Q: I’m a new diver and ready to start diving with my local club. I live in an area where jellyfish are common. What can I do to prevent stings?

Some of the most common types of hazardous marine life injuries are stings from creatures in the Cnidarian class, which inject toxins into prey using specialized cells (cnidocytes) that are triggered simply through contact.

Jellyfish
Jellyfish are one of the most commonly encountered hazardous marine creatures. Though jellyfish stings may be benign, some can be painful. Contact isn’t usually life threatening, although a specific type of jellyfish called Cubozoans (also known as sea wasps or box jellyfish), found in Australia’s northern territories, can be deadly.

Hydroids
Although hydroids look like harmless plants, these feathery animals live as colonies of small zooids (small, multicellular animals) that are physiologically linked together. With a smaller contact area, reactions caused by hydroids are usually more localized and less dramatic than jellyfish envenomations. Some examples of animals that can cause more significant symptoms are:

• Portuguese man-of-war — technically not a true jellyfish, but a colony of hydrozoans — can inflict excruciating pain and a wide array of systemic symptoms.

• Fire coral is also a colony of hydrozoans, and not a true coral. Stings can cause a mild to moderate burning reaction, and lacerations are possible among divers with poor buoyancy control. Fire-coral lacerations allow envenomation to occur within the open wound, which can be a problem because the toxins can cause dermonecrosis (skin-tissue death), potentially complicating the healing process.

Prevention
Implementing good diving skills and proper risk management can help to minimize injury. Mastering your buoyancy control and maintaining a respectful distance from marine life should be key considerations for safe diving. Regardless of water temperature, full body wetsuits, rash guards or other protective apparel can minimize exposed skin and may reduce the severity of contact with hazardous marine life. A good emergency-action plan should include researching dive sites for potential environmental risks and a discussion of how to manage marine encounters if they occur.

Basic First Aid Tips
In the event of a Cnidarian-related injury, first assess and monitor circulation, airway and breathing. Be prepared to perform CPR if necessary. Stabilize unfired cnidocytes in the affected area by generously pouring household vinegar over the wound before attempting to remove any visible tentacles or debris. Avoid rubbing the wound and do not use fresh water to cleanse the area as this could trigger unfired cnidocytes, potentially exacerbating the envenomation process. Finally, hot water can be used to manage pain and potentially neutralize some toxins. In its absence, a cold pack may be beneficial in pain management.

For more dive training, dive safety and diver health recommendations and tips, visit the Training, Safety and Health section of our website.

Abort your dive if you experience pain or discomfort caused by contact with hazardous marine life. If symptoms become serious, contact local EMS immediately, and then call DAN. For more questions about stings, call the DAN medical information line at (919) 684-2948 or email [email protected].