In April of 2010 a massive oil spill resulting from an explosion at the Deepwater Horizon rig occurred. The infamous spill lasted months and resulted in a number of oil worker deaths and at least 200 million gallons of oil to enter the Gulf of Mexico. Extensive damage occurred across the Gulf of Mexico, the beaches and to the wildlife calling the region home.
As was expected, some species which call the Gulf home did not show immediate signs of distress unless covered in oil. Such species include dolphins, sea turtles and corals. However, the likelihood is that the spill did cause major issues for such species, issues which may now be surfacing and will continue in the years to come.
Between 2002 and 2009, the average number of bottlenose dolphin deaths documented in the Gulf of Mexico was 31. In the months of January through April 2011, 186 bottlenose dolphin carcasses had been discovered along the beaches of the Gulf. Approximately fifty percent of the dolphins found decreased were either stillborn or were born in recent days. Due to the drastic increase in dolphin deaths, biologists were brought in to determine the cause.
Researchers have now published a report detailing their findings on the dolphin deaths in the journal PLoS ONE. The researchers determined that the cause of the deaths was likely two-fold: a cold 2010 winter and exposure to the BP spill. Their findings coincide with the National Oceanic and Atmospheric Administration’s findings in 2011 that the dolphins in the region were suffering from anemia and weight loss.
Researcher Graham Worthy stated: “The oil spill and cold water of 2010 had already put significant stress on their food resources. […] It appears the high volumes of cold freshwater coming from snowmelt water that pushed through Mobile Bay and Mississippi Sound in 2011 was the final blow.”
The combination of the cold winter and oil spill likely combined to limit food availability for the dolphins, leading to many stressed individuals. Therefore it took little to potentially push the individuals to the breaking point, such as the influx of cold melt water which they would have normally adjusted to without much trouble. Other species also suffered from both the cold winter and the oil spill, including sea turtles, seabirds and manatees.