• Korean Journal of Fisheries and Aquatic Sciences
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• 제37권6호
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• pp.485-491
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• 2004

Spawning induction, egg development and larval growth of ark shell (Tegillarca granosa) (L.) were investigated. The most effective method of spawning induction was steady temperature increasing from$4^{\circ}C\;to\;28^{\circ}C$ with irradiation of sea water by UV after T. granosa was exposed to air at $4^{\circ}C$ Optimum condition for larval roaring was under the 32.4 psu and two temperature $regimes:\;28{\pm}1^{\circ}C\;and \;25{\pm}1^{\circ}C$. Fertilized eggs was demersal isolated eggs, and egg diameter was $60{\mu}$. D-shaped larvae appear about 20 hr after hatching with $94.1{\mu}$ in shell length and $86.7{\mu}$ in shell height. Ten days were required from hatching to umbo larva stage, of a mean shell length $125.2{\mu}$. On 25th day, the larva grew to $450{\mu}$ in shell length and began to settle on the bottom. Effect of temperature between $25^{\circ}C$ (control group) and $28^{\circ}C$ on larval growth was not different. Survival rate of larvae settled on the bottom was about $19{\%}$ in both temperatures conditions $(25^{\circ}C\;and\;28^{\circ}C)$.

• Journal of Fisheries and Marine Sciences Education
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• 제29권2호
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• pp.409-414
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• 2017

Effects of human chorionic gonadotropin (HCG) on ovulation and spawning of the grass puffer, Takifugu niphobles, were investigated. Matured females spawned successfully by all doses of HCG. Spawning usually occurred 24 hours after hormone injection. Body weight of adult, gonadsomatic index (GSI), pseudo-GSI, body weight of spawned egg, success rate of spawn, fertilization rate, hatching rate, and survival rate of juvenile were correlated with increasing HCG doses. However, abnormal rate of juvenile was not correlated with increasing HCG doses. These results should be useful for developing aquaculture program of grass puffer.

• Journal of Aquaculture
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• 제10권1호
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• pp.17-24
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• 1997

In order to understand the spawning and larval development of Perinereis aibuhitensis for the effective seedling production, the influence of water temperature on spawning induction, egg and larval development of the worm were investigated from October 30, 1989 to October 30, 1990. Main spawning period was from July through September, and average diameter of mature eggs was $220\mu m$. The relationship between the adult weight (Wt) and the number of spawned eggs (NS) was given as follws : NS=48635.589Wt1.3044 (r=0.8572). Adult males and females died immediately after spawning. Trochophore larvae developed 12 hours after fertilization, and hatched out after 56 hours.

• Korean Journal of Fisheries and Aquatic Sciences
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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.

• Journal of Aquaculture
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• 제12권1호
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• pp.39-45
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• 1999

In order to obtain the basic biological data for artificial seedling production of sea cucumber, Stichopus japonicus, the influence of water temperature and air dry for spawning induction, egg development and larvae rearing was investigated during the period from April, 1995 through September, 1995. Spawning induction rate by the water temperature was 6.0~17.5% and air dry was responsed 1.4~4.0%. Number of eggs spawned of Stichopus japonicus were $50~500\times10^4$ individuals, the fertilization and hatching rate were ranged 84.0~96.0%, 71.4~84.6% respectively. The fertilized egg of Stichopus japonicus appeared mean diameter of $154{\mu}m$. At a constant water temperature of $23^{circ)C$, it become 4 tell stage from fertilization after 2 hours 10 minutes, hatching larvae after 14 hours half, auricularia larvae after 3 days, doliolaria larvare after 11 days and pentactula larvae after 15 days ready for settlement. The suitable food in the larvae reared for 17 days after fertilization were shown the best growth and survival in the larvae food of Chaetoceros calcitrans. Optimum density for larvae rearing were maintained of the larval density lower than 2 individuals/ml.

• Journal of Aquaculture
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• 제18권1호
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• pp.1-6
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• 2005

This study focused on spawning season, induce spawning, spawning and larval development of the Jicon scallop in Daehuksan Island of southwestern waters in Korea. The condition index and gonadosomatic index were used to investigate the reproductive pattern of the Jicon scallop. The major spawning season was from July to August, showing an unimodal gametogenic cycle per year. Several different tests were carried out to induce spawning of the mature male and female C. farreri. For females, the injection of serotonin, temperature induction technique and the combination of the both treatments produced significantly faster gamete release. Unlike females, males spawned only in response to the UV rays irradiation stimulation. Mean size of fertilized eggs was 69.5 $\mu$m in diameter. After fertilization, the zygote could be divided into 2 cells as early as 2 hours. It took about 8 hours to develop the 8-cell stage, about 20 hours to hatch trochophore larvae, and about 40 hours to be D-shaped larvae.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제9권1호
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• pp.61-68
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• 1976

For the artificial precocious breeding of abalone effects of changes in environmental parameters, water temperature and light period, on the induction of spawning have been studied. Subtidal specimens of Haliotis discus hannai were collected irregularly for 6 times from April to June 1975 in Chungmu Bay near Jukdo Island, the southern coast of Korea. One hundred and fifty specimens were reared in 4 aquarium tanks in the laboratory and in a creel submerged in the sea during the period of 60 days from April 24 to June 23, 1975. The all groups kept in the four tanks and a creel showed very high spawning rates $(70\~100\%)$, compared to those inhabited the natural environment at sea until right before the spawning time $(0\~50\%,\;average\;16.4\%)$. From the results of the present induced spawning, the parameters can be discussed as follows: It seems likely that photoenvironment may stimulate to produce and secrete some internal substances which may concern to giving the fertilizing ability to the eggs before spawning and to inducing spawning, but the temperature may not be a factor for this concern. For effective precocious breeding, it seems to require that abalones are to be realoed under controlled conditions of darkness below 2,000 lux even during day time for more than 60 days before inducing spawning.

• Journal of Aquaculture
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• 제17권2호
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• pp.97-102
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• 2004

We examined the effects of stimulants including sunlight and UV-irradiation on the spawning induction and early development of the noble scallop, Chlamys nobilis. The sunlight stimulation resulted in nuch faster spawning induction (100% success within 40 minutes) compared to UV-irradiation (100% success within 70 minutes). Early development of the scallop larva took place between 15$^{\circ}C$ to 3$0^{\circ}C$. The time to reach the early D-shaped stage was 63.5, 31.5, 18.5 and 17.0 hours at 15, 20, 25 and 3$0^{\circ}C$, respectively. The correlations between the water temperature-(WT) regimes and the time (t) required for each developmental stage are as follows. 2 cell stage: 1/t=0.0606WT-0.6194 ($r^2$=0.9791) 8 cell stage: 1/t=0.0304WT-0.3453 ($r^2$=0.9941) Morula: 1/t=0.0100WT-0.1049 ($r^2$=0.9663) Trochophore: 1/t=0.0058WT-0.0618 ($r^2$=0.9848) D-shaped larva: 1/t=0.0030WT-0.0282 ($r^2$=0.9731) These correlations indicated that the biological minimum temperature of the species is around 10.44$^{\circ}C$. The highest survival rate up to D-shaped larva at different water temperature was observed at $25^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• 제8권4호
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• pp.234-241
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• 1975

Reproductive cycle of Haliotis discus hannai Ino was studied based on the samples which were collected in Yeosu area from January, 1973 to December, 1974. Particular emphasis was paid on the seasonal variation of gonad maturity factor, coefficieot of gonad maturity, fatnesss, and relationship of gonad weight to growth of the abalone. seasonal fluctuation of water temperature and induction of artificial spawnings were also checked. The abalone of this area spawns twice a year: spring spawning(early May-late July) and Autumn spawning(early September-late November). peak spawning occurs from late May to middle of June for spring spawning: it occurs from late September to early November for Autumn spawning. Gonad maturity factor was closely related to the spawning seasons. For the spring spawning Gonad maturity factor reached to its maximum value as 18.84 in April; for the Autumn spawning it reached to its maximum value as 22.65 in September. Annual minimum value was 12.65 in January. Annual maximum values of coefficient of gonad maturity were 44.10 in May and 49.05 in September and the annual minimum was 10.09 in January. Fatnesswas highest in July as 0.221 and it was lowest in October as 0.1058. Ratios of shell length to gonad weight were formulated as follows : $$In\;September\;GW=0.000003710SL^{3.7860}$$ $$In\;January\;GW=0.000021198SL^{2.8564}$$ $$Annual\;mean\;GW=0.00000005013SL^{4.2273}$$ Relations of total weight to gonad weight were formulated as follows : In September GW=0.1918TW-4.9231 In January GW=0.0992TW-0.1759 Annual maan GW=0.1568UW-3.5256.

• Journal of Aquaculture
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• 제16권3호
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• pp.129-134
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• 2003

Spawning induction and early growth of the sea urchin, Strongylocentrotus intermedius were studied with the purpose of artificial seedling production. Gonadosomatic index(GSI) of the sea urchin showed the highest value in October, and rapidly decreased in December. It means that October and November is the peak of spawning season of the sea urchin in the latitude. Spawning induction by injection of potassium chloride solution in October has showed 44.0~100.0% reaction rate, and were produced 6,300$\times$10$^4$ eggs. Spawned eggs have shown the fertilization rate of 92.3~98.2% and the hatching rate of 78.2~87.0%. The metamorphosis of larvae after hatching in the seawater temperature of 13.7~17.1$^{\circ}C$ resulted in early eight-armed larvae in 13 days and late eight-armed larvae in 20 days. The collection of progenies was possible in 24~25 days after hatching and collection rate was 18.5~26.1% (mean 22.3%). Test diameter immediately after collection had a mean 350 ${\mu}{\textrm}{m}$. Survival rate and test diameter of juvenile sea urchin after collection were 58.5%, 1.32 mm in 30 days, 27.7%, 3.82 mm in 92 days and 15.6%, 11.70 mm in 181 days, respectively.