• Journal of Aquaculture
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• v.4 no.2
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• pp.85-95
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• 1991

Spawning inducement of flounder, Paralichthys olivaceus, was attemped by the control of water temperature and photoperiod from June 1, 1989 through January 5, 1990 (189 days) Water temperature was gradually decreased from $21.7^{\circ}C$ to $10.6^{\circ}C$ which was the minim biological temperature for spawning of flounder. Water temperature was increased asain to $15^{\circ}C$ gradually, and then maintained at this level through the end of spawning. Photoperiod was also changed gradually from 10L/14D in June 1, 1989 to 14L/10D in July 25, 1989. Spawning of the fish occurred from October 4, 1989 through January 5, 1990 (93 days). The average number of eggs spawned during the spawning season per female were 2.67 billion. The first spawning occurred on the 60th day after the time of minimun water temperature $10.6^{\circ}C$. The water temperature and photoperiod at the first spawning were $13^{\circ}C$ and 14L/10D respectively It took 71 days to spawn since the photoperiod had changed from 10L/14D to 14L/10D. Spawning period can be devided into three terms. The first term was continued for 30 days from the beginning of the spawning. The second term for 41 days was the major spawning period followed by the third term, the final period of the spawning, for 22 days. The percentage of average fertilization rate of the eggs in the first, second and third spawning terms were $37.4{\%},\;54.1\%\;and\;19.6\%$, respectively. Feeding rate was increased in the maturing period but, decreased in the spawing period. During the final spawning period, the abrubt decreasing of the feeding occurred again.

• 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.

• Development and Reproduction
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• v.25 no.3
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• pp.145-155
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• 2021

Reproductive cycle of the blue-striped angelfish, Chaetodontoplus septentrionalis were histologically investigated. Fish were monthly collected in the coastal waters of Munseom, Seogwipo, Jeju-Island from February to December 2018. The gonadosomatic index (GSI) increased from May and maintained high values in August. The reproductive cycle of female fish can be classified by the characteristics observed during gonadal development as followed: growing stage (November to June), early mature stage (May to June), mature and spawning stage (June to September), and degenerative and recovery stage (September to December). In the male, testicular development period was similar to that of ovarian development period, but mature and spawning period was one month longer from June to October. Fecundity of mature female ranged from 4,601 to 22,840 and was correlated positively with total length and body weight. The histological analysis of gonadal development indicated that the C. septentrionalis was summer-spawning type and is considered a multiple spawner during spawning season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.4
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• pp.251-255
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• 1976

Three hundred and sixty two specimens of Plecoglossus altivelis were randomly sampled from Chunji Stream in Seogwipo, Cheju-Do, during the period from 25 Aug., 1973 to 14 Feb., 1974 to investigate the relationship between total length and dody weight as well as the condition factor during the spawning period. Results obtained are summarized as follows : The relationships between total length and body weight are calculated as below, respectively : $W=0.008639\;L^{3.1806}$ : Prior to spawning period $W=0.01830\;L^{2.7689}$ : During spawning period The above equations differ each other significantly. Nevertheless, the significant difference is not found between sexes. The mean body length decreased during the spawning season. The fact seems to be caused by the death of large fish after spawning. The condition factor was $13.45\%_{\circ}$ on the average in August. The value decreased continuously from September, giving the minimum mean value of $10.25\%_{\circ}$ on Nobember 29. But the value increased again, showing $11.18\%_{\circ}$ in next February. Majority of the fish survived until next year was small ranging from 11 to 12cm in total length.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.739-744
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• 2015

The sexual maturation and spawning time of female ocean sunfish Mola mola in Korean waters were studied by observing the gonads histologically. Specimens were purchased in a fish market in October 2013 and May, June, and October 2014. Nine females (total length 100-250 cm, gonad weight 31-3,470 g) and one male (total length 131 cm, gonad weight 60 g) were studied. Histologically, the ovaries became active in May and spawning began in July and continued until October. In July, mature oocytes and yolk globule stage oocytes were observed; parts of the gonad showed traces of spawning, while others had degenerated and absorbed any oocytes. By October, many oocytes had degenerated and been absorbed. Therefore, the approximate spawning period of ocean sunfish is from July to October based on histological changes in the gonads. The asynchronous oocyte development suggests that the ocean sunfish is a multiple spawner, as reported previously. The catch distribution data suggest that the waters around Jeju Island are a sunfish spawning area.

• Korean Journal of Ichthyology
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• v.28 no.2
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• pp.93-99
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• 2016

Spawning period and spawning characteristics of Kichulchoia multifasciata (Pisces: Cobitidae) inhabiting the Yugokcheon (stream) of Nakdonggang (river) were investigated in the area of Segangyo (bridge), Yugok-myeon, Uiryeng-gun, Gyeongsannam-do, Korea from November 2008 to October 2009. The total length of population indicated that 45~55 mm group is one year old, 55~75 mm group is two years old and longer than 75 mm is regarded over three years old in males and 40~55 mm group is one year old, 55~75 mm group is two years old, 75~95 mm group is three years old and longer than 95 mm is considered over four years old in females (January 2009). It has predicted that the spawning period is from May to June (water temperature in the range $21.0{\sim}26.6^{\circ}C$). Sexually matured individuals appeared over the two years old. The number of eggs in the ovaries was 202~747 ($491{\pm}154.0$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.1-8
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• 2020

The reproductive biology of largehead hairtail Trichiurus japonicus, from near Jeju Island, Korea was investigated based on 4,384 individuals collected by commercial vessel from November 2016 to October 2019. There were more female specimens than male specimens (2.64:1). T. japonicus preanal lengths (PL) ranged from 10.5 to 53.5 cm; the relationships between PL and body weight (BW) were BW=0.0103PL^3.1293 for females and BW=0.0106PL^3.1251 for males. Monthly changes in gonadosomatic index were analyzed to estimate spawning season. The spawning period ranged from June to November. The size-frequency distribution of eggs suggested that T. japonicus exhibits multiple-spawning during a spawning period. The minimum size of females at maturity was 18.2 cm, while the size at sexual maturity was 25.0 cm.

• Journal of Aquaculture
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• v.10 no.1
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• pp.63-68
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• 1997

The spawning behavior of the silurid catfish, Silurus asotus, was observed from laboratory aquaria after treating with human chorionic gonadotropin (HCG) and injection with pituitary extract of grass carp. The details of the spawning behavior presented here are based upon the observations made from 10 trials with 40 male and 20 female catfishes artificially bred between May and July, 1995. Initial spawning activity started 15 to 16 hours after injection with pituitary extract of grass carp and HCG. The activity was continued with for 2 to 3 hours and repeated mating behavior of the catfish were observed during this period. Compared to the spawning activity of the Japanese catifish, S. biwaensis, S. asotus took a different male position during the period o fsearching its partner. This study also reports some other differences in mating behavior between S. asotus and S. biwaensis.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.633-641
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• 2009

Maturity and spawning of the atka mackerel, Pleurogrammus azonus, was investigated based on the samples collected by gill net and set net in the East Sea from January 2006 to March 2009. Gonadosomatic index (GSI) began to increase in October, and reached a maximum between November and December. After spawning GSI began to decrease from January. The spawning period was from October to January, and main spawning period was from November to December. Annual reproductive cycles of this species could be divided into five successive stages in females; early growing stage (June), late growing stage (July to August), mature stage (September to October), ripe and spent stage (November to January), and recovery and resting stage (January to May). Males showed four successive stages: growing stage (June to August), mature stage (September to October), ripe and spent stage (October to December), and recovery and resting stage (January to May). P. azonus could be one of polycyclic species spawning two times or more during one spawning season. Number of total and mature eggs in the fecundity were proportional to fork length. The fork length at 50% group maturity was estimated to be 26.9 cm.

• Korean Journal of Ichthyology
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• v.22 no.2
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• pp.121-125
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• 2010

To investigate the relationship between total length and fecundity of Pacific cod Gadus macrocephalus in Jinhae Bay, 45 individuals were sampled during the spawning period from Dec 2008 to Feb 2009. Fecundity ranged from 560,000 to 5,200,000 eggs for fish ranging from 64.0 cm to 74.0 cm in total length. The relationship between total length (TL) and fecundity (F) was F=103,273TL-5,124,302 and fecundity in Pacific cod from this study was correlated with total length. Average fecundity decreased from 2,620,000 eggs in early-spawning period to 1,650,000 eggs in late-spawning period. The wide range of relative fecundity at the same body size indicates that the timing of the spawning migration of Pacific cod in Jinhae Bay could be related to fecundity.