Scyphozoan Jellyfish Research Articles

Cassiopea andromeda (Forsskål, 1775) in the Gulf of Kutch, India: initial discovery of the scyphistoma, and a record of the medusa in nearly a century

Cassiopea andromeda is reported here after long gap of almost a century from the Gulf of Kutch, Gujarat. This is the first record of scyphistoma form of the species from India and first record of the medusa from the Arambhada coast. An upside down scyphozoan jellyfish Cassiopea andromeda belong to family Cassiopeidae. Identification and description of medusa and scyphistomae were given based on morphological characters. This paper discusses about the variation in colour form, aggregation of medusae and morphology of polyp.

Succession of generations is still the general paradigm for scyphozoan life cycles

A recent study proposed an unorthodox view of the long-known metagenetic life cycle of scyphozoan jellyfish. We argue that misinterpretations and imprecise information generated a misleading view of such life cycle patterns. In favor of our reasoning, we present the historical understanding of metagenesis, and contend that it can still be used as a shared general life cycle pattern for Scyphozoa, as well as for other medusozoans.

Abyssal fauna of the UK-1 polymetallic nodule exploration area, Clarion-Clipperton Zone, central Pacific Ocean: Cnidaria.

BackgroundWe present data from a DNA taxonomy register of the abyssal Cnidaria collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise ‘AB01’ to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration area ‘UK-1’ in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. This is the second paper in a series to provide regional taxonomic data for a region that is undergoing intense deep-sea mineral exploration for high-grade polymetallic nodules. Data were collected from the UK-1 exploration area following the methods described in Glover et al. (2015b).New informationMorphological and genetic data are presented for 10 species and 18 records identified by a combination of morphological and genetic data, including molecular phylogenetic analyses. These included 2 primnoid octocorals, 2 isidid octocorals, 1 anemone, 4 hydroids (including 2 pelagic siphonophores accidentally caught) and a scyphozoan jellyfish (in the benthic stage of the life cycle). Two taxa matched previously published genetic sequences (pelagic siphonophores), two taxa matched published morphological descriptions (abyssal primnoids described from the same locality in 2015) and the remaining 6 taxa are potentially new species, for which we make the raw data, imagery and vouchers available for future taxonomic study. We have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections. For some of the specimens we also provide image data collected at the seabed by ROV, wich may facilitate more accurate taxon designation in coming ROV or AUV surveys.

Reduced pH affects pulsing behaviour and body size in ephyrae of the moon jellyfish, Aurelia aurita

Our understanding of how reduced seawater pH affects the behaviour and growth of scyphozoan jellyfish is poor. Here, we investigated the effects of simulated Ocean Acidification (OA) (pH=7.6 for 7d) on pulsing behaviour (as an index of swimming behaviour) and aspects of the morphology of ephyrae of the moon jellyfish Aurelia aurita. Ephyrae exposed to reduced pH had a significantly smaller surface area, central disc area, and lappet length and width than controls. Pulsation rate was significantly lower, and the mean pulse-to-pulse period shorter, in the reduced pH treatment. There was, however, no significant treatment effect on either the maximum or minimum pulse-to-pulse period, suggesting that the ability for rapid pulsations was maintained. Ephyrae from the reduced pH treatment displayed a more variable pulsation behaviour, with an elevated standard deviation and root mean square of successive difference (RMSSD) in pulse-to-pulse period. In summary, reduced pH simulating future predicted Ocean Acidification conditions, had important effects on aspects of swimming behaviour and size of A. aurita ephyra, which may have consequences for survival and the population dynamics of field populations.

Tentacle Transcriptome and Venom Proteome of the Pacific Sea Nettle, Chrysaora fuscescens (Cnidaria: Scyphozoa).

Jellyfish venoms are rich sources of toxins designed to capture prey or deter predators, but they can also elicit harmful effects in humans. In this study, an integrated transcriptomic and proteomic approach was used to identify putative toxins and their potential role in the venom of the scyphozoan jellyfish Chrysaora fuscescens. A de novo tentacle transcriptome, containing more than 23,000 contigs, was constructed and used in proteomic analysis of C. fuscescens venom to identify potential toxins. From a total of 163 proteins identified in the venom proteome, 27 were classified as putative toxins and grouped into six protein families: proteinases, venom allergens, C-type lectins, pore-forming toxins, glycoside hydrolases and enzyme inhibitors. Other putative toxins identified in the transcriptome, but not the proteome, included additional proteinases as well as lipases and deoxyribonucleases. Sequence analysis also revealed the presence of ShKT domains in two putative venom proteins from the proteome and an additional 15 from the transcriptome, suggesting potential ion channel blockade or modulatory activities. Comparison of these potential toxins to those from other cnidarians provided insight into their possible roles in C. fuscescens venom and an overview of the diversity of potential toxin families in cnidarian venoms.

Evidence that summer jellyfish blooms impact Pacific Northwest salmon production

AbstractInterannual variability in salmon (Oncorhynchus spp.) production in the northeast Pacific is understood to be driven by oceanographic variability and bottom‐up processes affecting prey availability to juvenile salmon. Scyphozoan jellyfish have an important role in shaping the pathways of energy flow through pelagic food webs. While jellyfish obtain high production rates and biomasses as major consumers of zooplankton production, they have few predators and may divert plankton production away from higher trophic levels. Although jellyfish are planktivorous and juvenile coho (O. kisutch) and Chinook (O. tshawytscha) salmon are mainly piscivorous, they may be indirect competitors for plankton production. Ecosystem model simulations suggested that among all trophic interactions within the Pacific Northwest coastal food web, juvenile salmon are particularly sensitive to jellyfish blooms, and that salmon production will be suppressed in years of high summer jellyfish biomass. Pelagic surveys off Oregon and Washington (1999–2012) were used to examine the interannual relationship between salmon production and the dominant jellyfish species, the sea nettle Chrysaora fuscescens, off the Pacific Northwest coast. There was a significant, negative correlation between sea nettle biomass and the strength of adult coho and Chinook salmon returns to the Columbia River. Examination of spatial distributions across years showed a positive association between sea nettles and salmon. Within individual years, significant differences between the distribution of sea nettles and yearling coho and Chinook salmon generally occurred during cooler ocean summers, perhaps due to the greater expanse of optimal salmon habitat resulting from more upwelling. Whether the association is behavioral or a product of oceanographic processes, association enhances the opportunity for indirect competition. Examination of feeding incidence in September showed that salmon stomachs were less full at locations with higher sea nettle biomass.

Decapod crustacean associations with scyphozoan jellyfish (Rhizostomeae: Pelagiidae) in the Southeastern Brazilian coast

In southeastern Brazil, decapod crustaceans were found living in association with the scyphozoan jellyfish. In total, 2002 specimens of the Scyphozoa Lychnorhiza lucerna were collected of which 511 were associated decapods that were identified as three species of the crab Libinia ferreirae, Libinia spinosa, and one Grapsoidea sp. and two species of caridean shrimps Periclimenes paivai and Leander paulensis. This is the first record of an association between the caridean shrimp L. paulensis and a scyphozoan and the first report of symbioses involving the crabs L. spinosa and Grapsoidea sp. on the Brazilian coast.

Cotylorhiza erythraea Stiasny, 1920 (Scyphozoa: Rhizostomeae: Cepheidae), yet another erythraean jellyfish from the Mediterranean coast of Israel

An unfamiliar scyphozoan jellyfish species has been observed along the Mediterranean coast of Israel since 2003. Morphological characters such as the densely anastomosed radial canals and the stalked cupped appendages on the oral arms identified it as closely allied to Cotylorhiza. Comparison with the type of C. erythraea, collected over a century ago in the Suez Canal, shows close similarity. Molecular analyses based on the mitochondrial barcoding gene cytochrome oxidase sub unit I (COI) and 28S ribosomal DNA support its placement among the Cepheidae. This is the fifth-introduced scyphozoan species recorded along the Mediterranean coast of Israel. The presence of sexually mature specimens detected as far back as 2003, and the occurrence of the species in the past summer at sites nearly 90 kms apart, indicate the existence of widespread, established populations.

The Impact of Different Drying Modes of Scyphozoan JellyfishRhopilema EsculentumandAurelia Auritaon the Protein and Carbohydrate Components in their Composition and the Possibility of Their Use as Dried Prepared Food

The article studied the impact of convection drying on the stability of proteins and sugars in jellyfish species Rhopilema esculentum and Aurelia aurita. The interdependence of the drying time and the process parameters was studied. Stability of the proteins was evaluated by their denaturation degree, using the method of Ds-Na-PAAG-electrophoresis; the stability of monosaccharides was evaluated with regard to change in their composition using the Gas Liquid Chromatography method. Fixation of the dried jellyfish structure after hydration was performed by reducing the pH of the solution by adding the 70% acetic acid in quantity 0.3% into the 4% solution of salt. Acetic acid restrained the distinct smell of dried jellyfish, stabilized its structure. The dried semifinished product that has passed the hydration without adding acetic acid had an unstable, moist structure. Marinated products have gained good taste in 3 days; the smell of raw jellyfish disappeared completely after 5 days. Practical Applications It was found that at a drying temperature of 65C, the content of protein and carbohydrate components in Rhopilema esculentum reduced by 50% as compared with the content in the native sample, the content of amino sugars (glucosamine, galactosamine) does not change, which indicates the active ongoing reaction of melanoidin formation. The application of food production technology with the use of Rhopilema esculentum as dried prepared food along with the hydration process was substantiated. Therefore, the study justified specific drying mode for Rhopilema esculentum, which implies minimal loss of protein–carbohydrate components. The loss of proteins and sugars in the jellyfish Aurelia at a drying temperature 50C made 60%, as compared with their content in the native sample, indicating nonexpediency of further experiments. Thus, the research provided optimum parameters for drying of Rhopilema esculentum.

The use of ephyrae of a scyphozoan jellyfish, Aurelia aurita, in the aquatic toxicological assessment of Macondo oils from the Deepwater Horizon incident.

Ephyrae of the scyphozoan jellyfish, Aurelia aurita, were evaluated in 96-hr acute toxicity tests for lethal response to Macondo crude oils from the Deepwater Horizon (DWH) incident in the Gulf of Mexico (GOM), Corexit 9500, and oil-dispersant mixtures. Water accommodated fractions (WAFs) of weathered and unweathered Macondo crude oils were not acutely toxic to ephyrae (LC50s > 100% WAF). The total PAHs (TPAHs), measured as the sum of 46 PAHs, averaged 21.1and 152 µg TPAH/L for WAFs of weathered and unweathered oil, respectively. Mortality was significantly (p = <0.0001) higher in the three highest exposure concentrations (184-736 µg TPAH/L) of chemically dispersed WAFs (CEWAF) compared to controls. Dispersant only tests resulted in a mean LC50 of 32.3 µL/L, which is in the range of previously published LC50s for marine zooplankton. Changes in appearance and muscle contractions were observed in organisms exposed to CEWAF dilutions of 12.5 and 25%, as early as 24 h post-exposure. Based on the results of these tests, crude oil alone did not cause significant acute toxicity; however, the presence of chemical dispersant resulted in substantial mortality and physical and behavioral abnormalities either due to an increase in hydrocarbons or droplet exposure.

Do scyphozoan jellyfish limit the habitat of pelagic species in the Barents Sea during the late feeding period?

Do scyphozoan jellyfish limit the habitat of pelagic species in the Barents Sea during the late feeding period?

Comparative study of the toxic effects of Chrysaora quinquecirrha (Cnidaria: Scyphozoa) and Chironex fleckeri (Cnidaria: Cubozoa) venoms using cell-based assays

The venoms of jellyfish cause toxic effects in diverse biological systems that can trigger local and systemic reactions. In this study, the cytotoxic and cytolytic effects of Chrysaora quinquecirrha and Chironex fleckeri venoms were assessed and compared using three in vitro assays. Venoms from both species were cytotoxic to fish gill cells and rat cardiomyocytes, and cytolytic in sheep erythrocytes. Both venoms decreased cell viability in a concentration-dependent manner; however, the greatest difference in venom potencies was observed in the fish gill cell line, wherein C. fleckeri was 12.2- (P = 0.0005) and 35.7-fold (P < 0.0001) more potently cytotoxic than C. quinquecirrha venom with 30 min and 120 min cell exposure periods, respectively. Gill cells and rat cardiomyocytes exposed to venoms showed morphological changes characterised by cell shrinkage, clumping and detachment. The cytotoxic effects of venoms may be caused by a group of toxic proteins that have been previously identified in C. fleckeri and other cubozoan jellyfish species. In this study, proteins homologous to CfTX-1 and CfTX-2 toxins from C. fleckeri and CqTX-A toxin from Chironex yamaguchii were identified in C. quinquecirrha venom using tandem mass spectrometry. The presence and relative abundance of these proteins may explain the differences in venom potency between cubozoan and scyphozoan jellyfish and may reflect their importance in the action of venoms.

A bloom of an edible scyphozoan jellyfish in the Red Sea

A bloom of the edible jellyfish Cephea cephea (Forskal, 1775) in the Red Sea is reported here from archived photographic evidence. Animals (10–20 cm wide) were observed in seven different reefs and accumulated at high densities on some beaches of Marsa Alam, Egypt. Various coral reef fishes preyed on this temporary resource. Although the jellyfish is native to the Red Sea, this is the first record of such an event in this ecosystem, and only the second record of this phenomenon since the 1800s.

Trophic relationships between the large scyphomedusa Chrysaora plocamia and the parasitic amphipod Hyperia curticephala

Scyphozoan jellyfish develop dramatic population blooms, which may significantly alter marine food webs. In turn, hyperiid amphipods parasitising jellyfish can occur in such great numbers that they represent an important trophic link to diverse species of fish, and may contribute to the decline of their host populations. Therefore, there is an urgent need to assess the trophic function and energy transfer through jellyfish and their parasites. We studied the isotopic composition (i.e. δ13C and δ15N) of Chrysaora plocamia, the largest and most abundant scyphozoan jellyfish in the Humboldt Current System of Chile and Peru, and of its associated hyperiid parasite Hyperia curticephala. The isotopic composition of C. plocamia changed with body size, suggesting that that the diet of this species may include both pelagic and benthic prey as a consequence of the vertical distribution patterns observed. Although the density and intensity of infection of the parasite H. curticephala changed with the size of the host, their isotopic composition showed little variation, suggesting no shifts in the use of resources by the parasite. In contrast to other hyperiid parasites, reported to shift to a benthic mode of life when their hosts are lacking or in low abundance, the isotopic composition of H. curticephala revealed that their food source is mainly pelagic.

Not all jellyfish are equal: isotopic evidence for inter- and intraspecific variation in jellyfish trophic ecology.

Jellyfish are highly topical within studies of pelagic food-webs and there is a growing realisation that their role is more complex than once thought. Efforts being made to include jellyfish within fisheries and ecosystem models are an important step forward, but our present understanding of their underlying trophic ecology can lead to their oversimplification in these models. Gelatinous zooplankton represent a polyphyletic assemblage spanning >2,000 species that inhabit coastal seas to the deep-ocean and employ a wide variety of foraging strategies. Despite this diversity, many contemporary modelling approaches include jellyfish as a single functional group feeding at one or two trophic levels at most. Recent reviews have drawn attention to this issue and highlighted the need for improved communication between biologists and theoreticians if this problem is to be overcome. We used stable isotopes to investigate the trophic ecology of three co-occurring scyphozoan jellyfish species (Aurelia aurita, Cyanea lamarckii and C. capillata) within a temperate, coastal food-web in the NE Atlantic. Using information on individual size, time of year and δ13C and δ15N stable isotope values, we examined: (1) whether all jellyfish could be considered as a single functional group, or showed distinct inter-specific differences in trophic ecology; (2) Were size-based shifts in trophic position, found previously in A. aurita, a common trait across species?; (3) When considered collectively, did the trophic position of three sympatric species remain constant over time? Differences in δ15N (trophic position) were evident between all three species, with size-based and temporal shifts in δ15N apparent in A. aurita and C. capillata. The isotopic niche width for all species combined increased throughout the season, reflecting temporal shifts in trophic position and seasonal succession in these gelatinous species. Taken together, these findings support previous assertions that jellyfish require more robust inclusion in marine fisheries or ecosystem models.

The elusive life cycle of scyphozoan jellyfish--metagenesis revisited.

Massive proliferations of scyphozoan jellyfish considerably affect human industries and irreversibly change food webs. Efforts to understand the role of jellyfish in marine ecosystems are based on a life cycle model described 200 years ago. According to this paradigm the pelagic medusae is considered seasonal and alternates with the benthic polyp stage from which it derives. However, we provide evidence that a) the occurrence of several species of medusae is not restricted to a season in the year, they overwinter, b) polyp- and medusa generations are neither temporally nor spatially separated, and c) “metagenesis” which is defined as the alternation between sexual and asexual generations does not always occur. Hence we recommend additions to the current model and argue that the scyphozoan life cycle should be considered multi-modal, rather than metagenetic. The implications of these findings for jellyfish proliferations, including possible consequences and associated environmental drivers, are discussed.

Population genetic analyses reveal distinct geographical blooms of the jellyfishRhizostoma octopus(Scyphozoa)

Understanding the spatial integrity and connectivity of jellyfish blooms is important for ecologists and coastal stakeholders alike. Previous studies have shown that the distribution of jellyfish blooms can display a marked consistency in space and time, suggesting that such patterns cannot be attributed to passive processes alone. In the present study, we used a combination of microsatellite markers and mitochondrial cytochrome oxidase I sequences to investigate genetic structuring of the scyphozoan jellyfish Rhizostoma octopus in the Irish and Celtic Seas. The mitochondrial data indicated far higher levels of population differentiation than the microsatellites: ΦST[MT] = 0.300 vs. ΦST[NUC] = 0.013. Simulation studies indicated that the low levels of nuclear differentiation were not the result of limited power because of low levels of polymorphism. These findings, supported by palaeodistribution modelling and mismatch distribution analysis, are consistent with expansion of R. octopus from a single, limited refugium after the Last Glacial Maximum, followed by subsequent isolation, and that the discrepancy between the mitochondrial and nuclear markers is a result of the nuclear loci taking longer to reach mutation–drift equilibrium following the expansion as a result of their four-fold larger effective population size. The populations studied are probably not well connected via gene flow, and thus genetically as well as geographically distinct, although our findings also highlight the need to use a combination of organellar and nuclear markers to enable a more complete understanding of population demography and structure, particularly for species with large effective population sizes.

FIRST RECORD OF A CILIATE SUCTORIAN (CILIOPHORA, SUCTOREA) EPIBIONT ON THE JELLYFISH PELAGIA NOCTILUCA (SCYPHOZOA, SEMAEOSTOMAEIDA)

In the course of a survey of a specimen of the jellyfish Pelagia noctiluca (collected at Villefranche-sur-Mer, France) using scanning electron microscopy, the suctorian ciliate Trichophrya salparum was found on the jellyfish exumbrella. This ciliate species is reported for the first time on a scyphozoan jellyfish host. A redescription of this suctorian species is presented together with data on its distribution and host prevalence.

Evaluating energy flows through jellyfish and gulf menhaden (Brevoortia patronus) and the effects of fishing on the northern Gulf of Mexico ecosystem

Abstract Fishery management production models tend to stress only the elements directly linked to fish (i.e. fish, fish food, and fish predators). Large coastal jellyfish are major consumers of plankton in heavily fished ecosystems; yet, they are frequently not included as model components. We explore the relationship between gulf menhaden (Brevoortia patronus) and the large scyphozoan jellyfish (Aurelia spp. and Chrysaora sp.), and provide an examination of trophic energy transfer pathways to higher trophic levels in the northern Gulf of Mexico. A trophic network model developed within the ECOPATH framework was transformed to an end-to-end model to map foodweb energy flows. Relative changes in functional group productivity to varying gulf menhaden consumption rates, jellyfish consumption rates, and forage fish (i.e. gulf menhaden, anchovies, and herrings) harvest rates were evaluated within a suite of static, alternative energy-demand scenarios using ECOTRAN techniques. Scenario analyses revealed forage fish harvest enhanced jellyfish productivity, which, in turn, depressed menhaden productivity. Modelled increases in forage fish harvest caused pronounced changes in ecosystem structure, affecting jellyfish, marine birds, piscivorous fish, and apex predators. Menhaden were found to be a more efficient and important energy transfer pathway to higher trophic levels compared with jellyfish. A simulated increase in jellyfish abundance caused the relative production of all model groups to decline. These outcomes suggest that jellyfish blooms and forage fish harvest have demonstrable effects on the structure of the northern Gulf of Mexico ecosystem.

Effect of neurotoxic compounds on ephyrae of Aurelia aurita jellyfish

The aim of this study was to analyze the toxicity of two neurotoxic compounds on the ephyra stage of the Scyphozoan jellyfish Aurelia aurita, an innovative and sensitive model organism recently proposed in ecotoxicological bioassays. Indeed, jelly- fish play an important role in the marine ecosystem, being a key component of the gelatinous zooplankton and of the marine food web, but are not represented in routine ecotoxicology. In this study, ephyrae were exposed to several concentrations (0, 0.1, 0.5, 1, 5, 10, 50 mg l -1 ) of eserine (ES) and chlorpyrifos (CPF), a carbamate and an organophosphorous compound, respectively, in order to analyze their toxic effect on this model organism. Acute (% of immobility) and behavioral (% alteration of frequency of pulsations) end-points were investigated after 24 and 48 h of exposure. Exposure to both compounds caused a dose- dependent effect, and for each end-point, it was possible to quantify these effects by means of EC50. Results highlighted how these compounds reported a high toxicity for marine organisms and exerted their toxic effect on this innovative biological model (in particular, CPF resulted to be more toxic than ES), which proved to be more sensitive than other marine invertebrates commonly used for ecotoxicological bioassays.