BILOXI, Mississippi (Reuters) - Marine scientists are examining the deaths of 26 baby dolphins whose carcasses have washed ashore along the U.S. Gulf Coast this year, the bulk of them since last week, researchers said on Tuesday.
The alarmingly high number of dead young dolphins are being looked at as possible casualties of oil that fouled the Gulf of Mexico after a BP drilling platform exploded in April 2010, killing 11 workers and rupturing a wellhead on the sea floor.
An estimated 5 million barrels (205.8 million gallons) of oil spilled into the Gulf over more than three months.
The bodies of 26 infant and stillborn dolphins have been discovered since January 20, on islands, in marshes and on beaches along 200 miles of coastline from Louisiana east across Mississippi to Gulf Shores, Alabama, officials said.
“When the world sees something like baby dolphins washing up on shore, it pulls at the heartstrings, and we all want to know why,” said Blair Mase, marine mammal strandings coordinator for the Southeast region of National Oceanic and Atmospheric Administration.
That tally is more than 10 times the number normally found washed up along those states during this time of the year, which is calving season for some 2,000 to 5,000 dolphins in the region, said Moby Solangi, director of the Institute of Marine Mammal Studies in Gulfport.
“It’s an anomaly,” he told Reuters by telephone, explaining that the gestation period for dolphins runs 11 or 12 months, meaning that calves born now would have been conceived at least two months before the oil spill began.
Steve Tellis, a local environmental activist and member of the Nature Conservancy in Mississippi, called the discoveries “horrific.”
Most of the carcasses, measuring just over 3 feet in length, were found during the past week, the bulk of them washing up in Mississippi and Alabama.
The remains of about 10 adult dolphins, none of them pregnant females, have also been found so far this year.
BP cleanup crews found some of the carcasses. Others were discovered by park rangers, police and passersby.
“What makes this so odd is that the dolphins were spread out over such a large area,” Solangi said.
Dolphins encountering oil on the surface of the water would face serious health consequences, Solangi said.
“We take short breaths. These animals take a huge breath at one time and hold it. And when they take it, the fumes stay in the lungs for a long period of time and they cause two types of damage, one of which is immediate to the tissue itself. Second, the hydrocarbons enter the bloodstream,” he said.
None of the carcasses bore any obvious outward signs of oil contamination. But Solangi said necropsies, the equivalent of human autopsies, were being performed and tissue samples taken to determine if toxic chemicals from the oil spill may have been a factor in the deaths.
Documented mortality in the adult dolphin population off the Gulf Coast roughly tripled from normal numbers last year, climbing from about 30 typically reported in a given year to 89 in 2010, Solangi said.
Writing by Steve Gorman; Editing by Peter Bohan and Greg McCune