• The Korean Journal of Malacology
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• v.26 no.4
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• pp.275-283
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• 2010

Many freshwater snail taxa are difficult to identify using morphological traits due to phenotypic plasticity. However, using of molecular DNA marker in combination with morphological traits can provide a reliable means for discriminating among freshwater snail taxa including cryptic species. To discriminate among Korean freshwater snail taxa and resolve their systematic relationships, wesequenced a fragment of mtDNA cytochrome oxidase I (COI) gene from 82 specimens collected from ten different sites distributed along the Korean peninsula. We identified more than seven freshwater snail taxa including cryptic species in Korea. Whereas traditional shell morphology of freshwater snails offers only weak discriminatory power for recognizing 'good' taxa, DNA sequence data provided positive and reliable identification. In addition, a major Semisulcospira clade was clearly separated from the remaining lineages observed including cryptic species. However, a phylogenetic tree inferred from the COI gene data did not fully resolve systematic relationships among pleurocerid taxa in Korea. Establishing more robust shell characteristics for identifying taxa unambiguously and hence improving traditional key shell morphology characters for freshwater snail species is an urgent requirement and will require more rigorous examination of all nominal taxa. While molecular data generated here will be useful for species identification and for describing the systematic relationships among Korean freshwater snails, further analysis will be required.

• Korean Journal of Environmental Biology
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• v.30 no.2
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• pp.151-155
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• 2012

Korean freshwater turtles are divided into native turtles, Chinemys reevesii in Geoemydidae, Pelodiscus sinensis in Trionychidae, and imported turtles, Trachemys scripta elegans, T. s. scripta, Pseudemys rubriventris and Ocadia sinensis. In this study, we determined the distribution of Korean freshwater turtles based on a field study and literature study, and considered the taxonomic position of unidentified native turtles. The study was carried out between May 2010 and November 2011 during the day time, and the capturing tool used to collect turtles consisted of net and metal frame. C. reevesii and P. sinensis were found in 16 and 11 places, respectively. C. reevesii, which inhabits the Korean peninsula, is a taxonomically controversial species, but it is presumed that the turtle belongs to Mauremys. Moreover recent taxonomic studies of the soft-shell turtle have shown that the Korean native species is P. maackii, and P. sinensis was imported from abroad and has been in the natural habitats of Korea since 1970s. The exterior shape and skeletal form of P. maackii and P. sinensis are nearly similar. However, the skin color and yellow spots on the shell could be used to distinguish the two species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.557-562
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• 2002

This study was to estimate population growth parameters of the freshwater bivalve, Corbicula (Corbiculina) papyacca (Heude) in Korea. Samples were collected from Jojong stream in Chungpyeong from September 1999 to August 2000. Ages were determined from the ring of shell, The shell length of the samples ranged from 4,2 mm to 28.1 mm, The ring on the surface of shell was formed once a year from January to March, Marginal increment analysis of shell rings indicated that annuli were formed in June. Spawning period was estimated to be May to August with a peak between June and July through fatness analysis, and thus rings were considered to be true annual marks. Von Bertalanffy's growth parameter were estimated from a nonlinear method with the value of logical maximum shell length ($L_{propto}$) was 34,36 mm, K was 0.1531/year, logical age of shell length 0 ($t_{0}$) was -0,5246 year, and logical maximum total weight ($W_{propto}$) was 11.42 g.

• Journal of Species Research
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• v.2 no.2
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• pp.145-158
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• 2013

Candoninae is the most diverse group of freshwater ostracods with over 300 living species described from all around the world. However, only 11 species have been reported from South Korea. Considering abundant freshwater ecosystems here this number is very low. It is no wonder that newly collected samples of freshwater meiofauna often contain Candoninae ostracods which are new records for South Korea, or new taxa. Earicandona mounchyon gen. nov. sp. nov. and Typhlocypris (Pseudocandona) pratensis (Hartwig, 1901) were collected from two open freshwater bodies in Gangwon-do, and Gyeongsangbuk-do in South Korea. The new genus is most closely related to the breuili-group of Fabaeformiscandona Krstic, 1972. The most important apomorphic character of the new genus is a hemipenis with a poorly sclerified lobe "g", and prehensile palps with more rounded dorsal margins. Beside the new species, Earicandona contains only E. okuboi (Smith & Janz, 2008) comb. nov. from Lake Biwa. This species was originally described in Fabaeformiscandona, fabaeformis-group. They differ mostly in the morphology of the shell, but also some details of soft body, including the more pronounced genital process in the Korean species. Typhlocypris pratensis was so far known from Europe and this finding significantly broadens its area of distribution. Both Typhlocypris and Earicandona belong to the tribe Candonini and the key to the genera of this tribe is also presented here.

• The Korean Journal of Malacology
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• v.11 no.1
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• pp.70-77
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• 1995

The purpose of this study is to determine the differences of the conchiolin layer, prismatic layer and nacreous layer deposited within the shell of the freshwater family Unionidae. shether they possess species-specific characteristics and differences of the microstructure of these layers, A Scanning electron microscopic obwervations were conducted on seven species. The results indicate that all species possess thin and homogeneous layers within the periostracum. The prismatic layers of these species were composed of ednsely packed prisms. The prismatic layers of the shell in six species were typical shape of prisms. especially Inio douglasiae and Lamprotual gottschei. But, in Unio douglasiae sinuolatus, it was irregular and oblique prism shape.The nacreous layer of weven unionids characterized by possession of three types by lamillae shape: thin and homogeneous on genus Anodonta(0.4 pm size of lamella), Unio(1.3pm) and Lamprotual (1.7pm), homogeneous in shape and irregular in size of lamillae in Lanceolaria(1.0 pm)and irregulat in shape and size in Solenaia(0.2-0.4 pm). The microstructure of the naceous layer may be useful as a taxonomic character at the generic level.

• The Korean Journal of Malacology
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• v.2 no.1
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• pp.26-29
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• 1986

Corbicula fluminea, one of the 2 species in the family Corbiculidae living in the Lake Uiam, was used as an experimental material and the embryonic development and the structure of glochidia of this species were investigated. This freshwater mussels was oviparous, but some ovoviviparous: incubated their youngs in the inner-demibranchs or outer-demibranchs, however, chiefly used the inner-demibranchs as brood-pouch. The average time required from a fertilized egg to two-cell stage, veliger stage, and glochidium was 76 minutes, 3 hours, and 17 hours, respectively, The mean size of glochidium was $168{\mu}m$ in shell height, $195{\mu}m$ in shell lengh, $114{\mu}m$ in hinge legth and the form of glochidium was D-type and had no hooks or hooklets for attaching to fish like Unioidae.

• The Korean Journal of Malacology
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• v.24 no.2
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• pp.89-92
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• 2008

A new species of the mytiloidean freshwater bivalve is described from Baengnyong Cave, Pyeongchang-gun, Gangweon-do. Limnoperna coreana n. sp. belongs to the genus Limnoperna Rochebrune, 1882 with the byssus. This species has a small shell with the glossy surface and rounded-triangular and differs morphologically from all of its congeners.

• The Korean Journal of Malacology
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• v.9 no.1
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• pp.46-62
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• 1993

Six species of freshx\water Unionidae mussels in Korea, Anodonta arcaeformis flavotincta, A. woodiana, Unio douglasiae, U. douglasiae sinuloatus, Lamprotula gottschei, Lanceolaria acorohyncha were compared in regard to the various taxonomical characteristics of ultra structures of shells and glochidia. The results obtained in this study are summarized as follows;the orter demibranchs of all the females of six species have served as marsupial(gravid)pouch. However, all the foru demibranchs were used as the marsupium in some female individuals of L. gottschei. The glochidia of A. arcaeformis flavotincta, A. woodiana and L. gottschei were separated one by one with the mucous strings and U. douglasiae sinuolatus were round-subtriangular in shape, and those of L. gottschei were subelliptical in shape. Each of the glochidial shell valves of six species had a hook studded with many spines on the superior face on valve. The glochidial shell valve had two or three rows of large spines; A. arcaeformis flavotincta, A. woodiana, and L. gottschei had two rows and three rows in U. douglasiae, U. douglasiae sinuolatus, and L. acrorhyncha. The numbers of sensory hairs of A. arcaeformis flavotincta and A. woodiana were all eight, those of U. douglasiae, U. douglasiae sinuolatus and L. acrorhyncha were six. and that of L. gottschei was four. The external and internal surfaces of the glochidial shell valves of A. A. arcadformis flavotincta, A. woodiana, and L. gottschei had foveolate and psilate in U. douglaseae, U. douglasiae sinuolatus and L. acrorhyncha.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.3
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• pp.223-230
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• 2010

To compare seed collection and the growth of Anadara subcrenata in Suncheon and Boseong Bays, environmental factors and the growth of larvae and spats were investigated from August 2008 to July 2009 in commercial farming sites in both bays. The variation in water temperature in both bays was similar, but the salinity was lower in Suncheon Bay than in Boseong Bay. The chlorophyll-a content was higher in Suncheon Bay due to the large inflow of freshwater. The density and shell length of A. subcrenata larvae did not differ significantly between the two bays. However, the relative growth of shell height to shell length was significantly higher in Suncheon Bay (P<0.05). The growth of A. subcrenata spats attached to a collector was significantly faster in Suncheon Bay (P<0.05). The spats in Suncheon and Boseong Bays grew to 24.3 and 21.0 mm in shell length, respectively, within 1 year after spawning, and the shell length reached 35.6 and 34.8 mm, respectively, within 2 years of spawning. The initial spats density was higher in Boseong Bay, but the growth of spats was better in Suncheon Bay. The faster growth of A. subcrenata in Suncheon Bay can be explained by the high chlorophyll-a content in this bay. Based on the low survival (%) and slower growth rate of spats in Boseong Bay, the commercial culture density of A. subcrenata in Boseong Bay should be reduced to the optimum level of the carrying capacity.

• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.312-318
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• 2014

This study was conducted to establish models of filtrating rate and production of feces of a native freshwater bivalve, Anodonta woodiana, on removal organic matters in eutrophic waters. Among the applied shell size (4.3~15.5 cm), the filtrating rate and production of feces of Anodonta woodiana was $0.08{\sim}0.86L\;g^{-1}\;h^{-1}$ (average $0.24L\;g^{-1}\;h^{-1}$), $0.00{\sim}11.10mg\;g^{-1}\;h^{-1}$ (average $0.94mg\;g^{-1}\;h^{-1}$), respectively. In two different water current (high $48Lh^{-1}$, low $24Lh^{-1}$), the filtrating rate of Chl-a was $0.02{\sim}0.10L\;g^{-1}\;d^{-1}$ (average $0.05L\;g^{-1}\;d^{-1}$), $0.02{\sim}0.11L\;g^{-1}\;d^{-1}$ (average $0.07L\;g^{-1}\;d^{-1}$) and the removal rate was 65.4%, 82.1%, respectively. Response surface methodology, with a central composite design comprising 3 levels and 2 variables, was used to identify the optimal removal condition of shell length, water current and filtrating rate or feces production by bivalves. The optimum removal conditions were found that had optimized $6.21L\;mussel^{-1}\;d^{-1}$ at shell length 14.3~15.6 and water current $22{\sim}30Lh^{-1}$. The optimal conditions of production of feces ($4.2mg\;g^{-1}\;d^{-1}$) by freshwater mussels were shell length 14.3~16.3 cm and water current $36{\sim}44Lh^{-1}$.