Sea nettle

What is a sea nettle?

Sea nettles are the stinging jellyfish common in Maryland's coastal bays during the warm months, usually from midsummer into early fall. They concentrate in the sheltered, warmer, less salty back bay water rather than the open Atlantic, which is why bay swimming can be uncomfortable in August while the ocean beach is fine. Stings are painful but rarely serious for most people. Their abundance varies year to year with water temperature and salinity.

Also called: sea nettles, jellyfish, stinging nettles.

Bay versus ocean

Here is the practical version. Swimming from a bayside dock in August means nettles. If the plan is the guarded Atlantic beach, they are usually a non-issue. Paddling, boating, and jet skiing on the bay are unaffected as long as nobody goes in the water.

Treating a sting

Rinse with seawater, not fresh. Remove any tentacle material without using bare hands, then treat the pain. Ask the Beach Patrol or the outfitter for current guidance, since first-aid recommendations for marine stings get revised and local staff know what works here. Seek medical help for a large sting area, a severe reaction, or any breathing difficulty.

Planning around nettle season

Nettle abundance is seasonal and variable, not constant. Early summer is usually clear, late summer is the peak, and cooler falls thin them out. If bay swimming is central to your trip, ask locally about current conditions the same way you would ask about surf.

Where to swim in late summer

Current source: Ocean City Tourism outdoor adventures. Fees, hours, posted rules: all of it moves without much notice, so confirm anything time-sensitive on the day you go.

Related terms in this glossary

Sea nettle rarely settles a plan on its own. These come up in the same decision, and each one has its own page, so open whichever part you're still unsure about.