Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide


Rhopilema nomadica
(nomad jellyfish)



Rhopilema nomadica (nomad jellyfish)


  • Last modified
  • 20 November 2019
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Rhopilema nomadica
  • Preferred Common Name
  • nomad jellyfish
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Metazoa
  •     Phylum: Cnidaria
  •       Class: Scyphozoa
  •         Order: Rhizostomeae
  • Summary of Invasiveness
  • R. nomadica is a neritic epipelagic, swarming, planktotrophic jellyfish. It is native to the east coast of Africa and the Red Sea. It was introduced into the Mediterranean in the late 1970s through the Suez Canal...

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Preferred Scientific Name

  • Rhopilema nomadica Galil, 1990

Preferred Common Name

  • nomad jellyfish

Local Common Names

  • Israel: hutit nodedet

Summary of Invasiveness

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R. nomadica is a neritic epipelagic, swarming, planktotrophic jellyfish. It is native to the east coast of Africa and the Red Sea. It was introduced into the Mediterranean in the late 1970s through the Suez Canal and has spread along the Levantine coast, from Egypt to Turkey and Greece. It was estimated that in the summer of 1989 its swarms contained 5.5×105 specimens per square nautical mile. It is capable of delivering a painful sting.

Taxonomic Tree

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  • Domain: Eukaryota
  •     Kingdom: Metazoa
  •         Phylum: Cnidaria
  •             Class: Scyphozoa
  •                 Order: Rhizostomeae
  •                     Family: Rhizostomatidae
  •                         Genus: Rhopilema
  •                             Species: Rhopilema nomadica

Notes on Taxonomy and Nomenclature

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The genus Rhopilema Haeckel, 1880 (family Rhizostomatidae Cuvier, 1799) is generally accepted as containing 5 species (Kramp, 1961), 4 of which are Indo-Pacific and one Atlantic. Rhopilema nomadica was first named as Rhopilema hispidum in 1938 by Stiasny.


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R. nomadica is a medium-sized rhizostomid medusa. It has a nearly hemispherical umbrella, thickest centrally, thinning gradually towards margin. Exumbrella minutely granulate, granules fewer and blunter near margin. Margin of umbrella divided into 64 rounded velar lappets. Ocular lappets small, lanceolate, one third as wide as velar lappets. Subumbrellar circular muscles well developed, uniform. Arm disc prismatic, about one third of bell diameter, oral pillars quadrate. Distal corners of oral pillars prominently tuberculate. Subgenital ostium at each interradius kidney-shaped, as wide as oral pillar. A pear-shaped, tuberculate papilla interradially on subumbrella, opposite ostial opening. Eight pairs of large, deeply bowed scapulets arise from adradial sides of armdisc; underside concave, smooth; upper side bearing frilled mouths and numerous filaments. Distal part of scapullets bearing long filaments, sometimes twice as long as scapulets. Each scapulet is divided, midlength, into two, with five appendages on each side. Eight adradial mouth arms stout, smooth, fused to midlength. Lower part of mouth arm divided into two triangular flaps, each flap distally tripartite and terminating in claw-like digitate processes. Ventrally, mouth arms bear numerous frilled mouths and long filaments. Lowermost end bearing a vermicular appendage terminating in a thin filament. Stomach cavity nearly octagonal. Gastrovascular system consisting of four perradial, four interradial and eight adradial canals interconnecting in a complex network of anastomosing vessels extending almost to bell margin. Four principal canals extend from lower part of stomach to radii entering each scapulet and mouth arm, then branching to numerous minute canals leading to mouths (Galil et al., 1990).

Colour in life icy blue. It can reach up to 100 cm umbrella diameter, but is commonly 30-50 cm in diameter.


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R. nomadica is considered a native of east Africa and the Red Sea, although the exact limits of its range remain unknown (Stiasny, 1938, 1939).

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 10 Jan 2020
Continent/Country/Region Distribution Last Reported Origin First Reported Invasive Reference Notes


IsraelPresent, WidespreadIntroduced1976InvasiveGalil et al. (1990)Annual swarming in summer observed along the coast of Israel
LebanonPresent, WidespreadIntroduced1989InvasiveLakkis et al. (1990)Annual swarming in summer observed along the coast of Lebanon
SyriaPresent, WidespreadIntroduced2002InvasiveIkhtiyar et al. (2002)
TurkeyPresent, WidespreadIntroduced1995InvasiveKideys and Gücü (1995)In 1995 observed in southeastern Turkey, in 1998 off Izmir, on the Aegean coast of Turkey


GreecePresent, Few occurrencesIntroduced2006InvasiveSiokou-Frangou et al. (2006)Observed off Lakonikos Gulf. Greece, in summer of 2006

History of Introduction and Spread

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In 1976 it was first collected of the coast of Israel (Galil et al., 1990), in 1989 it appeared off Lebanon (Lakkis et al., 1990), in 1995 it appeared off the southeastern Turkey (Kideys and Gücü, 1995), in 1998 off Izmir, in 2002 off Syria (Ikhtiyar et al., 2002), in 2003 off Cyprus, and in 2006 off Lakonikos Gulf, Greece (Siokou-Frangou et al., 2006).

Risk of Introduction

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R. nomadica is already found in the Levantine basin of the Mediterranean Sea. It may spread westwards along the north African coast, as it is environmentally similar to areas in which it has become invasive. Further spread is likely with increase in the sea surface temperature in the Mediterranean.


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R. nomadica is a neritic epipelagic, its swarms are recorded at a distance of 2-4 kms off shore. Occasionally it is swept nearer shore and into the intertidal zone.

Habitat List

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Inshore marine Principal habitat Harmful (pest or invasive)

Biology and Ecology

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Reproductive Biology

R. nomadica has a two-stage life cycle consisting of the conspicuous, large, sexually reproducing swimming medusa stage and a benthic polyp stage (scyphistoma) that, because of its small size <2 mm), remains cryptic. Spawning occurs in summer. Fertilization is external and planulae are formed within hours. Settlement occurs within 3-4 days, and polyps developed within 3 weeks. Asexual reproduction occurs mostly through podocyst formation; polyps produce podocysts by growing stolons from the base of the disk. Polyps developed into polydisc strobilae within 45 days. The strobilation process is complete in 7 days; 5-6 ephyrae are formed on each strobila. Mature polyps may strobilate repeatedly. The development from the newly released ephyra (1.5-2 mm in diameter) to the young medusa (7-10 mm in diameter) may be completed within 2 months (Lotan et al., 1992).

Physiology and Phenology

In the Mediterranean the medusoid stage of R. nomadica has been recorded throughout the year, though swarms occur in the summer months (June to September). Individuals with fully developed gonads were found throughout the year.




The juveniles of the shrimp scad, Alepes djedaba, itself an invasive from the Indo-Pacific through the Suez Canal, are commonly found in association with R. nomadica, trailing in small schools with the jellyfish and when disturbed, taking shelter underneath its umbrella and among the filamentous mouth arms. It is possible that the great increase in the carangid’s abundance in the 1980s owes to the presence of R. nomadica sheltering juveniles.

Environmental Requirements

R. nomadica
tolerates a wide range of temperature from 16°C to 31°C. Swarms occur in the summer months when the sea surface temperature in the southern Levantine basin ranges from 26°C to 31°C.

Latitude/Altitude Ranges

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
38 20 0 0

Water Tolerances

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ParameterMinimum ValueMaximum ValueTypical ValueStatusLife StageNotes
Depth (m b.s.l.) Optimum 0-40 tolerated
Salinity (part per thousand) Optimum 39.5 tolerated
Water temperature (ºC temperature) 20 26 Optimum 16-31 tolerated. Reproduction begins when temperatures reach 20

Notes on Natural Enemies

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R. nomadica may be preyed upon by sea turtles and some pelagic fish.

Means of Movement and Dispersal

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Natural Dispersal (Non-Biotic)

Dispersal by currents is most likely as attested to by its temporally sequential appearance along the Levantine coastline, but its polyps may be dispersed in the fouling of slow moving vessels.

Accidental Introduction

Entered the Mediterranean through the Suez Canal (Galil et al., 1990).

Pathway Causes

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CauseNotesLong DistanceLocalReferences
Interconnected waterwaysKnown from the Red Sea and east coast of Africa Yes Yes Galil et al., 1990

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Watermedusoid life stage Yes Yes Galil et al., 1990

Impact Summary

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Cultural/amenity Negative
Economic/livelihood Negative
Environment (generally) Negative
Human health Negative

Economic Impact

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R. nomadica has a negative impact on the southern Levantine fisheries. Coastal trawling and purse-seine fishing are disrupted for the duration of the swarming due to net clogging and inability to sort yield: “It is not uncommon that fishermen, especially purse seines, discard entire hauls due to the overwhelming presence of poisonous medusae in their nets” (Golani and Ben Tuvia, 1995). Jellyfish-blocked water intake pipes pose a threat to cooling systems of port-bound vessels and coastal power plants: in the summer of 2001 Israel Electric removed tons of jellyfish from its seawater intake pipes at its two largest power plants, at estimated costs of US $50,000 (Galil, 2007).

Environmental Impact

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The annual swarms of R. nomadica along the Levantine coast, some stretching 100 km long, must compete with other planktotrophs for the limited resources of this oligotrophic sea.
Impact on Biodiversity

R. nomadica forms dense swarms annually, which outcompete the native rhizostomatid jellyfish Rhizostoma pulmo and may alter the planktotrophic species assemblages (Galil, 2007). 

The juveniles of the shrimp scad, Alepes djedaba, itself an invasive from the Indo-Pacific through the Suez Canal, are commonly found in association with R. nomadica, trailing in small schools with the jellyfish and when disturbed, taking shelter underneath its umbrella and among the filamentous mouth arms. It is possible that the great increase in the carangid’s abundance in the 1980s owes to the presence of R. nomadica sheltering juveniles.

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Rhizostoma pulmoNo detailsIsraelCompetition

Social Impact

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R. nomadica’s toxin-loaded nematocysts cause envenomation, usually expressed as immediate appearance of redness, burning sensation and papulovesicular and urticaria-like swelling of the affected skin, causing intensive pain and very itchy skin. The symptoms, in severe cases, may last several weeks (Silfen et al., 2003; Yoffe and Baruchin, 2004; Sendovski et al., 2005). As early as the summer of 1987 severe jellyfish envenomations requiring hospitalization had been reported in the medical literature: 30 patients, mainly children, suffering various degrees of painful injuries to different parts of their bodies were treated that summer in the emergency ward of the Soroka Medical Center Beersheva, Israel, alone (Benmeir et al., 1990). Local municipalities report a decrease in holiday makers frequenting the beaches because of the public’s concern over the painful stings inflicted by the jellyfish. The local newspapers and TV news report during the summer months the presence of jellyfish along the beaches.

Risk and Impact Factors

Top of page Invasiveness
  • Proved invasive outside its native range
  • Highly mobile locally
  • Fast growing
  • Has high reproductive potential
  • Gregarious
  • Has propagules that can remain viable for more than one year
  • Reproduces asexually
Impact outcomes
  • Altered trophic level
  • Damaged ecosystem services
  • Ecosystem change/ habitat alteration
  • Infrastructure damage
  • Negatively impacts cultural/traditional practices
  • Negatively impacts human health
  • Negatively impacts animal health
  • Negatively impacts livelihoods
  • Negatively impacts aquaculture/fisheries
  • Negatively impacts tourism
  • Reduced amenity values
  • Reduced native biodiversity
  • Threat to/ loss of native species
  • Negatively impacts animal/plant collections
  • Damages animal/plant products
Impact mechanisms
  • Causes allergic responses
  • Competition - monopolizing resources
  • Herbivory/grazing/browsing
  • Predation
  • Rapid growth
Likelihood of entry/control
  • Difficult/costly to control


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Economic Value

R. nomadica is cogeneric with the edible jellyfish, Rhopilema esculenta, a popular food in South-East Asian cooking (Hsieh et al., 2001). The latter species is also used for medicinal purposes (Omori and Nakano, 2001), such as treatment of high blood pressure and bronchitis and have been commercially exploited along the coasts of South-East Asia for more than 1,000 years (Morikawa, 1984; Hsieh et al., 2001; Omori and Nakano, 2001). The fishery is characterized by considerable fluctuations in annual catch and very short fishing season. Attempts to process and export R. nomadica from the Mediterranean to South-East Asian markets have not been successful thus far.

Uses List

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Human food and beverage

  • Meat/fat/offal/blood/bone (whole, cut, fresh, frozen, canned, cured, processed or smoked)

Medicinal, pharmaceutical

  • Source of medicine/pharmaceutical

Similarities to Other Species/Conditions

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R. nomadica is distinguished from its near relative R. hispidum by its blunt tuberculation of the exumbrella and the mouth arms ending in vermicular filaments as compared with the sharply conical warts and “swollen club” appendages of the latter.

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.


As R. nomadica may be transported in shipping, efforts should be concentrated on fouling and ballast control.

Public awareness

The local media report during the summer months the presence of jellyfish along the beaches.


Movement control

Coastal municipalities shovel tons of jellyfish off the beaches. Some have invested in booms and netting to create jellyfish-free zones at their most popular beaches. Marine biologists dislike the use of fixed nets or barriers around swimming areas as the waves amputate the filamentous tentacles of an ensnared jellyfish and carry the nematocysts-bearing filaments toward swimmers. Stray tentacles and even dead jellyfish can still be dangerous.

Biological control

No information is available on any biological control methods attempted on this species.

Gaps in Knowledge/Research Needs

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Control or possible eradication of invasive jellyfish are problematic in that the life history of jellyfish is complex, including a benthic phase (scyphistoma and strobila) and the short-lived planktonic phase (ephyra, medusa, planula). The presence of asexual stages (podocysts) is also relevant to control. Factors affecting stocks of jellyfish include natural mortality (through disease, parasitism, predation, old age, physical forcing), competition and anthropogenic disturbance. Although aspects of life history in the laboratory of this species have been studied (Lotan et al., 1992), data on the free-living population is urgently needed for proper management. We have no information where the benthic phase of R. nomadica is sheltered.


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Benmeir P; Rosenberg L; Sagi A; Vardi D; Eldad A, 1990. Jellyfish envenomation: a summer epidemic. Burns, 16(6):471-472.

Bodenheimer FS, 1935. Animal life in Palestine. An introduction to the problems of animal ecology and zoogeography. Jerusalem, viii + 506 pp.

Galil BS, 2007. Seeing red: alien species along the Mediterranean coast of Israel. Aquatic Invasions, 2(4):281-312.

Galil BS; Spanier E; Ferguson WW, 1990. The scyphomedusae of the Mediterranean coast of Israel, including two Lessepsian migrants new to the Mediterranean. Zoologie Mededelingen (Leiden), 64:95-105.

Golani D; Ben Tuvia A, 1995. Lessepsian migration and the Mediterranean Fisheries of Israel. In: Condition of the world's aquatic habitats. Proceedings of the World Fisheries Congress. Theme 1 [ed. by Armantrout NB, Wolotira RJ, ]: Oxford & IBH Pub. Co., 279-289.

Hsieh YHP; Leong FuiMeong; Rudloe J, 2001. Jellyfish as food. Hydrobiologia, 451:11-17.

Ikhtiyar S; Durgham H; Bakr M, 2002. [English title not available]. (Contribution a l'etude dy scyphomeduse Rhopilema [Rhopilema] nomadica dans les eaux cotieres syriennes) Journal of Union of Arab Biologists Cairo A Zoology, 18:227-244.

Kideys AE; Gücü AC, 1995. Rhopilema nomadica: a Lessepsian scyphomedusan new to the Mediterranean coast of Turkey. Israel Journal of Zoology, 41:615-617.

Kramp PL, 1961. A synopsis of the medusae of the world. Journal of the Marine Biological Association of the United Kingdom, 40:7-469.

Lakkis S; Avian M; Negro PDel; Rottini-Sandrini L, 1990. [English title not available]. (Les Scyphomeduses du Bassin Levantin (Beyrouth) et de l'Adriatique du Nord (Golfe de Trieste): comparison faunistique et ecologique) Rapports et Procès-Verbaux des Réunions, Commission Internationale pour I'Exploration Scientifique de la mer Méditerranée, 32(1):220.

Lotan A; Ben-Hillel R; Loya Y, 1992. Life cycle of Rhopilema nomadica: a new immigrant scyphomedusan in the Mediterranean. Marine Biology, 112:237-242.

Morikawa T, 1984. Jellyfish. FAO INFOFISH Marketing Digest, 1:37-39.

Omori M; Nakano E, 2001. Jellyfish fisheries in Southeast Asia. Hydrobiologia, 451:19-26.

Sendovski U; Goffman M; Goldshlak L, 2005. Severe delayed cutaneous reaction due to Mediterranean jellyfish (Rhopilema nomadica) envenomation. Contact Dermatitis, 52(5):282-283.

Silfen R; Vilan A; Wohl I; Leviav A, 2003. Mediterranean jellyfish (Rhopilema nomadica) sting. Burns, 29(8):868-870.

Siokou-Frangou I; Sarantakos K; Christou ED, 2006. First record of the scyphomedusa Rhopilema nomadica Galil, 1990 (Cnidaria: Scyphozoa: Rhizostomeae) in Greece. Aquatic Invasions, 1(3):194-195.

Stiasny G, 1938. [English title not available]. (Die Scyphomedusen des Roten Meeres. Verhandelingen der Koninklijke. Nederlandsche Akademie van wetenschappen te) Natuurkunde, 37(2):1-35.

Stiasny G, 1939. [English title not available]. (Über einige Scyphomedusen von Kamaran (Rotes Meer)) Zoologischer Anzeiger, 126:17-23.

Yoffe B; Baruchin AM, 2004. Mediterranean jellyfish (Rhopilema nomadica) sting. Burns, 30(5):503-504.

Links to Websites

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DAISIE species factsheet Rhopilema nomadica
GISD/IASPMR: Invasive Alien Species Pathway Management Resource and DAISIE European Invasive Alien Species Gateway source for updated system data added to species habitat list.
Global register of Introduced and Invasive species (GRIIS) source for updated system data added to species habitat list.


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Israel: National Institute of Oceanography, Israel Oceanographic and Limnological Research, IOLR Management and National Institute of Oceanography Tel- Shikmona, P.O.B. 8030, Haifa 31080,

Europe: DAISIE - Delivering Alien Invasive Species Inventories for Europe, Web-based service,


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06/07/09 Original text by:

Bella Galil, National Institute of Oceanography, Israel Oceanographic &, Limnological Research, Israel

Distribution Maps

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