Fernando Galvez and Andrew Whitehead, two professors at Louisiana State University, are leading a research team studying the effects of the Deepwater Horizon Oil Spill on the fish living in Louisiana marshes. The study is partially funded by the National Science Foundation (NSF) and the Gulf of Mexico Research Initiative and is being published in the journal Proceedings of the National Academy of Science (PNAS).
The study did find very low to non-detectable concentrations of oil in the water and also in the fish tissues. However, the study detected biological effects in fish that indicate dramatic responses that are common in exposures to oil. So the environmental chemistry may not have indicated effects from the oil spill, but the biological responses definitely did.
“Though the fish may be ‘safe to eat’ based on low chemical burdens in their tissues, that doesn’t mean that the fish are healthy or that the fish are capable of reproducing normally,” said Whitehead.
One finding was that gill tissues appeared damaged and had altered protein expression indicative of oil exposure. Gill tissues are important for maintaining critical body functions.
“This is of concern because early life-stages of many organisms are particularly sensitive to the toxic effects of oil and because marsh contamination occurred during the spawning season of many important species,” Whitehead.
Previous studies performed by Galvez and Whitehead showed the same genome expression responses in liver tissues that they found to be associated with development abnormalities and death. Additionally, these responses are predictive of impairment on fish reproduction. This could mean obvious effects on the fish populations, a vital part of the economy and lifestyle in the region.
These types of population effects are still being felt in the areas of the Exxon Valdez oil spill in Alaska, two decades later. The same types of signals observed in the Alaska spill are being seen in the Deepwater Horizon spill. The research team is in the process of performing follow-up studies, more closely examining the direct effects of the spill on reproduction, development and growth.