Here’s what we know about the ongoing dolphin deaths:
The deaths are concentrated in states closest to the Deepwater Horizon. Louisiana, ground zero for spill impacts, has also seen the largest number of dead dolphins. Stranding rates in Mississippi and Alabama remain elevated, while deaths in the less-affected Florida Panhandle have returned to normal historical levels.
An in-depth study of 32 dolphins in one particularly heavily-oiled area of the Louisiana coast found the animals there were seriously ill with symptoms indicating oil exposure. Specifically, the dolphins in the study were underweight, anemic, had low blood sugar, and some had symptoms of liver and lung disease. Half the dolphins also had abnormally low levels of the hormones that help with stress response, metabolism, and immune function.
Stillborn dolphin calves have been found in high numbers every spring since the oil disaster. Infant dolphins were found dead at almost four times historical rates during the first four months of 2013.
NOAA has ruled out the two most common causes of previous dolphin die-offs. Brucellahas never before been associated with a wave of deaths in any marine mammal in the United States.
More than three years after the well was capped, the disaster’s effects appear to still be unfolding—despite BP’s slick public relations campaigns. Scientists say it will still be many years, even decades, before we understand the true impact of the roughly four million barrels of crude oil unleashed on the ecosystem of the Gulf of Mexico.