• Title/Summary/Keyword: gonadal cycle

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Gonadal Maturation and Reproductive Cycle In Oblong Rockfish, Sebastes oblongus (황점볼락, Sebastes oblongus의 성숙과 생식주기)

  • Chang Young Jin;Lim Han Kyu;Byun Soon Gyu
    • Journal of Aquaculture
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    • v.8 no.1
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    • pp.31-46
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    • 1995
  • Gonadal maturation and annual reproductive cycle in ovoviviparous oblong rockfish, Sebastes oblangus on the basis of monthly gonadosomatic indices (GSI), hepatosomatic indices (HSI) and histological observations of gonadal tissues. GSI values of female were in a wide range from $0.l5\pm0.0l\;(July)\;to\;58.54\pm3.86$ (December) and began to increase in August and reached the maxium in December, then decreased rapidly thereafter. Male GSI values were in a range from $0.08\pm0.03$ (July) to $1.55\pm0.27$ (September) and began to increase rapidly in July and reached the maximum in September, then decreased gradually, thereafter. Female HSI was in a range from $0.89\pm0.12$ (December) to $3.73\pm0.15$ (October), and male's was from $2.09\pm0.76$ (October) to $3.62\pm0.48$ (August). HSI reached the maximum values one or two months before GSI reached their maxium values in both sex, and then decreased rapidly thereafter. Mature oocytes began to appear in late October as being oocytes began to mature in August, and the type of oocyte development is categorized in the roup-synchronous oocyte development'. Ovulation and fertilization of ripe oocytes occurred in November, and hatched larvae were born from December to January. Maturation of testis was progressed in short term from August to October and spermatozoa were released in October. Sperm balls consisted of many spermatozoa were preserved in ovarian cavity of female after copulation. These results may suggest that the annual reproductive cycle of oblong rockfish could be divided into the following successive stages: growing (August and September), mature (September and October), gestation (November and December), parturition (December and January) and resting (February to July) in female, and growing (August and September), mature (September and October), copulation (October) and resting (November to July) in male.

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Sexual Maturation and Artificial Spawning of the Hard Clam, Meretrix Iusoria (Bivalvia: Veneridae) on the West Coast of Korea

  • Chung, Ee-Yung;Kim, Yong-Min;Hur, Young-Baek;Ryu, Dong-Ki
    • The Korean Journal of Malacology
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    • v.21 no.2 s.34
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    • pp.81-93
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    • 2005
  • Reproductive cycle with the gonadal phases, first sexual maturity, artificial spawning amount by the size and spawning interval of the hard clam, Meretrix lusoria were investigated by histological observations and morphometric data by artificial spawning induction. Meretrix lusoria is dioecious and oviparous. The reproductive cycle of this species can be classified into five successive stages: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (June to September), and spent/inactive stage (September to February). The spawning period was from June to September, and the main spawning occurred between July and August when the seawater temperature exceeds over $20^{\circ}C$. Percentage of first sexual maturity of female and male clams ranging from 40.0 to 45.0 mm in shell length was over 50%, and all clams over 50.0 mm in shell length sexually matured. Female and male clams ranging from 40.0 to 45.0 mm in shell length are considered to be two years old. Therefore, we assume that the hard clams of both sexes begin reproduction from two years of age. The mean number of the spawned eggs increased with the increase of size (shell length) classes. In case of artificial spawning induction, the number of spawned eggs from the clams of a sized class was gradually decreased with the increase of the number of the spawning frequencies (the first, second, and third spawnings). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning was estimated to be 15-18 days (average 17 days).

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Reproductive Cycle of the Spring-Spawning Bitterling, Rhodeus uyekii(Pisces : Cyprinidae) (각시붕어, Rhodeus uyekii의 생식주기)

  • An, Cheul-Min
    • 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.

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Reproductive Cycle and Gonadal Development of the Naked-Headed Goby, Favonigobius gymnauchen (Teleostei : Gobiidae) (날개망둑 (Faronigobius gymnauchen)의 생식주기 및 생식소 발달)

  • LEE Jung Sick;KIM Jae Won;KANG Ju-Chan;SHIN Yun Kyung;CHIN Pyung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.33 no.3
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    • pp.219-224
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    • 2000
  • Reproductive biology of the naked-headed goby, Faronigobius gymnauchen was investigated by means of histological methods. The ovary was consisted of several ovarian lamellae and the oogonia originated from the inner surface of the ovarian lamella. The testis was seminiferous tubule One in internal structure. Seminiferous tubule was consisted of many testicular cysts which contained numerous germ cells in a same developmental stage. The size of group maturity was 4.5 cm intotal length. Gonadosomatic index(GSI) of the female and male was the highest in June and July, respectively. Reproductive cycle could be classified into the growing ($January{\~}March$), maturation ($April{\~}May$), ripe and spent (June{\~}July$), and recovery and resting ($August{\~}December$). Oocyte development was group-synchronous, and yolk nucleus was observed in the early growing oocyte.

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Experimental Studios on the Mechanism of Reproductive Cycle in the Longchin Goby Chasmichthys dolichognathus (HILGENDORF) (점망둑, Chasmichthys dolichognathus의 생식기구에 관한 실험적 연구)

  • BAEK Hea Ja;LEE Taek Yuil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.18 no.3
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    • pp.243-252
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    • 1985
  • The mechanism of reproductive cycle of longchin goby Chasmichthys dolichognathus was investigated for the annual variations of gonadosomatic index(GSI), histological changes of gonad, reproductive cycle, and initiating and terminating factors of the breeding season. The experimental fish were captured in the tide pool of Tongbaeksom, Pusan, Korea from February 1983 to September 1984. Experimental fish for the study of initiating and terminating factors of the breeding season were maintained in filtered recirculating aquariums and exposed to various temperature and photoperiod regimes. The ovary is a pair of sac-shaped organ, and the testicular structure is tubular and it is connected to the seminal vesicle which is located at the posterior end of the testis. GSI began to increase from February when the water temperature began to increase and reached peak in April. It began to decrease from August, the top water temperature season, and maintained relatively low values until January. The annual reproductive cycle includes successive six developmental stages : early growing from December to February, late growing from January to March, early mature from February to May, late mature and ripe from March to August, spawning from April to July, degeneration and resting stage from May to December. An experimental study based on the reproductive cycle of this species indicated that rising temperature under long photoperiod during spring stimulated gonadal maturation, whereas terminating factor of the breeding season with recrudescence of the gonads was demonstrated as high water temperature during summer regardless of photoperiod.

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Histological Study on the Reproductive Cycle of Coilia nasus (웅어, Coilia nasus의 생식주기에 관한 조직학적 연구)

  • 이봉우;정의영;이정열
    • Journal of Aquaculture
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    • v.16 no.3
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    • pp.179-186
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    • 2003
  • Reproductive cycle, gonadal development and the spawning period of the Korean anchovy Coilia nasus were investigated by histologhical observations. Samples were collected at the coastal area of Geumgang dyke which is connected to Gunsan and Janghang, Korea, from February 2002 to January 2003. C. nasus is dioecious; the ovary consists of a pair of saccular structure with many ovarian lobules, and the testis consists of a pair of lobular structure with many testicular lobules and connected to the posterior seminal vesicle. Monthly changes in the gonadosomatic index (GSI) began to increase in April when seawater temperature increased and reached the maximum in June when the ovary was getting mature, the summer season of longer day length with higher water temperature. The reproductive cycle can be classified into five successive stage in females: early growing stage (February to March), late growing stage (March to April), mature stage (May to June), ripe and spent stage (June to July), and recovery and resting stage (July to January): in males, the cycle can be divided into four successive stages; growing stage (February to April), mature stage (May to July), ripe and spent (June to July), and recovery and resting stages (July to January). According to the frequency distributions of egg diameters in the spawning season. C. nasus is presumed to be summer spawning species and polycyclic species to spawn 2 times or more during the spawning season.

Gametogenic Cycle and the Spawning Season by Quantitative Statistical Analysis and the Biological Minimum Size of Cyclina sinensis in Western Korea

  • Chung, Ee-Yung;Lee, Chang-Hoon;Park, Young-Je;Choi, Moon-Sul;Lee, Ki-Young;Ryu, Dong-Ki
    • The Korean Journal of Malacology
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    • v.27 no.1
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    • pp.43-53
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    • 2011
  • The gametogenic cycle and the spawning season in female and male Cyclina sinensis were investigated by quantitative statistical analysis using an image analyzer system, and the biological minimum size (the size at 50% of sexual maturity) was calculated by combination of quantitative data by size and von Bertalanffy's equation. Compared the gametogenic cycle by quantitative statistical analysis with the previous qualitative results in female and male C. sinensis, monthly changes in female and male gametogenic cycles calculated by quantitative statistical analysis showed similar patterns to the gonadal stages in female and male reproductive cycles by qualitative histological analysis. Comparisons of monthly changes in the portions (%) of each area to eight kinds of areas by quantitative statistical analysis in the gonads in female and male C. sinensis are as follows. Monthly changes in the portions (%) of the ovary areas to total tissue areas in females and also monthly changes in the portions of the testis areas to total tissue areas in males increased in March and reached the maximum in May, and then showed a rapid decrease from June to October. Monthly changes in the portions (%) of oocyte areas to ovarian tissue areas in females and also monthly changes in the portions of the areas of the spermatogenic stages to testis areas in males began to increase in March and reached the maximum in June in females and males, and then rapidly dropped from July to October in females and males when spawnig occurred. From these data, it is apparent that the number of spawning seasons in female and male C. sinensis occurred once per year, from July to October. Monthly changes in the number of the oocytes per mm2 and in the mean diameter of the oocyte in captured image which were calculated for each female slide showed a maximum in May and reached the minimum from December to February. Therefore, C. sinensis in both sexes showed a unimodal gametogenic cycle during the year. The percentage of sexual maturity of female and male clams ranging from 25.1 to 30.0 mm in length was over 50% and 100% for clams over 40.1 mm length. In this study, the biological minimum size (sexually mature shell lengths at 50% of sexual maturity) in females and males were 26.85 and 26.28 mm, respectively.

Induction of Intersex and Masculinization of the Equilateral Venus, Gomphina veneriformis (Bivalvia: Veneridae) by Zinc

  • Ju, Sun-Mi;Park, Jung-Jun;Lee, Jung-Sick
    • Animal cells and systems
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    • v.13 no.3
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    • pp.339-344
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    • 2009
  • This study aims to find out the effect of heavy metals, as is the case of EDCs (endocrine disrupting chemicals), on reproductive endocrine disruption of aquatic animals. In the present experiment zinc, which is a heavy metal well known for its androgenous activity, was used. The experimental period was 24 weeks, starting in November during the inactive stage of the clam's reproductive cycle. The experimental groups were composed of one control condition and three zinc exposure conditions (0.64, 1.07, and 1.79 mg/L). The sex ratio (F:M) was 1:1.06 in the control group and 1:1.70 in all the exposed group, illustrating the tendency for higher proportion of males with increases in zinc concentration. Gonad maturity was higher in 1.07, and 1.79 mg/L groups compared to the control group, with higher maturity observed in males than females. Intersex individuals made up 24.7% of the exposed group, while females exhibited a higher ratio than the males with increasing zinc concentration. The results of this study indicate that zinc functions as an androgenic effector on the reproduction of Gomphina veneriformis.

Reproduction study of purplish Washington clam, Saxidomus purpuratus in Jinhae bay, Korea : Spawning and shell length at 50% sexual maturity (한국 진해만 해역에 분포하는 개조개, Saxidomus purpuratus의 재생산 연구 : 산란 및 군성숙각장)

  • Lee, Sun Kil;Chang, Dae Soo;Kim, Jong Bin;Park, Mi Ae
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.49 no.4
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    • pp.449-458
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    • 2013
  • This study investigated purplish Washington clam, Saxidomus purpuratus on its gonadal development, reproductive cycle and shell length (age) at 50% female group maturity from January to December 2011 in Jinhae Bay, Korea. This species is dioecious. The gonad index (GI) began to increase in January, reached the maximum value in May and to decrease in June, reached the minimum value in September then to increase slowly in October again. The reproductive cycle of the clams can be divided into five successive stages: the early active stage (Ea, from February to March), the late active stage (La, from January to March and October to December), the ripe stage (R, from January to May), the spawning stage (S, from June to December) and the degenerative and inactive stage (Ia, from January to February and November to December). The spawning periods were from June to December and the main spawning periods were from July to October. The shell length at 50% female group maturity (SL50) was estimated to be 63.6 mm, which can be converted as sexual maturity age of 2.2 year.

Reproductive Biology of the Female Manila Clam, Ruditapes philippinarum (Bivalvia: Veneridae) on the West Coast of Korea

  • Chung, Ee-Yung;Hur, Young-Baek;Shin, Moon0-Seup;Kim, Yong-Min
    • The Korean Journal of Malacology
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    • v.21 no.1
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    • pp.1-11
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    • 2005
  • Reproductive cycle, first sexual maturity, spawning amount related with the size and spawning interval in female Ruditapes philippinarum were investigated by histological observation and the analysis of morphometric data during artificial spawning induction. Ruditapes philippinarum is dioecious and oviparous. The reproductive cycle of this species can be subdivided into five successive stages: early active stage (January to March), late active stage (February to May), ripe stage (April to August), partially spawned stage (May to October), and spent/inactive stage (August to February). The spawning period was once a year between May and early October, and the main spawning occurred between July and August when seawater temperature was approximately $20^{\circ}C$. Percentages of first sexual maturity of female clam of 15.1-20.0 mm in shell length were 56.3%, and 100% for the clams > 25.1 mm. The mean number of the spawned eggs increased with the increase of size classes (shell length). In case of spawning induction by the same size class, the number of spawned eggs were gradually decreased with the increase of spawning frequencies (the first, second, and third spawnings). In the experiments of artificial spawning induction during the spawning season, the interval of each spawning was estimated to be 15-17 days (average 16.5 days).

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