Mystery Trumps Beauty ... sometimes ...

In the mouth of the river, there seem to be four sea creatures, one black and three gray.
There have been no reports of anyone seeing more than one spout at a time,
so it seems that the black one must be a whale, either an Orca or an immature Humpback.
Some say that the gray ones seem to be sharks.
In this photo, the black and the gray came together head to head and circled.
Then it seems that the black rolled over on its back, showing the bottom of its fluck.

Where are the experts?

Help!