The first study showing the biological impacts to wildlife from last year’s Gulf oil spill has just been published in PNAS, and the news is not good for fish populations.
After being exposed to low levels of heavily weathered crude oil in marsh habitats, killifish, also called bull minnows, showed cellular changes in their livers which could impact reproduction and health. Killifish are an important part of the Gulf of Mexico food web, and impacts to their populations could have ecosystem-wide results.
“The message that seafood is safe to eat doesn’t necessarily mean that the animals are out of the woods,” said Andrew Whitehead, an assistant professor of biology at Louisiana State University and a lead researcher in the study.
These lesser-seen impacts to reproduction are predictive of more serious long-term threats to populations. In a way, these changes are even more tragic than the animals that washed up on the shore dead after the spill. The study found the same kind of cellular responses in killifish as were observed in herring, salmon and ducks that later had population crashes as a result of the Exxon Valdez oil spill and some populations never recovered.
The fish showed changes even when the water was seemingly clean and when there were very low levels of oil present. The researchers note that even when oil is not visible on the surface, the toxic components of the oil can remain in the sediment and get stirred up by waves and storms.
“Where’s the oil? It’s in the sediment,” Whitehead said.
He’s right. A couple of weeks ago Tropical Storm Lee unearthed miles of tar balls, tar mats and abandoned cleanup equipment left from last year’s oil spill, forcing BP cleanup crews back to the beaches.
As the science of the spill is just beginning to unfold and BP continues to clean up oil on the beaches, Congress is pushing hard for more risky offshore drilling in the same affected ecosystems of the Gulf of Mexico, and new pristine environments like the Arctic where there is no capability to clean up after a spill.
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