New Oil Spill Study: Gulf Bottlenose Dolphins Are Underweight, Anemic and Show Signs of Liver and Lung Disease


In the wake of the BP oil spill, hundreds of dead bottlenose dolphins – some visibly oiled – washed up on Gulf Coast beaches at a rate nearly 10 times the norm. Many more died at sea. Dozens were stranded alive, severely ill and disoriented. During the summer of 2011, NOAA conducted “comprehensive physicals” on 32 live dolphins to determine the “post-spill health” of the mammals in Barataria Bay, one of the areas hardest hit by the spill. NOAA just released the preliminary results of those physicals, and they’re confirming our worst fears.

From NOAA’s Natural Resource Damage Assessment (NRDA):

Bottlenose dolphins in Barataria Bay, Louisiana, are showing signs of severe ill health, according to NOAA marine mammal biologists and their local, state, federal and other research partners.

Barataria Bay, located in the northern Gulf of Mexico, received heavy and prolonged exposure to oil during the Deepwater Horizon oil spill.

Based on comprehensive physicals of 32 live dolphins from Barataria Bay in the summer of 2011, preliminary results show that many of the dolphins in the study are underweight, anemic, have low blood sugar and/or some symptoms of liver and lung disease. Nearly half also have abnormally low levels of the hormones that help with stress response, metabolism and immune function.

Researchers fear that some of the study dolphins are in such poor health that they will not survive. One of these dolphins was found dead in January 2012.

The fact that “many” of the dolphins are showing these debilitating symptoms of chronic exposure to a toxin (e.g., oil and dispersant) is disturbing indeed. Even more troubling is that some of the dolphins will not survive. If we extrapolate, that could translate to thousands – even tens of thousands – of dolphins dying out at sea. An entire generation could be lost.

And tragically, there seems to be no end to what NOAA has billed as an Unusual Mortality Event (UME). Is it accurate to describe these deaths as unusual when we’re talking about more than 200 million gallons of oil and 2 million gallons of toxic dispersant released directly into a habitat? More from the NRDA:

In the spring, it is typical to see some newborn, fetal and stillborn dolphins strand, and there has been an increase in strandings of this younger age class during this UME in 2010 and 2011. Yet all age classes continue to strand at high levels. NOAA is working with a team of marine mammal health experts to investigate the factors that may be contributing to the dolphin mortalities.

We will bring you updates as more data on the dolphin physicals become available. Stay tuned…

Read the NOAA report here:

View photos of Gulf dolphins here:

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Stuart H. Smith is an attorney based in New Orleans fighting major oil companies and other polluters.
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