The potential role of podocysts in perpetuation of the common jellyfish Aurelia aurita s.l. (Cnidaria: Scyphozoa) in anthropogenically perturbed coastal waters

Thein, Htun; Ikeda, Hideki; Uye, Shin-ichi

doi:10.1007/s10750-012-1045-9

Cited by 50 publications

(45 citation statements)

References 47 publications

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“…Since an exposure to temperatures lower than 15°C is a trigger to induce strobilation (Kakinuma 1962, Han & Uye 2010, the release of ephyrae of Aurelia aurita is programmed to occur during winter and early spring, in accordance with the annual temperature fluctuation (range: 10 to 28°C) of the Inland Sea of Japan (Uye & Shimauchi 2005, Thein et al 2012. A similar seasonal strobilation schedule is observed in many temperate regions (Lucas 2001, Miyake et al 2002.…”

Section: Ecological Significance Of Long Pnr 50 In Aurelia Aurita Ephmentioning

confidence: 87%

Body size reduction under starvation, and the point of no return, in ephyrae of the moon jellyfish Aurelia aurita

Fu¹,

Shibata²,

Makabe³

et al. 2014

Mar. Ecol. Prog. Ser.

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Scyphozoan ephyrae need to start feeding before their endogenous nutritional reserves run out, and the success of feeding and growth is crucial to their recruitment into the medusa population. To evaluate starvation resistance in first-feeding ephyrae of the moon jellyfish Aurelia aurita s.l., we determined their point of no return (PNR 50 ), i.e. days of starvation after which 50% of ephyrae die even if they then feed. PNR 50 values were 33.8, 38.4 and 58.6 d at 15, 12 and 9°C, respectively. Before reaching PNR 50 , the ephyrae showed significant body size reduction: ca. 30 and 50% decrease in disc diameter and carbon content, respectively. These PNR 50 values are nearly 1 order of magnitude longer than those of larval marine molluscs, crustaceans and fishes, which is attributable to the ephyra's extremely low metabolic (i.e. respiration) rate relative to its copious carbon reserves. Such a strong endurance under prolonged starvation is likely an adaptive strategy for A. aurita ephyrae, the release of which is programmed to occur during the annual period of lowest temperatures, allowing them to cope with the concomitant seasonal food scarcity. Future studies are needed to identify causes of death for wild ephyrae, which are prone to starvation and/or predation, to forecast outbreaks prior to the season of medusa blooms.

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Section: Ecological Significance Of Long Pnr 50 In Aurelia Aurita Ephmentioning

confidence: 87%

Body size reduction under starvation, and the point of no return, in ephyrae of the moon jellyfish Aurelia aurita

Fu¹,

Shibata²,

Makabe³

et al. 2014

Mar. Ecol. Prog. Ser.

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“…Although 8 different reproductive modes have been described for Scypho zoa, only Aurelia species and Sanderia malayensis fit into the multimode group. Several examples of other species exhibiting more than 1 mode have been described, such as LB in Catostylus mosaicus, Rhizostoma octopus and R. pulmo (Paspaleff 1938, Pitt 2000, Holst et al 2007, Straehler-Pohl 2009, Fuentes et al 2011, LBst and longitudinal fission in R. pulmo (S. Franke pers. obs.)…”

Section: Discussionmentioning

confidence: 99%

Asexual reproduction strategies and blooming potential in Scyphozoa

Schiariti¹,

Morandini²,

Jarms³

et al. 2014

Mar. Ecol. Prog. Ser.

118

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Scyphistomae show different modes of propagation, occasionally allowing the sudden release of great numbers of medusae through strobilation leading to so-called jellyfish blooms. Accordingly, factors regulating asexual reproduction strategies will control scyphistoma density, which, in turn, may influence blooming potential. We studied 11 scyphistoma species in 6 combinations of temperature and food supply to test the effects of these factors on asexual reproduction strategies and reproduction rates. Temperature and food availability increased reproduction rates for all species and observed reproduction modes. In all cases, starvation was the most important factor constraining the asexual reproduction of scyphistomae. Differences in scyphistoma density were found according to the reproductive strategy adopted by each species. Different Aurelia lineages and Sanderia malayensis presented a multi-mode strategy, developing up to 5 propagation modes. These species reached the highest densities, mostly through lateral budding and stolons. Cassiopea sp., Cephea cephea, Mastigias papua and Phyllorhiza punctata adopted a mono-mode reproductive strategy, developing only free-swimming buds. Lychnorhiza lucerna, Rhizostoma pulmo and Rhopilema esculentum also presented a mono-mode strategy, but they only developed podocysts. These 3 species had the lowest reproduction rates and polyp densities; not only their reproduction rates but also the need for a 2-fold set of environmental stimuli to produce new polyps (one for encystment, another for excystment) made this reproduction mode the slowest of those observed to be utilized for propagation. We conclude that blooms may be defined phylogenetically by the specific asexual modes each species develops, which, in turn, is regulated by environmental conditions.

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“…True blooms are associated typically with species displaying metagenic life histories comprising free‐swimming and sexually reproducing medusae and benthic polyps that reproduce through asexual strobilation (Graham et al ., ; Richardson et al ., ; Gibbons & Richardson, ). In most cases, a given cohort of medusae will persist from spring through to autumn, whereas the asexually reproducing polyps can survive for many years (Thein, Ikeda & Uye, ). This inter‐annual persistence of an asexually reproducing sessile life stage can lead to the regular re‐occurrence of blooms in specific locations (Houghton et al ., , b; Lilley, Houghton & Hays, ), population structuring (Pitt & Kingsford, ), and eventual phylogenetic differentiation.…”

Section: Introductionmentioning

confidence: 99%

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

Glynn

Houghton

Provan

2015

Biol. J. Linn. Soc.

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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: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.

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The potential role of podocysts in perpetuation of the common jellyfish Aurelia aurita s.l. (Cnidaria: Scyphozoa) in anthropogenically perturbed coastal waters

Cited by 50 publications

References 47 publications

Body size reduction under starvation, and the point of no return, in ephyrae of the moon jellyfish Aurelia aurita

Body size reduction under starvation, and the point of no return, in ephyrae of the moon jellyfish Aurelia aurita

Asexual reproduction strategies and blooming potential in Scyphozoa

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

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