Large numbers of strandings, mainly bottlenose dolphins, has been happening on the Gulf Coast.
There has been some press speculation that it is linked to the recent oil spill however its worth noting that numbers were up before the spill happened. It's unlikely that the spill has helped and it looks like the oil may have decreased dolphin immunity, increasing their susceptibility of brucella, but it's not the only/main problem in this situation.
Sorry I'm going to link to 2 stories, the first one has some excellent graphs and maps to get a clear picture of whats going on:
This second one has a good write up..
The strandings peaked this year in March, with 72 reported from Florida to the Texas-Louisiana border. Sixty-seven of those were bottlenose dolphins. Since August, 52 more strandings have been reported, including nine this month.
More than 45,000 dolphins are estimated to call the Gulf home, according to the National Marine Fisheries Service.
And while many speculate that the deaths may be linked to the Gulf oil spill, scientists say the phenomenon started months before the Deepwater Horizon rig exploded and began pouring oil into the Gulf.
“We were already consulting with the mortality group (to open up an investigation) when the oil spill occurred. And the number has never gone back down,” Fougères said.
Unfortunetly it is often very hard to tell what is causeing an event like this, not sure if we'll find out why this time.