• 한국발생생물학회지:발생과생식
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• 제14권1호
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• pp.21-25
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• 2010

Nile tilapia (Oreochromis niloticus) are mouth-brooders so that the females holding eggs in their mouth sacrifice their somatic growth for reproduction. For this reason, artificial control of reproduction for the culture of this species has been of interest. Manipulation of photoperiod is an emerging technique for such purpose, but little information is available to establish appropriate photoperiod regime. To obtain necessary basic information, sexually mature females were individually accommodated to glass aquarium, and the spawning activity of these females were monitored for two years under natural photoperiod regime. Female tilapia spawned most frequently on March, April and May when the day length gradually increased from 11 hours to 14 hours and least frequently on September, October, November and December when the day length gradually decreased from 13 hours to less than 10 hours in the first year. The decrease of spawning frequency as day length decreased was also observed in the second year, although the increase of spawning frequency as day length increased was less clear. Spawning of female tilapia was less active when the night was dark due to the disappearance of moonlight (Dark Phase), compared to the Phase of Getting Lighter, Light Phase and Phase of Getting Darker. Results from this study suggest that long day length, particularly increasing phase, is favoured for active spawning of Nile tilapia, and that this species, as a tropical fish species, may utilize changing lunar phases as a secondary environmental cue for reproduction.

• 한국어류학회지
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• 제25권4호
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• pp.216-221
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• 2013

2011년 12월부터 2012년 12월까지 수수미꾸리의 생식주기를 생식소중량지수와 조직학적 방법을 이용하여 조사하였다. 수수미꾸리 암컷과 수컷의 생식주기는 성숙기 (growing phase, 11~이듬해 3월), 산란기 (spawning phase, 4~5월), 퇴화기 (degeneration phase, 5~6월), 휴지기 (resting phase, 6~11월) 등 4단계로 구분되었다. 암컷과 수컷의 최적 수온이 $12.7^{\circ}C$, 일장시간이 13시간 이상으로 증가하기 시작하는 4월에서 5월 사이인 것으로 나타났다. 이러한 결과는 조직학적 실험 결과와 잘 일치하였다.

• 한국발생생물학회지:발생과생식
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• 제23권4호
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• pp.323-331
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• 2019

In this study, an experiment was conducted to investigate the annual reproductive cycle of a Korean flat bittering, Acheilognathus rhombeus, from Ogok-myeon located in Seomjin River. The reproductive cycle was examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), and developmental characteristics of female and male gonads. The maximum GSI was found to be 3.50±0.53 and 1.36±0.14 for females and males, respectively, when the water temperature and day light was 16.9℃ and 11.3 hours, respectively in October 2018. On the other hand, the minimum GSI was found to be 0.16±0.09 and 0.69±0.15 for males and females in December 2018 and February 2019, respectively. The ovipositor of females appeared from August to November 2018. We compared and calculated the stages of germ cell developmental characteristics in the testis and ovaries to determine the reproductive cycle. According to the result, we classified the female A. rhombeus reproductive cycle into four phases, which are ripe and spawning phase (October), degenerative phase (November to December), growing phase (January to March) and mature phase (April to September). The annual reproductive cycle of male A. rhombeus was categorized into four phases: mature phase (June to October), degenerative phase (November to March), resting phase (April) and growing phase (May). The Korean flat bittering is an autumn-spawner as the main spawning season in October. In male, testicular spermatogonia appeared all year-round, and the ripe and releasing phase, which is characteristics of the spawning season in other fish, did not appear.

• 한국발생생물학회지:발생과생식
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• 제21권3호
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• pp.297-305
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• 2017

An experiment was conducted to investigate the annual reproductive cycle of a Korean endemic species, Acheilognathus majusculus, from Jeokseong-myeon located in Seomjin River. The reproductive cycle is examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), the female ovipositor length index (OLI), monthly variation in egg diameter distribution, and developmental characteristics of female and male gonads. The maximum GSI was found in $19.21{\pm}2.32$ and $6.90{\pm}0.53$ for female and male respectively when water temperature ($14^{\circ}C$) and day length (11.1hr) began to rise. On the other hand, the minimum level was reached during August ($1.87{\pm}0.67$ for female and $0.88{\pm}0.50$ for male). No samples represent with measurable ovipositor between September and November, while the longest ovipositor length index was in April ($79.68{\pm}4.69%$). We compared and calculated the stages of testis and ovary development process in order to determine the germ cell development characteristics and the reproductive cycle. According to the result, we classified the female Acheilognathus majusculus reproductive cycle into four stages: Ripe (April) and spawning phase (May to June), degenerative phase (July), growing phase (August to December), and mature phase (January to March). The annual reproductive cycle of male Acheilognathus majusculus was categorized into five stages viz. Ripe and spawning phase (May to June), degenerative phase (July to August), resting phase (September to November), growing phase (December to February), and mature phase (March to April).

• Fisheries and Aquatic Sciences
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• 제10권3호
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• pp.150-158
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• 2007

Data on squid catches, water temperature, and climatic factors collected for the Northwest and subtropical North Pacific were analyzed to examine the influence of oceanic and climatic conditions in spawning grounds on catches of Japanese common squid, Todarodes pacificus, in the East (Japan) Sea. The main spawning ground was divided into four sub-areas: the South Sea of Korea (R1), the southern waters off Jeju, Korea (R2), the southwestern part of Kyushu, Japan (R3), and the northern part of Okinawa, Japan (R4). Interannual and decadal fluctuations in water temperatures correlated well with squid catches in the East/Japan Sea. In particular, water temperatures at a depth of 50 to 100 m in sub-areas R3 and R4 showed higher correlation coefficients (0.54 to 0.59, p<0.01) in relation to squid catches in the East/Japan Sea than for R1 and R2, which had correlation coefficients of 0.40 or less (p>0.05). Air temperature and wind velocity fluctuations in each sub-area are correlated with water temperature fluctuations and were closely connected with variations in the surface mixed layers. Water, air temperatures and wind velocities at the main spawning grounds are linked to the Southern Oscillation Index (SOI) with higher signals in the ca. 2-4-year band. Strong changes in a specific band and phase occurred around 1976/77 and 1986/87, coincident with changes in squid catches.

• 한국수산과학회지
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• 제56권5호
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• pp.644-650
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• 2023

We examined the effects of serotonin on the spawning response, sperm motility, and D-shaped larva production in Eastern Gooeyduck clam Panopea sp. based on the sperm densities at fertilization and washing after mixing the eggs and sperm. The highest spawning induction was found showed in females and males injected with 1 mL of 2 mM serotonin. The spawning responses in females and males were higher at concentrations greater than 1 mM and 0.75 mM, respectively. Regarding the activities of sperm in sea water after serotonin injection, the sperm showed activity at >90.0% until 120 mins. We also examined the effects of sperm concentration at the fertilization and washing times after mixing the eggs and sperm. We confirmed that washing within 1 minute at a concentration of 1,500 sperms/mL or less can prevent egg destruction by polyspermy and secure a large number of D-phase larvae. These results should be useful for developing the aquaculture process for Eastern Gooeyduck clam, Panopea sp.

• 한국동물학회지
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• 제36권2호
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• pp.181-192
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• 1993

The spawning and growth of eightspine stickleback,Pungitius sinensis kaiborae (Tanaka, 19151, were investigated in the Chavang Stream from March 1990 to february 1991 as a part of study on its life history. Nest building, spavming and parental behaviors were similar to those known on the sticklebacks of Europe, North America and Japan. Bht f sinensis kaibarae in the Chayang Stream, peculiarly, showed only superficial gluing behavior in nest building phase and made two nurseries iust behind the nest in Parental Phase. The individuals with fully mature eggs were found from late February to late June. The fecundity of an adult female was about 21 to 110 (mean 47.07) eggs and the diameter of kllv matured ovarian eggs ranged 1.3 to 1.5 mm. The smallest female with fully mature eggs was 25.8 mm in body length and had 21 eggs. The relationship between the number of mature eggs in ovary and body length was No. of eggs = 2.857BL -55.134 (r = 0.890). The number of deposited eggs in a nest was 27 to 637 and thew were composed of several clusters of various developmental stages. The distribution pattern of gonadsomatic index (GSl) against the body length shown that in females 1+ year-old fishes mainly participate in spawning but in males 11 and 2+ year-old fishes equally participate. From the fluctuat지n pattern of GSI and the number of mature eggs in ovary, it was assumed that the spawning season was from February to June and the peak of spawning was early March to late April. The newly hatched vouns was found at late April and their body length was about 10 mm. The vouns (O+) grew rapidly until late August. Then their srowth was slowed down and finallY ceased in midautumn. The young reached about 35 mm BL in their first year of life. The halting of growth was lasted to next Sune when the spawning season would be nearly closed. They (1+) began to grow asain from late june, grew rapidly until tate september and reached about 415 mm BL. Then there was no more grouvth until to die as 2+ yearold fish. Therefore it was assumed that the life span of P. sinensis kaibarae in the Chavang Stream would be about ko years. The relationship between the body length and the body weight was logBW = 2.9541ogBL -4.802 (r = 0.998).

• 한국패류학회지
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• 제22권2호
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• pp.143-150
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• 2006

The gonad index, condition index, reproductive cycle and spawning of the pen shell Atrina (Servatrina) pectinata were investigated using samples from the subtidal zone of Nokdo on the Boryeong coastal waters of Korea. Samples were collected monthly by SCUBA divers for one year from January to December, 2001. A. (Servatrina) pectinata is dioecious and oviparous. The spawning season of this species occurred once a year from June to August, with the main spawning occurring between June and July when the seawater temperature was around $20^{\circ}C$. Ripe oocytes were about 60-65 ${\mu}m$ in diameter. The reproductive cycle of this species could be classified into five successive stages; early active stage (November to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to August), and spent/inactive stage (August to October). Monthly changes in the gonad index reached a maximum (4.6) in May (ripe stage), thereafter, the GI values gradually decreased from June to August when spawning occurred continuously. Therefore, monthly changes in the GI values showed a similar pattern to the gonadal phase. The condition index (CI) of the meat part without the posterior adductor muscle reached the maximum in June (ripe and partially spawned stage) and the minimum in September (spent/inactive stage), Accordingly, monthly changes in the condition indice of the meat part without the posterior adductor muscle coincided with the gonadal phases.

• 한국어류학회지
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• 제22권2호
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• pp.90-95
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• 2010

파랑점자돔(Blue devil, Pomacentrus caeruleus, 혼용되고 있는 학명으로 Chrysiptera cyaneus)은 인도양과 태평양에 널리 분포하는 어종으로 전 세계 해수관상어 시장에서 가장 대중적으로 유통되고 있다. 그러나 파랑점자돔의 인공 생산 기술은 개발되어 있지 않다. 이 연구에서는 파랑점자돔의 성공적인 종묘생산 기술 개발을 목적으로 산란생태에 대한 연구를 수행하였다. 확인된 산란 행동은 태양력과 태음력을 기준으로 분석하였다. 사육조건은 수온 $27^{\circ}C$, 염분 30 ppt 전후이며 사육수조의 수용량은 80에서 125 L의 크기였다. 성공적으로 이루어진 인공번식 기술개발 과정에서 파랑점자돔은 1마리의 수컷과 2마리 이상의 암컷이 하렘(harem) 을 형성하는 것이 관찰되었으며 12월부터 10월까지 11개 월간에 2무리의 파랑점자돔 하렘으로부터 44회의 산란이 확인되었고 113,580개의 수정란을 수거할 수 있었다. 특히 5월과 6월에 산란횟수와 산란량이 크게 증가하였다. 그리고 태음력의 달의 위상(모양)에 따라 파랑점자돔의 규칙적인 산란생태가 관찰되었는데 대조에 해당되는 삭과 망에는 전혀 산란행동이 관찰되지 않았지만 소조에 해당되는 상현과 하현에는 가장 높은 산란량과 산란횟수가 관찰되었다.

• 한국어류학회지
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• 제7권1호
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• pp.33-42
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• 1995

1991년 8월부터 1993년 7월까지 경상남도 김해군 상동면 매리마을의 낙동강 지류에서 채집된 한국 특산어인 각시붕어, Rhodeus uyekii를 대상으로 생식생태를 파악하기 위하여 연간 생식소숙도지수(GSI)와 난경조성, 산란관 길이 변화를 조사하였고, 이들 생식소 발달과정을 광학현미경적 방법에 의해 조사하였다. GSI는 수온이 상승하기 시작하는 2월부터 증가하기 시작하여 5월에 연중 최대값을 나타내고, 7월부터 하강하여 8월에는 연중 최저값을 나타내었다. 이후 9월부터 11월까지 서서히 증가하다가 12월에는 일시적으로 증가를 멈추고 11월과 비슷한 수준을 유지하였다. 생식연주기는 7~8월의 퇴화 및 휴지기, 9~11월의 1차 성장기, 12월의 정체기, 1,2월의 2차 성장 및 성숙기, 3~6월의 완숙 및 산란기 등 연속적인 주기로 구분할 수 있었으며, 산란성기는 4월하순에서 5월이었다.