• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.132-138
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• 1984

The genus Squalidus of Korea, formerly regarded as genus Gnathopogon is reviewed and keys to following 4 species and subspecies: S. gracilis majimae, S. chankaensis tsuchigae, S. chankaensis ssp., and S. japonicus coreanus. The genus spualidus is distinguished from genus Gnathopogon by the position of snout, color pattern on the body sides, number of scales above lateral line, and distance from anus to anal finorgin. G. majimae Jordan et Hubbs is junior synonym of S. gracilis majimae, and G. coreanus (not Berg) is splitted and identified as S. chankaensis tsuchigae, S. c. ssp., and S. japonicus coreanus. S. c. tsuchigae is very similar to S. j. coreanus, but the eye diameter, barbel length, and the number of lateral line scales are useful characters in separating these species. S. thankaensis ssp. occurring only in the Yongdok-Oship River differs from S. chankaensis tsuchigae in the number of lateral line scales, eye diameter and their body size.

• Korean Journal of Environment and Ecology
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• v.26 no.3
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• pp.367-373
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• 2012

Population ecology (Ecological characteristics) of Squalidus japonicus coreanus from the Namhan River(Yangpyeong-gun Yangpyeong-eup Changde-ri), Gyeonggi-do, Korea were investigated from January to December 2011. Short barbel gudgeon inhabits habitats run of the lower river. The stream bed was mostly covered sand. Their current velocities were 0.14~1.38m/sec and depths were 80~120cm. The sex ratio of female to male was 1 : 0.82. It is presumed that the spawning season is from June to July and water temperatures were $18.5{\sim}24.3^{\circ}C$. Sexually matured individuals appeared over the two year of age. Frequency analysis of total length indicated that the group with 34~50mm in total length was one year old, the 51~74mm was two years old, and the group over 75mm was three years old. The average number of eggs in the ovaries was estimated as 1,871 per matured female. Stomach content of S. japonicus coreanus were Cyanophyta, Chlorophyta, Bacillariophyta, Rotatoria, Crustaceae, Copepoda, Ephemeroptera, Diptera, and Nematoda. omnivorous, mainly feeds on benthic invertebrates such as chironomidae larvae.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.252-261
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• 2021

The egg development and early life history of short barbel gudgeon Squalidus japonicus coreanus were investigated. For the experiments, the mature adults were collected at the stream Jicheon in Korea. The eggs from the females were obtain by injecting 10 IU/g of human chorionic gonadotropin and inseminated by wet method in the laboratory. The fertilized eggs were 1.12±0.03 mm (1.10~1.16 mm, n=30) in diameter. The embryo began to hatch about 49 hrs after fertilization under water temperature of 23±1℃. The newly-hatched larvae (Yolksac larva) were 3.7±0.1 mm (3.4~3.8 mm, n=16) in total length, and they haven't Melanophore. 5 days after hatching, the Preflexion larva were 5.3±0.2 mm (5.0~5.5 mm, n=16) in total length, and they began to eat a Rotifer. 19 days after hathing, the Flexion larva were 6.0±0.3 mm (5.4~6.5 mm, n=16) in total length, and they began to eat a Brine shrimp. 29 days after hatching, the Postflexion larva were 9.6±0.5 mm (8.3~10.5 mm, n=16) in total length, and dorsal fin rays are were formed. 44 days after hatching, the juvenile were 15.5±1.0 mm (13.5~17.0 mm, n=16) in total length, and all their fin-rays were formed.

• Korean Journal of Ichthyology
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• v.6 no.2
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• pp.244-250
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• 1994

The lchthyofauna was investigated at the nine sites in the Tam-jin River from September 10, 1990 to October 12, 1993. The fishes were collected by means of a casting net and hooks. The collected fishes were classified into 34 species of 26 genera in 13 families. In the present study 3species of Acanthogobius hasta, Macropodus chinensis and Channa argus were newly collected. Among the 34 species, 12 were known to be endemic species in korean waters they are Rhodeus uyekii, Acheilognathus yamatsutae, Acanthorhodeus gracilis, Sarcocheilichtys variegatus wakiyae, Squalidus chankaensis tsuchigae, Squalidus japonicus, Squalidus gracilis, Microphysogobio yaluensis, Cobitis longicorpus, Pseudobagrus koreanus, Liobagrus mediadiposalis, Odontobutis platycephala. The dominant species were Zacco platypus, Zacco temmincki and Acheilognathus yamatsutae.

• Korean Journal of Environment and Ecology
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• v.19 no.1
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• pp.46-54
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• 2005

The change of fish community in the Wonju-stream was investigated from May to November, 2004. During the period,24 species belonging to 6 families were collected. There were 10 Korean endemic species$(41.7\%)$, including Pseudopungtungia tenuicorpa, Coreoleuciscus spiendidus, Squalidus gracitis majimae, Squalidus japonicus coreanus, Microphysogobio yaluensis, Microphysogobio longidorsalis, Iksookimia koreensis, Koreocobitis rotundicaudata, Liobagus andersoni and Odontobutis interrupts. The dominant species was Zacco Platypus$(54.7\%)$, and the subdominant species was Rhynchocypris oxycephalus$(16.7\%)$. Also, Carassius auratus$(5.4\%)$, I. koreensis$(3.4\%)$, Orthrias toni$(3.3\%)$, and Pungtungia herzi$(3.0\%)$ appeared. According to the fish species compositions, the fish community was divided into 2 groups by an unweighted pair group method using arithmetic averages(UPGMA). The comparison of the fish community showed that benthic fish species were decreased, while, the number of water-column species, resistant 1,o substrate changes and water pollution were increased.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.61-66
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• 1998

The fish fauna and community structure were surveyed at the Naerin Stream of Puk'an River from June 1996 to September 1997. The fishes collected were 36 species, 28 genera belonging to 10 families, in which 16 species were endemic species of Korea. Oncorhynchus mykiss was an exotic fish. The dominant species was Zacco temmincki(relative abundance 42.94%), and subdominant species was Moroco kumgangensis(12.91%). The rare species less than 0.03% of all were Opsariichthys bidens, Squalidus japonicus coreanus, Misgurnus mizolepis, Leiocassis ussuriensis and Siniperca scherzeri. The species diversity, evenness, and dominance index on the fish community were 0.947, 0.609, and 0.218.

• Journal of agricultural medicine and community health
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• v.26 no.2
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• pp.1-6
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• 2001

To investigate which fresh-water fishes were infected with Clonorchis sinensis metacercariae, 13 species of the fishes in the Kum River, the Mangyong River, the Tongjin River, and the Sumjin River were surveyed from July to October 2001. The metacercariae of C. sinensis were found in Squalidus japonicus coreanus in the Kum River and the Mangyong River, Pseudorasbora parva in the Kum River, and Pungtungia herz i in the Sumjin River. The average number of the metacecariae in 1 gram of fish body weight was 12 in Squalidus japonicus coreanus, 26 in Pseudorasbora parva in the Kum River, 4 in Squalidus japonicus coreanus in the Mangyong River, and 7 in Pungtungia herz i in the Sumjin River. The C. sinensis egg-positive rates among the residents at the Sumjin River basin in 1999 and 2000 were 8.9% and 6.8%, respectively. In conclusion, C. sinensis infection was endemic in the above riverside areas.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.103-109
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• 2007

To investigate the effects of artificial vegetation island (AVI) on fish distribution, we compared fish fauna from artificial vegetation island (AVI) area, which installed in 2000, natural vegetation area (NVA) and vegetation-free area (VFA) at Kyungan Stream area of Lake Paldang from Jul. to Nov., 2005. Results showed that 11 families 23 genera 24 fish species were distributed in the AVI and NVA. Squalidus japonicus coreanus, a small-size fish which generally lives at the downstream, dominated absolutely in the individual numbers. However, only 6 families 11 genera 12 species of fishes caught at the VFA, and dominant fishes were Hemibarbus labeo and Erythroculter erythropterus, a medium to large-size migratory fishes which live in mid-depth of water column. The dominance index was high at the AVI (0.778) and NVA (0.868), whereas the diversity index and evenness index were high at the VFA. Fish distribution at AVI was similar to that of the NVA in numbers of species, indicating that the AVI could playa role as spawning and inhabitation zone to a variety of fishes. We believe that AVI may be used for a restoration of the damaged and disturbed littoral ecosystem.

• Parasites, Hosts and Diseases
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• v.56 no.5
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• pp.501-507
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• 2018

We described here the morphological characteristics for the species identification and fish hosts of Isoparorchis sp. (Digenea: Isoparorchiidae) in the Republic of Korea (Korea). Total 1,371 freshwater fishes collected in Yangcheon (Stream) in Sancheong-gun, Gyeongsangnam-do were examined by the artificial digestion methods to survey the infection status of digenetic trematode metacercariae for 4 years (2013-2016). Adult and larval worms of Isoparorchis sp. were detected in 38 (8.4%) out of 451 fish in 4 species, i.e., Pungtungia herzi, Acheilognathus koreensis, Squalidus japonicus coreanus and Odontobutis platycephala, examined. The infection density was 1.1 worm per fish infected. They were mainly found in the subcutaneous tissues and abdominal cavities. Nodules with worms in the subcutaneous tissues were revealed as the blue ink-colored bulges. Adults leaf-like, $21.6{\times}9.84mm$ in average size. The ratio of body length to body width was 2.20: 1. Oral sucker subterminal, $1.03{\times}1.22mm$. Pharynx muscular, $0.55{\times}0.54mm$. Esophagus very short. Ceca convoluted, terminated near the posterior end. Ventral sucker anterior 1/3.75, $1.99{\times}2.10mm$. The ratio of ventral sucker to oral sucker was 1.74: 1. Testes round to elliptical, both sides of ventral sucker, $1.43{\times}1.33mm$. Vitellaria highly dendritic, posterior 1/3 level. Eggs operculated, embryonated, $52{\times}32{\mu}m$ in size. By the present study, 4 fish species aforementioned are to be listed as the fish hosts of Isoparorchis sp. in Korea and additionally the morphological characteristics are to be described for the species identification.