• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.6
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• pp.393-398
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• 2005

Codium fragile is commercially farmed in Korea by natural blooming zygote attachment. Experiments found optimum conditions for artificial seed production and nursery culture of C. fragile by asexual reproduction. Isolated utricles and medullary filaments were regenerated to erect thalli using both indoor and outdoor culture experiments. Under the indoor culture conditions, irradiance was an important factor to control the development of erect thalli. Formation of erect thallus from the isolated medullary filaments in the indoor culture was induced after 30 days under $20^{\circ}C$ and $60{\mu}mol/m^2/sec$. The detachment of isolated utricles and medullary filaments from the substrates of seed strings was reduced by exposure to the air during 2 hrs before the indoor culture of seed strings. The maximum growth and development of erect thalli in the nursery culture was induced at a water depth of 0.5 m. Depending on the substrates of the seed strings the growth of erect thalli was not significantly different (p>0.05).

• The Journal of Fisheries Business Administration
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• v.28 no.2
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• pp.87-105
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• 1997

The objective of this study is to analyze the effects of the oyster seed selection on profitability of the oyster aquaculture business The results of the analysis are as follows ; 1) The comparison of profitability among four different oyster seed applied to the four different scale : 1ha, 3ha, 5ha, and 10ha. The results of the comparison show that, for all scale, the artificial oyster seed is more profitable than the natural oyster seed or the natural oyster seed imported from Japan. 2) There are four important determinant variables of profitability to aquaculture business. In the order of their effect, it is oyster price, quantity of production, labor cost, and seed price. 3) If differences of price between the artificial hardening oyster seed and the natural hardening oyster seed are more less 1,430 won, the former is better. 4) The effect of increasing income of fishermen are estimated about 58.5 billion won or 102 billion won from the artificial oyster seed on the oyster aquaculture.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.38 no.3
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• pp.164-171
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• 2005

Codium fragile (Suringar) Hariot, an edible green alga is farmed in Korea by natural blooming zygotes attachment. Experiments were conducted to reveal the conditions for artificial seed production of C. fragile by sexual and asexual reproduction. Growth was compared between zygotes attachment (sexual reproduction) and isolated utricles with medullary filaments (asexual reproduction). Zygotes and isolated utricles with medullary filaments were cultured under different light conditions (10, 20, 40, 60 and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and temperatures (5, 10, 15, 20 and $25^{\circ}C$) under 16:8LD. Maximum growth of zygote was $261.3{\pm}21.0\;{\mu}m$ under $15^{\circ}C$ and $20\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 13 days culture. Maximum regeneration of isolated medullary filament was $8.1{\pm}1.7\;mm$ per one isolated utricle under $20^{\circ}C$ and $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ after 15 days culture. After intermediate culture during two months in the field, morphogenesis occurred in both sexual and asexual reproduction, and growth of young thalli was not significantly different (p>0.05) between the both reproduction methods. Even though seed production of C. fragile is possible in both sexual and asexual reproduction, the mass artificial seed production of asexual reproduction is much more effective than that of sexual reproduction that is too much affected by maturity.

• ALGAE
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• v.35 no.2
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• pp.123-131
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• 2020

Sargassum macrocarpum is a rich source of anti-inflammatory compounds. Recently, one of the compounds, tuberatolide B, has been reported as a functional anti-inflammatory additive for foods and nutraceuticals. The artificial seeding, growth and maturation of S. macrocarpum were investigated from May 2018 to September 2019. Indoor culture experiments for induction of egg release were conducted at temperatures of 17, 20, 23, and 26℃ and irradiances of 0, 10, 20, 40, and 80 μmol photons m^-2 s^-1 under 14 : 10 h (L : D) photoperiod. Within a given treatment combination, higher temperatures and irradiance levels favoured the maturation of receptacles in S. macrocarpum. Using artificial temperature and irradiance control, thalli matured one month earlier than thalli in nature. Under natural condition, receptacle formation began in April, and the eggs were released in June and July. The release of eggs from the receptacles was promoted at 17-20℃ and 40-80 μmol photons m^-2 s^-1, and the fastest growth of germlings occuring at 15-17℃ and 40 μmol photons m^-2 s^-1. For mature thalli, 300 g wet-weight was sufficient to seed 100 m of seed string. Thalli grew to 10.5 ± 2.6 cm in length at a density of 6.7 ± 3.3 individuals m^-1 after 1 year of cultivation, from germination. This study demonstrates that it is possible to cultivate S. macrocarpum for the production of anti-inflammatory products.

• The Journal of Fisheries Business Administration
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• v.29 no.2
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• pp.143-161
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• 1998

The objective of this study is to analyze the effects of increase in the oyster hatchery on fishermen's income. The results of the analysis are as follows : \circled1 The necessary quantities of oyster seed are 18,000 thousand hanging line. The 29.4%, of that has been applied by ana-seed collection and 29.1% of that has been applied by proseed collection. The demage of oyster aquaculture business is estimated about 35 billion won or 83 billion won. \circled2 The production cost per hanging line of the oyster hatchery is 1,974 won. And if it is sold by 2,500 won, return on investment will be 31.9%. Therefore profitability of the oyster hatchery is very good. \circled3 There are four important determinant variables of profitability to the oyster hatchery. In the order of their effects, it is operation number, seed price, production cost, and quantity of production. \circled4 If differences of price between the artificial hardening oyster seed and the natural hardening oyster seed are more less 1,430 won, the former is better. \circled5 The necessarily quantities of the oyster hatchery are estimated 160 units in the scale of 10,000 hanging line production to one operation. \circled6 The effect of increasing income of fishermen are estimated about 85.3 billion won or 124.5 billion won from increase in the oyster hatchery.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.4
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• pp.486-492
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• 2016

This study investigates the relationship between environmental factors, such as semilunar rhythm and atmospheric pressure, and the release of Marphysa sanguinea larvae. During artificial seed production in a temperature-regulated culture system, there was an increase in the number of released larvae at tide times between 3-4 and 9-11. Numbers of larvae released were significantly correlated with tidal rhythms. Atmospheric pressure also appeared to influence larval release, with increased numbers released when a period of high atmospheric pressure followed a period of low pressure.

• Journal of Aquaculture
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• v.10 no.3
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• pp.373-380
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• 1997

The experiments were conducted to improve the mass production of Nile tilapia, Oreochromis niloticus, seed in closed recirculation systems. It was observed that smaller females (340g av. body weight) under lower stocking density (1.2 kg/$m^2$)) group produced 3.6 times more fry than larger females (612g av. body weight) under higher stocking density (2.1kg/$m^2$) group when the fry were collected at 30 days after the broods stocked. The clutch removal method where the eggs and sacfry were collected from female mouth followed by artificial incubation showed improved seed production, when compared to the traditional natural mouth-brooding method by harvesting free swimming fry from brood tanks (P<0.05). Under the clutch removal method, short-term incubatin of brooders (14 days) was proven to be more effective than long-term incubatin (21 days). Hatching success of clutch removed eggs was ranged from 55.7 to 91.5% in 1.8$\ell$ of upwelling incubators depending on the different development stages.

• Proceedings of the Korean Aquaculture Society Conference
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• 2005.05a
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• pp.65-65
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• 2005

• Journal of Aquaculture
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• v.10 no.2
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• pp.199-211
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• 1997

Effects of light and temperature on the early growth of Hizikia fusiformis were investigated for establishment of artificial seed production. Young germlings were cultured for 70 days under different culutre conditions : light intensities (500, 1, 000, 2, 000, 4, 000, 8, 000 lux), photoperiods (8 : 16, 12 : 12, 16 : 8, (L : D)) and temperatue (10, 15, 20, 25, $30^{\circ}C$). Growth of the germlings was facilitated in 2, 000~4, 000 lux of light intensities, 16 : 8 (L:D) of photoperiods and 15~$20^{\circ}C$ of temperature. Culture conditions were revealed for the mass culture of artificial seeds of effective early growth in Hizikia cultivation.

• Journal of Aquaculture
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• v.20 no.2
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• pp.81-84
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• 2007

We studied two research items that can be undetermined issues in the artificial seed production of the Japanese scallops, Patinopecten yessoensis, batch-specific quality of the reproductive outputs and nursery acclimation, in the embayed waters of Yangyang, Gangwon, Korea. The first batch of the spawner showed better results in terms of survival, growth, and resistance against parasitic ciliate infection over the second batch that was obtained in 5 days after first batch from the same spawner. The early attached spats directly placed in the farming ground (the unacclimated) were resistant against the water current of the open environment, by showing survival of about 80% for a month, a normal survival compared with other results. However, the spat survival during the nursery acclimation was significantly lowered in comparison with that in the unacclimated condition (P<0.01). We discussed the research results of the two items, particularly focusing on their availability for mass seed production for aquaculture in the Korean coastal waters of the East Sea (Sea of Japan).