Aurelia aurita

Geographic Range

Moon jellies ( Aurelia aurita ) are a cosmopolitan organism whose range includes 3 of the 4 oceans (all but the Arctic) and other saltwater locales. Their range specifically includes coastal waters of nearly all of North and South America, Eurasia (all but the northernmost reaches), southern Greenland, and likely all coasts of Australia. They are absent along much of Africa, though are apparently present in the waters around Madagascar.

• Biogeographic Regions
• nearctic nearctic
  • native native
• palearctic palearctic
  • native native
• oriental oriental
  • native native
• ethiopian ethiopian
  • native native
• neotropical neotropical
  • native native
• australian australian
  • native native
• indian ocean
  • native native
• atlantic ocean atlantic ocean
  • native native
• pacific ocean pacific ocean
  • native native

• Other Geographic Terms
• cosmopolitan cosmopolitan

Habitat

The habitat of moon jellies encompasses oceanic coastal waters as well as warm tropical waters ranging in temperatures from 6-19 degrees Celsius. These jellies can live in waters with a salt content as low as 0.6%. Salt content and water temperature affect shape, size and reproductive strategies. They thrive best in waters with temperatures are above 17.5°C and salinity greater than 38.0%, largest. Moon jellies range in depth between the epipelagic zone and the mesopelagic zone (200 to 1,000 m).

• Habitat Regions
• tropical tropical
• saltwater or marine saltwater or marine

• Aquatic Biomes
• coastal coastal
• brackish water brackish water

Physical Description

Moon jellies exhibit radial symmetry. They have transparent outer bells that range in diameter from 10 to 35 cm. Within the outer bell is another dome which has blue veins running through it; these veins are their gonads, which resemble horseshoe rings. These blue veins lead into elaborate coloring and patterns. Small tentacles, 1 to 5 cm long, radiate from the bells of moon jellies, out to their sides. Radiating from below the bell of moon jellies are four oral arms which contain stinging cells, or nematocysts, to aid in feeding by moving prey towards their gastric pouches. Small cilia radiate around their bells which also aid in feeding.

Moon jellies begin their lives as free floating planulae, which then morph into polyps – small sedentary organisms. Moon jelly polyps go through budding and create a number of disk-shaped segments. These disk segments detach and enter a free-floating stage, where they are called ephyrae. These ephyrae then develop into immature, mobile medusae before reaching sexual maturity.

• Other Physical Features
• ectothermic ectothermic
• radial symmetry radial symmetry
• venomous venomous

• Sexual Dimorphism
• sexes alike

Development

Once mature, sexual medusae mate. Fertilized eggs, called planulae, spend 10 days on average swimming around using small cilia before finding and attaching themselves to hard surfaces, becoming polyps. Polyps are benthic, bottom dwelling organisms. Once attached, these moon jelly polyps use asexual reproduction (budding) to create daughter polyps. These polyps then mature into strobilae, which are sacs of undeveloped jellyfish. In order for these strobilae to produce an adult, or medusa, strobulation must occur. This strobulation is the development of ephyrae from the strobilae. Once ephyrae are developed, they leave the strobilae, making room for other sacs to develop. These ephyrae then mature into juvenile medusae before maturing again to become sexually mature medusae. The time it takes for maturation from the ephyra to the mature medusa stage depends on environmental cues such as temperature, salinity and food. Under suitable conditions, this process takes 4 to 6 months.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

Moon jellies elicit no courtship behavior, and there is no social structure that affects mating systems. Male jellyfish in their mature medusa stage release sperm filaments into the water surrounding female jellies. These filaments ride water currents, entering the gastric pouches of nearby females. These animals also reproduce asexually when they are in their polyp stage.

The general mating behavior and reproductive system of moon jellies starts when sexually mature (4 to 12 months old) males release sperm filaments into the water surrounding females. Female mon jellies then use their cilia to internalize the sperm into their gastric pouches. These gastric pouches contain eggs which, once fertilized, are released into the water. Moon jellyfish breed year-round, with mating intervals depending on environmental conditions. Moon jellyfish reproduction occurs when medusae reach sexual maturity, generally a range of 2 to 3 months during summer and autumn. They also reproduce asexually while in their sessile polyp stage.

• Key Reproductive Features
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• asexual asexual
• fertilization fertilization
  • external external
• oviparous oviparous

There is no reported data on parental involvement.

• Parental Investment
• no parental involvement

Lifespan/Longevity

Moon jellies range widely on longevity and lifespan based on environmental factors. In most cases, strobilation of the ephyrae occurs between winter and spring, but has also been observed throughout the rest of the year. Moon jellyfish have an average lifespan of approximately 8 to 12 months, allowing for slow growth during colder months, and faster growth during spring. After reaching sexual maturity, medusae shrink, release gametes, and typically die in the later spring and early summer season. Maximum ages in the wild are reported as 2 years.

In aquarium settings, lifespans are as short as 6 months, but polyps have been recorded as living up to 25 years before maturing.

Behavior

Moon jellyfish elicit feeding behaviors based on availability of prey and oxygen levels. When oxygen levels are low, moon jellies engage in nutritional loading, and flourish when prey are abundant. Moon jellyfish spend their early life as a sedimentary polyp before becoming a motile medusa. Medusae use pulsate water through their bells to stay horizontal, close to the surface of the water. This allows for a further tentacle spread for prey capture. Large blooms of jellyfish are found worldwide based on temperature, prey availability, oxygen content and salt content.

• Key Behaviors
• natatorial natatorial
• motile motile
• sedentary sedentary
• colonial colonial

Home Range

No home ranges or territories are reported for these jellyfish.

Communication and Perception

Research into the communication of moon jellyfish is limited. It is hypothesized that moon jellyfish communicate via chemicals secreted into the water. Some jellyfish have ocelli, which are structures located on the bell that are used to detected changes in light and allow for vertical diurnal migration to avoid predation and to help with active foraging behavior. Another sensory organ is the rhopalium; many of these are located around the rim of the bell on a jellyfish. Rhopalia contain sensory organs called statocysts, these structures are used to maintain balance and determine depth and as well as sense gravity, helping jellyfish stay upright. Jellyfish also use touch to capture prey using stinger cells called cnidocytes or nematocysts.

• Communication Channels
• tactile tactile
• chemical chemical

• Perception Channels
• visual visual
• tactile tactile
• chemical chemical

Food Habits

As carnivorous organisms, moon jellies are known to feed on most organisms small enough to become entangled on their bells or in their tentacles. These include plankton, copepods, mollusks, fish eggs and smaller jellyfish. Once entangled, moon jellies uses their oral arms to move their prey towards their stomachs, located under the their bells.

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • eats eggs
  • eats body fluids
  • molluscivore molluscivore
  • eats other marine invertebrates
• planktivore planktivore

• Animal Foods
• fish
• mollusks
• cnidarians

Predation

Moon jellyfish are consumed by birds in the order ( Charadriiformes ), other jellyfish, chum salmon ( Oncorhynchus keta ), butterfish ( Peprilus ) in the family Stromateidae , sunfish, and leatherback sea turtles ( Dermochelys coriacea ).

Moon jellies have anti-predator adaptations, including small stinging cells on their oral arms. These stinging cells are called cnidoblasts or nematocysts, used for capturing prey and warding off predators. Another adaptation that moon jellies have is their translucent coloring, which makes them difficult to detect from below or above.

Ecosystem Roles

Moon jellyfish can be a harmful species when entering a new environment. Once they arrive, if resources are sufficient, jellyfish populations expand quickly, consuming plankton, adult fish and fish larvae. They also compete with fish for resources. They are known to negatively impact fisheries and plankton blooms. They are a generalist feeder, using cilia and tentacles to consume organisms that they encounter. Spider crabs ( Libinia dubia ) and amphipods ( Hyperia galba ) are moon jely parasites. They have been found in their bells as well as attached to their tentacles. They parasitize medusae by eating their prey and the medusae themselves.

Economic Importance for Humans: Positive

These jellyfish are being researched for uses as food, medicine and drugs. A fluorescent protein was developed from jellyfish, which was beneficial to biotechnology.

• Positive Impacts
• food food
• body parts are source of valuable material
• source of medicine or drug source of medicine or drug
• research and education

Economic Importance for Humans: Negative

Moon jellyfish cause economic problems for humans. Large jellyfish populations can harm fisheries, as well as compete for food with humans. They also clog up power plant water intakes, as well as desalination plants. Moon jellies also affect tourism by stinging humans that are swimming.

• Negative Impacts
• injures humans
  • bites or stings

Conservation Status

Jellyfish are an invasive species that have large population blooms and are currently not on any international or federal lists. They have not been evaluated by the IUCN Red List. There are efforts being taken to remove jellyfish from non-native areas as well as from power-plants and fisheries using trawlers and nets.

Additional Links

Encyclopedia of Life

Contributors

ross tombs (author), Radford University - Fall 2015, Karen Powers (editor), Radford University, April Tingle (editor), Radford University, Cari Mcgregor (editor), Radford University, Zeb Pike (editor), Radford University, Jacob Vaught (editor), Radford University, Galen Burrell (editor), Special Projects.

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