 Blacknose sharks are preyed upon by larger sharks, and captives have been observed to perform an apparent threat display towards encroaching divers or newly introduced members of their species.The display consists of the shark hunching its back, lowering its pectoral fins, gaping its jaws, and swimming with an exaggerated side-to-side motion.Known parasites of this species include the copepods "Nesippus orientalis", "Perissopus dentatus", "Pandarus sinuatus", "Kroyeria sphyrnae", "Nemesis atlantica", and "Eudactylina spinifera", as well as tapeworms in the genera "Paraorygmatobothrium" and "Platybothrium".