All About Moon Jellies!

You can find them in oceans, bays and harbors around the world, as well as in our Jellies Invasion: Oceans Out of Balance and Living Seashore exhibits—learn all about moon jellies!

Published June 16, 2017

With their translucent white bells—which can reach 12 inches in diameter—it’s not difficult to see where moon jellies get their name. Their luminous bells, with a blue-grey transparent disk in the center and glowing, horseshoe-shaped organs, give moon jellies their identifiable appearance. moon-jellies

Moon jellies can be found in temperate and tropical oceans around the world, especially near the surface of shallow bays and harbors. In Maryland, moon jellies can commonly be found in the lower Chesapeake Bay during the summer months. If you stumble upon a moon jelly drifting in the water, there’s no need to panic! Their saucer-shaped bells are fringed with short tentacles, but they deliver a very mild sting.

Their diet consists of zooplankton, which moon jellies trap with their delicate tentacles. When moon jellies are deprived of food, they can shrink to one-tenth of their original size to conserve energy. When food is available, they expand to their normal size. 

Their predators include sea turtles and jelly-eating fish, such as tuna, sunfish, butterfish and spiny dogfish. Like many other jelly species, moon jellies have experienced a population boom in recent years. Factors such as overfishing, ocean warming and pollution have negatively impacted populations of their predators, causing jelly populations to grow at an alarming rate and consequently throwing their ecosystems out of balance. 

Visit our Living Seashore exhibit to interact with a moon jelly in one of our touchpools! 


Previous Post

Featured Stories

Jellies in petri dish Welcome to the Jelly Jungle

Deep inside the Institute of Marine and Environmental Technology (IMET) building, the National Aquarium runs a little-known lab. Here we carry out the propagation of jellies, many of which later end up on exhibit in Jellies Invasion. Read on for a peek into the process!

Read the full story

Cold stunned turtle Cold Stunning: Where, How and Why?

Picture this: You’ve just spent a wonderful, late summer week on Cape Cod, swimming in the ocean and enjoying the sunshine with friends and family. As fall sets in, you know it’s time to head home. You get on the highway, but something strange happens … despite driving for hours, you end up back where you started. You feel sluggish, confused and exhausted. If you were a turtle, you just might be cold-stunned.

Read the full story

Related Stories

Species Spotlight: Nimble Spray Crab

Published October 24, 2017

Animal Update: Nimble Spray Crab and Debelius Cleaner Shrimp

Published June 02, 2017