Spike In Dolphin Deaths Directly Tied To Deepwater Horizon Oil Spill, Researchers Say

gulf dolphin

A dramatic increase in dolphin deaths in the Gulf of Mexico is directly linked to the Deepwater Horizon oil spill, scientists concluded in a report published Wednesday.

Following the 2010 explosion on the drilling rig owned by British Petroleum (BP) and the subsequent spill of 4.9 million barrels (205.8 million gallons) of oil into the ocean, scientists have documented 1,281 dead and stranded cetaceans, primarily bottlenose dolphins, along the northern coast of the Gulf of Mexico.

In this photo taken May 10, 2015, a dead dolphin washes ashore in the Gulf of Mexico on Grand Isle, Louisiana.

In 2011, Louisiana saw 163 dolphins stranded, while Mississippi had 111. By comparison, each of those states saw an average of 20 such incidents per year from 2002 through 2009, reported the National Oceanic and Atmospheric Administration.

One in three of the dolphins recovered from the coasts of Louisiana, Mississippi and Alabama suffered from otherwise rarely-seen adrenal lesions consistent with petroleum product exposure, according to a report from NOAA’s Office of Response and Restoration. In Barataria Bay, Louisiana, one of the areas hit hardest by the oil spill, half of the dolphins showed similar lesions. In contrast, only 7 percent of stranded dolphins found outside of the Deepwater Horizon spill zone have had similar adrenal gland damage.

The adrenal gland produces and regulates a wide range of hormones, which, in turn, help manage basic bodily functions including metabolism and blood pressure.

gulf dolphin
A dolphin lies on dead on a beach on Horn Island, in the Gulf of Mexico, Tuesday, May 11, 2010.

“Animals with adrenal insufficiency are less able to cope with additional stressors in their everyday lives,” Stephanie Venn-Watson, the study’s lead author and a veterinary epidemiologist at the National Marine —> Read More