• Fisheries and Aquatic Sciences
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• 제27권2호
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• pp.100-110
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• 2024

Biometric evaluation and reproductive biology of Oreochromis niloticus were studied from Geray Reservoir. Between November 2021 and August 2022, 316 O. niloticus specimens were collected from this reservoir. The observed male to female sex ratio was 1:1.14, which was statistically insignificant compared with the hypothetical 1:1 sex ratio (X² = 1.27, p > 0.05). The length-weight relationship was curvilinear with allometric growth (b < 3) and statistically significant from the expected isometric growth pattern (b = 3). The regression equation for females was TW = 0.0264TL^2.72 (r² = 0.90, n = 168), males (TW = 0.0183TL^2.79, r² = 0.93, n = 148), and combined sexes (TW = 0.0229TL^2.76, r² = 0.91, n = 316). Gonadosomatic index (GSI) ranged from 0.8 to 1.4 (males) and 1.8 to 4.9 (females). The breeding season lasted from March to June, with a GSI peak in April. Fecundity ranged from 279 to 1,528 eggs./fish, with a mean of 1,025 eggs./fish. The correlation between absolute fecundity and length was more significant (F = 0.76TL^2.8, R² = 0.94, p < 0.05) than with weight (F = 17.683TW^0.71, R² = 0.92, p < 0.05). This study provides basic information on the biology of O. niloticus in the Geray Reservoir for future fishery management tools for the conservation and utilization of this valuable freshwater fish.

• 한국어류학회지
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• 제7권2호
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• pp.150-159
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• 1995

1992년 5월부터 1993년 8월까지 부산 수영만 인근해역에서 채집된 망상어, Ditrema temmincki를 대상으로 조직학적 방법에 의해 생식주기와 군성숙도를 조사하였다. 조사된 결과는 다음과 같다. 본종의 군성숙도는 수컷은 체장 13.5cm, 암컷은 체장 12.5cm로 조사되었다. 생식소중량지수는 수컷은 10월, 암컷은 6월에 연중 가장 높은 값을 나타냈다. 정소의 내부조직상은 곡정세관형이며, 난소는 5∼6장의 난소습곡으로 이루어져 있는데, 곡정세관상피와 난소습곡상피에서 각각 정원세포와 난원세포가 유래한다. 생식주기는 수컷은 성장기(5∼8월), 성숙기(9∼10월), 교미기 (11∼12월), 퇴화 및 휴지기 (1∼4월)로 나눌 수 있으며, 암컷은 성장기 (9∼10월), 교미 및 성숙기 (11∼12월), 임신기 (1∼6월), 휴지기 (7∼8월)로 나눌 수 있다. 간중량지수는 암수 모두 4월에 최고치를 보여, 수컷에서는 생식소중량지수의 월변화와 역상관 관계를 보이고, 암컷에서는 정상관 관계를 보였다.

• 한국발생생물학회지:발생과생식
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• 제19권1호
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• pp.33-41
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• 2015

The gonadosomatic index (GSI), gonadal development and changes in hormones in plasma level of the indoor cultured grunt (Hapalogenys nitens) were investigated by histological study from August 2011 to October 2012. The GSI showed similar trends with gonad developmental stages during the culture periods. Changes in plasma level of estradiol-$17{\beta}$ of female H. nitens reached the highest value before the spawning period, and seasonal changes in plasma level of estradiol-$17{\beta}$ were similar in trends of oocyte developments and GSI changes. Testosterone levels of male H. nitens reached the highest value before and after the spent stage. Ovarian developmental stages of H. nitens could be classified into early growing stage, late growing stage, mature stage, ripe and spawning stage, recovery and resting stage. The testicular developmental stages could be divided into growing stage, mature stage, ripe and spent stage, and recovery and resting stage.

• 한국양식학회지
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• 제17권2호
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• pp.128-132
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• 2004

이 연구에서는 자연산 참가자미의 주 어획지역인 강원도 주문진 인근해역에서 1998년 9월부터 1999년 10월까지 연간 생식소중량지수의 변화를 조사하였으며, 조직학적 조사에 의한 생식소 발달과정과 생식주기를 밝혔다. 정소는 정소소엽 형태이며, 각각의 정소엽은 여러 개의 소낭구조를 가진다. 각 소낭내의 생식세포들은 같은 단계의 발달상태를 보인다. 난소는 원추형의 낭상으로 체강벽에서 연결되는 난소간막에 의해 부착되어 있으며, 내부는 결체성 조직인 다수의 난소박판으로 구성되며, 이곳에서 난원세포가 유래한다. 수컷의 GSI는 1월에 가장 높았으며, 암컷의 GSI는 3월에 가장 높은 값을 보였다. 생식주기는 성장기(6∼9월), 성숙기(10∼12월), 완숙 및 산란기(1∼3월)그리고 회복 및 휴지기(4∼5월)로 나눌 수 있었다. 난모세포의 발달양식은 난군동기발달형에 속하였다.

• 한국수산과학회지
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• 제40권3호
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• pp.141-146
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• 2007

We investigated the reproductive cycle of the striped eel catfish Plotosus lineatus. Specimens were sampled in the coastal waters of Sungsan and Jocheon, east of Jeju, Korea, from September 2001 to August 2002. The gonadosomatic index (GSI) in females and males were reached a maximum in June $(14.18{\pm}10.38)$ and July $(0.35{\pm}0.12)$, respectively. Based on histological observations and GSI variation, the reproductive cycle was classified into the following successive stages: in females, growing (September-April), mature (April-June), spawning (June-July), and degenerative and recovery (July-September) and in males, growing (August-December), mature (September-May), spent (April-July), and degenerative and recovery (June-August). The total length at 100% maturity exceeded 15 cm and the fecundity ranged from 525 to 1176 eggs. The fecundity was correlated positively with total length and body weight. Histological observations of the gonads suggest that this species is a spring-summer spawner with group-synchronous type oocyte development.

• 한국수산과학회지
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• 제49권3호
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• pp.404-409
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• 2016

We investigated the maturation and spawning of Sebastes thompsoni in the coastal waters off Ulleungdo, based on samples collected by gill net from March 2013 to February 2014. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity, and total length (TL) at 50% group maturity. The average TLs of female and male S. thompsoni were 22.6 cm and 22.5 cm, respectively. The main parturition period of females was during March and April. The GSI of females began to increase in January, and reached a maximum in March. The GSI of male reached a maximum between January and February. The spawning period of males was shorter than that of females. The egg diameter during gestation stage was 1.4±2.1 mm. The TL of females at 50% group maturity was 22.3 cm.

• Environmental Analysis Health and Toxicology
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• 제21권1호
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• pp.35-43
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• 2006

Reproduction and organ structure of the pale chub, Zacco platypus in Isa stream were investigated by means of histological methods. The results of the study confirmed reproductive abnormality and histopathological features in the pale chub. The gonadosomatic index (GSI) of the fish showed two peak in April and August. In summer season, GSI of the male was about two times of the female's GSI. Monthly variation of the gonadal development was very irregular. From the histological analysis of the organ structure, epidermal atrophy, necrosis and hyperplasia of pigment cell were observed in the skin. Epithelial layer lifting and clubbing of the lamella and bifurcation of the filament were observed in the gill. Also histological changes as congestion, cytoplasmic degeneration of hepatic cell, degeneration of bile duct, glomerular dilatation, degeneration of renal tubule and pycnosis of interstitial cell were identified in the liver and kidney, respectively.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2005년도 제20차 학술대회 논문집
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• pp.52-52
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• 2005

Oogenesis, the gonadosomatic index (GSI), reproductive cycle and first sexual maturation of the female Neptunea (Barbitonia) arthritica cumingii have been investigated by light and electron microscope observations. In the early vitellogenic oocyte, the Golgi complex and mitochondria were involved in the formation of glycogen, lipid droplets and yolk granules. In late vitellogenic oocytes, the rough endoplasmic reticulum and multivesicular bodies were involved in the formation of proteid yolk granules in the cytoplasm. In particular, compared with the results of other gastropods, it is a different result that appearances of cortical granules at the cortical layer and microvilli on the vitelline envelope, which is associated with heterosynthetic vitellogenesis, were not observed in vitellogenic oocytes during oogenesis. A mature yolk granule was composed of three components: main body (central core), superficial layer, and the limiting menbrane, Monthly changes in the gonadosomatic index in females were studied in 2002 and 2003 were closely associated with ovarian developmental phases. Spawning occurred between May and August in 2002 and 2003 and the main spawning occurred between June and July when the seawater temperature rose to approximately 18${\sim}$23${\circ}$C. The female reproductive cycle can be classified into five successive stages: early activestage (Septmber to October), late active stage ( November to February), ripe stage (February to June), partially spawned stage (May to Aygust), and recovery stage (June to August).

• 한국가축번식학회지
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• 제11권3호
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• pp.170-180
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• 1987

This study was undertaken to determine the effects of HCG and trout pitutary on sexual maturation and ovulation in the Korean loach, Misgurnus anguillicaudatus. Sexual maturation was observed in the fish treated with 250＋125 IU HCG within 2-4 days following injections. Total ovary weight and GSI were significantly greater in the hormone-treated fish than in the control fish. Furthermore, in the hormone-treated fish body weight increased by about 4-9 percent in 2 days. The water content of the ovulated eggs of the fish treated with 250＋125 IU HCG was also greater than that in the control. Changes in both macroscopic & microscopic appearnce of Korean loach ovaries are describled, as well as changes in the gonadosomatic index. Oocytes pass through seven cytologically changes in the relative stages. By examining these stages, it was found that oogenesis occures in two broad phases. The previtellogenic phasebegins as a new oogonia continues to arise following spawning. These rapidly develop into early perinucleolus oocytes, which in turn develop into resting stage oocytes. Most oocytes remain in this stage when they develop into late perinucleolus oocytes. The vitellogenic phase begins as these late perinucleolus oocytes become transformed into early maturing oocytes through the accumulation of yolk. The cytoplasm completely fills with yolk as oocytes reach the late maturing stage. Shortly before spawning the final hyaline stage of developing is reached. Changes in the microscopic appearances of the ovaries were well correlated with changes in both gonadosomatic index and macroscopic appearance.

• 한국패류학회지
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• 제22권1호
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• pp.1-11
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• 2006

The gonadosomatic index (GSI), oogenesis and reproductive cycle in female Neptunea (Barbitonia) afhritica cumingii were investigated by light and electron microscope observations. In the early vitellogenic oocyte, the Golgi complex and mitochondria were involved in the formation of glycogen, lipid droplets and yolk granules. Late in the vitellogenic oocytes, the rough endoplasmic reticulum and multivesicular bodies were involved in the formation of proteid yolk granules in cytoplasm. In particular, compared with the results of other gastropods, it showed a different result that appearances of cortical granules at the cortical layer and microvilli on the vitelline envelope, which is associated with heterosynthetic vitellogenesis, were not observed in vitellogenic oocytes during oogenesis. A mature yolk granule was composed of three components: main body (central core), superficial layer, and the limiting membrane. Monthly changes in the gonadosomatic index in females studied in 2004 and 2005 were closely associated with ovarian developmental phases. Spawning occurred between May and August in 2004 and 2005 and the main spawning occurred between June and July when the seawater temperature rose to approximately $18-23^{\circ}C$. The female reproductive cycle can be classified into five successive stages: early active stage (September to October), late active stage (November to February), ripe stage (February to June), partially spawned stage (May to August), and recovery stage (June to August).