• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1220-1225
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• 1999

Differences in carotenoid composition in the integument of Korean bittering, Cheilognathus signifer and bride bittering, Rhodeus ukekii which are Korean native fresh water fish were compared. Total ca rotenoid contents in the integument of wild Korean bittering was 2.11mg% and composed of 42.6% zeaxanthin, 12.1% diatoxanthin and 12.1% lutein epoxide which are predominant carotenoids and 10.3% cynthiaxanthin, 8.3% zeaxanthin epoxide, 6.4% lutein and 1.5% cryptoxanthin which are minor carotenoids. Total ca rotenoid contents in the integument of wild bride bittering was 4.99mg% during a spawning period but after the spawning period it was decreased to 4.17mg% and carotenoid composition of bride bittering during the spawning period was 46.7% zeaxanthin, 26.5% diatoxanthin and 12.3% lutein which are predominant carotenoids, and 6.2% zeaxanthin epoxide, 3.1% cynthiaxanthin, 2.9% cryptoxanthin and 0.7% canthax anthin which are minor carotenoids. These results indicated that the carotenoid composition of bride bittering during spawning period was very similar to that of Korean bittering and carotenoid composition of bride bittering after the spawning period was 30.5% diatoxanthin, 21.5% cynthiaxanthin and 16.8% zeaxanthin which are predominant carotenoids and 14.0% cryptoxanthin, 11.3% lutein and 3.4% can thaxanthin which are minor carotenoids, indicating that after the spawning period, the content of zeaxanthin was decreased while that of cryptoxanthin and cynthiaxanthin was increased as compared to that of the spawning period. Total carotenoid contents in Korean bittering and bride bittering was relatively higher than that in other species of cyprinidae whereas composition of the carotenoid was similar.

• Korean Journal of Ecology and Environment
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• v.34 no.4 s.96
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• pp.337-341
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• 2001

Studies were conducted to determine the effects of water temperature on the number of spawning, egg production, spawning intervals and hatching success of Chinese bleak, Aphyocypris chinensis. Adult fish were exposed to water temperatures of 19, 22, 25 and $28{\circ}^C$ for two months in the laboratory. The spawning number, egg productivity, and hatching rate increased as water temperature increased between $19{\circ}^C$ and $25{\circ}^C$. Maximum egg production and hatching rate occurred at $25{\circ}^C$, whereas the spawning intervals decreased as water temperature increased except for the treatment of $28{\circ}^C$. The shortest spawning interval observed at $25{\circ}^C$.

• Korean Journal of Ichthyology
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• v.31 no.3
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• pp.141-149
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• 2019

This study presents data on spawning season, weight-length relationships (WLRs) and condition factor of Gadus chalcogrammus inhabiting the middle East Sea, Korea. Monthly changes in the gonadosomatic index (GSI) revealed that the spawning period was from December to March. Overall value of the exponent b, estimated by nonlinear least squares from weight and length data was 2.806, ranging from 2.778 for female fishes to 2.985 for immature group. The b values were similar between spawning and non-spawning, and between female and male fishes, but it was significantly higher for immature than mature fishes. The condition factors were significantly higher for immature than mature groups, and during non-spawning than spawning periods, but it was not significant between male and female fishes.

• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.20-29
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• 2023

In order to identify the spawning characteristics of Barbatula nuda, seven surveys were conducted from March to May 2021 in the Sangcheoncheon Stream, a tributary of the Bukhangang River, Korea. During the survey period, 890 individuals were collected, and the sex ratio of female to male was 1 : 1.34. B. nuda spawned 15 March to 24 April, when temperature was 12~15.7℃. Total length of the individual with minimum maturity was 56.7 mm, and it was a 1-year-old. Spawning was observed from individuals with a total length of 80.5 mm more, and it was 2-year-old. The total length at 50% group maturity was 67.2 mm. As a result of injecting 10 IU/g of HCG hormone into B. nuda, about 15 hours later, spawning behavior in which the male wrapped around the body of the female in a circle was observed. After spawning, females and males rested, and fertilized eggs were feed by individuals not participating in spawning.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.572-573
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• 2006

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.90-95
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• 2010

Blue devil (Pomacentrus caeruleus, also called Chrysiptera cyanea) is widespread in the Indo-Pacific Ocean and very popular all over the world as an aquarium fish because it is so easy to keep in a marine aquarium. However, tank-breeding techniques are not completely known. In this study, we reared blue devil and investigated its spawning ecology, as a necessary precursor for successful artificial-tank breeding. We investigated the spawning volume according to time with two types of calendars: solar and lunar. Rearing conditions were set at 30 ppt salinity, $27^{\circ}C$ water temperature, in two aquariums with water volumes of 80 and 125 L. We successfully bred P. caeruleus in this artificial-tank system. The aquarium fish formed a spawning harem with one male and more than two females. We harvested about 113,580 eggs in 44 spawning episodes by two spawning harems during the 11-month period from December to October. They showed a peak season of spawning volume and time in May and June. We confirmed the two peak points in spawning volumes and times, which coincided with the first quarter and last (third) quarter of the lunar phases of the moon.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.4
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• pp.245-250
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• 2005

The maturity and spawning of Pacific cod, Gadus macrocephalus, was studied using samples caught by gillnets in the East Sea from January to December 2003. Monthly changes of maturity observed with the naked eyes for females showed that maturing Pacific cod appeared from August, and their numbers increased to $83\%\;and\;100\%$ in November and December, respectively. In January, mature and spawning Pacific cod were observed for the first time and composed over $40\%$ of the population. In February, the proportion of spawning individuals increased to over $50\%$, however, the mature individuals decreased to less than $10\%$. In March, mature fish were not found, and all were in an immature (spent) or spawning state. From April to July all fish remained in immature condition. The males maintained this trend with the females, whereas, mature males appeared from November to March. Monthly changes in the gonadosomatic index (GSI) of females and males showed higher values both in January and February and declined sharply in March. The lower value remained until October and then began to increase from November for the female population. For the males, however, this value remained lower until August, and then began to increase from September, and showed higher values in October through December than in January and February. These results indicated that the spawning season of Pacific cod was from December to March, and the main spawning season was from January to February, and the period of the spawning season was longer for males than the females. The diameter of the matured oocytes was 0.80-1.10 mm with a single mode of 0.95 mm. Fecundity was 1,300,000-9,400,000 in total length of 65-95 cm and the relationship between the total length (TL, cm) and fecundity (Fc) was Fc= $180,248\timesTL-10,883,638$. The total length at first maturity was observed at 57 cm for females and 47 cm for males. The size at $50\%$ group maturity was estimated to be 63.9 cm for females and 56.0 cm for males.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.234-241
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• 1975

Reproductive cycle of Haliotis discus hannai Ino was studied based on the samples which were collected in Yeosu area from January, 1973 to December, 1974. Particular emphasis was paid on the seasonal variation of gonad maturity factor, coefficieot of gonad maturity, fatnesss, and relationship of gonad weight to growth of the abalone. seasonal fluctuation of water temperature and induction of artificial spawnings were also checked. The abalone of this area spawns twice a year: spring spawning(early May-late July) and Autumn spawning(early September-late November). peak spawning occurs from late May to middle of June for spring spawning: it occurs from late September to early November for Autumn spawning. Gonad maturity factor was closely related to the spawning seasons. For the spring spawning Gonad maturity factor reached to its maximum value as 18.84 in April; for the Autumn spawning it reached to its maximum value as 22.65 in September. Annual minimum value was 12.65 in January. Annual maximum values of coefficient of gonad maturity were 44.10 in May and 49.05 in September and the annual minimum was 10.09 in January. Fatnesswas highest in July as 0.221 and it was lowest in October as 0.1058. Ratios of shell length to gonad weight were formulated as follows : $$In\;September\;GW=0.000003710SL^{3.7860}$$ $$In\;January\;GW=0.000021198SL^{2.8564}$$ $$Annual\;mean\;GW=0.00000005013SL^{4.2273}$$ Relations of total weight to gonad weight were formulated as follows : In September GW=0.1918TW-4.9231 In January GW=0.0992TW-0.1759 Annual maan GW=0.1568UW-3.5256.

• 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.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.2
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• pp.188-192
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• 2018

The reproduction characteristics of hagfish Eptatretus burgeri were examined using individuals caught in the South Sea of Korea. The spawning season and size at minimum sexual maturity of this species were characterized based on a gonad-somatic index (GSI) and monthly variation egg size (long axis). From monthly variation of GSI, the spawning season was estimated to be from August to September. Developing eggs larger than 10 mm were found in March, and the largest egg size was found in July. The first spawning length was 34.2 cm TL. Batch fecundity ranged from 13 to 117 eggs for hagfish sized from 34.2 cm TL to 77.0 cm TL, respectively, and increased linearly with total length.