Reply #37: Probably not.

[LeftyMom]

Attacks are almost invariably from below and not at the surface of the water. There might have been more than normal to see since this was shallow water, but that alone almost entirely rules out a large shark. Mostly what you'll see is splashing and the shark's dorsal thrashing as it throws itself back and forth to tear off flesh. Video of attacks is usually shown slowed down- at full speed you just see splashing and chaos- in person and in a panic it would be very difficult for an untrained eye to make sense of what they were seeing in order to give a good identification.