dead dolphin
© Courtesy Institute For Marine Mammal StudiesThis young male Atlantic bottlenose dolphin, found on the beach in Long Beach, was one of three dead dolphins found along the Mississippi Coast on Friday.

Gulfport -- So far in October, 14 dead dolphins have washed ashore in Mississippi and Alabama.

Three were found Friday in Mississippi -- one on Deer Island, one floating 200 yards off the beach at Cowan Road and one on the beach in Long Beach.

"Generally, you don't see this in October," said Moby Solangi, director of the Institute for Marine Mammal Studies. "This is not normal."

There was a time when one dolphin death was an unusual event.

But dolphins dying consistently, month after month, is something that has continued in the northern Gulf since the BP oil spill.

NOAA, the federal National Oceanographic and Atmospheric Administration, is investigating the deaths.

The agency said in a statement Thursday five of 21 dolphins that died in Louisiana in 2010 were killed by the bacterium brucella. That's 21 of the 580 that have been discovered dead in the northern Gulf since February 2010, three months before the spill.

NOAA has said something was killing dolphins before the spill, but added exposure to the oil could have worn down the animals and made them more susceptible to disease.

NOAA hasn't drawn any conclusion about the deaths, but the investigation is continuing.

Doug Inkley, senior scientist with the National Wildlife Federation, said Friday the fact that an unusual number of dolphins began dying before the spill "in no way means the oil spill did not contribute to dolphin deaths.

"What we do know is that every single month since the oil spill began through present, dolphin deaths have been far above normal and this is a real cause for concern."

Solangi said only one of the dead dolphins found Friday was in good enough shape for a necropsy, an animal autopsy. Samples from the other two were taken in the field and sent to NOAA.

Solangi said NOAA has admitted there is still a lot more to do in investigating the deaths.

The report this week of brucella in five of the dead mammals was an initial finding, he said. "And remember, 16 of the 21 did not have brucella."