• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.61-64
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• 2009

Four specimens (114.2~134.2 mm SL) of Icelus stenosomus Andriashev, family Cottidae, were collected from Goseong-gun, Gangwon-do, East Sea of Korea. They were identified based on the following characters : a pair of strong spines on occipital region, distinct row of scales on both dorsal and ventral sides of body, vermiculate white lines on dorsal side of body, and small prickled scales scattered sparsely on the head. We propose a new Korean name for the species as a new Korean name : 'Mu-nui-jul-ga-si-hoet-dae'.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.4
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• pp.418-423
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• 2019

We report the first occurrence of Ophichthus erabo (Jordan and Snyder, 1901) collected in the waters around Jeju Island. The morphologic characteristics of this species include rich brown semicircular spots distributed on the head, the back, and the dorsal fins. Ophichthus erabo has a similar body color to Ophichthus polyophthalmus but can be clearly distinguished from the latter by the number of vertebrae (152-155 in O. erabo vs. 147-149 in O. polyophthalmus) and the existence of a white spot at the center of a semicircle (i.e., no white spot in O. erabo vs. a white spot in O. polyophthalmus). We suggest a new Korean name for O. erabo to be "Mul-bang-ul-ba-da-baem-gang-eo".

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.15 no.1
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• pp.36-40
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• 2010

Ballast water has been known as a major vector for global dispersal of toxic dinoflagellates and other microalgae. In this study, biodiversity in ships’ ballast water was examined using a dinoflagellate-oriented PCR primer set and species-specific real-time PCR. While motile dinoflagellates could be observe at very low cell densities by light microscopy,a wide range of dinoflagellate taxa including parasitic and phototrophic pico-dinoflagellates as well as harmful species to marine fish/shellfish was detected when techniques for cloning/sequencing of SSU rDNA of sample cells were used. Present result suggests that molecular methods including species-specific PCR primers may offer rapid and accurate detection of invasive species in ballast water.

• Applied Microscopy
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• v.50
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• pp.18.1-18.7
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• 2020

The olfactory anatomy and histology of Lethenteron reissneri were researched using a stereo microscope, a light microscope, and a scanning electron microscope. As in other lampreys, it shows same characters as follows: i) a single olfactory organ, ii) a single tubular nostril, iii) a single olfactory chamber with gourd-like form, iv) a nasal valve, v) a nasopharyngeal pouch, vi) a sensory epithelium (SE) of continuous distribution, vii) a supporting cells with numerous long cilia, viii) an accessory olfactory organ. However, the description of a pseudostratified columnar layer in the SE and Non SE is a first record, not reported in sea lamprey Petromyzon marinus. In particular, both 19 to 20 lamellae in number and olfactory receptor neuron's quarter ciliary length of the knob diameter differ from those of P. marinus. From these results, it might be considered that the olfactory organ of L. reissneri shows well adaptive structure of a primitive fish to slow flowing water with gravel, pebbles, and sand and a hiding habit into sand bottom at daytime. The lamellar number and neuron's ciliary length may be a meaningful taxonomic character for the class Petromyzonida.

• Animal cells and systems
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• v.6 no.1
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• pp.45-51
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• 2002

We compared the complete mitochondrial cytochrome b gene sequences of Korean and European cobitids to provide independent evidence for assessment of systematic and biogeographic relationships of species in the genus Cobitis. The data suggested monophyly of the genus Cobitis and the inclusion of Korean Cobitis species within the group having one lamina circularis, a primitive condition. Also, all the phylogenetic analyses using maximum parsimony, maximum likelihood, and neighbor joining methods showed a monophyletic relationship among Cobitis. The basal position of the Caspian C. cf. sibirica reported here reflects the eastern Asiatic origin cf. the European Cobitis and establishes C. cf. sibirica as an independent lineage. The Korean C. pacifica diverged next to C. cf. sibirica in basal group from the genus Cobitis. This result is in agreement with the hypothesized Asiatic origin of some European freshwater fish lineages. The phylogenetic relationships in this study showed a close affinity between C. zanadreai and C. sinensis. Two new species, C. tetralineata and C. pacifica in Korea also are closely related to monophyletic group clustering the type species of the Acanestrinia subgenus (C. elongata) with all the endemic Italian species (C. bilineata and C. zanandreai). This may suggest that the affinity between the Korean and Danubian-Italian imply genetic convergence or genetic plesiomorphic state between allopatric species that are separated for the Miocene. The mtDNA-based phylogeny for the species of the genus Cobitis from Kores and Europe permits phylogenetic assessment of the morphological transitions of Iamina circularis.

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.35-48
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• 2022

Fish assemblage of total 325 of Korean peninsula estuaries were surveyed to analyze the characteristics of community structure and diversity by sea areas for three years from 2016 to 2018. The scale (stream width) of Korean estuaries were various (14~3,356 m), and 68.9% of all estuaries showed salinity of less than 2 psu. Total 149 species classified into 52 families of fish were identified, and the dominant and sub-dominant species were Tribolodon hakonensis (relative abundance, RA, 12.5%) and Mugil cephalus (RA, 9.5%), respectively. The estuary of the Korean Peninsula had different physical and chemical habitat environments depending on the sea area, and accordingly, fish community structure also showed statistically significant differences (PERMANOVA, Pseudo-F=26.69, P=0.001). In addition, the NMDS (nonmetric multidimensional scaling) results showed the patterns that indicating fish community difference by sea areas, even though low community similarity within sea area (SIMPER, 21.79~26.39%). The estuaries of east sea areas were distinguished from the others in the aspects of which, the higher importance of migratory fishes and endangered species, and that of brackish species were characterized at south sea estuaries. However, the estuaries of west sea showed higher importance of species that have a relation with freshwater (primary freshwater species, exotic species), which is the result that associating with the lower salinity of west sea estuaries because of the high ratio of closed estuaries(78.2%). The SIMPER analysis, scoring the contribution rates of species to community similarity, also showed results corresponding to the tendency of different fish community structures according to each sea area. So far, In Korea, most studies on fish communities in estuaries have been conducted in a single estuary unit, which made it difficult to understand the characteristics of estuaries at the national level, which are prerequisite for policy establishment. In present study, we are providing fish community structure characteristics of Korean estuaries in a national scale, including diversity index, habitat salinity ranges of major species, distribution of migratory species. We are expecting that our results could be utilized as baseline information for establishing management policies or further study of Korean estuaries.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.179-184
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• 2014

A histological study on the egg envelope and oogenesis of Gobiobotia brevibarba (Pisces, Cyprinidae) was carried out by a light microscope and a scanning electron microscope. Various developmental cells appeared in the ovary caught during May 2014, spawning season. For the relative area of oocyte, the ovary consisted of mature stage (74.5%), a vitellogenic stage (yolk granule stage, 16.6% and yolk vesicle stage, 6.6%) and previtellogenic stage (perinucleolus stage 2.2%), which means its spawning season. The cytoplasm of the perinucleolus oocyte is acidic and many nucleoli are located at the inner side of the nuclear membrane. The yolk vesicles, an early vitellogenic stage, has a follicular layer and a zona radiata clearly. Numerous villi, called an egg envelope, begin to form on the zona radiata. The yolk granules, an another vitellogenic stage, proceeds and they show a strong eosinophilic nature. Such yolk granules appeared between the yolk vesicles occupying most cytoplasm, and as the stage proceeds, there are some yolk masses fused with each other. Egg envelope is covered with plenty of villi ($2{\sim}3{\mu}m$ in the length) over the entire egg surface.

• Korean Journal of Ichthyology
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• v.31 no.3
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• pp.123-130
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• 2019

The olfactory organ of the Korean endemic fish, Rhodeus uyekii, a mussel-spawning species, was researched anatomically, histologically and histochemically, for looking into a relation to the physical and chemical condition of its habitat and ecological habit, using stereo microscopy, light microscopy and scanning electron microscopy. The external structure of the olfactory organ consists of the semicircular-shaped anterior nostril with arched shape at its forward position, posterior nostrils and the nasal flap. Within the olfactory chamber, it has the rosette structure with 14 to 15 lamellae which is largely divided into the sensory and non-sensory regions. The sensory region has the olfactory receptor neurons, the supporting cells, the basal cells, the lymphatic cells, and the plasma cells, while the non-sensory region has the stratified epithelial cells, the mucous cells with sulfomucin and 1 type of unidentified cell. In particular, the arched feature in the anterior nostril and the mucous cell of sulfomucin were unique.

• Journal of fish pathology
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• v.30 no.2
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• pp.135-148
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• 2017

Pathogen introductions associated with aquatic invasive species threaten ecosystems and biodiversity worldwide. Bigheaded carps (BHC), including Silver Carp Hypophthalmichthys molitrix, Bighead Carp H. nobilis, and their hybrids, are prolific, invasive pests in central US rivers. However, little is known about pathogen effects on invading BHC or how BHC affect the disease risk profile for native fishes in receiving ecosystems. We therefore conducted, from May 2013-December 2014, a systematic pathogen survey for BHC and native fishes in the Wabash River watershed, Indiana, USA. We found Pseudomonas fluorescens, P. putida, and Salmonella enterica DNA in BHC as well as native fishes, although none of these bacteria were exclusively present in BHC. DNA from other bacterial taxa was detected only in native fishes and Common Carp Cyprinus carpio. No gastrointestinal helminths were detected in BHC, although they were common in most native fishes examined. We also conducted in vitro studies on BHC tissues (skin, gill, fin, and fry) and found high sensitivity to Largemouth Bass virus, viral hemorrhagic septicemia virus, and infectious pancreatic necrosis virus. We conclude that BHC are not heavily burdened by bacteria, viruses and parasites in the invaded study ecosystems, although they do harbor native bacteria and show potential for high sensitivity to endemic viruses.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.71-85
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• 2018

A recent topic of interest within ecology is ecosystem services that are importantly connected with biodiversity. Biodiversity is a fundamental component of ecological studies and has been the subject of many studies worldwide. However, studies on the diversity and distribution of freshwater fish were not undertaken in earnest until 2000, and the number of internationally available studies is therefore still limited. In this study, we used data from "The Survey and Evaluation of Aquatic Ecosystem Health (hereafter SEAEH)" within the framework of which whole water systems on the Korean peninsula are annually monitored to investigate and determine the current status of the diversity and distribution of freshwater fish, as well as to elucidate major factors impacting freshwater fish. A total of 130 species from 28 families were identified at around 953 sites in the SEAEH investigation of 2014. The species Zacco platypus (relative abundance: 28.2%) and Z. koreanus (19.3%) were identified as the most abundant species on the Korean peninsula, and besides these 20 endangered species, 51 endemic species and 4 exotic species were also collected. Highest (96 species) and lowest (72 species) diversity were identified in the Han River Watershed and the Yeongsan/Seomjin River Watershed, respectively. The mean endemic rate was 32.7%, which is higher than the previous rate determined in 1995. The exotic species Micropterus salmoides, Lepomis macrochirus and Carassius cuvieri were found in the whole river system except north Yeongdong, whereas Oreochromis niloticus occurred only at three sites due to the cold water temperatures in winter. Totally, 28 species were found to be translocated to different water systems not connected with known original habitats, most translocations occurring in the Nakdong River and the Yeongdong region. Among the translocated species, Opsariichthys uncirostris amurensis, and Erythroculter erythropterus were dominantly distributed in the mid- to lower reaches of Nakdong River where they may be harmful to the native fish assemblages due to their strong predation. The construction of weirs in connection with the "4 River Project" generated changes in fish assemblages before, during and after the project, resulting in altered habitat condition. Especially, a decrease in the number of endemic species and an increase in the abundance of lentic species were seen. Human-induced global warming will allow exotic species requiring high water temperatures to adapt to the environmental conditions of the Korean peninsula, which may enhance the diversity of native fishes and create changes in distribution. For the establishment of realistic and efficient management and protection strategies for Korean freshwater fish, SEAEH, which produces fundamental and quantitative data for Korean streams, is an important and necessary tool.