I have been followed by large barracuda in the ocean and by bass in a quarry waiting for me to stir up some small fish. The little ones move away from me and they get nailed. I figure every time I dive some fish and other stuff will die because of my dive. As pointed out I assume that some fish will die or go hungry every time I do not dive. I have watched a big jack and a big moray hunt together. So using something large to help eat smaller stuff is one of the predators tricks of the trade.