"It was very eerie," said Dehart of the night diving, despite claiming that he's never once run into a problem while diving, which he's done nearly 450 times. "The sharks move a lot faster at night, and while during the day there seems to be a pecking order for which shark gets what food, we saw the rules at night change."
But even Dehart knows that the frightening content broadcast during "Shark Week" will instill fear in humans who may never be completely at ease with the idea of sharing the open sea with creatures, such as the great white shark.
While Dehart does admit that the "Shark Week" programming is extremely entertaining to watch, he hopes that TV viewers will be captivated enough by the weeklong event that they will begin to fear less and care more about a group of animals he says are in grave danger of disappearing altogether.
"To me, 'Shark Week' does a great thing in keeping sharks in the public eye," he said. "Sharks really need our help to survive; we're killing 250,000 sharks every day."
Fisherman, who catch sharks to profit from selling their lucrative fins, which are used for shark fin soup, are rapidly depleting the shark population, as are those fisherman who accidently catch sharks while fishing for other animals (known as by-catching), says the special.
For the past two decades, "Shark Week" has continued to build a fan base that has come to look forward to the week of shark programming on the cable channel.
According to Neilsen Media Research, last year's "Shark Week" was watched by 29.1 million viewers, and in 2007, 27.2 million people tuned in.
And it's likely that this year's audience will be just as huge, said Tim Molloy, a senior editor for TVGuide.com.
"Sharks are terrifying, and it's the whole fear of the unknown in a territory you're uncomfortable in," Molloy told ABCNews.com. "We like to confront those fears from the safety of our living rooms."
Followers were preparing to take in "Shark Week" even in the weeks before the broadcast: Fan groups dedicated to the network's event on Facebook multiplied, and people tweeted countdowns to the programs on the micro-blogging site Twitter.
Dehart is certain that it is the mastery -- as well as the inability to avoid sharks -- that makes "Shark Week" such a huge draw every year.
"Antarctica is the only place where, if you're looking to swim, you're absolutely guaranteed to not run into a shark," said Dehart.
But on second thought, Dehart reconsidered.
"Then again, we haven't even explored that area," he said, "so there very well may be some species down there."