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Severely ill dolphins sickened by Gulf oil spill?

Some Gulf of Mexico dolphins that saw heavy, prolonged exposure to oil in the Deepwater Horizon spill are showing signs of severe ill health.

Bottlenose dolphins in the Gulf of Mexico’s Barataria Bay are showing signs of severe ill health, according to NOAA marine mammal biologists, which might be the result of exposure to oil that gushed into the water after the Deepwater Horizon oil rig explosion of April 20, 2010.

During the three months it took to contain the oil leak, an estimated 4.9 million barrels of oil — or about 205 million gallons — gushed into the Gulf of Mexico. Barataria Bay, located in the northern Gulf of Mexico, received heavy and prolonged exposure to oil during the Deepwater Horizon oil spill.

Veterinarians collect samples from a Barataria Bay dolphin. Photo credit: NOAA

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, which was last observed and studied in late 2011, was found dead in January 2012.

NOAA and its local, state and federal partners started the Barataria Bay dolphin study in 2011 as part of the Natural Resource Damage Assessment (NRDA), the process for studying the effects of the Deepwater Horizon oil spill.

Following the Deepwater Horizon oil spill, numerous dolphins were documented encountering oil, such as those in this photo from July 2010. Photo credit: NOAA

NOAA is sharing the preliminary results from the study so that stranding responders and veterinarians can better care for live stranded dolphins and look for similar health conditions.

Since February 2010, more than 675 dolphins have stranded in the northern Gulf of Mexico –a much higher rate than the usual average of 74 dolphins per year. The vast majority of stranded dolphins have been found dead; however, 33 have stranded alive and seven have been taken to facilities for rehabilitation.

Bottom line: NOAA marine mammal biologists report that bottlenose dolphins in the Gulf of Mexico’s Barataria Bay are showing signs of severe ill health, which might be the result of exposure to oil that gushed into the water after the Deepwater Horizon oil rig explosion of April 20, 2010.

Read more from NOAA

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