(c) Anthony K. Grafton 2003

Kentucky Jellyfish

Did you know that freshwater jellyfish live here in Taylor county? In fact, this “jellyfish” lives in many parts of the country, not just Kentucky.

Though technically not an actual jellyfish, the freshwater jellyfish, known scientifically as Craspedacusta sowerbii, is a fascinating creature that most people are never lucky enough to notice. They generally live in large bodies of standing, clean water such as lakes and ponds, but they are usually only seen during July and August when the water is clear and calm.

C. sowerbii looks like what most people expect when they think of a jellyfish: umbrella-shaped with tentacles dangling underneath. But the freshwater jellyfish is small (a little larger than a fingernail) and almost transparent, which makes them somewhat hard to spot.

Locally, C. sowerbii have been seen in Green River Lake and Lake Cumberland, as well as several other places around Kentucky. When seen, they are usually floating just below the surface of the water, generally feeding on microscopic animals in the water called zooplankton. Sometimes the jellyfish will be seen in large groups called “blooms”. Although they are probably not uncommon, the difficulty in seeing the freshwater jellyfish if you’re not specifically looking for them means that sometimes they seem to appear in a pond or lake once, never to be seen again.

If you happen to see freshwater jellyfish, don’t be overly concerned about being stung. They do have stinging cells that they use on their prey, but there’s only anecdotal evidence that they are actually able to sting humans. But if you are lucky enough to spot a bloom of C. sowerbii, consider notifying a biologist such as Dr. Terry Peard at Indiana University of Pennsylvania. Dr. Peard is one of only a few scientists who study this unique but little-known creature, and he would very much like to hear the details of your sighting.