Jellyfish can be found both offshore and inshore. The Gulf Coast is home to the Portuguese man o' war, the sea nettle jellyfish, and the box jellyfish. Jellyfish are some of the oldest creatures on the planet, having roamed the seas for at least 500 million years. Jellyfish have tiny stinging cells in their tentacles to stun or paralyze their prey before they eat them, so they are very dangerous.
Contact with a jellyfish can trigger millions of stinging cells called nematocysts to pierce the skin and inject venom, causing mild to severe pain and skin irritation. Even beached and dying or seemingly dead jellyfish can still sting when touched. Vinegar is the most effective remedy for jellyfish stings—contrary to popular belief, urine is ineffective and may even release more venom, making the pain worse. Cleansing the area with salt water is also effective. Jellyfish stings can potentially cause allergic reactions, so if you normally carry an epinephrine autoinjector, such as the EpiPen, bring it with you to the beach. A purple flag is flown to indicate the presence of dangerous marine life on the beach.
Sea Nettle Jellyfish
The sea nettle jellyfish, sometimes called the Atlantic sea nettle or East Coast sea nettle, is typically pale, pinkish or yellowish, often with more deeply colored stripes near the edges of its body. Sea nettles are carnivorous and feed on plankton, other jellies, and sometimes crustaceans. They are typically several inches in diameter and can have tentacles as long as five feet or more. Their transparent appearance makes them difficult for swimmers to see and avoid. The pain from a sting is moderate to severe.