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Box Jellyfish

Box Jellyfish live in many tropical regions of the world, including Hawaii. They are named for the cube shaped appearance of their medusae. Like their close cousins sea anemones and corals, box jellyfish have no true head, heart, brain or skeleton. Their bodies are organized entirely differently from ours. They are made up of about 95 percent water and use the surrounding water of the ocean to support their shapes.

Box jellyfish have 24 eyes, four parallel brain clusters and 60 anal regions. Their eyes are collected on the four sides of the cube-like body. Sixteen of the eyes are pits of light sensitive pigment, however one pair in each cluster have complex development. These complex eyes include a lens, retina, iris and cornea. It’s not known how these jellyfish process visual information, since they have no central nervous system.

Most jellyfish feed on small animals that they catch with their tentacles stinging cells (called nematocysts). Box jellyfish eat in this manner, rather than filter feeding like some other jellyfish do. These stinging cells are what make box jellyfish so dangerous to snorkelers and swimmers alike.

Box Jellyfish in Hanauma Bay

You may or may not see Box Jellyfish during your snorkeling trip in Hanauma Bay. However, consider yourself lucky if you don’t. There has been a recent influx of the creatures to the shores of Oahu.

The summer of 2006 saw a great number of jellyfish stings in the Hanauma Bay region. This prompted authorities to shut down the area for a day or two, and post signs at close beaches. Box jellyfish will also wash up on shore nine to ten days after every full moon. If you encounter a dying or dead jelly on the beach, do not touch or approach it. Instead, report the sighting to the lifeguard on duty. If you visit during one of these “swarming periods” the Hanauma Bay park staff and lifeguards will no doubt warn you of their presence.

Box Jellyfish stings

Box Jellyfish are known for their powerful venom. Not all types of box jellyfish are venomous by those that are can be fatal. If you encounter a jellyfish and are stung, you may feel a stinging, burning sensation, redness in the affected areas and swelling of lymph nodes. Long red welt lines may appear where the tentacles touched your skin.

If you are stung, the lifeguard on duty can help with first aid. However, the best remedy is prevention. If you see jellyfish while you are snorkeling, steer clear of the area. Also, make sure to stay far away from any dead jellyfish on the beach. Their tentacles continue to sting long after they are dead.