The project is intended to track the health of sharks, turtles and sea snakes that live in the high seas.
"I did what anyone would have done," he said. "The shark was latched onto her leg. I just jumped into the water."
Future summers at the beach are going to be interesting.
An enraged boater recorded the incident and shouted for the men to release the creature.
The moment is perhaps proof of whale's intuitive nature to protect other species of animal - including humans.
A marine biologist believes a humpback whale shielded her from a 4.5m tiger shark in the South Pacific.
The dish, a delicacy in some countries, has been linked to severe animal cruelty.
This creature may have inspired legends of sea serpents.