• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.141-147
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• 2006

The matured female and male of A. signifer differed in external morphology and body color. There were significant differences in PAD, PAB, PMP and PQR between matured female and male. Green color was very widely distributed in whole as nuptial color, that is similar to green and cyan color in the body part, yellow color in the ventral part and red and yellow color in the tail part. The nuptial organ of A. signifer was formed in a cluster on the horny substance of both sides above the mouth. There were 25~30 nuptial organs in a side. The nuptial organs disappeared with crumbling down from middle part of nuptial organ after spawning period. The nuptial organs disappeared mostly in September as non spawning period and a part of the nuptial organs remained as a vestige in the edges of both sides.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.97-106
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• 2006

In the investigation of geographic variations on the Zacco koreanus distributed widely in southern Korean Peninsula, it was found that there were distinct differences in the nuptial coloration among geographic populations. These color variations were presence of red band on anterior margin of pectoral fin and color patterns of dorsal fin. On the basis of those color variations three color types were recognized in Z. koreanus, that is, HK, NS and NE types. HK types were distributed mainly in Han and Geum River, NS types in Nakdong and Seomjin River, and NE types in Nakdong River and small streams on the east coast. It was noted ecologically and taxonomically that these three types were well separated geographically and two types of them, i.e., NS and NE types cohabit in the Nakdong River and shown a tendency of microhabitat segregation between them.

• Korean Journal of Ichthyology
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• v.18 no.3
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• pp.193-201
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• 2006

We researched the reproductive ecology of pale chub, Zacco platypus that inhabits Gajeong-cheon and Wonju-cheon that are a tributary to the Han river. The nuptial organ was formed on the head part, the anal fin and the tail part in male, the change of nuptial color was outstanding. By their changing body shape, the anal fin was extended and body depth came to be high during the spawning season in both sexes. Territorial male of defending behavior were head butting, rotated fighting, parallel swimming, biting and expelling. After pale chub located himself from the upper of the female that was approached to the side parallelling with the female, male and female spawned digging sand with their anal fin by vibrating and any parental care of the eggs was not taken. The spawning interval and lasting time were relevant to individuals density of spawning ground.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.4
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• pp.520-524
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• 1999

The rose bitterling (Rhodeus uyekii), aboriginal fish of Korea, have beautiful nuptial colors on the body and fins in their spawning season. So, this species has high possibility to become a new ornamental Bish. However, nothing is known about the color composition of body colors of this species. Therefore, this study was conducted to investigate the color component of the skin and fins of the bitterling collected from natural environment. The major component of the nuptial colors was carotenoids according to the present study. Amount of total carotenoids on the skin and fins, had a tendency to be higher during the spawning season than the non-spawning season; it was $44.9mg\%$ during spawning season and $41.8mg\%$ during non-spawning season. The composition of carotenoid during spawning season was $36.7\%$ of zeaxanthin $30.1\%$ of $\beta$-carotene, and $16.4\%$ of diatoxanthin. The composition of carotenoid during non-spawning season was $41.2\%$ of $\beta$-carotene, $18.1\%$ of diatoxanthin, and $14.0\%$ of isocryptoxanthin. The major component of the carotenoid during spawning season turned out to be zeaxanthin while the major component of the carotenoid during non-spawning season was $\beta$-carotene.

• Korean Journal of Ichthyology
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• v.20 no.1
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• pp.13-20
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• 2008

Internal and external reproductive parameters of the striped bitterling, Acheilognathus yamatsutae were compared. Internal reproductive parameters was used gonadosomatic index (GSI), hepatosomatic index (HSI) and gonadal development stage. External reproductive parameters was used ovipositor in female and pearl organ, dorsal and caudal fin nuptial color in male. The GSI and HSI of the female and male showed highest in February. Gonadal development was observed mainly ripe and spawning/spent stage in February to May. The ovipositor length index (OLI) of the female showed highest in March to April. Pearl organ number and expression rate of the male showed highest in February to May. Dorsal fin nuptial color expression rate and index (NCI-DF) showed highest in February to May. Caudal fin nuptial color expression rate and index(NCI-CF) showed highest in February to April. The study suggested same change of internal and external reproductive parameters in female and male.

• Korean Journal of Ichthyology
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• v.8 no.1
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• pp.14-21
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• 1996

The sexual dimorphism of river sculpin (Cottus poecilopus Heckel) was investigated samples were collected from the Chiak stream from January 1993 to April 1994. Sexual dimorphism in body size and some morphological characteristics were observed in this species ; males were larger in size and had a larger mouth, anal fin, ventral fin and pevic fin than females. Males have a genital papilla and nuptial color, but females do not. Females may mate preferentially with large males. Larger males could be superior in nest defense and fanning of eggs to smaller ones, thus resulting in higher survival of eggs. Similary, the larger mouth in males could be advantageous in acquiring and defending their nests. Such sexual dimorphism in this species may reflect to outcome of sexual selection.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.276-279
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• 1999

The body color of fish fed were improved to be clearer by feeding the bitterling an artificial diet containing different carotenoids. The possibilities of using the bitterling, Rhodeus uyekii, an aboriginal fish of Korea, were studied by feeding the experimental diets supplemented with the various carotenoids (astaxanthin, lutein, and $\beta$-carotene). Amount of total carotenoids in the groups of fish fed by supplementation carotenoids were relatively higher than the control group of fish fed by no supplementation carotenoids. Especially, the group of fish fed by lutein supplementation diet showed most clarity in body color. The group of fish fed by astaxanthin supplementation diet showed the highest growth while the group of fish fed by lutein or $\beta$-carotene supplementation diet showed no significant different comparing to the control group of fish. The results from this study indicated that the bitterling could be a new ornamental fish as long as provided with the proper diet and culture condition.

• 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.22 no.1
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• pp.159-166
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• 2004

The effects of polychlorinated biphenyls (PCBs) on the reproduction of the oily bitterling, Acheilognathus koreensis were investigated using histological methods. The experimental fishes were exposed to 0. 3.4, 9.3 and 25.8 ${\mu}g\; L^{-1}$ PCBs fey 8 weeks. Dead fishes and abnormal behavior were not observed in control and PCBs exposure group. In compared with control group, PCBs exposure fishes showed differences of gonadal development, gonadosomatic index (GSI), hepatosomatic index (BSI), nuptial color index (NCI) and ovipositor length index (OLI). These results showed that PCBs could disrupt reproductive process in the fish.

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.261-266
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• 2017

Microphysogobio koreensis is an endemic Korean freshwater fish that is protected as an endangered fish by the Ministry of Environment in Korea. In this study, we attempted to investigate the spawning period and spawning characteristics of M. koreensis to obtain basic information for its conservation. Though natural and histological observation, the spawning season occurred between April and May, with peak spawning occurred in early May when the water temperature was $20{\sim}23^{\circ}C$. During the spawning season, males had a bright-orange body and a thick red horizontal line from the rear of the operculum to the caudal peduncle, along with a lateral line, while females had a dark brown body. Nuptial organ had not appeared. The number of eggs in the ovaries was 10,705~22,165 ($15,573{\pm}4,274$). The number and appearance ratio of mature eggs were 1,100~5,920 ($3,383{\pm}2,126$) and 10.3~44.8% ($22.4{\pm}15.6$), respectively. And the size of mature eggs was 0.60~1.00 mm ($0.74{\pm}0.06$).