Feds investigate dolphin deaths in Gulf

MELBOURNE, Fla., June 7 (UPI) -- A colder-than-usual winter likely killed an unusually large number of bottlenose dolphins from Louisiana to the Florida panhandle, officials said.

Sixty-two dolphin deaths were reported in the region in March with 39 more deaths reported in April. The average is 18 for March and 13 for April, said Erin Fougeres, a biologist with the National Oceanic and Atmospheric Administration Marine Fisheries Service.

NOAA has declared deaths an "unusual mortality event" and ordered an investigation, Florida Today, Melbourne, reported Monday.

The spike in dolphin deaths likely was caused by the cold winter, said Moby Solangi, head of the Marine Mammal Studies group in Gulfport, Miss. The number of deaths were unusually high, but there is some variation in death rates from year to year, Solangi said.

Most of the deaths occurred before the April 20 Deepwater Horizon oil rig explosion that caused the massive spill in the Gulf of Mexico. None of the dolphins showed external signs of damage from oil, authorities said.