My son and I were off Venice Beach near Sarasota FL. We had gone out about 300 yds looking for fossilized sharks teeth. There are a few megaladon teeth out there the size of your palm.
We surfaced to check out our find when my son saw a sharks dorsal fin circling us. That was a long long swim in. But we still go, just dont surface.
I think that if I came that close to one of those monsters, I’d head so far inland that salt water would just be a rumor.