Lifeguards assessed the beach in the morning and decided to close the popular snorkeling area for the day, said Bryan Cheplic, a spokesman for the city Emergency Services Department. A count was not available, but officials said the number of the stinging jellyfish is expected to decrease significantly by Saturday.

"It's not a larger influx than usual," Cheplic said. "It's just the kona winds is contributing to the problem."

Box jellyfish sightings are common along Hawaii's south and west shores, especially eight to 10 days after the full moon.

More than 80 jellyfish were counted in the Waikiki area this morning, officials said. Warning signs will be posted in the affected areas.