Moon Jellyfish

Graceful survivors- Moon jellyfish lived through the Ice Age and subsequent warming of the seas. What makes these translucent creatures so resilient?
By Sandy Bauers
Inquirer Staff Writer

Updated 9/22/11

-Dozens of moon jellyfish - diaphanous, graceful, eerily dreamlike in blue light - undulate in the artificial current.
Children racing in from a hippopotamus exhibit skid to a halt and gaze at the soundless ballet in Camden's Adventure Aquarium.

These are the subjects of Alejandro Vagelli, an ichthyologist whose groundbreaking research has painted new pictures of Aurelia aurita.

Moon jellies wash up dead on the beach, all flat and gooey, in sizes ranging from saucers to dinner plates, with cloverleafs visible inside. (Those are the gonads.)

Then there are the leafless faux moons, thick like a hockey puck and even more ubiquitous around Labor Day at the Jersey Shore. Scientists say these are actually the many-ribbed jelly, Aequorea aequorea.

Many are too ragged to tell the difference.
Neither's sting hurts.

Not jelly or fish, Aurelia aurita is one of nature's simpler organisms. It senses light with a primitive optical organ but has no brain. Bodily contractions are its only means of propulsion, mainly vertically; otherwise, it follows the currents.

Because the moon jelly is so uncomplicated, medical researchers study it to better understand living tissue. About 2,500 specimens rode the shuttle Columbia into space in 1991 so scientists could see how they fared sans gravity. (They pulsed faster and went in circles.)


COMMENT:

-I personally find Jellyfish fascinating. Their movements and basic but function structure amaze me. I have kept the Upside Down Jellyfish (Cassiopea Andromeda) for years in my Marine Aquariums and have thoroughly enjoyed them. Upside Down Jellyfish are one of the most common jellyfish in the pet trade. These invertebrates get their name because they spend most of their lives laying upside down on shallow sandy bottoms exposed to sunlight. Among the tentacle structures are rounded, bladder-like structures, which contain photosynthetic algae that help the Jellyfish produce its own food. Their flattened bells pulse gently to carry food and to aid in respiration.

The upside down jellyfish come from the Caribbean and is relatively easy to keep in a non aggressive Reef or Nano Reef aquarium. The Upside Down Jellyfish can make a unique and interesting aquarium occupant.
Upside Down Jellyfish will require bright aquarium lighting to thrive, such as Metal Halide, the newer LED and SHO and possibly VHO). Although Upside Down Jellyfish rely on symbiotic algae to create nourishment for them through photosynthesis, you may feed your Upside Down Jellyfish solid food once in a while such as puréed Spirulina 20. It is not advisable to reach into the aquarium any more often than necessary in order to avoid contact with nematocysts that can sting when they make contact with the skin, although my experience has been that unless you touch them with you more sensitive wrist, you will not feel anything.

These invertebrates get their name because they spend most of their lives laying upside down on shallow sandy bottoms exposed to sunlight. Among the tentacle structures are rounded, bladder-like structures, which contain photosynthetic algae that help the Jellyfish produce its own food. Their flattened bells pulse gently to carry food and to aid in respiration. I recommend keeping a sandy bottom with a low current near the bottom. Be careful in aquariums equipped with overflow filter intakes as this Jelly fish will often get caught in them.