• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.278-285
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• 2018

Monthly variation in species composition of fishes in the eelgrass bed of Jangpyeong in Tongyeong, Korea was determined using monthly samples from a seine net from May 2016 to April 2017. A total of 32 species, 2,042 individuals and 3,991.1 g of fishes were collected during the study period. The dominant species were Takifugu niphobles, Rudarius ercodes, Gymnogobius heptacanthus, Zoarchias glaber, Pholis nebulosi and Leucopsarion petersii. These species accounted for 79.5% of the total number of individuals. The fish assemblages in the eelgrass bed showed clear seasonal changes: the number of fish species increased in March and was highest in October, while the number of individuals increased in December and was highest in July.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.4
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• pp.320-326
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• 2019

The diet composition of Arctoscopus japonicus was studied using 448 specimens collected in the coastal waters of East Sea, Korea. The size of the specimens ranged from 6.2-25.3 cm in total length (TL). A. japonicus were fed mainly on amphipods that constituted 76.1% in IRI. Euphausiids were the second largest prey component. The diets also include small quantities of crabs, copepods, mysids, cephalopods, monogeneans, and fishes. A. japonicus showed ontogenetic changes in feeding habits. Smaller individuals (6-10 cm, TL) fed mainly on amphipods. The proportion of amphipods decreased as body size increased, whereas the consumption of euphausiids gradually increased (10-14 cm, TL). As the body size more increased, the proportion of amphipods increased whereas euphausiids decreased (14-26 cm, TL).

• Korean Journal of Ichthyology
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• v.29 no.2
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• pp.130-138
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• 2017

Fish species composition in eelgrass bed of Bongam on Hansando island, Korea was determined using monthly samples collected by a surf net from August 2009 to July 2010. A total of 30 species, 3,237 individuals and 6,850.1g of fish were collected. The dominant species were Gymnogobius heptacanthus, Rudarius ercodes, Takifugu niphobles, Chaenogobius annularis, Pterogobius elapoides and Syngnathus schlegeli which accounted for 86.7% of total number of individuals of fish collected. Eelgrass started growing from May ($DW61.9g/m^2$) showing a peak biomass in August ($DW81.6g/m^2$), and low values in November ($DW57.23g/m^2$) to February ($DW15.41g/m^2$). The fish assemblages in the eelgrass beds showed clear seasonal changes; the number of fish species and individuals were low from September to December 2009, and high from December 2009 to July 2010. Seasonal variation in species composition and abundance was related to the water temperature and standing crops of eelgrass.

• Korean Journal of Environmental Agriculture
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• v.36 no.2
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• pp.129-134
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• 2017

BACKGROUND: Yeasts are used in a variety of industries. However, most industries are biased toward Saccharomyces cerevisiae ; so we sought to explore non-conventional yeasts (NCY). This study aimed to isolate yeasts from seawater collected from the East Sea of Korea and to analyze the NCY. METHODS AND RESULTS: We first collected seawater and performed pure isolation using four kinds of medium (GPY, DOB + CSM, DG18, and SCG). In total, 314 strains and 17 genera were isolated by ITS sequencing, including Aureobasidum pullulans (236 strains), Cryptococcus (19 strains), Cystobasidium (18 strains), and Rhodotorula (9 strains). Upon in-depth analysis, A. pullulans, the most dominant genus (236 strains), was divided into Group II (147 strains), Unknown I (8 strains), and Unknown II (49 strains). CONCLUSION: In this study, a total of 314 strains were isolated from seawater; many of these yeasts have been found and reported in seawater previously. In-depth analysis of A. pullulans, showed the dominance of Group I (21 strains) and Group II (147 strains) We also discovered Unknown I (8 strains) and Unknown II (49 strains), which have not been reported previously.

• Journal of the Korean Applied Science and Technology
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• v.35 no.4
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• pp.1421-1432
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• 2018

Water soluble oil was obtained from the pyrolysis of coconut waste as a biomass at $600^{\circ}C$. It was studied that the combustion characteristics of bio-emulsion fuel by mixing and emulsifying 15~20% of water soluble oil which obtained from pyrolysis of coconut waste as a biomass and MDO(marine diesel oil) as a marine fuel. Engine dynamometer was used for detecting emissions, temperature, and power. The temperature of combustion chamber was decreased because the moisture in bio-emulsion fuel deprived of heat of evaporation in combustion chamber. While combustion, micro-explosion took place in the combustion chamber by water in the bio-emulsion fuel, MDO fuel scattered to micro particles and it caused to smoke reduction. The temperature reduction of combustion chamber by using bio-emulsion fuel reduced the NOx emission. The increasing of bio-oil content caused increasing water content in bio-emulsion fuel so total calorific value was reduced. So the characteristics of power was decreased in proportion to using the increasing amount of bio-emulsion fuel. Heavy oil as a marine fuel exhausts a lot of smoke and NOx. We expect that we can reduce the exhaust gas of marine engine such as smoke and NOx by using of bio-emulsion fuel as a marine fuel.

• Development and Reproduction
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• v.22 no.2
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• pp.183-192
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• 2018

The morphometric truss characteristics and classical dimensions of the marine medaka, Oryzias dancena, that might distinguish diploid and triploid fish were examined. Significant differences in all the classical and truss dimensions of the diploid and triploid fish were observed in both sexes (p<0.01). All the dimensions of the triploid fish were greater than those of the diploid fish. The triploid marine medaka shows sexual dimorphism in these characters, and the sexual dimorphism of the triploid marine medaka is similar to that of the diploid marine medaka. Thus, when their classical dimension and truss dimension was measured, the growth of triploid marine medaka is faster than that of the diploid fish, and it displays clear sexual dimorphism, with male fish having longer dorsal and anal fins than female fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.2
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• pp.111-118
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• 2013

The Norwegian coastal area is the most efficient region for fishery production in the world's oceans, the Norway is the world's top 10 fisheries countries through efficient fishing and fishing aquaculture technology and its scientific management of fisheries bio-resources, with Norwegian salmon having attained the world's highest level. In the late 1980s, fisheries resources were depleted due to overfishing and fish diseases, resulting in a crisis in the fishing industry that lasted until the early 1990s. Since the national fishery emergency, people involved in the fishing industry, including fishermen, research scientists, and government officers, have tried to overcome the challenges facing the industry and identify an appropriate management model for fisheries bio-resources in the Norwegian coastal area. First, research vessels were used to monitor water and sediment conditions and fishery species, with the long-term aim of predicting fishery resources in real time and collecting information on species diversity, abundance, and distribution. Second, a "Healthy Fish Project" was promoted to counter natural disasters and fish disease problems with the development of vaccines against viruses and bacteria, eventually allowing for a decrease in the use of antibiotics and the production of notably healthier fish in the 2000s. Third, a systematic management model was developed to help with preparations for decreases in the total number of fishermen and increases in the proportion of elderly fishermen in the fishery industry using the development of automatic fishing aquaculture systems and short-chain systems. We could learn from the Norwegian model of fisheries bio-resources, management and could adopt it for the preparation of fishery bio-resources management policy for South Korean coastal areas in the near future.

• Journal of Microbiology
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• v.44 no.6
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• pp.694-698
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• 2006

Several marine bacterial strains were isolated from Undaria pinnatifida (Miyok in Korean). Sixty-six strains were isolated on R2A agar media at $10^{\circ}C$ and identified by a phylogenetic analysis of the 16S rRNA gene sequences. They were grouped into 10 different sequence types based on the initial sequence analysis of the 5' domain of the gene (approximately 500 bp). Full sequences of 16S rRNA gene, were obtained from one strain in each sequence type and the species-affiliation was determined using phylogenetic and sequence similarity analyses. The results of the analyses indicated that they were closely related to Psychrobacter aquimaris, P. celer, P. nivimaris, P. pulmonis, Psychromonas arctica or Bacillus psychrodurans. These bacteria are marine or psychrotrophic bacteria. Because the sporophytes of U. pinnatifida are cultured on the costal area during winter, the U. pinnatifida-associated bacteria appeared to grow at low temperatures. U. pinnatifida sporophytes can be a good source for the isolation of psychrotrophic bacteria.

• Journal of Marine Bioscience and Biotechnology
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• v.12 no.1
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• pp.66-74
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• 2020

Marine algae contain a variety of substances, such as mycosporine-like amino acids, which can defend against UV irradiation. Among them, Porphyra-334 derived from Porphyra yezoensis is attracting attention as a novel active ingredient for anti-aging cosmetics because of its excellent anti-oxidative, anti-inflammatory, and wound-healing properties through promoting skin cell migration. In this study, a process using direct current (DC) for increasing the yield of large-scale purification of Porphyra-334 was developed. When DC was applied to obtain Porphyra-334 efficiently, the purification time was shortened by approximately 1/4 compared with the process wherein DC was not applied; moreover, the yield of purification was improved.

• Preventive Nutrition and Food Science
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• v.15 no.4
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• pp.309-315
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• 2010

A grilled-type shrimp flavor was developed through the Maillard reaction to reduce or mask fish odor or off-flavor in seafood. Model systems were created by using enzymatic hydrolysate of shrimp and adding precursors to increase flavor quality and stability. Amino acid precursors such as cysteine and methionine, sugar precursors such as glucose, xylose, ribose, and sucrose, and one particular compound of glucosamine were tried and their flavor qualities were tested by sensory evaluation. Also, the optimum reaction condition was investigated using the pH values of pH 5, 6, 7, and 8 with reaction times of 1 hr, 2 hr and 3 hr after the best precursors were determined. The best condition of the precursors for grilled-type shrimp flavor was the mixtures of methionine, threonine, xylose, and glucosamine. The optimum reaction condition was at pH 8.0 and 2 hr reaction time.