Dolphins dying of bacteria NOAA: BP oil spill may have contributed high mortality rate

Oct. 27, 2011
Dolphins dying of bacteria
NOAA: BP oil spill may have contributed high mortality rate
By KAREN NELSON - [email protected]

GULFPORT -- NOAA officials called a national media briefing Thursday and said that the BP oil spill could have played a role in the high number of dolphin deaths in the northern Gulf since 2010.

But they said further testing is needed to draw any conclusions.

NOAA called the briefing to let the public know that five of the 580 dolphins discovered dead, including some of the fetuses, died from a marine version of a bacteria that kills goats, sheep, cattle, pigs, elk and dogs.

AMANDA McCOY/SUN HERALD Institute for Marine Mammal Studies intern Rhiannon Blake, left, and research assistant Jamie Klaus take samples from one of the four dead dolphin calves found on Horn Island in February. NOAA officials said Thursday that the BP oil spill could have played a role in the high number of dolphin deaths since 2010, but further testing is needed.

Three fetuses and two adult bottlenose dolphin were found to have the bacteria brucella in their lungs or brains.

Teri Rowles, NOAA’s lead marine mammal veterinarian and coordinator for the national stranding response, said she knows of no other case where there has been a high mortality rate with brucella in dolphins.

Earlier this year, before the normal birthing season, dolphin fetuses were washing ashore along Mississippi and Alabama beaches in record numbers.

“We believe these five dolphins died from brucellosis,” she said. “Die-offs from bacterial infections could be occurring because the bacterium has become more lethal, but they could also be occurring, or be more severe, because the dolphins are more susceptible to infection.

“Severe environmental stress, including from exposure to oil, could have reduced the animals’ ability to fight infection,” she said.

There are no known cases of the marine brucella bacteria transferring to humans, but Rowles warned people to stay away from dead dolphins and to keep their dogs away from them and to report them to stranding experts.

Dolphins are continuing to die in unusual numbers in the northern Gulf, she said.

The bacteria is commonly found in marine animal populations, but usually isn’t deadly. It’s known to cause sporadic deaths, Rowles said.

NOAA officials said scientists found both the bacteria and evidence of the disease brucellosis. But how widespread it is among the dead is difficult to determine because most of the animal carcasses were too decomposed to provide good data, they said.

The bacterial disease can cause failed pregnancies, Rowles said. Two of the fetuses testing positive for the bacteria died in the womb and had brucella in their lungs.

Two adults died from meningitis, an inflammation of the tissue surrounding the brain, caused by brucella.

One fetus that had brucella in its lungs, died with its mother that had meningitis, she said.

Eight additional cases from Mississippi, Louisiana and Alabama have lesions matching ones on the dolphins found with brucella. Another 33 will be tested, she said.

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