This remarkable image was snapped by environmental photojournalist Thomas P. Peschak.

And no, it's not fake, photoshopped, or digitally manipulated in any way. In fact, Peschak’s most famous photograph was simply shot on slide film using a Nikon F5 camera and 17-35 mm lens.

It was originally published in the September 2005 issue of Africa Geographic. That article presented a study of Great Whites in South Africa by Peschak and fellow biologist Michael Scholl. Since sharks can be either repelled or attracted by the electrical fields emitted by a boat's engine, Peschak and Scholl had chosen to use kayaks to study the sharks' behaviour. Unlike motorised vessels, kayaks are easily manoeuvred in shallow waters, and they have no noisy engines that might disturb the sharks in their natural habitat.
 
The scientists hoped to discover why large groups of Great Whites regularly swim so close to beaches during the summer months (it was determined that they venture inshore to interact socially with others of their species, and use the opportunity to mate and give birth).
 
The kayaker was marine biologist Trey Snow, who had hoped to stealthily track the local sharks, but found the tables turned when he looked around to find himself stalked by one of the ocean’s most feared predators.
 
Snow described sitting in a three-metre yellow sea kayak, watching the approach of a five-metre shark, as a tense and nerve-wracking experience. While the scientists had previously tested the sharks' reactions to empty kayaks, and noted no signs of aggression, this was the first time they had come face-to-face with one of the creatures.

Nothing kills your surfing enthusiasm quicker than the thought of silent toothy predators lurking below. The glimpse of a fin, or a dark shadow in the water, can strike panic into the heart of even the most experienced surfer or ocean swimmer.

The majority of shark attacks occur in shallow water close to the coast, where large numbers of surfers, swimmers, and sharks occupy the same space. And while the odds of an encounter are remote, the gruesome and unpredictable nature of a shark attack affects us at a primal level.

Humans, like all mammals, possess an innate terror of being eaten alive. And when we’re floating unprotected in the ocean, we’re no longer at the top of the food chain.

Sharks see only in black and white, but they also boast the most sensitive electro-magnetic receptors of all known animals, which they use to evaluate shape, proximity, and even the heart rate of nearby creatures. These electrical receptors are small, gel-filled sacs called Ampullae of Lorenzini. On most occasions, the sharks get it right and leave humans alone – we’re generally not on the menu. But sometimes a curious shark might take a nibble, just to figure out what we are. These unprovoked hit-and-run encounters are the most common form of attack.

Some common-sense precautions can mitigate the already low risk. Avoid cloudy, turbid, or murky waters, and leave the water quickly if baitfish are present, especially when they're breaking the surface, as this normally means something is pursuing them from below (look out for seabirds diving at the baitfish). Dusk and dawn are also more dangerous, since these are typically feeding times for sharks, and reduced visibility increases the probability that a shark might mistake you for breakfast.

In the unlikely event that a shark does approach, you should be prepared to defend yourself. Striking the shark on the nose, or gouging at its eyes, may make it reconsider the attack and move away. In August 2015, surfing star Mick Fanning successfully used this approach to deter an inquisitive shark at the J-Bay Open Surf Event in South Africa, as shown in the terrifying clip below.