• Fisheries and Aquatic Sciences
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• v.7 no.4
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• pp.204-214
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• 2004

The effect of wind. stresses on the flow and water quality has been examined, particularly focused on the environment of oyster farms in Gamak Bay, by a two dimensional numerical model. In autumn (wind: $45.0^{\circ}$, 4.3 m/s), the overall flow turned out to be stronger than any other seasons and in addition, a pair of anticlockwise and clockwise vortices has been created at the northwest of the bay. Consequently, the wind in autumn seemed efficient not only for growing oyster but also for reducing the water pollution as the flow becomes much more active. In summer an anoxic condition appeared around the northwest of the bay where the flow is stagnant. According to a field survey, the majority of oyster farms tended to be densely distributed around the areas where DO concentration is high. Furthermore, oyster farms with a high production (over 1,300 kg per hanging string of 100 m) were distributed along with approximately 4 of Ch-a concentration. This suggests that oyster production is closely related to the concentration of DO or Ch-a.

• Ocean and Polar Research
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• v.36 no.2
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• pp.157-163
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• 2014

This study analysed the economic feasibility per hectare of grow out phase production of Oyster farming by rising water temperature in Ocean. Elevated Water temperature by climate change had a bad influence for oyster production and economic feasibility. In the case of production units, the total output of oyster decreases from 213,840 to 205,594 units. Using cost-benefit analysis with discounting rates (5.5%), we estimated the net present value (NPV) and benefit cost ratio (BCR) until 2100 years. The model results showed that the NPV without water temperature rise was 1,565,619,893 won and the NPV with water temperature rise was 1,540,493,059 won. Also, BCR estimated that the former was 2.095 better than the latter was 2.077. To summarise, the economic effect per hectare of water temperature rise in ocean did the damage to the economic loss about 25,126,834 won.

• Journal of Environmental Science International
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• v.25 no.1
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• pp.23-29
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• 2016

This study has conducted greenhouse gas emission reduction test as using Oyster-shells originated PCC paper filler compare to non-Oyster shells used PCC. This examination was estimated and calculated in accordance with both IPCC (Intergovernmental Panel on Climate Change) and World Business Council for Sustainable Development (WBSCD). The greenhouse gas emission reduction estimation result indicates that, when oyster shells are recycled and used as paper filler, it reduces $27.97tCO_2\;per\;100\;ton$ of oyster shells. It is greenhouse gas emission $44.27tCO_2$ from PCC production changed to carbon emission reduction when replaced with oyster shell. LNG greenhouse gas emission $16.3tCO_2$ in relation to the pre-treatment with oyster shell per 100 ton is also reflected. As a result, it is assumed that roughly $0.2797tCO_2/oyster\;shell{\cdot}ton$.

• The Journal of Fisheries Business Administration
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• v.53 no.4
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• pp.069-078
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• 2022

This study studied the characteristics of cultured oyster marketing in Sacheon Bay. The results of this study are summarized as follows. First, the GULDAE aquaculture is a unique production method of Sacheon Bay. Second, oysters in Sacheon Bay were low in production, but the price was more than 70% higher than in other producing areas. Third, profit is 12.5% higher and rate of return was 179.8%. Fourth, there were more out-of-market sales than other than other producing areas, and it is a bidding method. Fifth, the marketing cost was higher than the longline hanging aquaculture; however, the advantage of price offseted this point. Although the Sacheon Bay Oyster aquaculture is small, it was confirmed that it was a producing area with high profitability and a unique marketing form from other regions. Although the Sacheon Bay Oyster culture is small, it has been confirmed that it is a producing area with high profitability and shows a unique distribution form.

• Fisheries and Aquatic Sciences
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• v.21 no.4
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• pp.9.1-9.7
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• 2018

To establish a comprehensive management strategy, as part of the optimization of cultural practice for an oyster rack culture system, we used a numerical model to estimate the primary production in the waters on the eastern coast of Wando island, South Korea. The estimated primary production ranged from 17.12 to $1052.55mgC\;m^{-2}day^{-1}$ ($204.22{\pm}224.75mgC\;m^{-2}day^{-1}$ in average). Except for the times of peak phytoplankton blooms, the estimated primary production (PP) was consistently under $200mgC\;m^{-2}day^{-1}$, which is more similar to the value of PP measured off the western coast of South Korea than the southern coast. No clear relationship was observed between nitrogen content and rainfall with the exception of heavy rainfall events, indicating that precipitation might not be the main source of nutrients in these waters. No clear influence was observed from Doam tidal discharge, located 24 km north from these waters due to main tide comes in this area from the channel between Gunwe-myeon in Wando island and Pukpyeong-myeon in Haenam-gun. Because of the shallow water depth and strong tidal current, resuspension of sediments, which causes an input of nitrogen into the system, could be easily caused by even mild wind and the infrequent passing of ships. Microscopic examination of the phytoplankton composition showed additional contribution of benthic species such as Paralia sulcata into the waters, which increase the productivity of oyster farms in the waters. The availability of nitrate and phosphate for primary production was temporarily limited throughout most of the spring and autumn blooming season.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.434-444
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• 2021

The decrease in fatness of the Pacific oyster Crassostrea gigas, which consequently results in decrease in the profit of aquaculture industry, has become a source of serious concern in southeast coast of Korea. The ratio of flesh (edible portion) to total oyster weight, commonly called edible portion yield ("suyul" in Korean), have been used as a fatness index for the healthy and valuable state of oyster from the early stage of oyster farming in Korea. More than 360 data sets were collected from early culturing periods (in the 1970s) to the present from approximately 15 published literatures to evaluate the long-term fatness trend of oyster, reared particularly in submerged longline culturing system in Gyeongsangnam-do province. Slight decrease in oyster fatness during the 1970s to 1990s was detected in Tongyeong and Geoje Bays; however, from the 1990s to the present, clear decreasing trends were observed with a decrease of 0.04-0.08% year^-1, especially during harvest season. Oyster mass production per unit area almost doubled within a short period in the early 2000s; however, changes in coastal environment factors inhibited the fattening of shellfish from the mid 1990s. These results indicate that the severe competition in feeding and low biological production in water column might be some convincing reasons for the decrease in fatness of oyster from the 1990s, in Tongyeong and Geoje Bays, Korea.

• Journal of Environmental Science International
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• v.17 no.8
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• pp.841-856
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• 2008

This research outlines a new method for evaluation of shellfish production in Gamak Bay based on the concept of EMERGY. Better understanding of those environmental factors influencing oyster production and the management of oyster stocks requires the ability to assess the real value of environmental sources such as solar energy, river, tide, wave, wind, and other physical mechanisms. In this research, EMERGY flows from environment sources were 76% for shellfish aquaculture in Gamak Bay. EMERGY yield ratio, Environmental Loading Ratio, and Sustainability Index were 4.26, 0.31 and 13.89, respectively. Using the Emergy evaluation data, the predicted maximum shellfish aquaculture production in Gamak Bay and the FDA (Food and Drug Administration, U.S.) designated area in Gamak Bay were 10,845 ton/y and 7,548 ton/yr, respectively. Since the predicted shellfish production was approximately 1.3 times more than produced shellfish production in 2005, the carrying capacity of Gamak Bay is estimated to be 1.3 times more than the present oyster production.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.11-20
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• 2010

Oyster production is playing an important role in domestic aquaculture, but facing some problems such as exports decrease, a slowdown in domestic demand and marine environmental deterioration. In order to obtain the suitable and sustainable oyster production, suitable sites selection is an important step in oyster aquaculture. This study was conducted to identify the suitable sites for lunging culture of oyster using Geographic Information System(GIS)-based multi-criteria evaluation methods. Most of the parameters were extracted by Inverse Distance Weighted(IDW) methods in GIS and eight parameters were grouped into two basic sub-models for oyster aquaculture, namely oyster growth sub-model(Sea Temperature, Salinity, Hydrodynamics, Chlorophyll-a) and environment sub-model(Bottom DO, TOC, Sediment AVS, Benthic Diversity). Suitability scores were ranked on a scale from 1(leased suitable) and 8(most suitable), and about 80.1% of the total potential area had the highest scores 5 and 6. These areas were shown to have the optimum condition for oyster culture in GeojeHansan Bay. This method to identify suitable sites for oyster culture may be used to develop bivalve culture management system for supporting a decision making.

• Korean Journal Plant Pathology
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• v.14 no.2
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• pp.177-183
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• 1998

A DNA fragment which is involved in tolassin production was cloned to obtain a molecular marker of Pseudomonas tolaasii, a casual agent of bacterial brown blotch disease of oyster mushroom (Pleurotus ostreatus). Tolaasin is a lipodepsipeptide toxin and known as a primary disease determinant of the P. tolaasii. It is responsible for formation of white line in agar when P. tolaasii were cultured against white line reacting organisms (WLROs). White line negative mutants (WL-) were generated by conjugation between rifampicin resistant strain of P. tolaasii and E. coli carrying suicidal plasmid pSUP2021 : : Tn5. The ability of tolaasin production of the WL- mutants was examined by hemolysis test, pathogenicity test, and high pressure liquid chromatography (HPLC) analysis of culture filtrate. All of the WL- mutants were lost the ability of tolaasin production (Tol-). Genomic library of the Tol- mutant was constructed in pLAFR3 and the cosmid clone containing Tn5 was selected. DNA fragment fro franking region of Tn5 was cloned from the plasmid and used as a probe in Southern blot. DNA-DNA hybridization with the probe to total DNA from group of bacteria ecologically similar to P. tolaasii including WLORs, fluorescent Pseudomonads isolated from oyster mushroom, P. agarici, P. gingeri, and some of other species of Psedomonas showed that some of the tested bacteria do not have any hybridized band and others have bands sowing RFLP. The cloned DNA fragment or its nucleotide sequence will be useful in detection and identification of the P. tolaasii.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.7
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• pp.916-920
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• 2013

The triploid Pacific oyster, which is produced by mating tetraploid and diploid oysters, is favored by the aquaculture industry because of its better flavor and firmer texture, particularly during the summer. However, tetraploid oyster production is not feasible in all oysters; the development of tetraploid oysters is ongoing in some oyster species. Thus, a method for ploidy verification is necessary for this endeavor, in addition to ploidy verification in aquaculture farms and in the natural environment. In this study, a method for ploidy verification of triploid and diploid oysters was developed using multiplex polymerase chain reaction (PCR) panels containing primers for molecular microsatellite markers. Two microsatellite multiplex PCR panels consisting of three markers each were developed using previously developed microsatellite markers that were optimized for performance. Both panels were able to verify the ploidy levels of 30 triploid oysters with 100% accuracy, illustrating the utility of microsatellite markers as a tool for verifying the ploidy of individual oysters.