A research study conducted by the National Oceanic and Atmospheric Administration teaches us about the state of dolphins in the Gulf of Mexico following the 2010 Deepwater Horizon oil spill in which 4.9 million barrels of oil leaked into the sea. For the study, 32 bottlenose dolphins were captured briefly off of the coast of central Louisiana to assess their health. The health of these dolphins was compared to a separate 27 dolphins captured in Sarasota Bay, Florida. This region was not affected by the oil spill.
The results were shocking. Half of the Louisiana dolphins were found to be seriously ill or close to death. These dolphins also had very low hormone levels and a serious lung disease was found to be five times more common in the Louisiana dolphins. Other ailments included Pneumonia, liver disease, and miscarriage.
An interesting problem that plagued the oil spill affected dolphins is the loss of their teeth. Three of the affected dolphins has lost nearly all of their teeth. Three other dolphins had only half of the normal amount of teeth.
BP, the company who is blamed for the spill, announced their opinion on NOAA’s study: the results are “inconclusive as to any causation associated with the spill.” BP does have a valid point – three months before the spill over 1000 dolphins had mysteriously died off the Gulf Coast. There is also another issue with establishing causation between the spill and dolphin health: there are no studies of dolphin health before the spill to compare the recent study to. One big point NOAA makes to support causation is the fact that the Louisiana dolphins had less exposure to pesticides and agricultural runoff than the Florida dolphins, suggesting that normal pollution did not cause the Louisiana dolphin’s health issues.