• 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.

• Korean Journal of Ichthyology
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• v.7 no.1
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• pp.33-42
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• 1995

The reproductive cycle of the bitterling, Rhodeus uyekii was studied to observe the annual variations of gonadosomatic index(GSI), size frequency distribution of egg, ovipositor length and histological changes of gonad. GSI began to increase from February when the water temperature started to increase, and reached the maximum value in May, whereas it began to decrease from July and reached the minimum value in August which in the highest water temperature season. It began to incerase again but showed low value from September to November. The GSI remained stable thereafter. Monthly changes in GSI, ovipositor length, frequency of egg diameter and gonadal histology showed that the annual reproductive cycle was classified into the following successive phases : primary growing phase from September to November, quiescent phase in December, secondary growing and mature phase from January to February, ripe and spawning phase from March to June, and recovery and resting phase from July to August.

• Korean Journal of Ichthyology
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• v.24 no.4
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• pp.263-271
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• 2012

A female preference is a potentially complex function relating variation in multiple male traits with her probability of accepting the most optimal individuals as a mate. If mate preference is dominantly driven by additive fitness benefits, different females tend to be congruent in the decision of choice, whereas females will not necessarily share their mate preferences if non-additive benefits more strongly operate. Here, a sequential blocked design ($4{\times}4$) was applied to experimentally assess the relative contribution of additive and non-additive components to the female mate preference with Korean rosy bitterling, Rhodeus uyekii. In a total of 48 single stimulus presentations, behavioral elements of courtship activities were analyzed to derive the 'index of female preference'. Females showed a clear preference for males with more elaborate carotenoid colors, but mated randomly with respect to male body size and other color patterns. However, they were not individually consistent in their choice of mates, suggesting that non-additive components probably contribute to the evolution of female preference.

• Korean Journal of Ichthyology
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• v.24 no.2
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• pp.101-109
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• 2012

The egg development and early life history of Acheilognathus macropterus from Japan which is an exotic bitterling from China were observed under the controlled water temperature, $20.0{\pm}1.0^{\circ}C$. Fertilized eggs are opaque yellow in color and long elliptic globe shaped measuring $2.78{\pm}0.12mm$ in length and $1.44{\pm}0.04mm$ in breadth. The number of egg averaged 151 per an oviposition. The eggs of this species began to hatch about seventy eight hours after insemination and the mean of total length of larvae were 3.8 mm. S form moving of larvae were observed from three days after hatching. The larvae reached at the heterotrophic stage about twenty-five days after hatching. Morphological character and analysis of cytochrome DNA of this species from Japan were relatively similar to Korean but spawned egg shape was different remarkably. Taxonomical research is necessary in the future.

• Korean Journal of Ichthyology
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• v.18 no.2
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• pp.87-96
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• 2006

Reproduction and organ system of the oily bitterling, Acheilognathus koreensis in Isa stream were investigated by means of histological methods. Sex ratio was observed 1 : 1 in female to male. The gonadosomatic index (GSI) of the female showed two peak in December and April. The ovipositor length index (OLI) represented irregular change. From the histological analysis of the organ system, epidermal atrophy and hyperplasia of pigment cell were observed in the skin. Epithelial layer lifting of the lamella and bifurcation of the filament were observed in the gill. Also histological changes as congestion, cytoplasmic degeneration of hepatic cell, glomerular dilatation, hyaline droplet degeneration of renal tubule epithelium and pycnosis of interstitial cell were identified in the liver and kidney, respectively.

• Korean Journal of Ichthyology
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• v.24 no.1
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• pp.27-34
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• 2012

Population ecology of $Acheilognathus$ $macropterus$ was investigated at the part of the Bulgapcheon stream in Korea from March to November in 2006 and April in 2008. It mainly inhabited in slow water with sand and mud bottoms. The standard length of this population indicated that below 48 mm group is one year old, 48~58mm group is two years old, 58~64mm group is three years old and longer than 66 mm group is regarded over four years old. The sex ratio of the female to the male was 1:0.99. Spawning season from April to June with the water temperature in $15{\sim}20^{\circ}C$. The average number of eggs in ovary was $680{\pm}209$. The matured egg size was $1.92{\times}1.60mm$. Stomach contents were mainly phytoplanktons such as the genera Navicular, Cymbella, Fragilaria.

• Development and Reproduction
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• v.18 no.1
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• pp.33-41
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• 2014

We investigated the process of yolk absorption in Korean rose bitterling, Rhodeus uyekii, and determined the changes in its morphometric characteristics. The R. uyekii from 1 days post hatching (DPH) to 21 DPH, the eye diameter (ED) was 5.4 at 5 DPH. Thereafter, the ED/total length (TL) ratio increased to 10.7 at 21 DPH (p<0.05). The yolk length (YL) decreased from 95.4 to 1.1 by 21 DPH, and this rate of decrease was greater than that for any other dimension (p<0.05). 12 morphometric dimensions/TL for the R. uyekii were measured at each sampling day from 21 DPH to 170 DPH. At just hatching, the average TL and BW were $6.1{\pm}0.09mm$ and $4.9{\pm}0.07mg$, respectively. At 53 DPH, the average TL was $12.9{\pm}0.28mm$ and the average BW was $14.7{\pm}0.72mg$; the total length growth equation was $TL=5.507e^{0.038t}$ ($R^2=0.916$). Further, the body weight growth equation was $BW=3.3647e^{0.0296t}$ ($R^2=0.9354$). The dimensions with regard to body depth showed the greatest growth rates in the external characteristics of the fish (p<0.05). The patterns of the morphometric characteristics measured in this study can be classified in three ways. The patterns were shown to be increased (y=0.0992x+12.07, $R^2=0.8333$), decreased (y=-0.0569x+42.029, $R^2=0.8395$) or maintained (y=0.005x+18.263, $R^2=0.3678$) from 21 DPH to 170. These results will provide useful indices for the successful rearing of the R. uyekii.

• Animal cells and systems
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• v.12 no.4
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• pp.297-304
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• 2008

Morphology and distribution of the minute tubercles projected on the skin surface of larvae with its development were observed in the Korean bitterling, Acheilognathus somjinensis. The minute tubercles appeared to be two distinct morphologies, hemispheric or scaly and vestigial structures. Just after hatching, the epidermis of the larvae consists of a thin single cell layer having smaller basophilic flat or round-flattened basal cells. As the larvae grow, the epidermis contains more small flat cells and large epidermal cells which are round and hemispheric, or scaleshaped, called minute tubercles. They are distributed over the anterior part and most part of yolk sac, posterior region of yolk sac and the body region. Vestigial epidermal cells, another minute tubercle, occur only in the caudal fin-fold region, which they are shrunken and flattened, causing the cell boundary to be unclear. They increase in number and height from just to 5 days after hatching, but they become reduced as the larvae develop gradually. The required time for those disappearance was different each by regional body: at day 20 after hatching in the anteriormost part of yolk sac, and day 11 after hatching in the posterior part of yolk sac and the body, and day 21 after hatching in two regions such most part of the yolk sac and the caudal finfold regions.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.115-120
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• 2010

Genetic variation and population structure of the slender bitterling Acheilognathus lanceolatus of Korea (the Han, Geum, Dongjin, Seomjin and Nakdong Rivers) and Japan (the Katsura River) were assessed by amplified fragment length polymorphism (AFLP) analysis. Five combinations of selective primers generated 345~374 DNA fragments, of which 55~131 were polymorphic. The Nakdong River population had the highest genetic diversity and the Han River population had the lowest genetic diversity. Dendrogram based on the distance matrix revealed that individuals from each population consistently clustered together and bifurcated into two distinct clades (or population groups) composed of the Han, Geum, Dongjin and Seomjin River populations and of the Nakdong and Katsura River populations, supported with high bootstrap values. The pairwise genetic differentiation ($F_{ST}$) estimates showed that the six populations were genetically well differentiated (P<0.01). The analysis of molecular variance (AMOVA) after partitioning the six populations into two population groups revealed very strong biogeographic structuring between them with 25.49% of total variance (P<0.01). Taken together, the AFLP markers clearly divided six A. lanceolatus populations into two population groups.

• Korean Journal of Ichthyology
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• v.27 no.2
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• pp.78-85
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• 2015

Population ecology of Rhodeus uyekii (Pisces: Acheilognathinae) was investigated at the Bongseocheon, Mankyeonggang (River) in Korea, from January to December 2014. It mainly inhabits the slow-flowing waters having mud bottoms. Measurement of the standard length of the population indicated that the following standardization: 24~29 mm are one year old, 30~35 mm are two years old, 36~39 mm are three years old, and >40 mm group are regarded over four years old (October in 2014). The spawning season was from March to June, with water temperatures in the range $11.5{\sim}27.0^{\circ}C$. The sex ratio of female : male was 1 : 0.77. The number of eggs in the ovaries was 104~168 ($mean{\pm}SD$: $124{\pm}18.1$). The size of the matured eggs was 2.8~3.5 ($3.2{\pm}0.15$) mm in the long axis, and 1.4~1.5 ($1.4{\pm}0.03$) mm in the short axis. The eggs were found in Unio douglasiae and the number of eggs, larvae or both was 3~18 ($10.2{\pm}5.0$). Stomach contents were mainly phytoplanktons such as the genera Navicular, Cocconeis, Cymbella (Bacilariophyceae) and Cloniophora (Chlorophyceae).