WRLTHD: It’s a Nice Night for Surfing. Beware of Sharks!

Helmut Igel prepared to paddle out into the California surf. The popularity of surfing means more traffic on the water, but things can be quieter at night. Donald Miralle for The New York Times

SAN DIEGO — The ocean and the sky melted together in a gray mass, making it tough for the surfer to size up the coming waves. Would they crash down on top of him and hold him under — or break in just the right spot for him to catch the perfect ride?

By day, the surfer, Helmut Igel, is not fazed by six-foot waves. But it was after midnight, on a moonless sea. Surfing is not the same in darkness.

Igel, 55, is among a small subculture of surfers who dot coastlines from San Diego to Sydney after sunset, pursuing an adventure that’s a subject of curiosity on social media these days thanks to pro surfers on LED boards. Visibility is but one of the perils.

Sharks, while rare along the coast here, can hunt at night. And surfers cannot count on being rescued by lifeguards; they left hours ago.

So why paddle out under the stars? Elbow room, mainly.

“These days on a full moon, you can still paddle out to a crowd. On other nights, it’s like stepping

into a time in California pre-‘Gidget,’” said Igel, referring to the 1959 movie about a teenage girl’s infatuation with surf culture that helped kick-start a boom in the sport.

Estimates of the number of surfers worldwide vary greatly — the International Surfing Association says it is 35 million — but forecasts indicate that the sport is growing. More surfers means more traffic on the water as they wait for waves, continually battling for position, given that the surfer closest to the curl gets the wave. Crowding also strains surf etiquette, which calls for only one rider per wave (or two on a two-way peak).

So Igel agreed to an interview, as well as a request to shadow him in the water, on one condition: no naming the precise spot he frequents, somewhere between Camp Pendleton Marine Corps Base and the curving La Jolla coastline 40 miles to the south.

Before hitting the darkened seas, Igel strapped on a helmet that was crusty from all the exposure to salt water, snapped a selfie and texted the picture to his wife to try to put her mind at ease. It does not always work, he said.

Duct-taped to the helmet were orange and purple glow sticks, a longtime night surfer accessory that alerts riders streaking across a wave to paddlers in their path.

Glow sticks can seem primitive next to the LED technology employed by pro surfers in video and social media clips in recent years. The most famous night ride to date took place in 2011: The Australian big-wave surfer Mark Visser — equipped with a buoyancy vest and a board with specially engineered LED lights — surfed 30-footers at the Hawaiian break Jaws.

“It started off as, ‘This is the most terrifying thing,’ but once I settled down and was able to really feel what was happening and be in the moment, it was the most amazing experience,” said Visser, noting that his death-defying stunt had required four years of preparation.

Visser’s tricked-out life jacket and board were not designed to light up the waves, but rather to enable rescue crews to spot him in the event of a wipeout. He figured out during training that lights pointed in any direction but behind him were blinding.

The Australian board maker Mike Bilton — one of the few producing commercial LED surfboards — encountered the same problem while developing a prototype.

“Later designs moved the lights mostly to the underside of the board, which casts a bit of light, so particularly when you’re on the wave you can see,” he said. “You’ve still got the initial challenges of seeing a wave coming.”

But glow sticks suit Igel just fine. Their light was the only sign of him as he stroked into a peeler, drew S-shaped turns and kicked out before the wave dumped him on the shore. He immediately began clawing his way back to the takeoff spot.

After 20 years of night surfing, Igel is accustomed to dicey situations. He recalled collisions — and a 12-foot sneaker wave that gave him and a friend the spin-cycle treatment. But those incidents have not kept him from going out a few times a month.

For Igel, a former ship navigator, bobbing offshore under the cover of darkness is second nature. “It’s not only about trying to get away from the crowds,” he said. “It’s the ambience, which is hard for me to put into words.”

I got a taste of this eerie beauty between wave sets.

Digging my hands through the water left sparkly white trails — what Igel calls pixie dust — because of phosphorescence in the water. Stars twinkled. Headlights from the occasional car reflected off low, wispy clouds.

Yet for all its allure, night surfing is linked to tragedy.

On Oct. 27, 2015, just as night began to fall, the big-wave surfer Alec Cooke paddled out at Waimea Bay in Oahu, Hawaii. After Cooke was reported missing, emergency responders found his surfboard washed up on shore, but not him.

Three days later, the body of Kenneth Mann, a master surfboard sander who was known to ride waves at night, was found tethered to his broken surfboard on the beach in Encinitas, Calif.

James McDonald of Ireland surfed under a full moon this month in California. Credit Donald Miralle for The New York Times

The Encinitas lifeguard captain Larry Giles said he had seen Mann jogging to the beach with his surfboard an hour or so before sunset the previous day. It is not clear what happened after that or when Mann drowned.

Given the lack of light, it is common for surfers’ eyes to play tricks on them: Is that kelp or something worse?

“Sharks are a big part of night surfing, even if they are not actually there,” said James McDonald, who joined Igel in sharing stories but did not paddle out that particular night. “The thought is always with me.”

He half-jokingly added that if he had the misfortune of encountering a shark, he would receive “an amazing epitaph: ‘Eaten by Great White Whilst Night Surfing.’”

Brad Benter, also a part of San Diego’s night surfing scene, said he had once spotted a shark’s dorsal fin 100 feet from him under a full moon about 4:30 a.m. These days he wears an anklet meant to ward off sharks, although he is not confident it works.

Still, the night surfers are moonstruck.

“Your eyes start to adjust after a while, and while still hard to see, you catch a wave,” McDonald said.

“And in your head it feels like you ride two miles. Time stops.”

Night surfing is not new. A 1909 Collier’s magazine article on surfing in Hawaii described the annual Waikiki beachside carnival, in which surfers rode with acetylene lamps. In 1969, Hawaii’s Jock Sutherland, reportedly after taking LSD, rode 20-foot monsters at Waimea Bay well after sundown, according to Matt Warshaw, author of “The History of Surfing.”

“In the ’60s, young surfers would occasionally go out because the ingredients were there: summer, warm water and moonlight,” Warshaw said. “Later, it became a way to get away from the crowd, and I’m not even sure if that’s true anymore at prime spots.”

Back at the midnight break, Igel stroked into a wave that marched in from the darkness.

“This looks like a good one!” he said before dropping in.