• Journal of Aquaculture
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• v.17 no.2
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• pp.115-121
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• 2004

In a series of feeding experiments using the newly established the first laboratory strain of a temperate photosynthetic ciliate, Mesodinium rubrum MR-MAL01, direct evidence was obtained for ingestion of the cultured M. rubrum cells by the bivalves like the Korean scallop, Chlamys farreri and Manila clam. Ruditapes phil-ippinarum. Each experimental Korean scallop and Manila clam removed up to 9,590 and 23,200 cells min-1, respectively. Small particles almost identical to the ruptured cells of MR-MAL01 culture were observed in the gut of the experimental bivalves, although no intact M. rubrum cell was found. In a 28 days rearing experiment, Isoshrysis galbana (KMCC H-2), a microalga, supported better growth of small Manila clam spat (0.46 mm in shell length) than MR-MAL01 strain. For the large Manila clam spat (0.84 mm in shell length), however. MR-MAL01 strain was a better prey item. Mass culture methods for this photosynthetic marine ciliate may be developed for use as live feed in aquaculture of the spat and broodstock of bivalve and small-mouthed fish larvae.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.313-319
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• 2012

Mass production method on artificial seedling production of hard clam Meretrix petechialis was developed indoor culture system. Spawning of adult clam (SL $65.8{\pm}8.4mm$) was induced using the combined method of air exposure and water temperature raising. The fertilized eggs were developed to D-shaped larvae after 17.7 hours at $27^{\circ}C$ and hatching rate was 6.1%. Shell length (SL) of D-shaped larvae was measured to be $131.4{\pm}2.6{\mu}m$ and thereafter the larvae grew to the settled spats with SL $190.2{\pm}7.5{\mu}m$ in 4 days. Estimated survival rate of settled spats was 48.1%. Spat collection on 130,000 spats with SL $0.19{\pm}0.01mm$ performed conducted by sand bottom circulation filtering method. Collected spats grew up to $3.1{\pm}0.8mm$ in 46 days, $6.6{\pm}1.8mm$ in 87 days, and $10.5{\pm}0.9mm$ in 114 days. The relative growth between SL and shell height (SH) was calculated to be SH = 0.8501SL + 0.0196 ($R^2=0.9987$) during the whole spat period. During spats rearing, they were suffered from one time of mass mortality at SL 3.1 mm, but 51,000 spats were finally survived with the rate of 39.2% at 114 days of spat rearing in indoor tank system.

• The Korean Journal of Malacology
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• v.28 no.4
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• pp.293-303
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• 2012

Growth and survival (%) of the larvae and spats of Scapharca broughtonii fed on three different microalgal species (Isochrysis galbana, Pavlova lutheri and Chaetoceros simplex) were investigated with the analysis of fatty acid composition. The larvae fed on mixed diet with three microalgal species showed the highest growth in shell length ($261.3{\pm}13.5{\mu}m$) and survival ($27.4{\pm}5.3%$). The growth and survival (%) of the larvae fed on the single diet with C. simplex were significantly higher than those of the larvae fed on I. galbana or P. lutheri (P < 0.05). The growth and survival (%) of S. broughtonii spats reared for 30 days were also highest in the mixed diet group with $1,114.8{\pm}128.0{\mu}m$ and $61.3{\pm}5.5%$, respectively, and followed by C. simplex, I. galbana and P. lutheri. With respect to composition of fatty acid of the single or mixed microalgal diet, the content of PUFA and n-3 HUFA were the highest in C. simplex. This result can be considered as the reason for high growth and survival (%) of the larvae and the spats. C. simplex was the best species as the single diet, but the mixed diet with three microalgal species showed better dietary value than single diet did for the larvae and spat of S. broughtonii.

• Journal of Aquaculture
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• v.20 no.1
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• pp.31-40
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• 2007

To find out the effect of the spat planting time and environmental factors in the arkshell, Scapharca broughtonii (Schrenck), we investigated the growth, survival rate of arkshell and habitat characteristics in Gamak Bay, Yeoja Bay and Saryang Island. We planted artificial spats of arkshell in Gamak Bay and Yeoja Bay at November 2004, and also planted domestic and Chinese natural spats in Saryang Island at March 2005. We measured growth, survival rate of arkshell, physiochemical parameters of the water mass (water temperature, salinity, dissolved oxygen, nutrients and chlorophyll a) and characteristics of the sediment (oxygen penetration depth, oxygen microprofiles, ignition loss and chemical oxygen demand) by monthly. The cumulative survival ratio of arkshell in Gamak Bay was the highest at December, whereas the ratio of arkshell in Yeoja Bay was recorded as 0% at October. The monthly growth rates of arkshell length in Gamak Bay and Yeoja Bay were the highest in May and the growth rate of the Korean arkshell in Saryang Island was higher than Chinese ones significantly. The high mortality (> 65%) of the arkshell in Yeoja Bay during summer probably caused by high water temperature, inflow of low salinity water, and low dissolved oxygen concentration in sediment. The concentrations of nutrient and sediment COD were considered to play an important role in the monthly survival ratio of arkshell in Gamak Bay and Sarayng Island. We suggest that the growth and mortality of arkshell might be influenced to the planting time of spat and the habitat characteristics.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.563-567
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• 1999

Changes in proximate composition and meat weight of oysters cultured in shallow-water at Bukman bay of Tongyeong in Korea with Korean and Japanese spats were investigated. Protein content (dry basis) was rich in August and September, accounting for $70\~72\%$ in the oyster (Korean oyster) cultured with Korean spat and $75\~76\%$ in the oyster (Japanese oyster) cultured with Japanese spat. On the contrary to protein content, carbohydrate contents (dry basis) in the both oysters were poor in the both months, There was a negative correlation (r=-0.94, p<0.01) between protein and carbohydrate content during growing of the bath spats. Total lipid (TL) content was the poorest in August, which is known as spawning season, accounting for $1.4\~1.5\%$ in the both oysters. In addition, the korean oyster also showed the lowest level or TL content in october. Meat weights or the Korean and japanese oysterswere 4.2$\~$4.8 g/specimen and 7.5$\~$8.3 g/specimen, respectively, in the harvest season from November to December. Meat weight increased exponentially with TL content, $y=0,2081e^{1.5696x}$ (r=0.8856, p<0.001). These nutritional components per specimen were contained about two times more in the Japanese oyster than in the Korean one in the harvest period.

• The Korean Journal of Malacology
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• v.12 no.2
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• pp.99-104
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• 1996

우리나라 동해안에서 주요 양식대상종으로 각광을 받고 있는 가리비의 산란유발은 종묘생산시 생산성을 높이는 가장 중요한 요소라고 할 수 있다. 따라서 본 연구는 자극방법에 따른 가리비의 산란유발 효과와 유생사육에 관하여 조사한 결과, 가리비의 생식소 지수는 4월에 암수 각각 32.4와 33.2로 최고치를 보였고, 정자현탁액 첨가구에서 개체당 백만개 이상과 80%이상으로 가장 좋았다.

• The Korean Journal of Malacology
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• v.16 no.1_2
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• pp.25-29
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• 2000

In order to investigate the optimal environment factor for growth of the cockle shell, Anadara granosa bisenensis, tolerance experiment to the water temperature and salinity have been conducted. In the tolerance experiment to the temperature A. granosa bisenensis survived a very wide range from 3$^{\circ}C$ to 33$^{\circ}C$, but their survival rate was lower at higher water temperature up to 35$^{\circ}C$. In the case of salinity their tolerance range was from 0$\textperthousand$ to 100$\textperthousand$ and showed higher survival rate at lower salinity. Growth in shell length and total weight of the spat at the end of the rearing experiment was 13.17${\pm}$0.98 mm and 0.69${\pm}$011 g.

• Fisheries and Aquatic Sciences
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• v.2 no.2
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• pp.113-121
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• 1999

Changes in lipid content, lipid class and fatty acid compositions of the cultured oysters in shallow-water, Bukman bay (Tongyeong, Korea), using both Korean and Japanese spats were investigated. The content of non-polar lipid (NL) comprised approximately $60- 80\%$ of total lipid (TL) in the cultured oysters. There was a positive correlation between NL content and meat weight, y=0.287lx-15.309 (r=0.834l, p<0.001). The prominent fatty acids of the oysters were 16:0, 20:5n-3 (eicosapentaenoic acid, EPA), 22:6n-3 (docosahexaenoic acid, DHA), 18:0, l8:1n-7, l8:1n-9, l6:1n-7, 14:0 and l6:4n-3. During the growth of the oysters, l6:4n-3 showed the highest coefficient of variation, accounting for $41.8\%$ for the Korean oyster and $32.3\%$ for the Japanese one, respectively. Both oysters showed low level of n-3 fatty acids such as DHA and EPA and high level of n-6 fatty acid, 20:4n-6, in the spawning period (August). During growth of the oysters, both EPA and DHA were the richest fatty acids in the harvest period (December, 314 mg/100g sample) and in the pre-spawning period (July, 237-247 mg/100g sample), respectively. Consequently, the cultured oyster with Japanese spat contained approximately two times more n-3 fatty acids per oyster individual than those with Korean one in the harvest season.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.259-267
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• 2012

Due to the oil spill incident in December 2007, every facility of oyster culture was removed in western coast especially in Taean and Seosan. To restore oyster resources in Taean and Seosan, we brought oyster seeds from southern area and monitored their growth. In addition we monitored the culture environment throughout the year, and observed the number of oyster larvae and attached spats on collectors during summer. The factors of water environment were appropriate for oyster culture in both study area. The growth of shell height was larger in Uihang-ri, Taean than Jungwang-ri, Seosan. Spawning was more intensive in a short time in Jungwang-ri, Seosan than Uihang-ri, Taean. The number of oyster larvae and spats of collectors were much more in Jungwang-ri, Seosan than Uihang-ri, Taean. This study showed that transplantation of healthy oyster seeds from southern area can be a way of restoration of oyster resources in western coast. In addition, systematic approaches are necessary by building a better understanding of regional characteristics to restore and enlarge the oyster culture farms in western coast. In summary Uihang-ri, Taean will be appropriate for cultivation farms and Jungwang-ri, Seosan for seedling grounds to increase oyster culture productivity.

• The Korean Journal of Malacology
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• v.6 no.1
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• pp.1-10
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• 1990

The occurrence of the larvae, the size of the spats daily attached to the collectors, the difference of the spat size with temperature, and the darly growth of a mussel, Mytilus edulis, were investigated at the off Songpo, Chinhae Bay, the southern part of Korea during the period from March 1 to August 30 in 1986. The water timperature and specific gravity ranged from 7.0 $^{\circ}C$ to 27.4$^{\circ}C$ (mean 17,24$\pm$5.9$0^{\circ}C$), and from 1.0126 to 1.0126(mean, 1.0242$\pm$0.0023), respectively. D-shaped larvae had two peak occurrences in March 8, April 19, Umbo-shaped larvad three peaks in March 8, April 21 and June 17, and full grown larvae two peaks in May 13 and June 23, respectively. Therefore, it is assumed that the mussel had two mass spawning time in early March and mid April and two mass settling time in mid May and alte June. The maximum size of the planktonic mussel larvae ranged from 375-400${\mu}{\textrm}{m}$ and most larvae sizing below 300${\mu}{\textrm}{m}$ long settled in adquate substrate. Spats just after settlement had the range from 26.5 to 547.3${\mu}{\textrm}{m}$ with the minimum of 225.0 ${\mu}{\textrm}{m}$ in mean shell length. The spats settled in summer season, when the water temperature raised above $25^{\circ}C$, were smaller than those settled in spring season in mean shell length. The early growth of the mussel spat had been assumed considerably fast.