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By Roberto J. Rodriguez
Geographic Range
Aurelia aurita are found near the coast, in mostly warm and tropical waters (but they can withstand temperatures as low as -6 and as high as 31 degrees Celsius). They are prevalent in both inshore seas and oceans.
Biogeographic Regions:
indian ocean (native 
); atlantic ocean (native ); pacific ocean (native ).
Habitat
Their habitat includes the costal waters of all zones, and they occur in huge numbers. They are known to live in brackish waters with as low a salt content as 0.6%. Decreased salinity in the water diminishes the bell curvature, and vice versa. An optimum temperature for the animals is 9 - 19 degrees Celsius.
Physical Description
These animals range between 5 and 40 cm.. They can be recognized by their delicate and exquisite coloration, often in patterns of spots and streaks.
Reproduction
Sexual maturity in Aurelia aurita commonly occurs in the spring and summer. The eggs develop in gonads located in pockets formed by the frills of the oral arms. The gonads are commonly the most recognizable part of the animal, because of their deep and conspicuous coloration. The gonads lie at the bottom of the stomach. Males and females are distinct and reproduction is sexual.
Behavior
Their behavior depends on a number of external conditions, in particular, food supply. Aurelia swim by pulsations of the bell-shaped upper part of the anima. Swimming mostly functions to keep the animal at the surface of the water rather than to make progress through the water. They swim horizontally, keeping the bell near the surface at all times. This allows the tenticles to be spread over the largest possible area, in order to better catch food. The coronal muscle allows the animal to pulsate in order to move. Impulses to contract are sent by way of the subumbrellar nerve net and are nervous in origin. The Moon Jelly has rhopalial centers, which allow it to control the pulsations. As the oxygen rate in the water goes down, so too does the resiratory rate of the jellyfish.
Food Habits
The Saucer Jelly is carnivorous and feeds on plankton. Their primary foods include small plankton organisms such as mollusks, crustaceans, tunicate larvae, copepods, rotifers, nematods, young polychaetes, protozoans, diatoms, and eggs. They are also sometimes observed to eat small hydromedusae and ctenophores. These foods collect chiefly on the surface of the animal, where they become entangled in mucus. Food items are then passed on to the margins by flagellar action, where they collect on the lappets. They are then moved, again by flagellar currents, along eight separate canals, which are unique to this species of jellyfish. These canals branch off and run into the stomach, and they bring the food to it via the ring canal.
Economic Importance for Humans: Negative
Predation on copepods and fish larvae. May significantly affect a plankton community through predation.
Economic Importance for Humans: Positive
Represent an important step in pelagic organic matter transformations.
Conservation Status
They are very plentiful.
Contributors
Roberto J. Rodriguez (author), University of Michigan.
