About 200 competitive swimmers — and perhaps dozens more — had to be plucked from the ocean by rescue crews Monday as strong currents dogged the 47th annual Waikiki Roughwater Swim.

“It was a very, very rough swim,” said race director Kaia Hedlund, noting some swimmers couldn’t handle the strong current after the first buoy. “This was not just a little walk-in-the-park race. If you’re going to to do this, you need to train and need to be prepared for the elements.”

Of the approximately 700 people registered for the event, at least 455 finished, Hedlund said. Swimmers who didn’t reach the halfway point by a certain time were picked up by rescue crews, she said.

Hedlund said every participant was accounted for.

The 2.4-mile race started at Kaimana Beach at 8:30 a.m. and ended at Hilton Hawaiian Village. Those who struggled — or straggled — were picked up by city lifeguards, Honolulu Fire Department crews and volunteers hired by the event organizers.

Shayne Enright, spokeswoman for the Honolulu Emergency Services Department, said participants who sought assistance were too tired to finish the race or to make it to shore on their own.

There were conflicting reports of the number of swimmers assisted. Enright said more than 300 swimmers got help, while event organizers said the number was 200 or less.

The Waikiki Roughwater Swim Committee hired water patrol crews that consisted of 17 professional lifeguards equipped with three craft. In addition, more than 90 kayakers, stand-up paddlers and surfers volunteered to help during the event.

“We take safety very, very seriously,” Hedlund said.

During the race a 15-year-old swimmer was taken to the hospital by her father after she had an asthma attack.

Paramedics treated and transported a 32-year-old woman in serious condition after she suffered an injury on the reef.

HFD brought tired swimmers to shore via rescue boat or Jet Ski.

Spokesman Capt. David Jenkins said the department deployed its Air One helicopter to survey waters for any swimmers who might have drifted off course.

The swimmers included Jarrod Poort of Australia, who recently competed in the 10-kilometer marathon swimming competition in the 2016 Olympics in Rio. He told event organizers that Monday’s event was one of the hardest he’s ever been in, Hedlund said.

Alissa Tambone, 36, flew to Hawaii from Wisconsin to participate in both the Waikiki Roughwater and Maui Channel swims during the Labor Day weekend.

“It was a tough swim but it was beautiful,” Tambone said of Monday’s race. “The water was gorgeous.”

Heading out and back to shore was a challenge due to the strong current, she said.

“There were a lot of people struggling.”

She noted the event was well staffed, with a lot of rescue crews on hand to assist swimmers. Tambone said there was constantly someone watching over the swimmers.

The National Weather Service said a combination of tides, a south swell and wind gusts of 25 mph may have contributed to the currents. The surf was 1 to 3 feet.

The event was held as Tropical Storm Lester continued to retreat from the islands.

At 5 p.m. Monday the center of Lester was 800 miles north-northwest of Honolulu and moving in that direction at 13 mph. The former hurricane had maximum sustained winds of 60 mph.

“It’s going to make a turn toward the north and northeast and accelerate away from us in a day or so,” said National Weather Service forecaster Tom Birchard.

In 2003 rescuers assisted at least 267 swimmers in the Waikiki Roughwater Swim due to powerful currents. That year 1,055 swimmers entered the competition, which was held as Hurricane Jimena was passing the southern tip of Hawaii island.

In 2014 a Punahou School English teacher, Dan Min-dich, 48, died after being pulled from the water during the swim.

Last year the swim was canceled due to rough seas less than an hour before it was due to begin.