Mass suicides of whales?

There were several hundred whales stranded in New Zealand. Because whales are not dumb they could easily avoid being stranded. The only thing it would require is to start swimming to the opposite direction, when the water gets shallow. But the whales decide not to do it. Instead they continue to go to the beach, where they know that they cannot avoid heating up and soon dying. This makes it a purposeful act of suicide.

Why would whales decide to commit mass suicide? There is a simple reason for that - noise pollution. The propellers of the millions of boats and ships transfer the engine noise to water where it travels hundreds of kilometers. The noise under water is about the same amplitude as that well heard by whales, and is making their head burst. Rather than letting that to go on for days, months and years, they end it by stranding...