Aurelia auritaMoon jellyfish

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. (Brekhman, et al., 2015; Browne, 1901; Conniff, 2000; El-Serehy and Al-Rasheid, 2011; FitzGeorge-Balfour, et al., 2013; Schiariti, et al., 2015)


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). (Brekhman, et al., 2015; Browne, 1901; Conniff, 2000; El-Serehy and Al-Rasheid, 2011; FitzGeorge-Balfour, et al., 2013; Purcell, 2005; Schiariti, et al., 2015)

  • Range depth
    1000 to 200 m
    3280.84 to 656.17 ft

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. (Browne, 1901; Crowder, 1926; Fuchs, et al., 2014; Schiariti, et al., 2015)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    10 to 35 cm
    3.94 to 13.78 in


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. (El-Serehy and Al-Rasheid, 2011; Lucas, 2001)


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. (Lucas, 2001)

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. (Brekhman, et al., 2015; El-Serehy and Al-Rasheid, 2011; Lucas, 2001; Schiariti, et al., 2015)

  • Breeding interval
    Moon jellyfish breed all year round, however mating intervals depend on properties of the environment.
  • Breeding season
    Reproduction of the moon jelly occurs when medusae reaches sexual maturation, generally during the summer and autumn months for a period of 2-3 months.
  • Range age at sexual or reproductive maturity (female)
    4 to 12 months
  • Range age at sexual or reproductive maturity (male)
    4 to 12 months

There is no reported data on parental involvement.

  • Parental Investment
  • no parental involvement


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. (Lucas, 2001)

  • Range lifespan
    Status: wild
    1 to 24 months
  • Range lifespan
    Status: captivity
    25 (high) years
  • Typical lifespan
    Status: wild
    1 to 24 months
  • Average lifespan
    Status: wild
    12 months
  • Typical lifespan
    Status: captivity
    0.5 (low) years
  • Average lifespan
    Status: captivity
    1 years


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. (Lucas, 2001; McHenry and Jed, 2003; Shoji, et al., 2005)

Home Range

No home ranges or territories are reported for these jellyfish. (Lucas, 2001; McHenry and Jed, 2003)

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. (Graham and Kroutil, 2001; Graham, et al., 2001; Jacobs, et al., 2007)

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. (Browne, 1901; Crowder, 1926; FitzGeorge-Balfour, et al., 2013; Graham and Kroutil, 2001; Lucas, 2001)

  • Animal Foods
  • fish
  • mollusks
  • cnidarians


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. (Conniff, 2000; Gold, et al., 2015; Jachowski, 1963)

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. (Jachowski, 1963; Lucas, 2001)

Commensal/Parasitic Species

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. (Brotz, et al., 2012)

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. (Brotz, et al., 2012; Lucas, 2001)

  • 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. (Brotz, et al., 2012)


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.


Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

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Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

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living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

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living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

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living in the southern part of the New World. In other words, Central and South America.

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Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

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living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

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reproduction that is not sexual; that is, reproduction that does not include recombining the genotypes of two parents

brackish water

areas with salty water, usually in coastal marshes and estuaries.


an animal that mainly eats meat


uses smells or other chemicals to communicate


the nearshore aquatic habitats near a coast, or shoreline.


used loosely to describe any group of organisms living together or in close proximity to each other - for example nesting shorebirds that live in large colonies. More specifically refers to a group of organisms in which members act as specialized subunits (a continuous, modular society) - as in clonal organisms.


having a worldwide distribution. Found on all continents (except maybe Antarctica) and in all biogeographic provinces; or in all the major oceans (Atlantic, Indian, and Pacific.


a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

external fertilization

fertilization takes place outside the female's body


union of egg and spermatozoan


A substance that provides both nutrients and energy to a living thing.


A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.


eats mollusks, members of Phylum Mollusca


having the capacity to move from one place to another.


specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.


found in the oriental region of the world. In other words, India and southeast Asia.

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reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.


an animal that mainly eats fish


an animal that mainly eats plankton

radial symmetry

a form of body symmetry in which the parts of an animal are arranged concentrically around a central oral/aboral axis and more than one imaginary plane through this axis results in halves that are mirror-images of each other. Examples are cnidarians (Phylum Cnidaria, jellyfish, anemones, and corals).

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

seasonal breeding

breeding is confined to a particular season


remains in the same area


reproduction that includes combining the genetic contribution of two individuals, a male and a female


uses touch to communicate


the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.


an animal which has an organ capable of injecting a poisonous substance into a wound (for example, scorpions, jellyfish, and rattlesnakes).


uses sight to communicate


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Brotz, L., W. Cheung, K. Kleisner, E. Pakhomov, D. Pauly. 2012. Increasing jellyfish populations: Trends in large marine ecosystems. Hydrobiologia, 690: 3-20.

Browne, E. 1901. Variation in Aurelia aurita. Biometrika, 1/1: 90-108.

Conniff, R. 2000. Jelly bellies. National Geographic, 197/6: 82-101. Accessed September 11, 2015 at

Crowder, W. 1926. The life of the moon jelly. National Geographic, L/2: 187-202.

El-Serehy, H., K. Al-Rasheid. 2011. Reproductive strategy of the jellyfish Aurelia aurita (Cnidaria scyphomedusae) in the Suez Canal and its migration between the Red Sea and Mediterranean. Aquatic Ecosystem Health & Management, 14/3: 269-275.

FitzGeorge-Balfour, T., A. Hirst, C. Lucas, J. Craggs, E. Whelan, S. Mombrikotb. 2013. Estimating digestion time in gelatinous predators: a methodological comparison with the scyphomedusa Aurelia aurita. Marine Biology, 160/4: 793-804.

Fuchs, B., W. Wang, S. Graspeuntner, Y. Li, S. Insua, E. Herbst, P. Dirksen, A. Böhm, G. Hemmrich, F. Sommer, T. Domazet-Loso, U. Klostermeier, F. Anton-Erxleben, P. Rosenstiel, T. Bosch, K. Khalturin. 2014. Regulation of polyp-to-jellyfish transition in Aurelia aurita. Current Biology, 24: 263-273.

Gold, D., N. Nakanishi, N. Hensley, K. Cozzoline, M. Tabatabaee, M. Martin, V. Hartenstein, D. Jacobs. 2015. Structural and developmental disparity in the tentacles of the moon jellyfish Aurelia sp.1. PloS ONE, 10/8: 1-12.

Graham, W., S. Gelcich, K. Robinson, C. Duarte, L. Brotz, J. Purcell, L. Madin, H. Mianzan, K. Sutherland, S. Uye, K. Pitt, C. Lucas, M. Bøgeberg, R. Brodeur, R. Condon. 2014. Linking human well-being and jellyfish: Ecosystem services, impacts, and societal responses. The Ecological Society of America, 12/9: 515-523.

Graham, W., R. Kroutil. 2001. Size-based prey selectivity and dietary shifts in the jellyfish, Aurelia aurita. Journal of Plankton Research, 23/1: 67-74.

Graham, W., F. Pages, W. Hamner. 2001. A physical context for gelatinous zooplankton aggregations: a review. Hydrobiologia, 451: 199-212.

Jachowski, R. 1963. Observations on the moon jelly, Aurelia aurita, and the spider Crab, Libinia dubia. Chesapeake Science, 4/4: 195.

Jacobs, D., N. Nakanishi, D. Yuan, A. Camara, S. Nichols, V. Hartenstein. 2007. Evolution of sensory structures in basal metazoa. Integrative and Comparative Biology, 47/5: 712-723.

Lucas, C. 2001. Reproduction and life history strategies of the common jellyfish, Aurelia aurita, in relation to its ambient environment. Hydrobiologia, 451: 229-246.

Mayorova, T., I. Kosevich, O. Melekhova. 2012. On some features of embryonic development and metamorphosis of Aurelia aurita (Cnidaria, Scyphozoa). Russian Journal of Developmental Biology, 43/5: 271-285.

McGraw, K. 1974. Two aberrant forms of the moon jellyfish, Aurelia aurita (linné), in the northeastern Gulf of Mexico. Chesapeake Science, 15/1: 55-56.

McHenry, M., J. Jed. 2003. The ontogenetic scaling of hydrodynamics and swimming performance in jellyfish (Aurelia aurita). The Journal of Experimental Biology, 206: 4125-4137.

Morales-Alamo, R., D. Haven. 1974. Atypical mouth shape of polyps of the jellyfish, Aurelia aurita, from Chesapeake Bay, Delaware Bay, and Gulf of Mexico. Chesapeake Science, 15/1: 22-29.

Purcell, J. 2005. Climate effects on formation of jellyfish and ctenophore blooms: a review. Journal of the Marine Biological Association of the United Kingdom, 85: 461-476.

Schiariti, A., V. Melica, T. Kogovsek, A. Malej. 2015. Density-dependent effects control the reproductive strategy and population growth of Aurelia aurita s.l. scyphistomae. Marine Biology, 162/8: 1665-1672.

Shoji, J., R. Masuda, Y. Yamashita, M. Tanaka. 2005. Effect of low dissolved oxygen concentrations on behavior and predation rates on red sea bream Pagrus major larvae by the jellyfish Aurelia aurita and by juvenile Spanish mackerel Scomberomorus niphonius. Marine Biology, 147: 863-868.

Werner, S., J. Gerhard, S. Bruno, Bernd Schierwater. 2002. Speciation and phylogeography in the cosmopolitan marine moon jelly, Aurelia sp. BMC Evolutionary Biology, 2/1: 1-15.