Hydroidomedusae and Siphonophorae
Jellyfish and Siphonophores
Maximum Size:
7 ft (2 m) with tentacles extending much farther.
Longevity:
From a few hours to several years.
Typical depth:
0–66 ft (0–20 m)
Behavior:
Jellyfish and siphonophores are both types of cnidaria, closely related to corals and sea anemones. Jellyfish are individual animals, while siphonophores are colonies of specialized cells called zooids, such as the Portuguese man o’ war. They both drift in the water and use stinging cells called nematocysts to capture and paralyze prey, including plankton and small fish.
Predators:
Salmon, tuna, some sharks, and some sea turtle species.
Did you know?
Box jellyfish, such as the sea wasp and Irukandji jellyfish, found in Australian coastal waters, are among the world’s most venomous. They are capable of causing death within minutes.
WARNING!
Jellyfish and siphonophores have stinging cells called nematocysts located on their tentacles. These cells can inject a toxin when brushed against bare skin. Depending on the species, jellyfish toxin can cause mild tingling to intense pain, and can be fatal in some rare cases. The contact site may also become red and blistered. Even dead jellyfish found on the beach can sting, so avoid touching them.
TREATMENT
Exit the water as quickly as possible, watching out for other jellyfish. Rinse the affected area with seawater to remove any piece of tentacle on the skin. Do not rinse with fresh water, which can trigger any remaining nematocysts to sting. The best treatment for jellyfish stings may depend on the species, but most can be treated by rinsing the affected area with vinegar or creating a paste using baking soda and seawater. The papain enzyme found in meat tenderizer and papaya can also help. Consider seeking medical attention.
MEDICAL DISCLAIMER
The treatment advice contained in this book is meant for informational purposes only and is not intended to be a substitute for professional medical advice, either in terms of diagnosis or treatment. Always seek the advice of your physician or other qualified health provider if you are injured by a marine organism. Never disregard professional medical advice or delay seeking it because of something you have read in this book.
