We rented a boat this last spring down in Marathon Key and it was amazing how many sharks we caught or saw fishing in shallow water, they are everywhere down there. The last one we hooked was a hammerhead that first swam by our boat to our jack crevalle carcass in our chum bag before we hooked it. Honest to God it was about 14' in 12' water near 7 Mile Bridge, massive beast! It took 500 yards of my line into the Gulf so fast we couldn't get the anchor up in time. We probably shouldn't have hooked it but I couldn't resist and it was funny watching the kids trying to stop it and pouring water on their thumb as the line peeled off.
I do not swim down there...