The man in the cage below is not nicknamed “lefty.”

After the frightening-looking encounter captured here, the great white shark vanished into the abyss and the man kept his arm.

But cage-diving scenes that promise close encounters with sharks are creating a frenzy at Guadalupe Island west of Baja California, because some feel it’s only a matter of time before a person gets killed.

“It’s an arms race and it’s the worst example of one that I’ve ever seen,” said Patric Douglas, who runs Shark Divers, a shark-related tourism, filming and consulting business.

The half-dozen operators that set up shop seasonally at the remote Mexican island have become so competitive that they’re constantly seeking new ways to lure high-dollar customers away from other operators.

Customers also have become bolder. They routinely lean from the gaps of cages to get better camera angles, despite instructions to keep limbs and torsos inside. In some cases, divers are even swimming out the cages or climbing on top of them in waters that are home each summer and fall to dozens of adult great whites.

Cage diving is relatively new to Guadalupe Island but its evolution beyond the traditional stern-attached surface cages, which still exist, has been swift.

The so-called arms race began when Lawrence Groth of Shark Diving International started submersing cages to depths at which the sharks lurk — about 50 feet — so he wouldn’t have to rely on “chumming” them to the surface with ground-up fish and blood (now illegal but still practiced by some).

Groth also built a submersible “cinema cage” that has no sides, affording film crews unobstructed views but providing sharks with direct access to human flesh, if that’s what they desire. Fortunately, they do not.

Groth’s latest invention is a horizontal two-person cage that “flies around like an airplane,” with the client laying in the front with a camera and Groth in back driving with a joystick.

When informed that another operator has built a double-deck cage with no bars on the upper deck, Groth said, “I’ll have to do a fly-by and check it out.”

The split-level cages are the brainchild of Mike Lever, who runs the Nautilus Explorer, a luxury vessel that has a hot tub from which divers can warm up after their chilly cage dives and watch sharks circle the boat in gorgeous blue water with 100-foot visibility.

Divers in these submersible cages can enjoy the company of white sharks from behind steel bars or scamper upward, with experienced dive masters, to stand atop a deck for an open-water experience.

“It is an unforgettable rush when a great white looks at you from 50 feet away and then swims over for a very close look,” says Daniel Dayneswood, who works for the Nautilus Explorer, which is based in British Columbia.

But the daring does not end here. A relative newcomer to Guadalupe is Amos Nachoum, who has raised the bar to what some might consider the ultimate level.

Nachoum, a famous photographer and outfitter who runs Big Animal Expeditions, openly advertises outside-the-cage opportunities and charges what some might consider an arm and a leg: $5,900 for a week-long trip.

Nachoum, whose trips are aboard a 110-foot La Paz, Mexico-based vessel named Sea Escape, says he takes only “qualified individuals” but other operators claim Nachoum’s idea of a qualified individual is anyone who shells out the money for one of his trips.

“He’s new to the whole thing,” says Groth, a pioneer at Guadalupe who himself has been referred to as a “cowboy” using questionable tactics. “He has an inexperienced boat crew and he’s doing this stupid stuff with anyone who will pay him the money.”

Lever believes Nachoum’s operation is an accident waiting to happen. “What concerns me is that someone outside the cage gets freaked out by a shark, and it’s easy to get freaked out by a shark; I’ve been freaked out by them,” Lever says. “So what happens when you’re at mid-water on SCUBA gear and you get freaked out and panic.

“If that person bails to the surface what kind of reflex are they going to trigger in that animal? And then that person is on the surface thrashing, and then what happens?”

It should be noted that white sharks are not bloodthirsty killers. They’re generally very cautious around divers. Other operators have let veteran film crews outside the cages for brief periods, always flanked by dive masters who look for any changes in the sharks’ behavior. If a shark becomes even remotely aggressive, divers are ordered back into the cages.

Nachoum maintains that he’s as cautious as the sharks. He only runs one trip a year to Guadalupe, and only takes 10 people. Only half of them even want to venture out of the cages, he says. Those who do must have extensive scuba experience and must bring lawyer-signed and notarized documents stating they’re aware of the risk of death and serious injury.

The expedition leader adds that he only allows one diver at a time to venture outside, only after he has gone outside and feels comfortable in the presence of the shark or sharks in the area. A second dive master swims behind the customer with a stick to push the shark away if it gets too close. (These sharks can measure 18 feet and weigh 3,000-plus pounds.)

Groth and Lever say what Nachoum is doing is illegal. Nachoum says other operators — he did not name them — are in violation for using whole tuna attached to ropes to lure sharks to surface cages and inspire them to open their mouths for camera-toting passengers. The crews yank the tuna away before the sharks can snatch them and this, Nachoum says, “makes the sharks crazy.”

What’s legal and illegal is largely moot because Guadalupe is 160 miles from the Baja California peninsula and enforcement of any rules is difficult, though the Mexican navy makes a sporadic inspection.

Mostly it’s up to the operators to watch each other, and they do so suspiciously.

One thing they all agree on is that if a shark does kill someone, Mexico might kick everyone out and close what is arguably the world’s premier white shark-diving destination.

That, they say, would remove the operators’ watchful eyes and open the island to poaching, which would decimate the sharks. So it’s in everyone’s best interest — though it hardly seems that way — to keep their customers alive.

— Top photo and bottom two photos are copyright images courtesy of Don Carpenter. Any use without his permission is illegal.

— Second image of a scuba diver outside the cage is courtesy of Amos Nachoum