• Animal Systematics, Evolution and Diversity
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• v.17 no.1
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• pp.13-19
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• 2001

Hydra and hydromedusa specimens were collected from the Jisanchon Stream in Kyonggi-do (Pyongtaek-shi) and the coasts of Geojedo Island (Jangmok-ri), Korea during the period July 1999-June 2000. They were identified into Hydra magnipapillata Ito, 1947 (Hydridae, Athecatae) and Phialidium folleatum (McCrady, 1857) (Campanulariidae, Leptomedusae) respectively. H. magnipapillata is blackish or light brown color, its cylinder-shaped trunk reaches to 20 ㎜ long and 0.5-0.6 ㎜ wide in fully extended, and has generally 5-6 highly delicate long tentacles. P. folleatum is a small marine hydromedusa, below 5 ㎜ wide and has a minute statocyst between successive tentacles.

• Animal Systematics, Evolution and Diversity
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• v.23 no.2
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• pp.175-181
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• 2007

Some hydromedusae were collected from Gijang (Busan), Yeounggwang, Munseom (Jejudo Is.) and Shinhangman with Issacc-Kidd Midwater trawl net or by SCUBA diving from 2001 to 2003. They were identified into five species of five families in three orders and are new to the Korean fauna. Bougainvillia ramosa (van Benenden, 1844) of the family Bougainvilliidae in the order Anthomedusae, Phialidium hemishaericum (Linne, 1767) of the family Campanulariidae and Aeguorea macrodactyla of the family Aequoreidae in the order Leptomedusae, Diphyes dispar (Chamisso and Eysenhardt, 1821) of the family Diphydae and Abylopsis tetragona (Otto, 1823) of the family Abylidae in the order Siphonophora. With a result of this work, the Korean hydromedusa fauna consists of 31 species of 18 families in six orders.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.110.2-110
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• 2000

No Abstract, See Full Text

• Journal of the korean society of oceanography
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• v.38 no.4
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• pp.211-215
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• 2003

A huge freshwater reservoir (ca. 12,000 ha) will be created when the construction of a 33­km dike on a huge mud flat of the Saemankeum areas is established. A large quantity of freshwater will emerge to the adjacent sea from the reservoir through two big gates. Marine organisms outside the dike are expected to frequently experience low salinity waters. To investigate the salinity effects on the dominant metazooplankton in the coastal waters off Saemankeum areas, we measured the survival (Survival 1H and Survival 24H) of 11 different taxa (the copepods Acartia omorii, A. pacifica, Calanus sinicus, Centropages abdominalis, Paracalanus indicus, Pseudodiaptomus inopinus, Tortanus forcipatus, and a hydromedusa, and barnacle nauplius, polychaeta larva, and a chaetognath Sagitta sp.) at salinities of 0, 5, 10, 15, 20, 25, 30, 35, and 40 psu when the organisms were exposed for 1 and 24 h, respectively. Survival 1Hs of P. inopinus and barnacle nauplius were 100% between 5 and 35 psu, while they were 0% at salinities of 0 and 40 psu. Survival 1Hs of A. omorii and A. pacifica, P. indicus, T. forcipatus, and polychaeta larva were 100% at $salinities\;\geq\;10$ psu, while they were 0% at lower salinities. Survival 1Hs of a hydromedusa and Sagitta sp. were 100% at $salinities\;\geq\;15$ psu, while they were 0% at lower salinities. Survival 1H of C. abdominalis and C. sinicus was 100% at $salinities\;\geq\;20$ psu, while they were 0% at lower salinities. Survival 24Hs of A. omorii, A. pacifica, C. abdominalis, barnacle nauplius, and polychaeta larva were the same as Survival 1 Hs at the same salinity, while those of the other metazooplankton were lower than Survival 1Hs. The results of the present study suggest that low salinity water emerging from big gates may cause the death of the metazooplankton, but the salinities at which death of the metazooplankton occurs may differ by species.

• BMB Reports
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• v.28 no.4
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• pp.323-330
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• 1995

Recent studies have shown that dopamine applied to cultured swimming motor neurons of Polyorchis penicillatus produces an inhibitory action by opening potassium channels through $D_2$-like receptors. In this study, it was demonstrated that dopamine found in the hydromedusa was not from exogenous sources and the content of dopamine depended on the $Ca^{2+}$ content of the dissecting media. In addition, a combination of thin layer chromatography and high performance liquid chromatography showed the presence of DOPA and DO PAC-like compounds in the jellyfish. The glyoxylic acid method for catecholamines suggested that a population of small cells, neither swimming motor neurons nor B-like neurons, had dopaminergic systems. From all these results, it is suggested here that DA synthesized from DOPA in some cells is released. being dependent on calcium concentrations, into a synaptic cleft and degraded into DOPAC after acting as an inhibitory transmitter to swimming motor neurons.

• Animal Systematics, Evolution and Diversity
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• v.12 no.1
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• pp.67-77
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• 1996

Some hydromedusae were collected from the western and southern coasts of Korean Peninsula during May to October, 1995. They were identified into Turritopsis nutricula(McCrady, 1856); Cladonema radiatum Dujardin, 1843; Eirene menoni Kramp, 1953 and Gonionemus vertens A. Agassiz, 1862. Of which the hydromedusa of T. nutricula is preliminary known in Korean waters, and the remainders are new to the Korean fauna.

• Animal Systematics, Evolution and Diversity
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• v.22 no.2
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• pp.169-177
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• 2006

Some hyromedusae were collected from Korean waters with Issacc-Kidd Midwater trawl net or by SCUBA diving during the period from May 2001 to Nov. 2005. They were identified into 14 species of 11 families in six orders. Of these, the following six species are new to Korean fauna: Olindias formosa (Goto, 1903) and Proboscidactyla stellata (Forbes, 1846) of the order Limnomedusae; Aglantha digitale ($M\ddot{u}ller$, 1776) and Rhopalonema velatum Gegenbaur, 1854 of the order Trachymedusae; Solmundella bitentaculata (Quoy and Gaimaud, 1833) and Aegina citrea Eschscholtz, 1829 of the order Narcomedusae. The order Narcomedusae and the families Rhopalonematidae and Aeginidae are first recorded in Korean waters. As a result of the present study, the Korean hydromedusae consist of 26 species of 19 families in six orders so far.

• Animal Systematics, Evolution and Diversity
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• v.19 no.1
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• pp.111-117
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• 2003

Some hydromedusae were collected from Shiwhaho (Kyonsgi-do), Korea Strait and Yeosu, Korea during years 2000-2002. They were identified into Sorsia tubulosa (M. Sars, 1835) of the order Anthomedusae, and Liriope tetraphylla (Chamisso and Eysenhardt, 1821) of the order Trachymedusae respectively. They are new to the Korean fauna. The order Trachymedusae is first recorded in Korea. The long tube-like manubrium and four marginal tentacles are characteristics of S. tubuloso. In L. tetraphylla, the four triangle-shaped gonads and their positions upon half of surface of subumbrella, the seven blind centripetal canals in a quadrant and the long fat manubrium are its distinct characteristics. Resulting from this work, the Korean hydromedusae identified so far consist of 13 species of 11 families in five orders.

• Ocean and Polar Research
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• v.31 no.4
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• pp.327-338
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• 2009

Zooplankton community structure was investigated in the Saemangeum region in March, May, July and October of 2007 and 2008 in order to understand the potential effect of post construction of Saemangeum dyke on their temporal and spatial distribution. Mean abundance of zooplankton in the inner and outer area of the dyke, except for dinoflagellate Noctiluca scintillans, ranged from 173 to 15,830 ind.m$^{-3}$, showing higher variability in the inner area compared to the outer area. Zooplankton abundance was higher in the outer area than the inner area in 2007, and vice versa in 2008. In the inner area of the dyke, zooplankton abundance was the highest in May 2007 and March 2008. In the outer area of the dyke, abundance was the highest in October 2007 and July 2008. Brackish species such as Tortanus derjugini and Pseudodiaptomus inopinus were dominant prior to construction of the dyke, and appeared less frequently in the inner area. Marine zooplankton taxa such as juvenile hydromedusa, and calanoid copepods Acartiahongi and Paracalanus parvus s.l. dominated both areas of the dyke. In CCA analysis, zooplankton community structure in the inner and outer area was similar in March and May, but different in July and October. Temperature, salinity and COD were important environmental factors affecting zooplankton community structure. These results suggest that zooplankton community structure in the inner and outer area of Saemangeum dyke are significantly affected by whether the sluice gates are closed or open.

• Animal Systematics, Evolution and Diversity
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• v.20 no.1
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• pp.31-37
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• 2004

Some hydromedusae were collected from the coasts of Seogwipo(Jejudo Island), Hoenggando Island and Ilsanhaesuyokjang(Ulsan), Korea on July 11, 1985; July 23, 1990 and July 16, 1994. They were identified into Aequorea coerulescens (Brandt, 1838) of the order Leptomedusae, and Physalia physalis utriculus La Martiniere, 1829 of the Siphonophora, respectively. The unique morphological characteristics of A. coerulescens are smooth even surface of exumbrella, large mouth with 60 highly fringed oral lobes, shallow stomach, 120 simple radial canals and flat beret-shaped bell. In P. physalis utriculus its morphological characteristics are a triangular large pneumatophore with very low or rudimentary crest, a ribbon like long slender main tentacle, siphon-shaped gastrozooid with mouth, finger-shaped dactylozooid and branched gonozooid with gonophores. P. physalia. utriculus is the Pacific form and distinguished from the Atlantic form, P. p. physalis which has a much larger pneumatophore with high crest, numerous large main tentacles, and compact arrangement of basal and ventral cormidia. As a result of this work the Korean hydromedusan fauna consists of 15 species of five orders.