They are blacktips. And even though I don't know for sure if I have seen them on the flats, there are enough bull sharks around here to make me think twice about EVER getting in the water. Let me list the sharks I have seen that I can definiteley identify in the waters I fish in around the Cape Lookout area:
Tiger (very big ones too)
Lemon (swam within rod length of me)
and of course the ever present dogfish.
Unidentified sharks have also eaten numerous false albacore off of my line from time to time.
Plenty of teeth to go around. I don't swim at the beach from here all the way to Florida. Just too many of them.