A box jellyfish advisory has been issued for Waikiki and Ala Moana beaches, in whose waters the stinging invertebrates have been spotted, the City and County of Honolulu announced this morning.

A common hazard to swimmers and surfers, who can be caught in their tentacles, box jellyfish also wash up on beaches and contact with any part of their bodies, whether alive or dead, whole or in pieces, can result in excruciatingly painful stings and, in allergic people. a deadly reaction such as anaphylactic shock.

Lifeguards at beaches have posted signs warning the public against swimming in jellyfish-infested waters. Beachgoers are urged to check with lifeguards for the latest beach and ocean conditions before entering the water.

Box jellyfish stings can cause severe pain, and in rare cases, serious medical complications. In the event of a sting or other emergency, beachgoers should call 911 immediately.