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Virginia Institute of Marine Science

Jellyfish Sting?

  • Sea Nettle
    Sea Nettle
    The jellyfish for which Chesapeake Bay is widely known in the summer is the sea nettle (Chrysaora quinquecirrha). It occurs from Cape Cod south along the U.S. East Coast and into the Caribbean and Gulf of Mexico, but is most abundant in Chesapeake Bay. It occurs most abundantly in tributaries of the middle Bay (salinities 10 - 20 ppt), where it is white. In the southern Bay, it often has red/maroon markings on the long central tentacles and on the swimming bell. It has an annoying sting, but is not dangerous to swimmers.
    Photo by Rob Condon.
  • Sea Nettle
    Sea Nettle
    A sea nettle (Chrysaora quinquecirrha) pulses through the York River. Note the white color and absence of red markings typical of sea nettles from the lower Bay.
    Photo by David Malmquist.
  • Comb Jelly
    Comb Jelly
    These barrel-shaped jellyfish have a transparent body with four rows of ciliated “combs” that emit an iridescent glow when disturbed. Unlike other jellies, comb jellies don't sting. They are small animals, 3-5 inches long and about an inch in diameter. Mnemiopsis eats zooplankton (including copepods), other comb jellies, and the eggs and larvae of fish. It thus plays an important role in the Chesapeake Bay food web.
  • Lion's Mane Jellyfish
    Lion's Mane Jellyfish
    The Lion's Mane jellyfish (Cyanea capillata) is most common in Chesapeake Bay during the winter. It has long tentacles and a potent sting. While it is not dangerous to swimmers, it is very unpleasant to encounter.
    Photo by Rob Condon.
  • Sea Nettle Sting
    Sea Nettle Sting
    VIMS graduate student Jessie Campbell shows the typical sting marks left by the tentacles of a sea nettle (Chrysaora quinquecirrha).
    Photo by Rob Condon.
I want to avoid jellyfish while swimming in Chesapeake Bay. What steps can I take?

Several different species of jellyfish inhabit Chesapeake Bay and nearby coastal waters. The most common jellyfish in the summertime Bay, and the one most responsible for stinging swimmers, is the sea nettle Chrysaora quinquecirrha (Cry'-sore-ah kwin-kah-sehr'-ah). Because these organisms occur within a  narrow range of temperature (78 to 86°F) and  salinity (brackish waters of 10 to 16 parts per thousand), scientists have been able to develop an experimental real-time computer model that predicts the likelihood that sea nettles might be found in an area based on the appearance of water masses that meet these criteria. The model uses no field data concerning sea nettle abundance or distribution, it simply shows where the water is of the appropriate temperature and salinity to support sea-nettle blooms.

Because jellyfish are planktonic animals that tend to move with tides and currents, another way to minimize the likelihood of encountering sea nettles and other jellyfish is to avoid swimming or boating along windward shorelines or where a flood tide encounters an obstacle.

Covering exposed areas and applying topical sprays may also help prevent stings. Beached jellyfish and dislodged stinging cells can continue to sting, so avoid touching any jelly-like masses you might encounter on the beach.

If I’ve been stung, what should I do?

A jellyfish sting results when one or more of the stinging cells (nematocysts) embedded in the animal's tentacles discharges its small, harpoon-like structure and venom into the tissues of its prey. Jellyfish stings are painful yet rarely life-threatening, particularly from the species present in Chesapeake Bay. The rare fatalities are either due to the effects of the venom itself [e.g., the tropical box jellyfish], or to an allergic reaction.

The following information on treating a jellyfish sting is taken from "I've Been Stung: What Should I Do?," an article by Paul S. Auerbach, M.D., M.S. from the Divers Alert Network (re-used with permission). To view the full article, which contains information about treating the stings and bites of other marine creatures as well, visit http://www.diversalertnetwork.org/medical/articles/article.asp?articleid=36

BE PREPARED TO TREAT AN ALLERGIC REACTION FOLLOWING A JELLYFISH STING. If possible, carry an allergy kit, including injectable epinephrine (adrenaline) and an oral antihistamine.

The following therapy is recommended for all unidentified jellyfish and other creatures with stinging cells:

  1. If the sting is believed to be from the box jellyfish (Chironex fleckeri) [Steinberg note: not found in Chesapeake Bay], immediately flood the wound with vinegar (5 percent acetic acid). Keep the injured person as still as possible. Continuously apply the vinegar until the individual can be brought to medical attention. If you are out at sea or on an isolated beach, allow the vinegar to soak the tentacles or stung skin for 10 minutes before attempting to remove adherent tentacles or to further treat the wound. In Australia, surf lifesavers (lifeguards) may carry antivenin, which is given as an intramuscular injection a first aid measure.
  2. For all other stings, if a topical decontaminant (e.g., vinegar, isopropyl [rubbing] alcohol, one-quarter-strength household ammonia, or baking soda) is available, apply it liberally onto the skin. If it is a liquid, continuously soak a compress. (Be advised that some authorities advise against the use of alcohol because of scientific evaluations that have revealed that some nematocysts discharge because of this chemical's application.) Since not all jellyfish are identical, it is extremely helpful to know ahead of time what works for the stingers in your specific geographic location.

    Apply the decontaminant for 30 minutes or until pain is relieved. A paste made from unseasoned meat tenderizer (do not exceed 15 minutes' application time, particularly on the sensitive skin of small children) or papaya fruit may be helpful. Concentrated citrus (e.g., lime) juice may be helpful. Do not apply any organic solvent, such as kerosene, turpentine, or gasoline.

    Until the decontaminant is available, you may rinse the skin with sea water. Do not simply rinse the skin gently with fresh water or apply ice directly to the skin. A brisk freshwater stream (forceful shower) may have sufficient force to physically remove the microscopic stinging cells, but non-forceful application is more likely to cause the cells to fire, increasing the envenomation. A non-moist ice or cold pack may be useful to diminish pain, but take care to wipe away any surface moisture (condensation) prior to the application.
  3. After decontamination, apply a lather of shaving cream or soap and shave the affected area with a razor. In a pinch, you can use a paste of sand or mud in sea water and a clamshell.
  4. Reapply the primary decontaminant for 15 minutes.
  5. Apply a thin coating of hydrocortisone lotion (0.5 to 1 percent) twice a day. Anesthetic ointment (such as lidocaine hydrochloride 2.5 percent or a benzocaine-containing spray) may provide short-term pain relief.
  6. If the victim has a large area involved (entire arm or leg, face, or genitals), is very young or very old, or shows signs of generalized illness (nausea, vomiting, weakness, shortness of breath or chest pain), seek help from a doctor. If a person has placed tentacle fragments in his mouth, have him swish and spit whatever potable liquid is available. If there is already swelling in the mouth (muffled voice, difficulty swallowing, enlarged tongue and lips), do not give anything by mouth, protect the airway and rapidly transport the victim to a hospital.