• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.1
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• pp.41-47
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• 2017

Perhaps the most common type of reproductive dysfunction in captive fish is failure of females to undergo final oocyte maturation and thus to ovulate and spawn. The success of aquaculture could therefore be improved by developing techniques to enhance natural spawning, artificial maturation, and/or to induce ovulation in farmed fish. This study aimed to investigate the effects of prostaglandin $E_2$ ($PGE_2$) and prostaglandin $F_{2{\alpha}}$ ($PGF_{2{\alpha}}$) on in vitro oocyte maturation (germinal vesicle breakdown, GVBD) and ovulation in the marine fish Chasmichthys dolichognathus. Post-vitellogenic follicles (0.80-0.94 mm diameter oocytes) were incubated with $PGE_2$ or $PGF_{2{\alpha}}$ at concentrations of 5, 50, or 500 ng/mL for 24 hours. A significant increase in GVBD was seen in 0.84 mm and 0.94 mm oocytes incubated with 50 ng/mL $PGE_2$ compared with the control. There was no significant increase in GVBD in any of the other experimental conditions (5 or 500 ng/mL $PGE_2$ or 5, 50, or 500 ng/mL $PGF_{2{\alpha}}$). Neither of the prostaglandins induced ovulation at the concentrations tested.These results suggest that GVBD was induced by incubation with 50 ng/mL $PGE_2$.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.05a
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• pp.565-566
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• 2001

To investigate the food organisms of the Chasmichthys dolichognathus during the juveniles stage, the stomach contents of fish, captured in the intertidal zone of Chungchongnam-do Sochon-gun Su-myon Dodun-ri between on early June from end of May 1998, were observed. Total length of the juveniles of C. dolichognathus was 6.5mm ∼10.0mm size, and the participation rate of feeding was 67.7％. Main food organisms were such as copepods, amphipods, shrimp larvae, polychaete larvae, and these occupied more than dry weight 2％. Copepods among them dominated the most quantitys by avergage 65.5％, and next, food organismsms appeared much by order of polychaete larvae and shrimp larvae etc. Therefore, most important food organisms of juvenile stage of C. dolichognathus were copepods, polychaete larvae, shrimp larvae etc.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.37 no.3
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• pp.192-196
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• 2004

The in vitro effect of bisphenol A (BPA) on ovarian steroidogenesis of the longchin goby (Chasmichthys dolichognathus) was investigated. Oocytes taken during the maturing phase (vitellogenic, fully vitellogenic or germinal vesicle breakdown stage) were incubated with BPA (100 ng/mL) in the presence of exogenous precursor $^{3}H-17\alpha\;hydroxyprogesterone\;(^{3}H-17\alphaOHP).$ Steroids were extracted from the media and the isolated oocytes, and the extracts were separated and identified by thin layer chromatography and gas chromatography-mass spectrometry. The identities of the major metabolites were progestogens $[17{\alpha}-hydroxy,20{\alpha}-dihydroprogesterone\;(17{\alpha}20{\alpha}OHP)\;and\;17{\alpha}-hydrxy,20{\beta}-dihydroprogesterone\;(17{\alpha}20{\beta}OHP),$ androgens [androstenedione (A4) and testosterone (T)] and estrogens [estrone $(E_1)\;and\;estradiol-17{\beta}(E_2)].$ BPA treatment inhibited production of estrogens in all the maturing phases and progestogens in the germinal vesicle migrating stage. Percentage yield of estrogens was decreased with increased yield of androgens. In conclusion, BPA had an inhibitory effect on the conversion of $^3H-17\alphaOHP$ to estrogens and progestogens. These results demonstrate that BPA can act either estrogenic or anti-estrogenic effects.

• Development and Reproduction
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• v.23 no.2
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• pp.111-117
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• 2019

This study focused on the association of prostaglandins and a progestin, $17{\alpha}$, $20{\beta}P$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}P$) during the ovulation process in longchin goby, Chasmichthys dolichognathus. We performed several in vitro experiments using $850-920{\mu}m$ diameter oocytes which were at the migratory nucleus stage. With the $890-920{\mu}m$ diameter oocytes, no significant difference in ovulation was observed in any of the prostaglandins (PGE1, PGE2, and $PGF2{\alpha}$) treated groups although PGE2 and $PGF2{\alpha}$ at concentrations of 50 ng/mL increased ovulation slightly compared with controls; however, $17{\alpha}20{\beta}P$ production was stimulated with PGE1 alone at low concentrations (5 ng/mL). In $850{\mu}m$ diameter oocytes, $PGF2{\alpha}$ at concentrations of 50 and 500 ng/mL resulted in a significant increase in ovulation. $17{\alpha}20{\beta}P$ (50 ng/mL) alone had no observable effect on ovulation, but in the combined of $PGF2{\alpha}$ 50 or 500 ng/mL it caused the greatest effect on ovulation. The sensitivity of oocytes to the induction of ovulation varies between 850 and $890-920{\mu}m$, it appeared to vary depending on the migration status of nucleus. These results suggest that $PGF2{\alpha}$ (or combined of $17{\alpha}20{\beta}P$) was more potent in inducing ovulation of the longchin goby.

• Development and Reproduction
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• v.12 no.1
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• pp.107-112
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• 2008

To investigate the $C_{21}$-steroids produced from maturating oocytes in the longchin goby, Chasmichthys dolichognathus, the oocytes ($0.74{\sim}0.97\;mm$) were incubated with radiolabeled $17{\alpha}$-hydroxyprogesterone ($^3H-17{\alpha}OHP$) for 24 hours. The resulting metabolites were analyzed by thin layer chromatography and identified by gas chromatography-mass spectrometry. Two $C_{21}$-steroids, $17{\alpha}$-hydroxy, $20{\alpha}$-dihydroprogesterone ($17{\alpha}20{\alpha}P$) and $17{\alpha}$-hydroxy, $20{\beta}$-dihydroprogesterone ($17{\alpha}20{\beta}P$), were converted from $^3H-17{\alpha}OHP$ in the maturing oocytes. These two main metabolites were detected at 0.80 mm diameter oocytes or greater. In addition, the effects of these metabolites on in vitro germinal vesicle breakdown (GVBD) were tested. The sensitivity of oocytes to the induction of GVBD was greater at $17{\alpha}20{\beta}P$ than $17{\alpha}20{\alpha}P$. This result showed that $17{\alpha}20{\beta}P$ is a major maturation inducing steroid (MIS) in longchin goby, suggesting $17{\alpha}20{\alpha}P$ may play a role in regulating the oocyte maturation process.

• Korean Journal of Ichthyology
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• v.12 no.4
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• pp.259-263
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• 2000

The investigation of the fishes was conducted based on the specimens from the Wooi-Islands, southern west coast of Korea in August, 1998. The fishes were composed of 25 species and 22 genera belonging 15 families. Among them, the gobiid fishes composed of 6 species and the combtooth blennies of 3 species. The gobiid fishes, Chasmichthys dolichognathus, Tridentiger trigonocephalus and Synechogobius hasta were most commonly found in the intertidal area of these islands. One specimen collected from tidepool at tentatively identified as Abudefduf bengalensis of the family Pomacentridae for the first time from Korea. This species was characterized by having seven black bars on the trunk of body. A new Korean name "Huk-jul-dom" is proposed for this species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.2
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• pp.161-166
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• 2012

The estuarine Gobiidae $Tridentiger$ $trigonocephalus$, $Chasmichthys$ $dolichognathus$ and $Favonigobius$ $gymnauchen$ were exposed to various heavy metals. As a measure of acute toxicity, the 96h-$LC_{50}$ in the three species exposed to copper, lead, zinc and chromium was 740-990, 1,660-1,980, 6,180-8,490 and 8,830-11,296 ${\mu}gL^{-1}$, respectively. In order of toxicity, the heavy metals were ranked copper>lead>zinc>chromium. The Gobiidae $C.$ $dolichognathus$ was more sensitive to heavy metals than $T.$ $trigonocephalus$ and $F.$ $gymnauchen$.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.251-252
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• 2002

야생의 수서생물들은 환경에 방출되는 유해화학물질들에 의해 난발생과 생식기능 작용에 영향을 받는다. Bisphenol A (BPA)는 에스트로겐적 잠재성을 가진 물질중의 하나로 폴리카보네이트와 에폭시수지, 캔 용기, 병 뚜껑 등의 코팅제로 사용되며 (Brotons et al., 1995) 치과 재료에도 많이 사용되고 있다 (Olea et al., 1996). (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.253-254
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• 2002

경골어류의 난소 성숙 과정은 여포층에서 생성ㆍ분비되는 성 스테로이드 호르몬에 의해 조절된다. 성 스테로이드 호르몬 중에서도 C2l-스테로이드가 난소 성숙 과정에 중요한 역할을 하는 것으로 알려져 있으며, 특히 20$\alpha$와 20$\beta$-hydroxy group을 가지고 있는 스테로이드, 17 $\alpha$-hyoxy, 20 $\alpha$-dihydroprogesterone (17 $\alpha$ 20 $\alpha$ OHP)과 17$\alpha$-hyoxy, 20$\beta$-dihydroprogesterone (17$\alpha$20$\beta$OHP)가 성숙유도에 가장 효과적인 것으로 보고하고 있다 (Canario and Scott, 1989; 1990). (중략)

• 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.