There is only one species of jellyfish native to the Southern Appalachian Mountains. Although very rare, this animal is more common than might be expected in a habitat devoid of beaches, saltwater, and other oceanic accoutrements. Jellyfish in abundance were reported this past September from a two-acre pond at a summer camp near Black Mountain.

Craspedacusta sowerbyi, the Freshwater Jellyfish, is widely but sporadically distributed across the warmer portions of North America. Seldom more than half an inch in diameter, these organisms can suddenly appear in such numbers as to attract the attention of even a casual observer. Children visiting the summer camp discovered the Black Mountain population.

Like all jellyfish, the Freshwater Jellyfish begins its life as a polyp; an immobile animal shaped like a tiny hollow bowling pin made of jelly and permanently attached to rocks or mud at the bottom of a pond or sluggish stream. The polyp stage, which may last a number of years, subsists by feeding on small invertebrate animals, which are captured by means of specialized stinging cells surrounding the mouth. Since Freshwater Jellyfish polyps are transparent, less than a quarter of an inch in diameter, and attached to the bottom of a pond, they are usually unnoticed by people.

The polyp stage reproduces asexually by forming buds. Buds may remain attached to the original polyp, forming extensive colonies, or they may break off of the parent polyp, creep across the bottom of the pond like tiny slugs (called frustules), and form a new colony of polyps in a different location. At irregular intervals a third type of bud may develop on a polyp. These buds do not form polyps or frustules but develop into the free swimming, sexually mature, medusa stage - the Freshwater Jellyfish!

Freshwater Jellyfish are extremely small as they begin the free-swimming stage of their life cycle. After three weeks of steady growth they are between a quarter and a half-inch in diameter and become noticeable to the unaided eye. At this age they become sexually mature and release eggs and sperm into the pond water, where fertilization occurs. Fertilized eggs develop into tiny ribbon shaped larvae, equipped with muscular whiplike cilia, which enable them to swim freely for a day or two before settling down on the pond bottom to begin a new colony of polyps.

Appalachian Mountain jellyfish are carnivores. They capture their prey by means of stinging tentacles extending from the fringes of their umbrella shaped bodies. Their hunting technique consists of swimming upward toward the pond surface and then drifting slowly downward, tentacles extended, encountering prey species purely by chance. Jellyfish swim by means of jet propulsion. Rings of muscle and nerve tissue line the lower rims of their bodies, and by contracting these muscles they can close their "umbrellas" and force water out, thereby propelling themselves forward. It is this flamboyant swimming method along with their habit of approaching the surface to begin their hunting descent, which make the jellyfish noticeable when they attain sufficient size.

The body of an Appalachian Mountain jellyfish is a double skinned umbrella joined at the edges, with the inner space filled with jelly. The jelly is actually the structural support for the body (Jellyfish do not have bones) and is rigid enough to provide a bed against which muscles can pull during the swimming motion. The animal's mouth is located where the umbrella handle would be. A canal leads from the mouth into a hollow space within the jelly where digestion and distribution of food occurs (Jellyfish do not have blood vessels). Excretion of wastes is also through the mouth.

Although jellyfish cannot see, certain of their cells possess pigments and they probably are sensitive to the presence or absence of light. Jellyfish are sensitive to touch and will swim around encountered objects by contracting muscle fibers more on one side of the body than the other in order to change direction.

The jellyfish stage of Craspedacusta's life cycle lasts for one or two months. The jellyfish do not appear every year, even in ponds in which polyps occur abundantly on the bottom. One factor which apparently affects jellyfish production is water temperature. Jellyfish are never produced in water temperatures below 82 degrees (Fahrenheit). The very warm temperatures we experienced during late August and early September of this year undoubtedly helped to induce the jellyfish bloom in the Black Mountain pond.

How did jellyfish find their way into this particular pond in Black Mountain? At no stage in its life cycle can this animal cross dry land or swim vigorously upstream.. Are polyps transported from pond to pond in mud clinging to the feet of waterfowl? Was it purely by chance that Craspedacusta polyps were transported to this particular pond, or are conditions in this pond more suitable to the jellyfish life cycle than those in other regional aquatic habitats?

Freshwater Jellyfish are found much more frequently in artificial ponds and reservoirs than in natural bodies of water and are more common in relatively new reservoirs (less than forty years old) than in older impoundments. The Black Mountain pond meets these criteria, but why are they important to jellyfish? Could it be that animals that eat jellyfish or their polyps are less common in newer ponds than in more established bodies of water? Can the Appalachian Mountain jellyfish only survive in noticeable numbers in ponds with incomplete food chains?

Crayfish have been observed feeding on mature Freshwater Jellyfish and parasitic amoebae have been isolated from collected specimens. What other parasites, predators, and diseases play a role in the population ecology of Craspedacusta? If this species arrives in new habitats in mud clinging to the feet of birds, it may thrive only in ponds where it arrives before its competitors.

Each pond is a new world to the creatures which inhabit it. A lesser species may enjoy its heyday until a superior species arrives. A pond community may enjoy a "golden age" prior to the arrival of parasitic or disease producing organisms. A small pond in the Appalachian Mountains may even resemble a miniature ocean if the weather is warm, the pond is shallow, and the crayfish are slow in arriving.