Around 200 dolphins had been stranded in Manila Bay. Fishermen and other volunteers have managed to drive them back into deeper water. One theory for the stranding is that a underwater earthquake could have damaged their eardrums and disoriented them. Another theory is that the pod followed a sick leader.
The animals have been identified as melon-headed whales. Apparently 2 adult females (one pregnant), and a juvenile male died.
There is more information here. And the BBC has a video from before the dolphins were driven out to sea.