Sharkman, real name Mike Rutzen, has earned worldwide fame for swimming with the predators without the safety of a diving cage.
The former fisherman is on a crusade to show that the huge fish are not bloodthirsty killers but are intelligent and sensitive creatures.
He also wants to highlight their status as an endangered species - their jaws can fetch tens of thousands of pounds on the black market.
To successfully swim with sharks, Mike has learned to mimic their body language, changing his posture in response to their actions.
He is seen neither as prey nor predator and the sharks happily glide past him, occasionally letting him ride with them by hanging on to their dorsal fins.
It has not always been plain sailing, though - his body bears more than 30 scars from close encounters. But now he has decided to take on the ultimate challenge - as depicted in this picture - the remarkable phenomenon of "tonic immobility".
This is a natural state of paralysis, which animals sometimes enter when faced with an imminent threat.
However, it can be induced in sharks by turning them on their heads and massaging their snouts, close to the eyes.
The effects last for around 15 minutes and has proved a useful tool for scientists wanting to study shark behaviour. Being able to get so close to the Great White, Mike discovered that they do not have beady black eyes, as previously thought, but they are actually a startling blue.