Think they were testing out a new carrier. It's part of sea trials to explode a huge bomb relatively close and relatively deep to the carrier to test structural integrity. Been doing this forever. Why Florida? Could be because they leave the dock in the Virginia area perform a multitude of test while heading south finishing off with the bomb.

To all the people saying this is what killed all that sea life it makes no sense. This bomb was set off in the Atlantic off the coast of north Florida. All that dead sea life was in the gulf of Mexico on the other side of the state. Seems like a physical impossibility, dead sea life would have to go all the way down the east coast under Florida and back up without ever hitting the shore anywhere else.

But obviously as we all know there could be more going on that meets the eye.