Sorry, my post from my mobile must not have worked.
These large sharks are not just ocean dwellers. Below is a link to a blog by a Duke grad student about studying large bull sharks in the Neuse River. Turnagain Bay is down near the mouth, almost to the bombing range.
I have heard of large bull sharks being caught as far up as the bridges at New Bern, but can't document that, however, the link details a scientific study.
Tagging Bull Sharks in the Neuse River | Southern Fried Science