A rare mass influx of box jellyfish rolled onto shore at Kailua Beach Thursday morning.
Lifeguards counted and collected an estimated 400.
Ocean Safety said that four stings were reported to lifeguards, but none were serious enough to warrant Emergency Medical Services.
Lifeguards posted warning signs and verbally warned beach goers throughout the day.
Officials said that at Waikiki and Ala Moana beaches, 21 jellyfish were counted and 34 stings were reported. None of the stings required EMS. Warning signs are also posted at these locations.
The Waikiki Aquarium’s website includes a box jellyfish calendar as the influx normally happens between eight to 12 days after a full moon. The current influx period of box jellyfish is April 17 – 22.
The aquarium notes that jellyfish arrival dates are estimates, and that jellyfish may be present on any day of the year.