Expert likens Rob Lowe's great white shark encounter to 'winning the lottery'

— -- Fortunately for actor Rob Lowe, the great white sharks that he encountered off the California coast don't shift to a marine mammal diet "until they're much bigger,” a shark expert said on “Good Morning America” today.

Paddleboarding near Malibu recently, Lowe maintained his chill demeanor while hovering inches above two of the ocean predators that appear to pose little threat, at least at first glance.

"Just because he's inches above these small sharks doesn't mean that there's not a big one down there as well," shark expert Dr. Stephen Kajiura told "Good Morning America."

"On the other hand, these are not particularly the big sharks so, as a result, they're feeding primarily on fishes and their tooth shape reflects that.”

A relaxed Lowe, who doesn’t appear to provoke the fish, said he felt comfortable around the sharks that, Kajiura said, don’t hunt for larger prey "until they're much bigger and their teeth become big, broad, triangular serrated teeth.”

But Kajiura, a Florida Atlantic University biology sciences professor, cautioned that "it's never really a good idea to go provoking wildlife," though adding that people should embrace the opportunity if they find themselves in the water with a shark.

"The first thing you should do is say, 'Wow, I'm really lucky to get a chance to see this,' and enjoy the fact that you're actually experiencing it," he said.

"And then the next thing you should do is say it would be prudent to go in [out of the water] at this point," Kajiura said, adding that the large animals could do whatever they want, including accidentally knocking a person from their paddleboard, for instance.

The rise of sightings and encounters of this top-level predator on both U.S. coasts is a sign of a healthy ecosystem, he said.

"Seeing large numbers of sharks means that the ecosystem is rebounding. We're building healthy populations again, so let's view that as a positive and not a detriment at all,"

Seeing a great white shark in its natural habitat is like "winning the lottery," Kajiura added, and a very positive thing.