locations in 2010 and 2011show developmental abnormalities including heart defects, delayed hatching and reduced hatching success. "These effects are characteristic of crude oil toxicity," said study co-author Andrew Whitehead, a professor of environmental toxicology at the University of California, Davis. The killifish is an environmental indicator species, or "canary in the coal mine," used to predict broader exposures and health risks, the researchers said. "It's important that we observe it in the context of the Deepwater Horizon spill because it tells us it is far too early to say the effects of the oil spill are known and inconsequential," Whitehead said in a UC Davis release Thursday. "By definition, effects on reproduction and development -- effects that could impact populations -- can take time to emerge." Killifish, abundant in the coastal marsh habitats along the Gulf Coast, are not fished commercially but are an important forage fish and a key member of the ecological community, the researchers said. The study suggests longer-term impacts to killifish populations, they said. "Our findings indicate that the developmental success of these fish in the field may be compromised," lead author Benjamin Dubansky, who recently earned his doctorate from Louisiana State University, said.