The National Oceanic and Atmospheric Administration (NOAA) suggests that prolonged oil exposure from the Deepwater Horizon disaster is causing “incredibly ill” dolphins in the Gulf of Mexico.
Dolphins are exposed to oil through inhalation of vapors at the water’s surface, ingesting oil from the sediment or water while feeding, eating whole fish, including internal organs and fluids, such as liver and bile, which can harbor chemical contaminants and absorption through their skin.
NOAA conducted extensive physicals on 32 live dolphins in Louisiana’s Barataria Bay, a body of water that was “heavily oiled for a prolonged time during the Deepwater Horizon spill” and has remained closed to commercial fishing since the spill. NOAA found the dolphins to be suffering from ailments “consistent with those seen in other mammals exposed to oil”, particularly in the Exxon Valdez spill. The dolphins’ symptoms include: low body weight, low hormone levels, low blood sugar and signs of liver damage.
The researchers additionally studied dolphins in the un-oiled Sarasota Bay, and found the “severe health problems’ seen in Barataria Bay dolphins were not evident “in dolphins from the un-oiled area and have not been seen in previous studies of dolphins from other sites.”
Though NOAA has yet to officially tie the Unusual Mortality Event of dolphins in the entire northern Gulf to oil or dispersant, they did state that “there is no evidence that two of the most common causes of previous dolphin die-offs in the Gulf, morbillivirus and marine biotoxins, are the cause of this Unexplained Mortality Event.”