Boaters and Stinging Sea Nettles
Coping Strategies for the Boating Season's Unwelcome Jellyfish
Mar 19, 2008
Stinging sea nettles and jellyfish are part of an aquatic invertebrate phylum known as coelenterates. This group of creatures is divided into four different classes, hydrozoa (fire coral), scyphozoa (sea nettle), cubozoa (box jellyfish), and anthozoa (sea anemone). Coelenterates are responsible for more envenomations or injections of venom than any other marine phylum.
Thousands are stung by jellyfish and other coelenterates each year. Most incidents only result in minor skin irritation. More rarely, some people suffer allergic reactions and risk death from jellyfish stings. Agencies like NOAA's Sea Grant College Program document many natural hazards and offer advice to recreational beachgoers and boaters on contact with jellyfish. Maryland Sea Grant is known for its sea nettle prediction and jellyfish education efforts in Chesapeake Bay.
Sting Physiology - Venomous coelenterates release a complex toxin that acts at many different body levels, impacting the neurotransmitters, skin, heart, and blood. Stinging cells used by these creatures are carried in specialized sub-organs called nematocysts. Nematocysts are located near the coelenterate's mouth and designed to immobilize prey. Stinging cells located in a nematocyst have a trigger that fires a coiled injection tube on contact with bare skin, forcing toxins below the skin's surface. Nematocysts will continue to fire their stinging cells even after a jellyfish is dead.
Preventing Jellyfish Stings - Beachgoers and boaters can avoid coelenterate stings in a number of ways:
- Mapping Jellyfish Concentrations - The NOAA Mapping Sea Nettles in Chesapeake Bay Project is one experimental effort to warn people of jellyfish concentrations
- Erecting Swim Barriers - Another entity in Chesapeake Bay region is manufacturing floating net rings that protect swimmers from contact with jellyfish. This product is called a Nettle Net Boat Pool and comes in variety of sizes
- Protective Coverings - Swimmers can avoid stings by protecting bare skin. This can be accomplished by wearing a lycra suit, wetsuit, coating the skin with petroleum jelly or using a product like Safe Sea Lotion. In a study published in the Journal of Travel Medicine, the Safe Sea topical barrier cream was more than 80% effective in preventing jellyfish stings under realistic conditions
Jellyfish Sting First-Aid - A key point to remember is that a detached tentacle or dead jellyfish can still sting. Here are some first-aid pointers from Alaska Sea Grant and the Hawaii Lifeguard Association to consider after coming into contact with a stinging coelenterate:
- Flush the skin with a saline solution or saltwater to remove tentacles and inactivate nematocysts. Washing the skin with fresh water can cause stinging cells to fire
- Irrigating the skin with dilute vinegar will neutralize the nematocysts of certain species like the Box Jellyfish. The use of vinegar on Portuguese Man-of-War stings is no longer recommended
- Once the nematocysts are deactivated, carefully scrape off broken tentacles and nematocysts off the skin. Using a disposable razor and shaving cream works well. Wear gloves
- Treat resulting wounds to prevent an infection. Bacteria are always present in marine waters
- In the rare instance of a life threatening allergic or anaphylactic reaction, call 9-1-1 and provide basic life support until the ambulance arrives
Being aware of risk posed by coelenterates stings is important. The United States National Institutes of Health points out that jellyfish stings are common occurrences with an estimated envenomations happening each year. A little preparedness can make your next boating excursion or trip to the beach safer and much more enjoyable.
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