A shadowy image captured in the waters surrounding a Louisiana baseball star who jumped off a party boat for a dare has sparked speculation the teen was swimming away from a shark.

Cameron Robbins, 18, jumped off the Blackbeard's Revenge sunset cruise ship while celebrating his high school graduation near Athol Island, in the Bahamas last Wednesday. The search for the missing teen was called off two days later.

Footage shows Robbins swimming in the water as a life preserver is thrown out to him and classmates tell him to grab on. But the teenager seems to be fixated on a shadowy shape which appears in the water and immediately begins swimming away.