Jellyfish Rhopilema Nomadica Research Articles

From ctenophores to scyphozoans: parasitic spillover of a burrowing sea anemone

Most host-parasite associations are explained by phylogenetically conservative capabilities for host utilization, and therefore parasite switches between distantly related hosts are rare. Here we report the first evidence of a parasitic spillover of the burrowing sea anemone Edwardsiella carnea from the invasive ctenophore Mnemiopsis leidyi to two scyphozoan hosts: the native Mediterranean barrel jellyfish Rhizostoma pulmo and the invasive Indo-Pacific nomad jellyfish Rhopilema nomadica, collected from the Eastern Mediterranean Sea. Edwardsiella carnea planulae found in these jellyfish were identified using molecular analyses of the mitochondrial 16S and nuclear 18S rRNA genes. Overall, 93 planulae were found on tentacles, oral arms, and inside of the gastrovascular canals of the scyphomedusae, whereas no infection was observed in co-occurring ctenophores. DNA metabarcoding approach indicated seasonal presence of Edwardsiella sp. in the Eastern Mediterranean mesozooplankton, coinciding with jellyfish blooms in the region. Our findings suggest a non-specific parasitic relationship between Edwardsiella carnea and various gelatinous hosts based on shared functionality rather than evolutionary history, potentially driven by shifts in host availability due to jellyfish blooms. This spillover raises questions about the ecological impacts of parasitism on native and invasive scyphozoan hosts and the potential role of Edwardsiella in controlling their populations.

Directional swimming patterns in jellyfish aggregations

Having a profound influence on marine and coastal environments worldwide, jellyfish hold significant scientific, economic, and public interest.1,2,3,4,5 The predictability of outbreaks and dispersion of jellyfish is limited by a fundamental gap in our understanding of their movement. Although there is evidence that jellyfish may actively affect their position,6,7,8,9,10 the role of active swimming in controlling jellyfish movement, and the characteristics of jellyfish swimming behavior, are not well understood. Consequently, jellyfish are often regarded as passively drifting or randomly moving organisms, both conceptually2,11 and in process studies.12,13,14 Here we show that the movement of jellyfish is modulated by distinctly directional swimming patterns that are oriented away from the coast and against the direction of surface gravity waves. Taking a Lagrangian viewpoint from drone videos that allows the tracking of multiple adjacent jellyfish, and focusing on the scyphozoan jellyfish Rhopilema nomadica as a model organism, we show that the behavior of individual jellyfish translates into a synchronized directional swimming of the aggregation as a whole. Numerical simulations show that this counter-wave swimming behavior results in biased correlated random-walk movement patterns that reduce the risk of stranding, thus providing jellyfish with an adaptive advantage critical to their survival. Our results emphasize the importance of active swimming in regulating jellyfish movement and open the way for a more accurate representation in model studies, thus improving the predictability of jellyfish outbreaks and their dispersion and contributing to our ability to mitigate their possible impact on coastal infrastructure and populations.

Selecting 16S rRNA Primers for Microbiome Analysis in a Host-Microbe System: The Case of the Jellyfish Rhopilema nomadica.

Amplicon sequencing of the 16S rRNA gene is extensively used to characterize bacterial communities, including those living in association with eukaryotic hosts. Deciding which region of the 16S rRNA gene to analyze and selecting the appropriate PCR primers remains a major decision when initiating any new microbiome study. Based on a detailed literature survey of studies focusing on cnidarian microbiomes, we compared three commonly used primers targeting different hypervariable regions of the 16S rRNA gene, V1V2, V3V4, and V4V5, using the jellyfish Rhopilema nomadica as a model. Although all primers exhibit a similar pattern in bacterial community composition, the performance of the V3V4 primer set was superior to V1V2 and V4V5. The V1V2 primers misclassified bacteria from the Bacilli class and exhibited low classification resolution for Rickettsiales, which represent the second most abundant 16S rRNA gene sequence in all the primers. The V4V5 primer set detected almost the same community composition as the V3V4, but the ability of these primers to also amplify the eukaryotic 18S rRNA gene may hinder bacterial community observations. However, after overcoming the challenges possessed by each one of those primers, we found that all three of them show very similar bacterial community dynamics and compositions. Nevertheless, based on our results, we propose that the V3V4 primer set is potentially the most suitable for studying jellyfish-associated bacterial communities. Our results suggest that, at least for jellyfish samples, it may be feasible to directly compare microbial community estimates from different studies, each using different primers but otherwise similar experimental protocols. More generally, we recommend specifically testing different primers for each new organism or system as a prelude to large-scale 16S rRNA gene amplicon analyses, especially of previously unstudied host-microbe associations.

Selecting 16S rRNA primers for microbiome analysis in a host-microbe system: the case of the jellyfish Rhopilema nomadica

Selecting 16S rRNA primers for microbiome analysis in a host-microbe system: the case of the jellyfish Rhopilema nomadica

Selecting 16S rRNA primers for microbiome analysis in a host-microbe system: the case of the jellyfish Rhopilema nomadica

Selecting 16S rRNA primers for microbiome analysis in a host-microbe system: the case of the jellyfish Rhopilema nomadica

Knowledge needs in economic costs of invasive species facilitated by canalisation

Canals provide wide-ranging economic benefits, while also serving as corridors for the introduction and spread of aquatic alien species, potentially leading to negative ecological and economic impacts. However, to date, no comprehensive quantifications of the reported economic costs of these species have been done. Here, we used the InvaCost database on the monetary impact of invasive alien species to identify the costs of those facilitated by three major canal systems: the European Inland Canals, Suez Canal, and Panama Canal. While we identified a staggering number of species having spread via these systems, monetary costs have been reported only for a few. A total of $33.6 million in costs have been reported from species linked to European Inland Canals (the fishhook waterflea Cercopagis pengoi and the zebra mussel Dreissena polymorpha) and $8.6 million linked to the Suez Canal (the silver-cheeked toadfish Lagocephalus sceleratus, the lionfish Pterois miles, and the nomad jellyfish Rhopilema nomadica), but no recorded costs were found for species facilitated by the Panama Canal. We thus identified a pervasive lack of information on the monetary costs of invasions facilitated by canals and highlighted the uneven distribution of costs.

Developing novel microsatellite markers by NGS technology for Rhopilema nomadica, an invasive jellyfish.

Twelve microsatellite loci, obtained by whole genome sequencing approach, were developed and validated for the rhizostomatid jellyfish Rhopilema nomadica, the most pernicious invasive species in the Mediterranean Sea. A sample of 40 specimens collected at six locations along the Mediterranean coast of Israel were genotyped and all loci presented suitable outcomes to population genetic studies, revealing 5-19 alleles/locus with clean and reproducible amplifications. Observed and expected heterozygosity ranged 0.0.353 to 0.971 and 0.335 to 0.870, respectively, and the fixation index (inbreeding coefficient) and the polymorphic information content (PIC) ranged between - 0.190 and 0.240 and 0.32 to 0.858, respectively. The new set of microsatellite loci will be used to study long-term changes in the population genetic parameters of this invasive species.

The Levantine jellyfish Rhopilema nomadica and Rhizostoma pulmo swim faster against the flow than with the flow

Jellyfish locomotion and orientation have been studied in the past both in the laboratory, testing mostly small jellyfish, and in the field, where it was impossible to control the seawater currents. Utilizing an outdoor water flume, we tested the locomotion of jellyfish when swimming against and with currents of up to 4.5 cm s−1. We used adult jellyfish from two of the most abundant species in the eastern Mediterranean, Rhopilema nomadica and Rhizostoma pulmo, and measured their pulsation frequency and swimming speed relative to the water. While pulsation frequency was not affected by the water velocity, jellyfish swam faster against the current than with it. This finding suggests that jellyfish possess a sensory ability, whose mechanism is currently unknown, enabling them to gauge the flow and react to it, possibly in order to reduce the risk of stranding.

Validation and redescription of the hyperiidean amphipod Brachyscelus rapacoides Stephensen, 1925 (Crustacea: Amphipoda: Hyperiidea: Brachyscelidae), a new record of association with the scyphozoan jellyfish Rhopilema nomadica Galil, 1990 (Scyphozoa: Rhizostomeae: Rhizostomatidae) in the Mediterranean Sea.

The hyperiidean amphipod Brachyscelus rapacoides Stephensen, 1925 is recorded from the scyphozoan jellyfish Rhopilema nomadica Galil, 1990, a new record of association for the genus Brachyscelus, as well as the first record of hyperiid infestation of a non-indigenous scyphozoan host. Because of some past confusion concerning the status of B. rapacoides and the closely related species B. rapax (Claus, 1871) a redescription of B. rapacoides and molecular analysis are provided in order to validate it as a species distinguished from B. rapax.

New Mediterranean Biodiversity Records (October 2015)

The Collective Article “New Mediterranean Biodiversity Records” of the Mediterranean Marine Science journal offers the means to publish biodiversity records in the Mediterranean Sea. The current article is divided per countries, listed according to a Mediterranean west-east geographic position. New biodiversity data are reported for 7 different countries, although one species hereby reported from Malta is overall new for the entire Mediterranean basin, and is presumably present also in Israel and Lebanon (see below in Malta). Italy: the rare native fish Gobius kolombatovici is first reported from the Ionian Sea, whilst the alien jellyfish Rhopilema nomadica and the alien fish Oplegnathus fasciatus are first reported from the entire country. The presence of O. fasciatus from Trieste is concomitantly the first for the entire Adriatic Sea. Finally, the alien bivalve Arcuatula senhousia is hereby first reported from Campania (Tyrrhenian Sea). Tunisia: a bloom of the alien crab Portunus segnis is first reported from the Gulf of Gabes, from where it was considered as casual. Malta: the alien flatworm Maritigrella fuscopunctata is first recorded from the Mediterranean Sea on the basis of 25 specimens. At the same time, web researches held possible unpublished records from Israel and Lebanon. The alien crab P. segnis, already mentioned above, is first formally reported from Malta based on specimens collected in 1972. Concomitantly, the presence of Callinectes sapidus in Maltese waters is excluded since based on misidentifications. Greece: the Atlantic northern brown shrimp Penaeus atzecus, previously known from the Ionian Sea from sporadic records only, is now well established in Greek and international Ionian waters. The alien sea urchin Diadema setosum is reported from the second time from Greece, and its first record date from the country is backdated to 2010 in Rhodes Island. The alien lionfish Pterois miles is first reported from Greece and concomitantly from the entire Aegean Sea. Turkey: the alien rhodophyte Antithamnion hubbsii is first recorded from Turkey and the entire eastern Mediterranean. New distributional data are also offered for the native fishes Alectis alexandrina and Heptranchias perlo. In particular, the former record is constituted by a juvenile of 21.38 mm total length, whilst the latter by a mature male. Cyprus: the rare native cephalopod Macrotritopus defilippi, and the alien crab Atergatis roseus, sea slug Plocamopherus ocellatus and fish Cheilodipterus novemstriatus are first recorded from the entire country. Lebanon: the alien crabs Actaea savignii and Matuta victor, as well as the alien fish Synanceia verrucosa, are first recorded from the entire country. In addition, the first Mediterranean record of A. savignii is backdated to 2006, whilst the high number of M. victor specimens observed in Lebanon first suggest its establishment in the basin. The Atlantic fishes Paranthias furcifer and Seriola fasciata, and the circumtropical Rachycentron canadum, are also first reported from the country. P. furcifer record backdate its presence in the Mediterranean to 2007, whilst S. fasciata records backdate its presence in the eastern Mediterranean to 2005. Finally, two of these latter species have been recently ascribed to alien species, but all the three species may better fit the cryptogenic category, if not a new one.

The invasive tropical scyphozoan Rhopilema nomadica Galil, 1990 reaches the Tunisian coast of the Mediterranean Sea

The alien Erythraean jellyfish Rhopilema nomadica was first recorded in Tunisia waters (Gulf of Gabes) in 2008. Subsequently it was sighted in the Bizerte Channel and Gulf of Tunis where it has been regularly observed since 2010 during summer and autumn months.

The first confirmed record of the alien jellyfish Rhopilema nomadica Galil, 1990 from the southern Aegean coast of Turkey

The scyphozoan jellyfish Rhopilema nomadica Galil, 1990 has been observed in June 2011 in Marmaris Harbour, on the southern Aegean coast of Turkey. Information on previous records of this invasive species from the Mediterranean coast of Turkey is provided.

Low abundance and skewed population structure of the whelk Stramonita haemastoma along the Israeli Mediterranean coast

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 218:189-202 (2001) - doi:10.3354/meps218189 Low abundance and skewed population structure of the whelk Stramonita haemastoma along the Israeli Mediterranean coast G. Rilov1,*, Y. Benayahu2, A. Gasith1 1Institute for Nature Conservation Research and 2Department of Zoology, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Ramat-Aviv, Tel-Aviv 69978, Israel *Present address: Duke University Marine Laboratory, Nicholas School of the Environment, Duke University, 135 Duke Marine Lab Road, Beaufort 28516, North Carolina, USA. E-mail: gr3@duke.edu ABSTRACT: Stramonita (=Thais) haemastoma (Kool, 1987), a relatively large predatory snail found in rocky littoral ecosystems, can attain densities of hundreds of individuals per m2 in warm temperate coasts of the western Atlantic. It has also been reported as common along the Israeli Mediterranean coast; however our preliminary observations there suggested low abundances of this species. We measured densities of the whelk and those of its major potential prey by quadrat and belt transect (plots) methods, supported by underwater photography when applicable. Our study demonstrates that indeed densities of S. haemastoma along the Israeli Mediterranean coast are very low (<0.5 m-2) in most habitats and locations, with the exception of some midlittoral habitats (density of ca 7 snails m-2) where food and shelter are abundant. Food is probably not a limiting factor in most midlittoral habitats, and the low abundance of S. haemastoma is likely to be associated with scarcity of shelters and high risk of dislodgment or of desiccation. The population structure of the whelks is skewed to large snails. Small individuals were absent throughout the entire 5 yr of the study, while mean whelk size increased during this period. These results suggest impaired recruitment of whelks in recent years. Assuming that S. haemastoma was once abundant along the Israeli coast, it is possible that the following contemporary changes which occurred in the Levant basin may have affected whelk reproduction and/or juvenile survival rates and therefore may also explain the low recruitment rates: (1) diminished seasonal reduction in salinity due to the damming of the Nile; (2) unregulated use of tributyltin-based antifouling paints in Israel, which may impair reproduction through imposex; and (3) massive periodic appearance of a new plankton feeder along the Israeli coast, the Indo-pacific jellyfish Rhopilema nomadica, which may prey on the snail larvae. KEY WORDS: Stramonita haemastoma · Mediterranean · Levant · Population structure · Distribution Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 218. Online publication date: August 20, 2001 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2001 Inter-Research.

SCYPHOZOAN JELLYFISH'S MESOGLEA SUPPORTS ATTACHMENT, SPREADING AND MIGRATION OF ANTHOZOANS' CELLS IN VITRO

Mechanically and enzymatically dissociated cells from five anthozoan species were laid on seven substrates in vitro. Cells were taken from two sea anemones (Aiptasia sp. and Anemonia sulcata), a scleractinian coral (Stylophora pistillata) and two alcyonacean corals (Heteroxenia fuscescence andNephthea sp). Substrates tested: glass (coverslips), plastic (uncoated tissue culture plates), type IV collagen, gelatin, fibronectin, mesoglea pieces from the scyphozoan jellyfish Rhopilema nomadica and acetic acid extract of jellyfish mesoglea. Except for the mesoglea pieces, cells did not respond to any one of the other substrates, retaining their rounded shape. Following contact with mesoglea pieces, cells attached and spread. Subsequently they migrated into the mesogleal matrix at a rate of 5–10μm/h during the first 2–5h. No difference was found between the behavior of cells from the five different cnidarian species.

Toxin compartmentation and delivery in the Cnidaria: the nematocyst's tubule as a multiheaded poisonous arrow.

With the aid of dialysis and ion exchange chromatography, a new polypeptide toxin was purified from the tentacles of the Mediterranean jellyfish Rhopilema nomadica. The amino acid sequence of the N-terminal segment of the new toxin revealed that it is a phospholipase A2 (PhA2) toxin closely resembling those previously isolated from reptile and hymenopterous venoms. The occurrence of a PhA2 toxin in the jellyfish tentacles may explain both their local (dermanecrotic) and systemic (cardiac-respiratory) effects upon human envenomation. We used an antibody raised against the above toxin as a probe to explore, for the first time, the site of toxin allocation in cnidarian nematocysts and its morphological route of delivery. Our immunocytochemical approach revealed that the toxin is stored on the outer ("cytoplasmic") surface of the inverted tubule folded in the capsule of the resting nematocyst. During discharge the toxin is translocated to the internal surface surrounding the lumen of the everting tubule, and its delivery via extended spirally arrayed barbs is apparently propelled by the high hydrostatic pressure of the capsule. This is a unique example where subcellular translocation and transfer of a polypetide is driven by mechanical forces.