• Korean Journal of Ichthyology
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• v.24 no.3
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• pp.177-182
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• 2012

Population sizes of an endangered species, Gobiobotia macrocephala (Cyprinidae, Gobioninae) were investigated in the Seom River, a tributary of the Han River drainage system, in Wonju-si, Gandgwon-do, Korea from September to October 2010. G. macrocephala occurred at 14 stations surveyed in this study and inhabited around the downstream riffles with pebble and coble bottoms. Its population sizes were estimated to be $8,295{\pm}4,922$ and $39,846{\pm}14,232$ individuals at two main stations using the mark-recapture method. The quadrat methods by a spoon net and snorkeling revealed that the population sizes were estimated to be 9,216 and 37,873 individuals, and 5,593 and 24,347 individuals, respectively.

• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.92-99
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• 2018

Feeding ecology of endangered Korean endemic miho spine loach, Cobitis choii, was investigated in Jicheon Stream, Geumgang River, Korea to provide ecological characteristics and baseline data for its restoration. C. choii is active during daylight hours above sand from March to October when the water temperature exceeded $13^{\circ}C$, but tended hibernate in the stream bottoms (sand) in the winter months (November~February) when the water temperature was lower than $13^{\circ}C$. They fed (index of relative importance, IRI) mainly Diptera (69.9%), Copepoda (23.2%), Arcellidae (2.3%), Branchiopoda (2.0%) and Ploima (2.0%). And their small juvenile (age 0+) fed mainly small size, Ploima and Branchiopoda, however, they ate mainly large size, Chilonomidae, while growing to adult fish (age 2+~3+).

• Korean Journal of Environment and Ecology
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• v.37 no.2
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• pp.151-162
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• 2023

This study investigated the characteristics of fish communities and inhabiting status of the endangered species, Rhodeus pseudosericeus, in the Geumdang Stream in Korea from March to October 2021. A total of 1,698 fish in 5 families and 25 species were collected from 7 survey stations during the survey period. The dominant species was Zacco platypus (relative abundance, 46.5%), and the subdominant species was Squalidus gracilis majimae (16.7%), followed by Rhynchocypris oxycephalus (12.0%), Z. koreanus (5.7%), Pungtungia herzi (3.2%), R. pseudosericeus (2.0%), R. notatus (1.9%), and Acheilognathus rhombeus (1.8%). Nine Korean endemic species (36.0%) were collected, including R. pseudosericeus, R. uyekii, Sarcocheilichthys variegatus wakiyae, Microphysogobio yaluensis, S. gracilis majimae, Z. koreanus, Cobitis nalbanti, Iksookimia koreensis, and Odontobutis interrupta. An exotic species, Micropterus salmoides, designated as an invasive alien species (IAS), was collected downstream. The investigation of the habitat patterns of the endangered species (class II), Rhodeus pseudosericeus, showed a habitat range of about 6 to 7 km in the middle of Geumdang Stream (RP-1 to RP-4), and this species inhabited the edge with water depths of 0.3 through 1.0 m with slow water flow and many aquatic plants. According to the community analysis results, the overall dominance and evenness indexes were low, while diversity and richness indexes were high, and the cluster structure was largely divided into upstream and middle-downstream areas. The river health (fish assessment index) evaluated using fish was assessed as good (3 stations), normal (3 stations), and bad (1 station), and water quality was evaluated as good both upstream and downstream. Compared to previous studies, the number of species was relatively similar, and among the species that appeared in the past, 13 species did not appear in this survey, while 6 species appeared for the first time in this survey. Disturbance factors included river construction, many weirs, and the appearance of the ecosystem-disturbing species, M. salmoides. Since Geumdang Strem has high conservation value because it is home to many species in the Acheilognathinae subfamily, including the endangered species R. pseudosericeus, continuous attention and systematic conservation measures are required.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.22-23
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• 2003

Primordial germ cell (PGC) is the progenitor cell of the germ cell lineage and eventually give rise to gametes that are responsible for creating individual organisms via a fertilization process. This means that PGC is a unique cell that can be converted into individual fish. This advantage of PGCs would make it possible to develop various applications in the field of fish bioengineering. First, PGCs may make it easier to preserve the genetic resources of fish. Cryopreservation of fish eggs or embryos has not been successfully achieved so far. Therefore, the only possible method to preserve genetic resources of fishes is to raise fish as live individuals. If PGCs isolated from various fishes could be cryopresewed, these cells could be converted into live fishes via germ-line chimera production. This is particularly useful for preserving genetic materials of endangered species. Even if the species of interest were to become extinct, it could be recovered by the transplantation of cryopreserved PGCs into the embryos of a closely related species. Another application of this technology is in what could be termed "surrogate broodstock technology". (중략)

• Korean Journal of Ichthyology
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• v.24 no.1
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• pp.56-61
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• 2012

The distribution status and population size of the endangered species, $Cobitis$ $choii$, were investigated in the Guem River, Korea. From 1984~2004, this species occurred at 20 survey stations; however, their numbers have but rapidly decreased in recent years (2006~2011), during which time they were only observed at six stations. The area of their habitat is narrow and occurs in primarily downstream, sandy zones. Using the mark-recapture method, populations were estimated at 9,106 and 34,717 individuals for the main habitats of Baekgok and Ji Stream, respectively.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.490-502
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• 2021

This study was conducted to analyze the current status of fish fauna and characteristics of the fish community according to the habitat of Woraksan National Park, Korea. The spatially balanced sampling selected 20 stations from major streams of Woraksan National Park, and three surveys were conducted in each season. The physical environments of the habitat were mostly mountain streams (Aa), with large stones and gravels scattered over the stream. The average altitude of the habitat was 304.4 m, and the average depth of water was 40.3 cm, being less than 1 m in most cases, and the river water level was distributed from 3rd to 5th streams. The principal component analysis of the physical environmental factors by habitat showed that the substrate properties differed according to the altitude. The survey identified a total of 2,183 individuals in 16 species belonging to 7 families. The dominant species was Zacco koreanus(86.2%), and the subdominant species was Rhynchocypris oxycephalus(3.8%). Pseudopungtungia tenuicorpa, classified as the endangered wildlife II, was the first endangered legally protected species found in this survey. Analysis of the rank abundance curve model in the fish community showed the Zipf model at 9 out of 20 points, the Lognormal model in 3 points, and the Preemption model in 4 points. The remaining 4 habitats showed only one species and were not analyzed. The canonical correspondence analysis of 20 stations and fish species was performed to understand the characteristics of the fish community according to environmental factors. The fish communities were divided according to differences in habitat environment by the altitude.

• Korean Journal of Ichthyology
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• v.26 no.1
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• pp.11-16
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• 2014

The best spawning timing in a day and the first spawning position of Pseudopungtungia nigra was investigated at the Jujacheon stream in Jinan-gun Jeollabuk-do, Koera from May to July 2009. P. nigra spawned only at the nest of Coreoperca herzi from 7 May to 11 July, 2009. P. nigra spawned at 56 nests among 61 nests of C. herzi, and the spawning of P. nigra started on after 1st or 2nd day spawning of C. herzi. The spawning behavior was dominantly observed at around 06:00 to 07:00 AM, when parental C. herzi males are usually inactive in the territorial defence. The hatching rate of P. nigra eggs was closely related with the parental activity of the guarding C. herzi, and P. nigra deposit their eggs as close as possible to the egg clutches of C. herzi (normally at the perimeter of the clutch), likely to take much of the potential effects from fanning and guarding, as the hosts focus their care on the centre of the egg clutch.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.156-164
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• 2020

The accurate estimation of fish assemblages is highly dependent on the sampling gear used for sampling. We used data from 15 sampling sites along the Nakdong River, which is a large river in South Korea, to identify differences in assemblages and sizes of freshwater fishes collected with either cast nets or gill nets, the two most commonly used sampling gear in South Korea. The two gears differed in the fish assemblages they captured, with more species caught by gill nets. Further, due to its tighter mesh size, the cast net caught significantly smaller fishes than the gill nets(independent t-test, p<0.05). We found the cast net to be appropriate for species that inhabit shallow (less than 2 m) and open water, but inappropriate for deep water, habitats with plant beds, and nocturnal species. Thus, cast net sampling is not efficient in a large river environment, and a combination of sampling methods is more suitable for understanding fish assemblages in such habitats. In general, appropriate selection of fishing methods to specific habitats is necessary to improve data quality and minimize the misrepresentation of environmental conditions.

• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.199-208
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• 2021

Environmental DNA (eDNA) metabarcoding is effective method with high detection sensitivity for evaluating fish biodiversity and detecting endangered fish from natural water samples. We compared the richness of operational taxonomic units(OTUs) and composition of freshwater fishes according to filters(cellulose nitrate filter vs. glass fiber filter), extraction kits(DNeasy2^® Blood & Tissue Kit vs. DNeasy2^® PowerWater Kit), primer sets (12S rDNA vs. 16S rDNA), and PCR methods (conventional PCR vs. touchdown PCR) to determine the optimal conditions for metabarcoding analysis of Korean freshwater fish. The glass fiber filter and DNeasy2^® Blood & Tissue Kit combination showed the highest number of freshwater fish OTUs in both 12S and 16S rDNA. Among the four types, the primer sets only showed statistically significant difference in the average number of OTUs in class Actinopterygii (non-parametric Wilcoxon signed ranks test, p=0.005). However, there was no difference in the average number of OTUs in freshwater fish. The species composition also showed significant difference according to primer sets (PERMANOVA, Pseudo-F=6.9489, p=0.006), but no differences were observed in the other three types. The non-metric multidimensional scaling (NMDS) results revealed that species composition clustered together according to primer sets based on similarity of 65%; 16S rDNA primer set was mainly attributed to endangered species such as Microphysogobio koreensis and Pseudogobio brevicorpus. In contrast, the 12S rDNA primer set was mainly attributed to common species such as Zacco platypus and Coreoperca herzi. This study provides essential information on species diversity analysis using metabarcoding for environmental water samples obtained from rivers in Korea.

• Korean Journal of Ecology and Environment
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• v.43 no.4
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• pp.503-512
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• 2010

This study was conducted to evaluate fish fauna, species composition, and various guilds against stream orders along with analysis of fish community structure and diversity in Geum River watershed from 2005 to 2007. The total number of fish collected was 4,216 representing 12 families with 56 species. Zacco platypus was the most abundant fish species with 26% in relative abundance (RA). Korean endemic species were 24 species including Zacco koreanus, Microphysogobio yaluensis, Gobiobotia nakdongensis, and Iksookimia koreensis, etc. We also collected endangered fish species such as G. nakdongensis, Liobagrus obesus, and Pseudopungtungia nigra, etc., and their new distribution sites were found in the survey, providing some sites of the fish conservation and protection. Fish tolerance and trophic guilds analysis showed that the proportion of sensitive species, intermediate species, and tolerant species were 33.4%, 29.3%, and 37.3%, respectively and omnivores and insectivores were 48.1 % and 38.4%, respectively. Analysis of site-base study indicated that tolerant species and omnivore species were high in some polluted tributary streams (i.e., Gap and Miho stream) and sensitive and insectivore species were low. In the functional relations, expressed as simple linear regression equations, of stream order on fish metric attributes, showed that the number of species and the number of individuals increased as the stream order increases. This phenomenon was explained by greater availability of stable water volume, rich food, and higher physical habitat capacity. Such guild compositions and stream order characteristics of the river influenced the community structures, based on species diversity, dominance and evenness index in the study. This study may be used as important data in the future for comparisons of fish fauna and compositions before and after two weir (dam) constructions in the middle of Geum River by the government.