Unusual Dolphin Deaths Along Gulf of Mexico Probed by U.S.

WASHINGTON — The National Oceanic and Atmospheric Administration announced Friday that it is investigating an unusual number of bottlenose dolphin deaths in five states along the Gulf of Mexico.

As many as 160 of the dolphins have died since the beginning of the year, with at least 93 deaths occurring in Texas, 50 in Louisiana and Mississippi and 16 in Alabama and the Florida Panhandle, officials said.

“We’re greatly concerned over the unusual number of strandings at this time of year,” said Dean Wilkinson, a marine research management specialist for the agency’s Marine Fisheries Service.

“We don’t know yet how serious the situation is, but we’re making every effort to determine the magnitude and cause of the deaths as quickly as we can,” he said.

The deaths have occurred before the normal stranding peak during the calving season in March and April.

In 1987 and 1988, about 740 bottlenose dolphins died on the East Coast. An investigation indicated that the deaths were related to a naturally occurring toxin called brevetoxin traveling up the food chain to the animals.

The Marine Mammal Stranding Network, a group of volunteers along coastal areas that investigates marine mammal strandings, has provided the agency with carcasses of the recently found dolphins to study, officials said.

About 30 carcasses were fresh enough to provide tissue samples from the liver, blubber and stomach for analysis.

There is no way to know whether the recent deaths also were caused by natural toxins until the analysis is completed, Wilkinson said.

Agency marine biologists are using aircraft to search remote areas, such as the barrier islands in Louisiana and Mississippi, for more dead dolphins, officials said.