• 수산해양교육연구
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• 제24권6호
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• pp.854-861
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• 2012

To investigate the role of water temperatures and photoperidos as environmental cues regulating reproductive rhythm in banded catfish Pseudobagrus fulvidraco, rearing experiments were conducted using sveral rearing regimes conbined with changes in photoperiods and water temperatures during growing and spawning periods. GSI of $23^{\circ}C$ was significantly higher than $18^{\circ}C$ in female, but 9 light of 18 and $23^{\circ}C$ were no difference in male. In case of estradiol, $18^{\circ}C$ and 15 L was higher than other experintal precinct after 20 days. But, end of the experiment, all of experimental precinct were no difference. Testosteron of female was no difference in $18^{\circ}C$-9 and 15 L after 20 days. Testosteron of male was no difference in $18^{\circ}C$-9 L. In case of 11-KT, control level was $0.39{\pm}0.03$ ng/mL and $18^{\circ}C$-9 L was no significantly difference after 20 days. But, 15 L was higher than other experimental precinct.

• 수산해양교육연구
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• 제27권5호
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• pp.1229-1235
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• 2015

Juvenile banded catfish(Pseudobagurus fulvidraco, mean length $10.7{\pm}0.42cm$ and mean weight $15.0{\pm}0.23g$) were exposed to varies TAN(total ammonia) concentrations at pH levels of $6.12{\pm}0.51$, $7.00{\pm}0.26$ and $8.04{\pm}0.07$ for 96hrs to check the level of acute toxicity on biofloc technology aquaculture system(BFT). The result showed that cumulative mortalities for juvenile banded catfish at TAN levels 48.95, 55.96, 66.47, and 78.88 mg/L at pH $6.12{\pm}0.51$ were 0, 30, 30, and 50%, respectively. At pH $7.00{\pm}0.26$, its mortalities to TAN 5.20, 11.68, 15.31, and 18.31 mg/L were 0, 10, 20, and 70%, respectively and at pH $8.04{\pm}0.07$, the mortalities to TAN 0.96, 1.49, 2.13, and 3.62 mg/L were 10, 20, 40, and 100%, respectively. Its $96h-LC_{50}$ (median lethal concentration, $LC_{50}$) at pH $6.12{\pm}0.51$, $7.00{\pm}0.26$, and $8.04{\pm}0.07$ were 78.12, 15.87, and 2.21 mg/L for TAN, and 0.05, 0.10, and 0.14 mg/L for $NH_3$, respectively, and the acute toxicity for ammonia to juvenile banded catfish increased exponentially with increase of pH.

• 수산해양교육연구
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• 제27권1호
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• pp.41-48
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• 2015

Juvenile banded catfish(Pseudobagurus fulvidraco, mean length $10.4{\pm}0.37cm$ and mean weight $14.5{\pm}0.46g$) were exposed to several nitrite(${NO_2}^-$) concentrations for 96h at pH levels of $6.18{\pm}0.54$, $6.5{\pm}0.30$ and $7.07{\pm}0.22$. The result showed that cumulative mortalities of fish to ${NO_2}^-$ levels of 12.4, 19.8, 33.9 and 53.6 mg/L at pH levels of $6.18{\pm}0.54$ were 20, 25, 40 and 85%, respectively. At pH $6.5{\pm}0.54$, mortalities to ${NO_2}^-$ 22.4, 36.4, 45.3 and 63.2 mg/L were 25, 35, 50 and 100%, respectively. At pH $7.07{\pm}0.22$, mortalities to ${NO_2}^-$ 25.5, 45.7, 56.3 and 66.4 mg/L were 0, 55, 70 and 100%, respectively. The 96h-$LC_{50}$(median lethal concentration, $LC_{50}$) of fish to several ${NO_2}^-$ concentrations at pH levels of $6.18{\pm}0.54$, $6.5{\pm}0.30$ and $7.07{\pm}0.22$ were assessed in these experiments. 96h-$LC_{50}$ at pH levels of $6.18{\pm}0.54$, $6.5{\pm}0.30$ and $7.07{\pm}0.22$ were 32.68, 40.49 and 45.85 mg/L, respectively. It indicated that acute toxicity of ${NO_2}^-$ to juvenile banded catfish increased with low levels of pH and lengthening of exposure time to ${NO_2}^-$. In particular, smaller fish(mean weight $14.5{\pm}0.46g$) were more sensitive to ${NO_2}^-$ than larger fish(mean weight $81.7{\pm}1.42g$; not published). The 96h-$LC_{50}$ of juvenile banded catfish to ${NO_2}^-$ would be primary guideline for water quality management in the intensive culture system such as RAS and BFT.

• 한국수산과학회지
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• 제30권5호
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• pp.823-833
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• 1997

동자개, Pseudobagrus fulvidraco (Richardson)의 명확한 생식년주기를 밝히기 위하여, 본 종을 1992년 5월부터 1993년 6월까지 전라남도 영산강 상류로부터 채집하여 암수의 GSI, HSI, 비만도, 난모세포 발달 단계의 분포빈도, 그리고 생식소와 간의 조직학적인 주년 변화를 조사하였다. 이들 결과를 토대로 하여 생식년주기를 다음과 같은 5단계로 구분 할 수 있었다. 1) 성장기 (4월$\~$5월초): 암컷의 GSI값이 증가하고 주변인기 난모세포들이 점진적으로 성장하였으며, 수컷의 세정관 상피에서는 정원세포들이 활발히 분화되기 시작하였다. 2) 성숙기 (5월$\~$6월초): 암수 모두 GSI가 빠르게 증가하고 여러 단계의 난모세포들이 관찰되었으며, 정소 내에는 정자 형성이 활발하게 일어났다. 3) 성숙 및 산란기 (6월$\~$8월): 암컷의 GSI는 높은 값을 유지하였고, 난모세포들은 많은 양의 난황을 축적하였으며, 수컷의 세정관에는 대부분 정자로 채워져 있었다. 4) 퇴화기 (9월$\~$11월): 암수 GSI는 감소되고, 난소 내에는 대부분 주변인기 세포들로 채워져 있고, 간세포에는 지방구들이 많이 축적되었다. 5) 휴지기 (12월$\~$다음해 3월): 암수 GSI는 낮은 값을 유지하며, 난소 내의 주변인기 세포의 증가와 정자 형성은 보이지 않았다.

• 수산해양교육연구
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• 제24권6호
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• pp.845-853
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• 2012

To investigate the role of temperatures and photoperiods as environmental cues regulating reproductive rhythm in Pseudobagrus fulvidraco, rearing experiments were conducted using sveral rearing regimes conbined with photoperiods and water temperatures during gonadal degeneration periods. Gonadosomatic index (GSI) in control was $8.16{\pm}1.50%$, while in other experiment GSI levels in female were lower than that in the control. In case of experimental precinct of 9 light (L) and 15 L, GSI levels were decreased. But GSI level with $20^{\circ}C$ was no diffrence after 40 and 60 days. GSI level in male of control was $0.35{\pm}0.05%$. GSI under 9 L and $25^{\circ}C$ was similar to that in control, whereas its level in other experiments was lower than that in control. Testosterone (T) of female was $3.68{\pm}0.22$ ng/mL at experimental precinct. In case of 9 L and 15 L, concentration of T were lower than experimental precinct in all of water temperature. Estradiol-$17{\beta}$ ($E_2$) and $7{\alpha}$, $20{\beta}$-dihydroxy-4-pregnen-3-one ($17{\alpha}20{\beta}OHP$) levels of female were $0.42{\pm}0.02$ and $0.83{\pm}0.01$ ng/mL at experimental precinct. $E_2$ levels of 9 and 15 L were higher than experimental precinct and $17{\alpha}20{\beta}OHP$ levels of 9 and 15 L were higher than experimental precinct. In case of T and 11-ketotestosterone levels were $0.69{\pm}0.11$ and $.62{\pm}0.03$ ng/mL in male. During the period of gonadal degeneration, gonadal maturation did not occur in any of the experimental regimes. However, comparatively high levels of $E_2$ observed at low temperature regimes ($20^{\circ}C$) regardless of photoperiods.

• 한국수산과학회지
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• 제30권2호
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• pp.203-210
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• 1997

동자개 난모세포의 성숙과 배란에 있어 스테로이드와 HCG(human chorionic gonadotropin)의 효과에 대한 실험이 in vitro에서 이루어졌으며, 난모세포들은 $17\alpha,\;20\alpha-dihydroxy4-pregnen-3-one\;(17\alpha\;20\alpha\;OHP),\;17\alpha-hydroxyprogesterone\;(17\alpha\;OHP),\;progesterone\;(P_4),\;estradiol-17{\alpha}E_2)$ 과 HCG가 첨가된 Leibovitz L15 배지에서 성숙되어졌다. 60시간 배양후에 난모세포의 성숙능력은 난핵포붕괴(germinal vesicle breakdown, GVBD) 비율에 의해 평가되었다. GVBD 비율은 $17\alpha\;20\alpha\;OHP,\;17\alpha\;OHP,\;P_4$ 그리고 HCG의 첨가에 의해 유의하게 (P<0.05) 증가하였으며, 그 중 $17\alpha\;20\alpha\;OHP$ HCG에서 가장 높은 GVBD 비율을 보였다. 난모세포들 $17\alpha\;20\alpha\;OHP,\;17\alpha\;OHP,\;P_4$가 $10\~1,000ng/ml$포함된 배지에서 16시간 배양한 결과, $17\alpha\;20\alpha\;OHP\;10\~100ng/m1(65\%)$의 GVBD 비율은 $17\alpha\;20\alpha\;OHP(40\%)$와 $P_4(35\%)$에서 보다 나은 효과를 보였다. GVBD유도에 대한 효과는 $17\alpha\;20\alpha\;OHP$에서 $10\~100\;ng/ml$배지, HCG를 첨가하여 60시간 배양한 배란유도 실험에서 $17\alpha\;20\alpha\;OHP\;10\~100ng/ml$에서, HCG는 $50\~500IU/ml$의 배지에서 배란율이 유의하게 증가하였다. 그러나 $17\alpha\;20\alpha\;OHP\;1,000ng/m1$와 HCG 5IU/ml의 배지에서는 대조구의 배란율과 차이를 보이지 않았다. 이러한 결과로 $E_2$를 제외한 스테로이드와 HCG는 동자개의 난모세포 성숙과 배란을 in vitro에서 유도할 수 있으며, $17\alpha\;20\alpha\;OHP$와 HCG는 다른 스테로이드에 비해 높은 율의 난모세포 성숙과 배란을 유도하였다.