Oil pollution doesn’t have to kill fish to have a long-term impact, according to a recent study in the Proceedings of the National Academy of Sciences (PNAS). Researchers found that Gulf killifish (Fundulus grandis) that had been exposed to very low to non-detectable levels of oil contamination from the Deepwater oil spill last year, still showed developmental problems that are likely to impact fish populations for decades to come.
“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,” explains Andrew Whitehead with Louisiana State University.
Whitehead and colleagues measured water contamination and took tissue samples from Gulf killifish and spawning marshes three times following the Deepwater spill. While the water showed little to no contamination, the fish’s tissue revealed another story. The liver showed responses connected to developmental abnormalities that likely impaired the fish’s ability to reproduce successfully. Gill tissues showed stress linked to oil exposure, which didn’t go away even after the little recorded oil did. As an important prey species, Gulf killifish provide food to a host of other Gulf marine organisms, including the commercially sought-after red snapper.
“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 says.
Research from the Exxon Valdez oil spill backs up the study’s prediction that the Deepwater disaster will have long-term impacts on fish and fisheries. Two decades of research follow Exxon Valdez, showed that the biggest predictor of fish populations was not direct fish mortality, but non-lethal impacts that hit fish reproduction.
CITATION: Whitehead, A., J. Roach, S. Zhang, and F. Galvez (2011). Genomic mechanisms of evolved physiological plasticity in killifish distributed along an environmental salinity gradient. Proceedings of the National Academy of Sciences of the United States of America, 108(15): 6193-6198.
(03/22/2011) Yesterday the US Bureau of Ocean Energy Management, Regulation and Enforcement awarded Royal Dutch Shell PLC the first deep-water exploration permit since the BP disaster last year, which sent some 4.9 million barrels of oil and up to 500,000 tons of methane into the Gulf of Mexico over three months.
(02/28/2011) Every year a few baby dolphins in the Gulf don’t make it and are found on the shores of the Gulf, but this year something is different. To date, 24 baby dolphins have been found dead in Alabama and Georgia, some are stillborn, others aborted fetuses. Researchers, who say death-toll is ten times the average, are currently studying the dead porpoises for clues to cause. These could include colder-than-average waters, algal blooms, disease, or the incident in the back of everyone’s mind: the BP oil spill last year.
(02/21/2011) Samantha Joye of the University of Georgia has seen the bottom of the Gulf of Mexico and the view wasn’t pretty. Speaking at the American Association for the Advancement of Science, Joye told the conference that she found places where oil lay on the Gulf floor nearly 4 inches (10 centimeters) thick. Joye’s findings contradict rosier pictures of the overall damage caused by the 2010 BP oil spill, including a recent statement by Kenneth Feinberg, the US government czar for oil compensation, that the Gulf would largely recover by next year.