From: Allison Winter, ENN
Published May 6, 2013 09:34 AM

Gulf Killifish Affected by 2010 Oil Spill

The Deepwater Horizon oil spill in the Gulf of Mexico happened over three years ago, but according to scientists, crude oil toxicity still continues to sicken a sentinel Gulf Coast fish species.

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Researchers from the University of California, Davis, teamed up with researchers from Louisiana and South Carolina to find that Gulf killifish embryos exposed to sediments from oiled locations in 2010 and 2011 show developmental abnormalities, including heart defects, delayed hatching and reduced hatching success. 

The killifish is an environmental indicator species, or a "canary in the coal mine," used to predict broader exposures and health risks. Indicator species are sensitive to disease outbreaks, pollution, species competition or climate change so biologists often study them in order to monitor the ecosystem. These fish are not fished commercially but they are nonmigratory and share similar habitats with other species like the speckled trout, flounder, blue crabs, shrimp, and oysters, and who may be at risk of similar effects.

The findings are part of an ongoing collaborative effort to track the impacts of the Deepwater Horizon oil spill on Gulf killifish populations in areas of Louisiana that were heavily affected. 

"These effects are characteristic of crude oil toxicity," said co-author Andrew Whitehead, an assistant professor of environmental toxicology at UC Davis. "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. By definition, effects on reproduction and development - effects that could impact populations - can take time to emerge."

Researchers collected Gulf killifish from an affected site at Isle Grande Terre, La., and monitored them for measures of exposure to crude oil. They also exposed killifish embryos in the lab to sediment collected from oiled sites at Isle Grande Terre within Barataria Bay in Louisiana.

"Our findings indicate that the developmental success of these fish in the field may be compromised," said lead author Benjamin Dubansky, who recently earned his Ph.D. from Louisiana State University.

Whitehead said the report's findings may predict longer-term impacts to killifish populations. However, oil from the Deepwater Horizon spill showed up in patches, rather than coating the coastline. That means some killifish could have been hit hard by the spill while others were less impacted.

The research can be found in an advanced publication in the journal Environmental Science and Technology.

Read more at the University of California Newsroom.

Oil spill image via Shutterstock.

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