Chironex

Chironex is a genus of box jellyfish in the class Cubozoa, commonly known as sea wasps. Members of this genus are among the most venomous marine animals, delivering their toxin through nematocysts on their tentacles. They are distinguished by a cube-shaped bell and fast, precise swimming.

Distribution and species: The genus comprises several described species, with Chironex fleckeri, the Australian box jellyfish, being the best known. It inhabits warm coastal waters of northern Australia and parts of Southeast Asia. Other described species include Chironex yamaguchi, reported in East Asian waters, among others.

Venom and effects: Chironex venom contains potent toxins that disrupt cell membranes and ion channels, resulting in intense pain, tissue damage, cardiovascular collapse, and, in some cases, death within minutes if untreated. Envenomation requires urgent medical care; fatalities have been reported, particularly in children and in areas with limited access to treatment.

Life cycle and ecology: Like other cubozoans, Chironex species cycle between a sessile polyp stage and a free-swimming medusa stage. Reproduction is sexual in the medusa form; planula larvae settle as polyps and bud to produce juvenile medusae. They prey on small fish and crustaceans using their nematocysts.

First aid and treatment: If stung, rinse the area with vinegar to inactivate unfired nematocysts, carefully remove visible tentacles with forceps, and avoid rubbing the area. Seek urgent medical care. In regions where available, antivenom for box jellyfish can improve outcomes.