While jellyfish can be found year-round along the South Florida shoreline, they are most common in May through October, with the peak period for jellyfish “blooms” occurring in August and September.

Jellyfish are prevalent along the Atlantic Coast and in the Florida Keys, often drifting ashore, carried by ocean currents, winds and tides. Children and other beachgoers can get stung when they brush against jellyfish while splashing in the surf or walking and playing on the shore.

Close Encounters of the Jellyfish Kind 

The most common jellyfish found in South Florida waters include the Moon Jellyfish, Cannonball jellyfish, Atlantic sea nettle and Portuguese Man o’ War. The most painful stings locally are associated with the sea nettle and the Man o’ War, which is actually not a true jellyfish. The bubble-like creature features long deep-blue tentacles that can cause painful welts when they come into contact with skin.

Signs of Trouble Ahead  

Parents should look for purple flags at lifeguarded Miami-Dade and Broward County beaches. These indicate the presence of dangerous marine life, including jellyfish.

If you are not at a guarded beach, watch the shoreline for Man o’ War and jellyfish, supervise children continuously and teach them to avoid jellyfish both in the water and on shore.

Separating Myth From Fact

Should a jellyfish sting occur, be aware of common treatment myths that, in reality, can worsen the associated discomfort.

• The Urine Myth: One of the most common myths suggests that urinating on a jellyfish sting is an effective treatment approach. The fact is that urine is mostly water and its inconsistent chemical balance can actually cause jellyfish stinging cells to release more venom. Instead, pour vinegar over the sting for at least 30 seconds. This can prevent the stinging cells from firing.
• Fresh Water Myth: Another common fiction is that fresh water is best for washing jellyfish stings. In fact, fresh water can cause unfired tentacles to release their sting. Instead, use salt water and vinegar to rinse stings.
• The Credit Card Myth: Despite popular lore, scraping jellyfish stings with a credit card or towel is not good practice. This physical pressure can release more venom into the skin. Instead, pick jellyfish tentacles off with tweezers or a gloved hand.
• Dead Jellyfish Myth: Do not heed the notion that a dead jellyfish cannot sting. The stingers in tentacles of dead jellyfish still have potential to fire and inflict pain.

What to Do if Stung

If you or your child is stung by a jellyfish, treat the sting with vinegar and salt water and alert the lifeguard if one is available. Some people may have allergic reactions to jellyfish stings. Call 911 or seek emergency care if you or your child exhibits any of the following symptoms:

• Difficulty breathing or swallowing
• Chest pain
• Severe muscle cramps or spasms
• Dizziness or fainting
• Rapid, whiplike welts spreading on the skin
• Nausea, vomiting, or abdominal pain

All of us at Nicklaus Children’s Hospital wish you and your family a safe and healthy summer!