• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.385.2-386
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• 1998

• Proceedings of the Zoological Society Korea Conference
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• 2001.04a
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• pp.83-83
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• 2001

No Abstract, See Full Text

• Environmental Analysis Health and Toxicology
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• v.25 no.2
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• pp.161-168
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• 2010

The observed the toxic effect of WSF (Water Soluble Fraction) on development time, development rate, attachment rate, survival rate and growth of the larva during the early stage of the Pacific oyster, Crassostrea gigas. The time required early juvenile from the fertilized eggs exposed to crude oil (WSF) was about 13 hours in control group. But that of the crude oil dose group takes 12 hours, with shorter compared to control group. Development and attachment rate of the oyster significantly higher in 0.4 and 0.8 mg/L WSF compared to control group (P<0.05) but significantly lower more than 1.6 mg/L WSF (P<0.05). Survival rate of the oyster larva significantly higher in 0.4 and 0.8 mg/L WSF compared to control group (P<0.05) but significantly lower more than 2.4 mg/L WSF (P<0.05). Survival rate of spot showed no significantly difference compared to control group (P>0.05). Shell growth of the oyster were significantly lower more than 1.6 mg/L WSF compared control group (P<0.05). The effect concentration of crude oil showed that more 0.4 mg/L in development and attachment rate and more 1.6 mg/L in growth. Also, chronic exposure of crude oil even effect also in low concentration.

• The Korean Journal of Malacology
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• v.25 no.3
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• pp.213-222
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• 2009

In order to investigate contamination of heavy metal in seawater and cultured oyster, samples were collected November 2003 to July 2004 from 12 sites (13 sites for seawater) along the coast of Tongyeong, Korea. The mean concentrations of metal in oyster tissues were as follows: 0.09 (0.01-0.3) ${\mu}g/l$ for Cd, 0.47 (0.01-1.4) ${\mu}g/l$ for Cr, 0.59 (0.2-2.3) ${\mu}g/l$ for Ni, 1.02 (0.1-4.2) ${\mu}g/l$ for Pb and 0.48 (0.01-3.9) ${\mu}g/l$ for Hg in the seawater, whereas 2.45 (0-5.47) mg/kgDW for Cd, 3.63 (0.10-12.91) mg/kgDW for Cr, 3.2 (0.01-15.73) mg/kgDW for Ni, 3.51 (0.01-6.47) mg/kgDW for Pb and 0.39 (0.004-0.74) mg/kgDW for Hg, respectively. Most metal concentration values were below the permissible range for the related regulations. Mean bioconcentration factors (BCF) for each metal were as follows: 38,964 (1,771-207, 171) for Cd, 9,583 (1,231-80, 162) for Cr, 191 (3-20, 980) for Ni, 1,416 (245-5, 207) for Pb and 180 (5-716) for Hg, respectively. The BCF values from this study corresponded to the transitional phase from the pristine to the contaminated waters. Notably, Cd showed the highest BCF, which suggest that the Pacific oyster could be utilized as a useful biomarker for Cd contamination in sea water. The multidimensional scaling analysis suggested that the metal contaminants are mainly originated from combustion of fossil fuel and accumulated to oyster through food web.

• Korean Journal of Environmental Biology
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• v.27 no.3
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• pp.279-284
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• 2009

In order to understand food sources-metabolism for the pacific oyster (Crassostrea gigas), the stable isotope ratios of carbon (${\delta}^{13}C$) and nitrogen (${\delta}^{15}N$) of its gut, gill, and muscle as well as potential food sources (particulate organic matter, sedimentary organic matter, benthic microalgae, seagrass detritus) were determined in Dongdae Bay. Average ${\delta}^{13}C$ and ${\delta}^{15}N$ values reflect that oysters primarily fed on sedimentary organic matter as opposed to suspended organic matter during summer and winter seasons. However, the relatively enriched $^{15}N$ values of particulate organic matter (>$250{\mu}m$) and sedimentary organic matter in the summer may be due to the photosynthetic incorporation of $^{15}N$-enriched nitrogen (DIN) or the spawning events of bivalves. Specific oyster tissues (gut, gill, and muscle) revealed different metabolic pathways, which were determined through analysis of ${\delta}^{13}C$ and ${\delta}^{15}N$ in each organ. The present results suggest the determination of carbon and nitrogen stable isotopes to be a useful approach in ecological research related to the food sources- metabolism of Crassostrea gigas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.489-494
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• 2010

The nutritional demand of oyster larva (Crassostrea gigas) were investigated to determine the optimal culture conditions and improve micro-algae utilization. Changes in nutrients and shell growth were examined in fed and 96-h (48 h in late umbone stage) oysters at four larval stages. Shell growth increased significantly in D shape larvae, regardless of feeding variations. No growth was observed in starved larvae, except in shell length of umbone (to 11.9 ${\mu}m$). Fed larvae showed significant growth in all development stages (P < 0.05). During starvation, lipids were most significantly decreased in all larval stages (by 76.8%, 68.3%, 76.3%, and 40.3%, respectively), followed by protein (41.1%, 31.1%, 33.1%, 16.7%) and nitrogen-free extracts (40.8%, 24.3%, 36.9%, 20.1%), Gross energy (kcal/g) consumption in each larval stage was 49.6%, 35.1%, 39.1%, and 20.4%, respectively. Our results indicate that lipids are the most important energy source during the early larval development stages of C. gigas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.668-673
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• 2015

The pacific oyster Crassostrea gigas has a desirable taste and flavor that differs from those of other fish and shellfish. In order to develop a high value-added product from individually quick-frozen oyster extract (IQFOE), we prepared an oyster sauce from IQFOE and characterized its volatile compounds using vacuum simultaneous steam distillationsolvent extraction / gas chromatography / mass spectrometry. The moisture, crude protein, crude ash, salinity, pH and volatile basic nitrogen contents of the oyster sauce were 60.6%, 8.2%, 9.2%, 9.3%, 5.7 and 21.0 mg/100 g, respectively. Seventy-six volatile compounds were detected in the cooked odor of the oyster sauce. These volatile compounds included 14 esters, including ethyl acetate, 13 nitrogen- containing compounds, including 2,4,6-trimethyl pyridine, 13 acids, including hexadecanoic acid, 12 alcohols, including ethyl alcohol and 6-methyl heptanol, 6 alkanes, 5 aldehydes, including benzaldehyde, 5 ketones, including 1-(2-furanyl)-ethanone, 4 furans, including 2-furancarboxaldehyde and 2-furanmethanol, 3 aromatic compounds, including d-limonene, and 1 miscellaneous compound. Esters, acids and nitrogen-containing compounds, and alcohols were the most abundant compounds in the odor of the cooked oyster sauce, with some aldehydes, ketones, and furans.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.6
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• pp.641-645
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• 2003

Spermatogenesis, ultrastructure, and sperm morphology of the Pacific oyster (Crassostrea gigas) were investigated with TEM and SEM. C. gigas sperm were primitive consisting of a head midpiece and tail. Sperm size (head and midpiece) was about 1.78 ${\mu}m$. Sperm morphology was similar to a sharp of a small water jar with a rough surface. Sperm had both anterior nuclear fossa (anf) and posterior nuclear fossa (pnf). Acrosome forms had a hat-like shape. The axial rod was projected in front of the acrosome. C. gigas sperm had four large mitochondria in the midpiece.

• Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.118-129
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• 2009

To develop a sustainable management model for oyster farming in Pukman Bay, Korea, we estimated the carrying capacity for oyster farming using food availability data. Optimal culture densities were calculated to be 124-133 individuals per unit flux area ($m^2$) and 310-330 individuals per string. The present annual production is approximately 1,038 tons/year, which is 87% of the estimated maximum yield of 1,193 tons/year. Therefore, considering annual fluctuations and a critical buffer to reduce ecological impacts, the current level is within optimal conditions. During periods of increased water temperature, energy demand was largely met by high primary production. The food supply significantly decreased as the harvest season approached, and 10 out of 21 oyster farms had a deficient food supply for at least 1 month. Therefore, these farms (39% of the farms within the bay) exceeded optimal densities.

• Proceedings of the Malacological Society of Korea Conference
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• 2002.11a
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• pp.13-13
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• 2002