• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.2
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• pp.97-106
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• 2018

The objective of this study was to estimate physical properties and fishing performances of net twine with improved PBS copolymer resin (Bio-new), the existing PBS/PBAT blending resin (Bio-old) and commercial Nylon (Nylon). The tensile strength of Bio-new monofilament was equal to Bio-old and the elongation of Bio-new was about 6 % higher than that of Bio-old in wet condition. The physical properties tests were carried out to estimate breaking load and stiffness in dry and wet conditions, respectively. In the results, the breaking load of Nylon netting was the highest whereas the elongation of Bio-new was 1.4 times higher than that of Nylon netting in wet condition. The breaking load of Bio-old netting was about 9.2 % higher than that of Bio-new netting. However, the elongation of the Bio-new netting was about 3% higher than that of Bio-old. The stiffness of the Bio-new compared to Bio-old was improved about 34 % in dry condition and about 32 % in wet condition. The filed experiments of the fishing performance were conducted with three kinds of drift nets with different netting materials in the coastal sea of Jeju. The each experimental drift net made of different materials showed the similar fishing performance. Bio-old drift net yielded less catches of small sized yellow croaker than other drift nets. The netting materials affected the fishing performance and length distribution of catches in the drift nets.

• The Journal of Fisheries Business Administration
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• v.45 no.1
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• pp.63-77
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• 2014

This study is to estimate the recent changes in total factor productivity of 15 Korean adjacent water fisheries based on Malmquist productivity indices. The study adopted both input and output oriented productivity measures utilizing a hyperbola distance function. In addition to this point, the study also calculated the 95% confidence interval for the various components of the productivities in order to access the statistical significance of estimates using 2000 times of re-sampling process through the smoothed bootstraping. The results of the study showed us that there was 18% reduction in the overall total factor productivity during the study period from 2007 to 2011, which turned out to be 5% of annual decrease in productivity. The study found that the main reason of this decrease in total productivity is about 22% downward shift of a fisheries production function due to recent conditions of a devastated fishing ground. When we evaluated the statistical significance of changes in technical efficiency combining both pure technical and scale efficiency based on the 95% confidence intervals, we could not find any evidence of changes in those components of total factor productivity. When we accessed the productivity of the each of 15 adjacent water fisheries methods, only the large danish seine fisheries showed us about 7% increase in productivity. Even though the large trawling and the large tow-boat trawling revealed no changes in productivity, all of the other 12 fisheries suffered the decreases in productivities.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.2
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• pp.126-135
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• 2013

This study was performed to have an effect on control the growth of algae such as "Actinastrum fluviatile" which occurs frequently in the aquaculture tank using by a cold plasma, and it also would be expected to promote the growth of water plants due to active element causing OH radicals in the water. In addition, it was verified on the death rate as 99.9% on the scale protrusion of "Aeromonas hydrophila" as well as E. coli, especially, under extreme conditions more than 100 million pathogenic bacterium in the aqua pet tank, the ornamental fish had to act in a safe and healthy environment at over 98% death rate within 48 hours. It has been proven to give no affect on aerobic bacteria that exist in the filter or soil because there was no residual toxicity in the water tank. As the results, it will help to develop and apply on the sterilization device in other industries as well as aquarium organisms due to adopted energy-saving algorithm and reliability in use.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.161-166
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• 1979

To know the influence of temperature on the fermentation process, a strain of Lactobacillus bulgarius was experimentally cultured three different temperature conditions of $39^{\circ}C,\;42^{\circ}C\;and\;45^{\circ}C$, pH 5.8 and mechanical agitation of 500rpm. During 20 hour's fermentation, the microbial growth attained the maximum concentration under the conditions mentioned above. However, the culturing conditions resulted different outcomes in terms of maximum concentration of the microbes and the residual concentration of substrate. Among the three temperature conditions, the fermentation at $45^{\circ}C$ was most effective and the maximum specific growth temperature conditions, the fermentation at $45^{\circ}C$ was most effective and the maximum specific growth rate was 0.58/hr. Activation energy deduced from the Arrhenius equation was 9,220cal/mole and entropy was $-33.74\;cal/^{\circ}K$ mole. Activation enthalpy was 9,845 cal/mole and free energy was 19,800 cal/mole.

• Journal of Practical Agriculture & Fisheries Research
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• v.21 no.1
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• pp.135-148
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• 2019

King oyster mushroom(Pleurotus eryngii) is one of the most commercially important mushrooms in Korea. Development of fruit body and disease occurrence are sensitive to environmental conditions such as temperature, humidity, carbon dioxide(CO₂) concentration. The purpose of this study was to investigate the changes in the growth environment of king oyster mushroom by installing Airocide, an air purifier for the purpose of improving mushroom cultivation environment. The results of the environment conditions, identification of pathogenic organisms and pathogenesis during the cultivation were as follows. Airocide operation increased the CO₂ concentration of the cultivation room by more than 400 ppm on average, but the increase of CO₂ concentration at this level had little effect on the quality and growth of fruit body. Operation of the Airocide tended to reduce the air humidity of the cultivation room and required more humidification. In humidifying conditions, the Airocide has the effect of lowering the species and density of bacteria and reducing bacterial symptoms and abnormal fruiting body of mushroom. Pseudomonas sp., the mushroom pathogen, was isolated from the cultivation room without Airocide, resulting in serious disease and loss of yields, so that only about 83% of substrate could harvest normal fruiting bodies. No disease symptom caused by bacteria and fungi in the cultivation room with Airocide. Trichoderma sp., Penicillium sp. and Cladosporium sp. were isolated from all experimental conditions, but did not inhibit fruit growth or caused diseased.

• Fisheries and Aquatic Sciences
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• v.3 no.3_4
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• pp.217-221
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• 2000

In previous study, marine actinomycetes producing the antibiotics were investigated to invent new antibiotics from east coast of Korea. The optimum growth conditions of Streptomyces sp. NS 13239 were $28^{\circ}C$, pH 7.0 and $3\%$ of NaCl concentration in various media. Streptomyces sp. NS 13239 showed strong antimicrobial activity against gram-positive bacteria, specially Methicillin resistant Staphylococcus aureus (MRSA), but just weak antimicrobial activity against yeasts and mold. On the other hand, it did not show antimicrobial activity against gram-negative bacteria. The optimum conditions for producing antibiotics were almost consistent with optimum growth conditions except carbon source and nitrogen source.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.2
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• pp.187-192
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• 2003

To evaluate the oceanographic conditions for the artificial upwelling we measured vertical stratification coefficients, current speed distribution and grain size distribution of bottom sediment in the vicinity of Gukdo and Somaemuldo near Geojedo. There were a strong stratification between surface and bottom layers in summer, the stratification was weak from autumn to winter, and the water was well mixed during winter. In summer nutrient concentration of the bottom layer was 4 times higher than that of the surface layer. Underwater currents were strong in the bottom layer. We conclude that the oceanographic conditions in the area will meet the basic requirement for the construction of artificial upwelling.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.1
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• pp.36-43
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• 2015

We examined sensory characteristics to determine the optimal conditions for flounder Verasper moseri Jordan et Gilbert sikhe preparation, using response surface methodology. Our aim was to develop the optimum mixing rates and materials for producing highly palatable flounder sikhe. The optimal fermentation temperature, salt concentration, and fermentation period for preparing flounder sikhe of acceptable quality were $11.63^{\circ}C$, 4.66% and 9.12 days, respectively. The optimal percentages of red pepper powder, garlic, monosodium glutamate, ginger, radish and foxtail millet were 16.08%, 7.21%, 2.96%, 3.70%, 10.12% and 13.72% respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.640-647
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• 2012

Squid Sikhae is a traditional salt-fermented food in Korea. We evaluated the standardization of optimal processing conditions for desirable quality-controlled squid Sikhae using analyses of physiochemical properties, microbiological species, and organoleptic tests. The optimal fermentation temperature, sun-dried sea salt concentration, and fermentation period for manufacturing squid Sikhae products of the aceeptable quality were $10^{\circ}C$, 4%, and 6 days. In addition, optimal concentrations of the additional ingredients of red pepper powder and crushed garlic for acceptable quality squid Sikhae were both 6%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.45 no.6
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• pp.627-634
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• 2012

Squid Sikhae is traditional salt-fermented food in Korea. We evaluated the standardization of optimal processing conditions for desirable quality-controlled squid Sikhae using analyses of physiochemical properties, microbiological species, and organoleptic tests. Among several squid Sikhae preparation processes, the optimal fermentation temperature sun-dried sea salt concentration, and fermentation period for squid Sikhae of acceptable quality were $10^{\circ}C$, 4%, and 6 days, respectively. Amino-N and volatile basic nitrogen (VBN) contents of the acceptable quality squid Sikhae were 162.51 mg/100 g and 15.25 mg/100 g, respectively.