Rhopilema nomadica (nomad jellyfish)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Biology and Ecology
- Latitude/Altitude Ranges
- Water Tolerances
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Impact Summary
- Economic Impact
- Environmental Impact
- Threatened Species
- Social Impact
- Risk and Impact Factors
- Similarities to Other Species/Conditions
- Prevention and Control
- Gaps in Knowledge/Research Needs
- Links to Websites
- Distribution Maps
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IdentityTop of page
Preferred Scientific Name
- Rhopilema nomadica Galil, 1990
Preferred Common Name
- nomad jellyfish
Local Common Names
- Israel: hutit nodedet
Summary of InvasivenessTop of page
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 TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Cnidaria
- Class: Scyphozoa
- Order: Rhizostomeae
- Family: Rhizostomatidae
- Genus: Rhopilema
- Species: Rhopilema nomadica
Notes on Taxonomy and NomenclatureTop of page
DescriptionTop of page
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.
DistributionTop of page
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 TableTop of page
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.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Israel||Widespread||Introduced||1976||Invasive||Galil et al., 1990||Annual swarming in summer observed along the coast of Israel|
|Lebanon||Widespread||Introduced||1989||Invasive||Lakkis et al., 1990||Annual swarming in summer observed along the coast of Lebanon|
|Syria||Widespread||Introduced||2002||Invasive||Ikhtiyar et al., 2002|
|Turkey||Widespread||Introduced||1995||Invasive||Kideys and Gücü, 1995||In 1995 observed in southeastern Turkey, in 1998 off Izmir, on the Aegean coast of Turkey|
|East Africa||Present||Native||Stiasny, 1938; Stiasny, 1939||Exact limits of range unknown|
|Greece||Present, few occurrences||Introduced||2006||Invasive||Siokou-Frangou et al., 2006||Observed off Lakonikos Gulf. Greece, in summer of 2006|
History of Introduction and SpreadTop of page
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 IntroductionTop of page
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.
HabitatTop of page
Habitat ListTop of page
|Inshore marine||Principal habitat||Harmful (pest or invasive)|
Biology and EcologyTop of page
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).
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.
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 RangesTop of page
|Latitude North (°N)||Latitude South (°S)||Altitude Lower (m)||Altitude Upper (m)|
Water TolerancesTop of page
|Parameter||Minimum Value||Maximum Value||Typical Value||Status||Life Stage||Notes|
|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 EnemiesTop of page
Means of Movement and DispersalTop of page
Natural Dispersal (Non-Biotic)
Entered the Mediterranean through the Suez Canal (Galil et al., 1990).
Impact SummaryTop of page
Economic ImpactTop of page
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 ImpactTop of page
R. nomadica forms dense swarms annually, which outcompete the native rhizostomatid jellyfish Rhizostoma pulmo and may alter the planktotrophic species assemblages (Galil, 2007).
Threatened SpeciesTop of page
Social ImpactTop of page
Risk and Impact FactorsTop of page Invasiveness
- Proved invasive outside its native range
- Highly mobile locally
- Fast growing
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Reproduces asexually
- 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
- Causes allergic responses
- Competition - monopolizing resources
- Rapid growth
- Difficult/costly to control
UsesTop of page
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.
Similarities to Other Species/ConditionsTop of page
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 ControlTop of page
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.
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.
No information is available on any biological control methods attempted on this species.
Gaps in Knowledge/Research NeedsTop of page
ReferencesTop of page
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.
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.
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.
OrganizationsTop of page
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, http://www.ocean.org.il
Europe: DAISIE - Delivering Alien Invasive Species Inventories for Europe, Web-based service, http://www.europe-aliens.org
ContributorsTop of page
06/07/09 Original text by:
Bella Galil, National Institute of Oceanography, Israel Oceanographic &, Limnological Research, Israel
Distribution MapsTop of page
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