Identification key for young ephyrae: a first step for early detection of jellyfish blooms

Straehler-Pohl, Ilka; Jarms, Gerhard

doi:10.1007/978-90-481-9541-1_2

Cited by 14 publications

(28 citation statements)

References 14 publications

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“…However, based on our data it cannot be excluded that in previous work polyps of other species were present and it is recommended that any future study on field-sampled polyps includes species identification based either on molecular identification or on the traditional method of rearing, strobilation and identification of ephyrae. Ephyrae of all North Sea species (Holst 2012a , b) as well as many other species (Straehler-Pohl and Jarms 2010 ; Straehler-Pohl et al 2011 ) can be identified to species level.…”

Section: Discussionmentioning

confidence: 99%

Where are the polyps? Molecular identification, distribution and population differentiation of Aurelia aurita jellyfish polyps in the southern North Sea area

et al. 2016

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For many species of metagenic jellyfish the location of the benthic polyps is unknown. To gain insight in the distribution, species composition and population structure of scyphozoan jellyfish polyps in the southern North Sea area, polyp samples were collected from natural and artificial substrates (settling plates, marina floats and wrecks) at ten inshore locations in the Netherlands, seven offshore locations in the North Sea and in the Gullmar Fjord in Sweden. Polyps were identified to species level by sequencing both a fragment of 18S rDNA and a fragment of mitochondrial COI, and comparing these sequences to reference sequences available in GenBank and to newly obtained sequences from medusae collected in the area. All polyps sequenced did belong to Aurelia aurita. For this species, molecular diversity in mitochondrial COI was high, with 50 haplotypes among 183 polyps. Population differentiation was detected between the Dogger Bank and other—more coastal—locations, indicating extremely low connectivity. No significant differences were found between coastal samples. The location of polyps of Cyanea capillata, Cyanea lamarckii, Chrysaora hysoscella and Rhizostoma octopus in the study area remains unresolved.Electronic supplementary materialThe online version of this article (doi:10.1007/s00227-016-2945-4) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Where are the polyps? Molecular identification, distribution and population differentiation of Aurelia aurita jellyfish polyps in the southern North Sea area

et al. 2016

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“…Monitoring data are fundamental to defining such events (Genzano et al, 2008). It is also important to consider the various stages of the life cycle, such as planulae and polyps, which are often neglected in ''bloom'' studies (but see Arai, 2009;and Htun et al, 2012 on podocysts;Bayha & Graham, 2009;Astorga et al, 2012;Holst, 2012;and Purcell et al, 2012 on polyps;Straehler-Pohl & Jarms, 2010 for ephyrae detection). The biological concept of ''bloom'' also has weaknesses because there may be different, non-homologous processes for the origin of the ''blooms''.…”

Section: Resultsmentioning

confidence: 99%

Do Staurozoa bloom? A review of stauromedusan population biology

2012

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“…Afterwards, the medusa was transferred back into the culturing flask. The following standard measurements for scyphistomae [ 25 ] and ephyrae [ 18 ] were used: total body length (TBL), hypostome length (HL), calyx length (CL), stalk length (StL) and mouth disc diameter (MDD), total body diameter (TBD), central disc diameter (CDD), total marginal lappet length (TMLL), lappet stem length (LStL), rhopalial lappet length (RLL) and manubrium length (ML). We used the following proportions (%) to compare body proportions of scyphistomae compared to body length: CL/TBL x 100, HL/TBL x 100, StL /TBL x 100, MDD/TBL x 100.…”

Section: Methodsmentioning

confidence: 99%

“…Furthermore, as the ephyra stage of most species is very similar, it is important to include a detailed identification key when describing a new life cycle, which can be used to identify ephyrae, thus enabling the early detection of harmful jellyfish blooms in plankton samples. A study in 2010 established in the pattern of the gastric system, the only character that was constant in newly detached ephyra which was, therefore, the most reliable characteristic for identification [ 18 ].…”

Section: Introductionmentioning

confidence: 99%

First description of the life cycle of the jellyfish Rhizostoma luteum (Scyphozoa: Rhizostomeae)

et al. 2018

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Jellyfish blooms are a significant environmental problem that is increasing and may be influenced by anthropocentric practices such as overfishing, pollution, eutrophication, translocation, climate change, and ocean acidification. Many jellyfish have unknown life cycles leading to these blooms. We describe for the first time, the life cycle of scyphozoan jellyfish Rhizostoma luteum from the planula to the young medusa stages, based on laboratory observations. We also provide a preliminary assessment of temperature related to life stages. Comparisons were made with early life history stages of its sibling species Rhizostoma pulmo and Rhizostoma octopus. The life cycle of R. luteum follows the general pattern of metagenesis of scyphozoans. Scyphistoma culture was maintained in filtered seawater at 17–17.5 °C, salinity 37 and light photoperiod (12:12 h light:dark). Scyphistomae were exposed to an experimental temperature descent for two days to test their survival capacity under severe winter conditions. Only one asexual reproduction mode was observed, which is employed for propagation, consisting of podocyst formation with excystment, subsequent development of scyphistoma, strobilation and liberation of viable ephyra. The development of the ephyra to metaephyra was photodocumented, reaching the metaephyra stage in approximately 21–25 days. Young medusae grow rapidly and maturity was reached after a 3-month post-liberation period with a mean bell diameter of 13.27 ± 2.26 cm and wet weight of 181.53 ± 53 g. The life cycle of R. luteum resembles that of its congeners, with the distinction that it has the unique features of being a brooding species (internal fertilisation with subsequent release of planulae) and under the conditions tested, the predominantly strobilation type observed was monodisc, and not polydisc as with the other two species in the genus Rhizostoma. As R. luteum shows sufficient requisite to form blooms if environmental circumstances change, it is important to understand its life cycle.

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Identification key for young ephyrae: a first step for early detection of jellyfish blooms

Cited by 14 publications

References 14 publications

Where are the polyps? Molecular identification, distribution and population differentiation of Aurelia aurita jellyfish polyps in the southern North Sea area

Where are the polyps? Molecular identification, distribution and population differentiation of Aurelia aurita jellyfish polyps in the southern North Sea area

Do Staurozoa bloom? A review of stauromedusan population biology

First description of the life cycle of the jellyfish Rhizostoma luteum (Scyphozoa: Rhizostomeae)

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