Dolphins stranded in Philippines

http://www.youtube.com/watch?v=UK4M8AsQSq0

This was around Feb.9 were fishermen in the Philippines spotted hundreds of dolphins stranded around the shallow water in Manila area. I never heard anything like this before and as many as this dolphins. Nobody knows the reason why this dolphins stranded around the area and a lot of people helps trying to lead this dolphins go back to the much deeper water.