• 한국어병학회지
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• 제24권1호
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• pp.19-27
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• 2011

The production of surf clam, Mactra veneriformis, an important fishery resource in Korea, has recently been decreasing. This study was carried out to examine effects of spawning on immune functions of this species. Total hemocyte count (THC), phenoloxidase (PO) activity, phagocytic activity, neutral red retention (NRR) time and antibacterial activity were assessed. Spawned clams showed reduction in THC, PO, phagocytic activity and NRR times compared with unspawned ones. While spawning event did not elicit any change of antibacterial activity in both spawned and unspawned ones. This study indicates that spawning process decreases immune functions in the surf clams which could cause mortality increment and yield reduction.

• 한국수산과학회지
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• 제42권5호
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• pp.481-486
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• 2009

In 2007, 43.5% mortality of the cultured oyster population occurred in Gamak Bay. Mortality rapidly increase in September and peak in October. To prevent future mass-mortality event, we investigated spawning and variation of oyster body composition. The main spawning period of culture oyster occurred from August to September. Condition index and body composition (protein and glycogen) appeared to be influenced by the spawning activity. Condition index and glycogen content in September were lowest (13.5% and 5.6 mg/g, respectively). However, protein, lipid and glycogen contents did not rapidly recover after the spawning activity. The data indicates that mass-mortality of cultured oysters in Gamak Bay may be due to deteriorated health, spawning activity, stress of the high water temperature and decreasing food resources.

• 한국양식학회지
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• 제10권1호
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• pp.63-68
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• 1997

메기의 산란행동을 관찰하기 위하여 1994년 5월부터 1995년 7월까지 산란시기에 HCG, 초어의 뇌하수체 등의 호르몬을 주사하여 이들의 행동을 관찰하였다. 이들의 산란행동은 기본적으로 chasing-clinging-embracing (enfolding) 순으로 이루어 졌는데, 주사후 15-16시간이 경과하면 산란행동을 시작하였고, 2-3시간 동안 산란행동을 하다가 19시간이 지나면 모든 행동이 끝났다. 그러나 지금까지 알려진 일본에서 메기의 자연산란 행동과는 수컷이 접근하는 방법과 수컷이 암컷을 감싸 조일 때 수컷의 뒷지느러미의 방향이 달랐다. 그리고 한국산 메기는 수컷이 암컷에 접근할 때 등쪽에서 접근하여, 배쪽에서 접근하는 S. biwaensis 와도 차이를 보였다.

• Fisheries and Aquatic Sciences
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• 제7권3호
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• pp.136-140
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• 2004

We examined the ovaries of 312 robust tonguefish (Cynoglossus robustus) collected each month from January to December 2001, off the coast of Yeosu, Korea. The samples were used to investigate robust tonguefish reproductive activity. Monthly changes in the gonadosomatic indexindicated that spawning peaked between June and August. Fish size at first spawning was 15-19 cm total length (TL). Over $50{\%}$ of female fish 25-29 cm TL were sexually mature, and this rose to $100{\%}$ for female fish 35-39 cm TL. The tonguefish spawned four or more times during the spawning season. Most females commenced spawning in their second year. The relationship between total length (cm TL) and fecundity (F) was F=528646Ln(TL)-1E+06.

• 한국어류학회지
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• 제33권1호
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• pp.15-21
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• 2021

멸종위기에 처한 우리나라 고유 담수어류인 얼룩새코미꾸리 Koreocobitis naktongensis의 호르몬 처리에 의한 산란행동을 관찰하기 위하여 2010년 4월 20~27일까지 산란시기에 성 성숙 호르몬(Ovaprim)을 주사하여 산란행동을 관찰하였다. 산란행동을 분석한 결과 산란 전 행동, 산란행동, 산란 후 행동으로 구분되었다. 산란 전에는 주로 휴식과 유영을 반복하였다. 호르몬 주사 후 평균적으로 11~12시간 경과하면 산란행동을 시작하여 암·수 1 : 1로 1~18회 산란하였고, 수중에서 수컷이 골질반을 이용하여 암컷의 등지느러미 뒷부분의 몸을 원의 형태로 감싸안고 산란이 이루어졌다. 산란 후 행동에서는 특별한 난 보호행동은 보이지 않았으며 산란에 참여하지 않은 개체들이 수정란 일부를 섭식하는 것이 관찰되었다.

• 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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• 제26권1호
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• pp.11-16
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• 2014

2009년 5~7월까지 전북 진안군 주천면 주양리에 위치한 주자천에서 감돌고기의 일중 산란 타이밍 및 초기 산란위치에 대한 연구를 실시하였다. 감돌고기의 산란은 5월 7일부터 7월 11일까지 이루어졌으며 꺽지 산란장에만 탁란을 했다. 61개 꺽지 산란장 중 56개의 산란장에 탁란했으며, 꺽지 산란 후 1~2일 사이에 시작되었다. 하루 중 감돌고기의 탁란은 꺽지의 공격횟수가 낮게 나타난 6~7시 사이에 가장 높은 빈도로 관찰되었다. 감돌고기가 탁란한 알의 부화율은 지속적인 꺽지의 산란장 방어와 가장 밀접한 상관관계를 나타냈으며, 감돌고기는 자신의 알을 중심으로 난 보호를 하는 꺽지 난괴와 가까운 곳부터 산란을 함으로써 꺽지의 난 보호를 통한 이득을 얻는 것으로 생각된다.

• 한국수산과학회지
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• 제23권6호
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• pp.425-438
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• 1990

쉘리코프 해협에서 산란하는 명태의 정확한 산란장소 및 시기를 조사하기 위하여 1981 년, 1984년, 1985년에 음향학적 조사 및 난치자어 조사를 하였다. 알라스카만의 명태는 산란하기 위하여 늦겨울 내지 초봄에 쉘리코프 해협으로 이동한다. 명태는 대륙사면으로 부터 따뜻하고 염분도가 높은 해수를 이용하여 해협 남동쪽 입구의 바닥을 타고 들어와 중앙부의 서쪽면에 있는 깊은(>200 m) 곳에 모여들고, 3월부터 산란을 한다. 최대산란은 이곳에서 3월 하순부터 4월 초순에 걸쳐 일어나고, 해협내 수괴의 성질(해수온, 염분도, 밀도 등)은 해마다 다르지만 산란시기 및 장소는 거의 변함이 없다. 이 해역은 어류의 산란장이 보육장과 가까이 있다는 지리적 이점 이외에도 해마다 이 시기에는 해수의 이동량이 최저치로 내려가고 식물플랑크톤 번식의 핵심요소인 해수의 표면 혼합층이 최소로 된다는 해양학적 현상 때문에 알라스카만 명태의 최적합 산란장이 되어왔다고 추측된다. 4월 초순 이후, 산란행위는 급격히 감소하며 산란장은 북동쪽과 남서방향으로 약간 확장됨을 보여준다.

• 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.

• 환경생물
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• 제20권3호
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• pp.268-275
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• 2002

Seasonal variation in reproductive condition of the Pacific oyster Crassostrea gigas was investigated from a suspended cultured oyster population in Gosung Bay, South Korea using histological techniques, Gametogenesis of oysters initiated in February when water temperature reached 11 to $13^\circ{C}$. Increase in oocyte size and the number resulting in follicle expansion was observed from March to May First spawning of oysters observed in mid Jun when the surface water temperature reached 22 to $25^\circ{C}$. Spawning activity of oysters extended from mid June to late September with two marked spawning peaks in June and August. Most oysters collected from October to December exhibited few residual eggs in packed follicles exhibiting a typical spent condition. No gametes were observed from December to February from oysters collected in the Bay. Gonadal development of oysters in the Bay seemed to follow a seasonal fluctuation in environmental conditions such as water temperature and food availability in the water column. Spawning of oysters in late June was in part associated with sudden drop in salinity due to vast amount of freshwater input in the Bay after the summer flooding. Sex ratio of oysters was 59.5% male and 39.8% female. Less than 1 percent (0.6%) of the oysters examined were hermaphrodite; few eggs were observed in testis.