• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.742-750
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• 2022

This study aimed to monitor the distribution of Cobitidae in Korea by the identification of species using genetic analysis. Based on the genetic analysis, Cobitidae species in four of five domestic fish farms consisted of only Chinese muddy loach Misgurnus mizolepis, but muddy loach Misgurnus anguillicaudatus was also present it in one fish farm. In the case of imported Cobitidae species, in addition to Chinese muddy loach and muddy loach, the harmful species Paramisgurnus dabryanus, was also present. Chinese muddy loach accounted for 20%, 67%, and 60% of the S6, S7, and S8 samples, respectively. An analysis of the total length, body length, and weight showed that domestic Chinese muddy loach showed higher values than imported muddy loach, and imported Chinese muddy loach showed similar values to P. dabryanus. There were no significant differences in the country of origin of the three species. Thus, the mitochondrial cytochrome c oxidase subunit I gene sequence was analyzed and compared the verification of species identification. The three species of Cobitidae were genetically divided into three groups and determined to have genetic differences. These results indicate that it is necessary to reduce the heterogeneous mixing rate through discriminating species by genetic analysis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.1
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• pp.30-36
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• 2022

We collected a total of four butterfly ray specimens (Gymnura japonica, 213.4-695.0 mm in total length) in Korea from 2016 to 2021 and investigated their morphological and molecular characteristics in order to clarify their taxonomic status. These features are summarized as follows. Disc lozenge-shaped, 1.8-2.0 times broader than long. Tail very short, post-cloaca length 23.9-28.2% in disc width. Snout short, no rostral cartilage. Clasper short, no hook. Dorsal surface uniform yellow or brownish grey, with or without rounded light yellow spots. An analysis of 434 base-pair sequences of mitochondrial DNA cytochrome c oxidase subunit I showed that all four specimens corresponded to G. japonica from Japan (Kimura-2-parameter distance = 0-0.2%), suggesting that the color patterns found may be due to intraspecific color variation. G. japonica resembles Gymnura poecilura but differs in that it has a shorter tail length to disc width (23.9-28.2% in G. japonica vs. 40.1-48.3% in G. poecilura). This study revealed that G. japonica occurred in areas affected by the Tsushima Warm Current, tentatively suggesting that G. japonica may be an indicator species for monitoring marine ecosystem changes due to climate change.

• Korean Journal of Ichthyology
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• v.34 no.4
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• pp.225-230
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• 2022

The single postlarval specimen (7.53 mm in standard length) of Thalassoma quinquevittatum (Lay & Bennett, 1839), belongs to the family Labridae, was collected by a bongo net from the southern coastal waters of Jeju-do Island, Korea in November 2020. T. quinquevittatum has a deeply curved dorsal contour before the dorsal fin, the oval eyes, and no melanophores throughout the body. While T. amblycephalum has a slightly curved dorsal contour before the center of the dorsal fin, the circular eyes, and few melanophores on the body. A molecular analysis based on 548 base pairs sequences in the mitochondrial DNA cytochrome c oxidase subunit I region shows that the specimen was closely matched to adult T. quinquevittatum (K2P distance=0.002-0.005). We report the first record of T. quinquevittatum in Korean waters, and suggest its new Korean name "Da-seot-jul-saek-dong-nol-rae-gi".

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.57-63
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• 2023

Four individuals of Lipolagus ochotensis larvae (13.4~21.3 mm SL), belong to the family Bathylagidae, were collected by a Bongo net from the southern waters off Jejudo Island, Korea in February to March 2018. L. ochotensis is characterized by a elongated and compressed body, the eye stalks, series of melanophores on posterior of body, dorsal fin origin above the middle of the body. A molecular analysis based on 625 base pairs sequences in the mitochondrial DNA cytochrome c oxidase subunit I region shows that specimens were closely matched to adult L. ochotensis (genetic distance=0.024). We report the first record of family Bathylagidae, genus Lipolagus, L. ochotensis in Korean waters, and suggest their new Korean names, "Sim-hae-bing-eo-gwa", "Geom-eun-bing-eo-sok", and "Geom-eun-bbyam-bing-eo", respectively.

• Korean Journal of Ichthyology
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• v.35 no.4
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• pp.244-252
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• 2023

This study compared the morphological and molecular characteristics of the two Pampus spp. in Korea, Japan and China to clarify the long-confused taxonomic status of the two Korean pomfrets named as "Byeong-eo" and "Deok-dae". Among them "Byeong-eo" was identified as Pampus punctatissimus in having the following morphological traits: patch of wavy ridges extending beyond the anterior tip of the pectoral fin, the groove on the lower ridge of gill cover absent, and the number of vertebrae 34. On the other hand, "Deok-dae" was identified as Pampus argenteus in having the following morphological traits: patch of wavy ridges not reaching to the anterior tip of the pectoral fin, the groove on the lower ridge of gill cover reaching to the lower jaw, and the number of vertebrae 38~42. In addition, "Byeong-eo" almost corresponded to P. punctatissimus from Japan in the mitochondrial DNA cytochrome c oxidase subunit I sequences (genetic distance=0.1%), while "Deokdae" showed genetic distance of 0.3% when compared to P. argenteus from China. Our comprehensive results suggest the validify of P. punctatissimus for "Byeong-eo", and P. argenteus for "Deok-dae".

• Journal of Environmental Science International
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• v.33 no.1
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• pp.87-95
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• 2024

The giant jellyfish, Nemopilema nomurai, is an endemic species found in Northeast Asian waters and their population structures, such as size and genetics, and their environmental characteristics were investigated. N. nomurai was obtained from the Yellow and Northern East China Seas during the summers of 2006, 2007, and 2009. In the northern Yellow Sea, small-sized jellyfish were found to be dominant and towards the southern seas, the size of the jellyfish increased. In the northern East China Sea, only one mode of jellyfish was found in May, and the number of modes increased up-to five in July. However, at the center of the Yellow Sea, one or two modes were found in July, 2007. Thus, different jellyfish populations were present in the northern East China Sea and the Yellow Sea. However, based on first appearance and a cohort analysis using the bell diameter, the jellyfish population in the northern Yellow Sea might be recognized as a distinct group that differed from those found in the northern East China Sea. Furthermore, mitochondrial DNA sequences (cytochrome c oxidase subunit I) of N. nomurai were, determined and compared with genetic structures obtained from jellyfish in the Yellow Sea. The genetic diversity of N. nomurai was highest in the regions around the northern East China Sea and at the center of the Yellow Sea and was the lowest around the northern Yellow Sea. Thus, N. nomurai populations in the Yellow Sea and northern East China Sea might be different concerning their seeding places.

• Korean Journal of Ichthyology
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• v.36 no.1
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• pp.101-106
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• 2024

In May 2020, a single larval specimen (5.14 mm in total length) was collected from the southeastern sea of Jeju Island of Korea using bongo net. The specimen was identified as Lepidotrigla longifaciata based on mitochondrial DNA cytochrome c oxidase subunit I sequences. The morphological traits of the L. longifaciata larva are as follows: a long snout, a large mouth, large fan-shaped pectoral fins, and black melanophores scattered on the abdominal cavity and nape. We propose the new Korean name 'Gin-meo-ri-dal-jae' for this species, which was first discovered in Korea.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.193-198
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• 2024

Two specimens of Ostorhinchus fleurieu (54.25 mm, 55.64 mm SL) were collected by angling for the first time from Seogwipo-si, Jejudo Island, Korea on September and November 2023. This species is readily distinguished from the congeneric species, O. aureus by the number of total gill rakers (19~23 in O. fleurieu vs 22~27 in O. aureus) and shape of dark stripe on caudal peduncle (poorly defined, barrel shaped in O. fleurieu vs. well-defined, hourglass shaped in O. aureus). A total of 560 base pairs of mitochondrial DNA cytochrome c oxidase subunit I region of our two apogonid individuals perfectly matched with those of O. fleurieu (MT076481) registered in NCBI. Here, we propose the new Korean name "Kkoch-dong-gal-dom" for the species O. fleurieu.

• The Plant Pathology Journal
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• v.40 no.2
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• pp.171-191
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• 2024

Identification of Helicotylenchus species is very challenging due to phenotypic plasticity and existence of cryptic species complexes. Recently, the use of rDNA barcodes has proven to be useful for identification of Helicotylenchus. Molecular markers are a quick diagnostic tool and are crucial for discriminating related species and resolving cryptic species complexes within this speciose genus. However, DNA barcoding is not an error-free approach. The public databases appear to be marred by incorrect sequences, arising from sequencing errors, mislabeling, and misidentifications. Herein, we provide a comprehensive analysis of the newly obtained, and published DNA sequences of Helicotylenchus, revealing the potential faults in the available DNA barcodes. A total of 97 sequences (25 nearly full-length 18S-rRNA, 12 partial 28S-rRNA, 16 partial internal transcribed spacer [ITS]-rRNA, and 44 partial cytochrome c oxidase subunit I [COI] gene sequences) were newly obtained in the present study. Phylogenetic relationships between species are given as inferred from the analyses of 103 sequences of 18S-rRNA, 469 sequences of 28S-rRNA, 183 sequences of ITS-rRNA, and 63 sequences of COI. Remarks on suggested corrections of published accessions in GenBank database are given. Additionally, COI gene sequences of H. dihystera, H. asiaticus and the contentious H. microlobus are provided herein for the first time. Similar to rDNA gene analyses, the COI sequences support the genetic distinctness and validity of H. microlobus. DNA barcodes from type material are needed for resolving the taxonomic status of the unresolved taxonomic groups within the genus.

• Journal of Life Science
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• v.26 no.9
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• pp.1007-1014
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• 2016

A highly efficient, rapid, and reliable multiplex polymerase chain reaction based method for distinguishing ten species of genus Cynoglossus (C. senegalensis, C. abbreviates, C. macrolepidotus, C. arel, C. semilaevis, C. interruptus, C. joyneri, C. lingua, C. robustus, and C. monodi) is described. The species-specific primer sets were designed base on the cytochrome oxidase subunit I gene (1,500 bp). The optimal PCR conditions and primers were selected for ten of Cynoglossus species to determine target base sequences using single PCR. Multiplex PCR using the ten pairs of primers either specifically amplified a DNA fragment of a unique size or failed, depending on each species DNA. The length of amplification fragment of 208 bp for C. senegalensis, 322 bp for C. abbreviates, 493 bp for C. macrolepidotus, 754 bp for C. arel, 874 bp for C. semilaevis, 952 bp for C. interruptus, 1,084 bp for C. joyneri, 1,198 bp for C. lingua, 1,307 bp for C. robustus, and 1,483 bp for C. monodi with the species-specific primers, visualized by agarose gel electrophoresis, allowed perfectly distinction of the Cynoglossus species. The multiplex PCR assay can be easily performed on multiple samples and attain final results in less than 6 hours. This technique should be a useful addition to the molecular typing tools for the tentative identification of Cynoglossus species.