Like the tuna fishery in the Pacific, dolphins are dying to increase the profits of the fishing companies.

On January 26, 2013, a dolphin entered the canal at low tide, was unable to get out and died.

One dolphin died of disease during work in the Persian Gulf, it said.

Sometimes the songs were sad - from the times when many dolphins died in nets that entangled them.

Now dolphins are dying and you start to wonder.

In 88 percent of the cases, he said, no more than five dolphins died.

Scientists know where the dolphins died and when, but the identity of the killer is an environmental mystery that could take months to solve.

Many dolphins die unnecessarily after getting caught in fishermen's nets.

Four dolphins died after overstaying in the river in 1994.

The dolphins may have died from a specific disease, but a leading suspect for these marine massacres is pollution.