• Korean Journal of Environment and Ecology
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• v.33 no.3
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• pp.256-265
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• 2019

We investigated the ecological characteristics of Phoxinus phoxinus in the spring water in Eocheon stream from January to December 2016. The water temperature was $9.7{\sim}14.3^{\circ}C$ and remained below $15^{\circ}C$ throughout the year. The fishes cohabiting with minnow were Rhynchocypris kumgangensis (70.14%), Cottus koreanus (13.63%), Rhynchocypris oxycephalus (3.16%), Oncorhynchus mykiss (0.97%), Zacco koreanus (0.49%), and Iksookimia koreensis (0.24%). The sex ratio of female to male was 1:0.86. The frequency analysis of total length indicated that the fishes with the total length of 30 - 50 mm were one year old, those of 50 - 65 mm were two years old, those of 65 - 75 mm were three years old, and those of 75 mm or more were four years old. The sexually mature fishes were 50 mm or longer for female and 60 mm or longer for male. The spawning season was from April to July, and the water temperature was $12.3-14.3^{\circ}C$ during the period. The prosperous spawning season was from June to July, and the water temperature was $13.8-4.3^{\circ}C$ during the period. The average number of eggs in the ovaries was 508 per matured female, and the matured eggs were yellowish and spherical with a mean diameter of $1.58{\pm}0.13mm$. The length-weight correlation of P. phoxinus was $BW=0.000007TL^{3.09}$ with the constant a as 0.000007 and the parameter b as 3.09. The condition factor (K) was 0.99 (0.76 - 1.32) in average.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.90-100
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• 2019

This study was carried out from March to November, 2013 to investigate the fish community structure and distribution characteristics of Phoxinus phoxinus and Rhynchocypris kumgangensis appearing in Gihwacheon Stream, Pyeongchang. A total of 6 families and 19 species of fish emerged during the survey period. The dominant species were R. kumgangensis (Individuals 44.7%, Biomass 30.2%) and P. phoxinus (Individuals 27.7%, Biomass 15.9%). Endemic species were 10 species including Pseudopungtungia tenuicorpus, Coreoleuciscus splendidus, Hemibarbus mylodon, Gobiobotia brevibarba, Microphysogobio longidorsalis, R. kumgangensis, Zacco koreanus, Korecobitis rotundicaudata, Iksookimis koreensis and Coreoperca herzi. Endogenous species were P. tenuicorpus, G. brevibarba and P. phoxinus. Hemibarbus mylodon was a natural monument. Oncherhynchus mykiss was exotic species and translocated species was Oncorhynchus masou masou. The dominant species, R. kumgangensis, appeared at all survey sites. Except for St.6, the b value was more than 3.0 and the slope of K value showed positive correlation. P. phoxinus appeared in St. 3~St. 6 and St. 3 and St. 4 only showed stable populations.

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.461-462
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• 2004

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.52-52
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• 2003

For the evaluation of hormonal control of spermiation in fish, a method to quanify the spermiation response or mature Rhynchocypris oxycephalus (Sauvage and Dabry) to hormonal therapy is described. Spermatocrit was determined after 7 min centrifugation at 18,000 $\times$ｇ and sperm density was estimated by a standard hemocytormer method. Sperm density can be predicted from spermatocrit since their relationship is linear as described by the regression equation, Y=3.68X-27,18 ($R^2$=0.82, N=50), where Y is spermatocrit and X is sperm density. Milt production by mature R. oxycephalus was highest at 24 h after injection of 1,000 IU human chorionic gonadotropin (HCG) and 50 $\mu\textrm{g}$ luteinizing hormone-releasing hormone analogue (LHRHa) per kg body weight. Increased milt production coincided with low spermotocrit and sperm density levels. These results demonstrate that spermition in mature R. oxycephalus can be reliably evaluated by a spermatocrit method and that HCG and LHRHa are effecove in stimulating of spermiation in this species.

• Animal Systematics, Evolution and Diversity
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• v.27 no.2
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• pp.151-158
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• 2011

Fish community structure in the Pyeongchanggang River was investigated from April to November 2009. About 900 individuals representing 24 species from eight families at six sites in the Pyeongchanggang River were collected. It was similar to the 2001's survey and it was less than 2006's survey. The Korean endemic species, Zacco koreanus was the most abundant, whereas subdominant species were native species, such as Pungtungia herzi, Zacco platypus, Rhynchocypris kumgangensis and Rhynchocypris oxycephalus. Three endangered species were collected at the sampling area, Acheilognathus signifier (relative abundance [RA] 0.9%), Pseudopungtungia tenuicorpa (RA 1.4%), and Cottus koreanus (RA 3.6%). One natural monument species, Hemibarbus mylodon, was included. According to the analysis of ecological indicator characteristics, the relative proportion of tolerant species was 6.3% (57 individuals), whereas the proportion of sensitive species was 65.9% (593 individuals). Species evenness, richness and diversity indices decreased gradually through the month from April to November during the study. Community indices in Pyeongchanggang River showed a high evenness index (J'>0.6), a low level of species richness (R<3.5) and a medium level of diversity (1.5

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.446-455
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• 2004

The ichthyofauna and community structure in Hongcheon river, Korea, was investigated from April to October 2002. During the surveyed period, 52 species belonging 11 families were collected. There were 23 Korean endemic species (44.23%), including Rhodeus uyekii, Acheilognathus signifer, A. yamatsutae, Coreoleuciscus splendidus, Koreocobitis rotundicaudata and Silurus microdorsalis. Dominant species were Zacco platypus (20.38%), and subdominant species were Z. temmincki (19.62%). Also, Rhynchocypris oxycephalus (8.45%), Pungtungia herzi (8.01%), C. splendidus (6.63%) were numerous. Of the 6 introduced fishes in Hongcheon river Carassius cuvieri, Lepomis macrochirus and Micropterus salmoides were originated from foreign countries but Anguilla japonica, Gymnogobius urotaenia, Rhinogobius giurinus were introduced from other native river systems. According to the fish distribution, the fish community of Hongcheon river was divided into 4 groups by principle component analysis (PCA).

• Korean Journal of Ichthyology
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• v.11 no.2
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• pp.177-183
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• 1999

This study was conducted to observe the spawning behavior and early life history of chinese minnow, Rhynchocypris oxycephalus reared in the laboratory. The spawning period of Rhynchocypris oxycephalus is from May to June in nature. The eggs of Rhynchocypris oxycephalus were spawned on the sand and surface of the gravel. The fertilization eggs were demersal in shape and adhesive, released as a clump forming a thin layer and their diameter were 1.70~1.90mm (mean 1.80 mm, n=20). Hatching of eggs was started in 88 hour 45 minute after fertilization at water temperature $19{\pm}0.5^{\circ}C$ and finished in 90 hour. Newly-hatched larvae were measured 4.87~5.02 mm in total length (TL, mean 4.94 mm), mouth and anus were not opened. 6 days old larvae were 6.32~6.56 mm in TL (mean 6.44 mm). Yolk sac was almost absorbed, mouth and anus was began to open. 13 days old larvae were 6.74~6.91 mm in TL (mean 6.82 mm). Part of Dorsal fin was began to rising and myomere number was 15+23=38. 25 days after hatching, total length of larvae was 8.45~8.60 mm (mean 8.52 mm). Dorsal and anal fin rays became differentiated, and also caudal part of the notocord flexion was achieved at $45^{\circ}C$. In the time, growth rate was higher than the other stage. Aggregate numbers of all fin rays were completed at 16.39~16.57 mm in TL (60 days after hatching), at which time the larvae reached the juvenile stage, but fin-fold on ventral was remained yet. External features of adult specimens were almost completed at 80 day old juveniles (18.69~18.87 mm in TL).

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.351-368
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• 2004

Following the previous experiments, a starvation experiment was conducted to determine the influence of feeding and starvation on the histological and biochemical changes, the morphormetric changes in the sectioned body and the morphometric changes in Rhynchocypris oxycephalus (Sauvage and Dabry). The influence of starvation on nutritional conditions of the histological changes of hepatocyte and intestinal epithelium as hepatosmatic index (HSI), protein, RNA and DNA concentrations of liver in R. oxycephalus was tested. Although the starved group showed higher concentrations of protein, DNA and RNA than the fed group, food deprivation resulted in a decrease in the HSI, hepatocyte nucleus size and nuclear height of the intestinal epithelium. The RNA - DNA ratio appears to be a useful index of nutritional status in R. oxycephalus and may be useful for determining if R. oxycephalus is in a period of rapid or slow growth at the time of sampling. Additionally, the data have been interpreted in detail and some biologically important relationships discussed. The effects of starvation on the morphometrical changes in sectioned body traits, condition factor, viscera index and dressing percentage were determined for evaluating nutritional conditions of R. oxycephalus. Starvation for nine weeks resulted in a decrease in most sectioned traits as well as in condition factor and viscera index (P<0.05). These findings suggest that nutritional parameters used in this study appear to be a useful index for nutritional status in this species. The data has been interpreted in detail and some important body sectioned values of interest to commercial growers discussed. A 75-day study was conducted to determine the effect of starvation on classical and truss parameters in R. oxycephalus. Truss dimensions of almost the entire head and trunk region as well as the abdomen were increased significantly through feeding or starvation (P<0.05). Truss dimensions of the caudal region generally decreased through feeding or starvation, particularly those dimensions at the hind part of the trunk. There were some significant decreases in classical dimensions of the head region during feeding, in relation to body depth characteristics in the trunk and caudal region during starvation, whereas there was only one decreasing classical dimension in the caudal region during feeding. The results of this study indicate that application of the truss network as a character set enforces classical coverage across the body form, discrimination among experimental groups thus being enhanced. Considering that the dimension of the lower part of the head and some truss and classical dimensions were least affected by feeding and starvation, these dimensions may then be useful as a taxonomical indicator to discriminate the species of Rhynchocypris sp. The value of trunk region dimensions with a large component of body depth in R. oxycephalus is most likely to be compromised by variability related to differences in feeding regimes of fish in different habitats.

• Applied Microscopy
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• v.40 no.1
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• pp.1-8
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• 2010

The ultrastructure of spermatogenesis and sperm in Chinese minnow, Rhynchocypris oxycephalus belonging to Leuciscinae was investigated by light and electron microscopes. The whitish testis was located between intestine and air bladder. The size of testis was major axis 2.3 cm, minor axis 6 mm. The testis contained numerous testicular cysts, and spermatogenesis was non-synchronized in these testicular cysts. In the case of spermatogonium, the nucleus was comparatively large ellipsoidal, and mitochondria showed a marked development. The size of primary spermatocyte was smaller than that of spermatogonia, and secondary spermatocyte was smaller than primary spermatocyte. The chromatin of spermatocyte was highly condensed according to their development. The nucleus with electron-dense was round shape. In spermiogenesis, flagella started to be formed and chromatin was more condensed. The mitochondria were rearranged in a middle piece. The sperm was formed by loss of cytoplasm. The head of mature sperm was a spherical shape and have not acrosome. The microtubules of flagella were arranged 9+2 structure. Also, the tail of sperm have not lateral fins.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.3
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• pp.215-220
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• 2010

An experiment measuring the concentration ratios of $^{137}Cs$ and $^{85}Sr$ in fish as an index aquatic animal was performed. The species was Chinese minnow (Rhynchocypris Oxycephalus), a Korean native freshwater species. Chinese minnows were reared in acryl aquarium which was 45 cm wide, 85 cm long and 50 cm high. Water in the aquarium was successively purified using filtering devices attached on the floor and the wall. Fish powder in a particulate form was supplied twice a day for feeding. After a radioactive solution was added to make the initial water concentrations approximately $0.02\;{\mu}Ci/l$ and $0.1\;{\mu}Ci/l$ for $^{137}Cs$ and $^{85}Sr$, respectively, the fish and water were sampled 10 times for a month. The concentration ratios were measured to be $0.348lkg^{-1}\sim13.906lkg^{-1}$ for $^{137}Cs$ and $0.474lkg^{-1}\sim13.089lkg^{-1}$ for $^{85}Sr$.