Dealing With Jellyfish While Scuba Diving
Jellyfish Facts And How To Manage A Sting From Jellyfish Nematocysts
Jan 9, 2009
A diver is sure to encounter a jellyfish during their scuba diving career. There are two main types:
1) The common variety of jellyfish that can deliver a painful and annoying sting.
2) The killer jellyfish: the Box Jellyfish (or Sea Wasp) and the Irukandji.
What Is A Jellyfish?
A jellyfish is a glutinous animal, that propels itself through the water. There are around 200 different types of jellyfish, of all different shapes and sizes, and stinging capability. They have tentacles containing tiny stinging mechanisms called nematocysts that inject their venom.
The jellyfish is related to other stinging marine animals such as Fire Coral, stinging hydras, and anemones. They are found throughout the world.
Nematocysts - The Jellyfish Stinging Mechanism
A jellyfish stings by the use of nematocysts. These are microscopic needles housed within a tiny cell. When the jellyfish brushes against an enemy or food, these needles fire from their housing and drill into the victim.
Hundreds, or even thousands, of these nematocysts fire off. It is the sheer number of nematocysts all delivering a minute dose of toxin that scuba divers need to be aware of. It is also why the tentacles are so difficult to remove; they are held on by these small needles.
Symptoms Of Jellyfish Stings
Jelly fish stings can range from mildly annoying pain to death.
Mild symptoms include:
- pain
- itching
- raised red welts
- numbness
- muscle spasms
These can lead to further physiological symptoms:
- nausea
- vomiting
- swelling of the lymph nodes
- abdominal pain
Severe symptoms are difficulty breathing and unconsciousness.
Treatment of Jellyfish stings
If stung by a jellyfish:
- Immediately flood the area of the sting with vinegar. This reduces the nematocysts releasing more venom. Scuba divers in jellyfish infested waters should always have vinegar in their gear bag or spares kit. If no vinegar is available, rinse the area with salt water. Fresh water shouldn’t be used as it can activate the nematocysts to release more venom. For the same reason, hot water or ice should not be used.
- Do not rub the area. An old remedy was to rub the area of the sting with sand. All this does is spread the nematocysts.
- After soaking in vinegar, the tentacles can be removed. This should be done wearing gloves or with a stick or other implement. E-medicine.com recommends shaving the area with a razor or a credit card to remove the last of the tiny nematocysts.
Preventing Jellyfish Stings
To prevent jellyfish stings, a scuba diver can take the following precautions:
- Jelly fish prefer times of low light, such as the morning, late evening or during overcast conditions, so be aware when diving at these times.
- Jellyfish are usually found near the surface, so watch out on the ascent and descent. On the ascent, it can be useful to expel air from the alternate air supply to clear a path to the surface.
- Wear full protective clothing when diving with jellyfish around. When in warm waters, an all-over covering like a lycra suit can provide the freedom of movement while providing protection.
- Always have vinegar in the scuba kit bag or spares kit.
Most jellyfish might give an annoying sting, but all divers need to be aware that some jellyfish species (The Box Jellyfish and the Irukandji ) can kill a human in minutes.
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