• Animal cells and systems
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• v.2 no.1
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• pp.27-31
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• 1998

A new bitterling, Acheilognathus majusculus is described from 20 specimens collected from the Somjin and Nakdong River, Korea. The new species is similar to Acheilognathus yamatsutae, but distinguished from the latter and congeners by the combination of the following characteristics: 15-21 gill rakers, 37-40 vertebrae, longer barbel, greenish body coloration, nuptial color of males and slightly protrusive snout. A key to species of Acheilognathus from Korea is included.

• Korean Journal of Environmental Biology
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• v.17 no.4
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• pp.499-501
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• 1999

Morphological characteristics of Opsariichthys uncirostris amurensis from Panbyon-river of Naktong system is examined. This is the first record of the Opsariichthys uncirostris amurensis collected from Panbyon-river of Naktong- river system, Korea.

• The Korean Journal of Zoology
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• v.35 no.4
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• pp.505-508
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• 1992

한국산 담수어류인 버들치(Moroco)속의 동버들개(M. percnums)는 한반도 이북에 서식하며 이남지역에는 분포하지 않는 것으로 보고되어 있었으나 본 형태연구 결과와 유전적 연구(Yang and Min, 1989) 결과, 강원도 강릉 경포호지역에서 동버들개가 서식 분포하는 것이 확인되어, 동버들개의 분포상 최남단 지역으로 보고하며, 한국산 버들치속 어류는 총 5종이 한반도 이남지역에 분포하는 것으로 확인되었다.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.153-158
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• 2014

A natural intergeneric hybrid between Rhodeus pseudosericeus and Acheilognathus signifer was collected in their sympatric area, the Jucheongang (stream), the Namhangang (river), Korea. Morphological characters as well as mitochondrial cytochrome b (mt-cyb) gene were investigated to confirm the natural hybrid origin. In the comparison of morphological characters, the natural hybrid appeared to have intermediate characters between two parental species in several key characters such as the band of dorsal fins, the color pattern of body, and the body spot and stripe. Also, the collected specimen had an incomplete lateral line with a large number of pored scales. In analysis of mt-cyb gene, it revealed that the maternal species of the natural hybrid appeared to be R. pseudosericeus due to their 100% sequence identity. Thus, such results gave convincing evidence for the occurrence of a natural intergeneric hybrid between Rhodeus pseudosericeus and Acheilognathus signifer.

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.1-7
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• 2005

A new chub, Zacco koreanus sp. nov., is described on the basis of 104 specimens from six localities in Korea. The new species is distinguished from other Zacco species by the following characteristics: 9~10 scales above lateral line to dorsal fin origin, yellowish anterolateral side of body, no hemicircular red blotch on the upper margin of the eyes, reddish anterior margin of pectoral fin, larger orbit diameter and narrow interorbital width. The new species is widely distributed in the most streams of Korea, except the Yeongsan R., while Zacco temminckii is restricted in the Dongjin R., Yeongsan R., Seomjin R., Tamjin R. and Nakdong R. in Korea. When the two species occurred sympatrically in the same stream, Z. koreanus sp. nov. prefered mostly rapid lotic environments while Z. temminckii inhabited lentic ones. The Korean Z. temminckii was redescribed herein. A key to the Zacco species of Korea and Japan is provided.

• 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.13 no.2
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• pp.123-128
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• 2001

The reproductive ecology of Gobiobotia brevibarba was investigated at Hongchen River of Bangokri, Seomyon, Hongcheongun, Kangwondo, from March 1999 to February 2000. The favorite habitat was a stretch of river with fast flow and a stream bed mostly covered with cobbles and pebbles. The spawning ground was a riffle area 20~50 cm deep, with a current velocity of 0.6~1.3 m/sec, and a bottom consisting of cobble and boulder. The sex ratio of female to male was 1 : 0.86. Peak spawning season was May when water temperatures rose to $18{\sim}20^{\circ}C$. Male and females became sexually mature when they attained more than 40 mm and 50 mm in body length, respectively. The average number of eggs in the ovary was $2,040{\pm}400.57$ and the egg diameter was $1.98{\pm}0.06\;mm$. The matured eggs were demersal, spherical, and dimmed light yellow in color.

• Korean Journal of Ichthyology
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• v.13 no.2
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• pp.111-116
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• 2001

Factors influencing elongation of the ovipositor in the bitterling Rhodeus uyekii were examined under several conditions. The ovipositors of the females were periodically elongated under the presence of mussels or males, and in some cases without either. When females were reared without mussels and males, the ovipositor did not elongate in one fish in a large aquarium, but it did become elongated in another fish in a small aquarium and in many fishes in a large aquarium. Duration of the elongated state of the ovipositor was 1~3 days (mean 1.2~2.5 days) and the periodicity of elongation was 4~15 days (mean 6.4~11.9 days). Length of the elongated ovipositor was 68~100% (mean 78.5~98.8%). Length of ovipositor in the interpeak period was 20~51% (mean 27.3~33.1%); in the post-elongation period it did not elongated further 3~30% (mean 11.1~19.9%). The effect of aquarium size and number of individuals in the aquarium on the elongation of the ovipositor, and inter-specific or inter-generic differences based on previous reports are discussed.

• Applied Microscopy
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• v.30 no.4
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• pp.321-326
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• 2000

The ultrastructure of the fertilized egg envelope from pale chub , Zacco platypus belong to Cyprinidae was studied using scanning and transmission electron microscopes. The fertilized egg was an adhesive type, have a single micropyle resembling the pathway of sperm in the area of the animal pole. The micropyle was surrounded by 5 peaks of hill. An outer surface of the fertilized egg envelope was arranged by pore canals irregularly. In section of fertilized egg, the egg envelope consistes of three layers, an outer adhesive layer, a middle electron dense layer and an inner lamellae layer consisting of 9 layers. These ultrastructural characters of fertilized egg envelope from pale chub can be utilized in taxonomy of teleost.

• Parasites, Hosts and Diseases
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• v.56 no.1
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• pp.41-48
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• 2018

The infection status of Clonorchis sinensis metacercariae (CsMc) was examined in freshwater fish from a highly prevalent site, Wicheon (a branch of Nakdong-gang), which is located in Gunwi-gun, Gyeongsangbuk-do, the Republic of Korea. Total 1,162 fish in 32 species were examined by the artificial digestion method through 6 years. CsMc were detected in 720 (67.5%) out of 1,067 fish (26 spp.) and their density was 610 per fish infected. In the susceptible gobioninid fish group, i.e., Pungtungia herzi, Squalidus gracilis majimae, Squalidus japonicus coreanus, Sarcocheilichthys variegatus wakiyae and Pseudorasbora parva, all of 323 fish were infected with an average of 1,310 CsMc. Total 23 (95.8%) gobioninid fish, i.e., Pseudogobio esocinus, Abbottina springeri, Hemibarbus longirostris, Microphysogobio koreensis, and Microphysogobio jeoni, were infected with 127 CsMc in average. In the acheilognathinid fish (bitterlings) group, the prevalence was 77.0%, and the density was 50 CsMc per fish infected. In the rasborinid fish (chubs) group, i.e., Zacco platypus, Zacco temminckii, Zacco koreanus, and Opsariichthys uncirostris amurensis, 147 (36.5%) out of 403 fish examined were infected with 15 CsMc in average. The susceptibility indices of CsMc were 412 in the overall positive fish group, 1,310 in the gobioninid group-1, 122 in the gobioninid group-2, 38.5 in the acheilognathinid group, and 5.5 in the rasborinid fish group. Conclusively, it was confirmed that CsMc are highly prevalent in fish from Wicheon, and their infection tendency varied according to the subfamily groups in Cyprinidae fish hosts.