• Ocean and Polar Research
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• v.36 no.2
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• pp.135-143
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• 2014

The effect of salinity on the survival, oxygen consumption and blood physiology of Korean rockfish Sebastes schlegelii (body weight $97.4{\pm}1.7g$, $mean{\pm}SD$) was investigated at nine different salinities of 33.4 (control), 33.1, 32.8, 32.2, 31.0, 28.7, 23.9, 14.5 and 3.8 psu, respectively. Survival and blood physiology were measured at each salinity in two separate trials of 96 and 24 hr duration, respectively. Oxygen consumption rate (OCR) was determined at stepwise salinity exposure ($33.4{\rightarrow}33.1{\rightarrow}32.8{\rightarrow}32.2{\rightarrow}31.0{\rightarrow}28.7{\rightarrow}23.9{\rightarrow}14.5{\rightarrow}3.8$ psu) with an interval of 24 hr for each salinity. No death of fishes were observed in the range of 33.4 to 14.5 psu, but the survival rate was reduced to 26.7% at 3.8 psu after 96 hr. The OCRs were not significantly different in the range 33.4 to 28.7 psu (p > 0.05), but significantly increased until 14.5 psu and then drastically decreased at 3.8 psu compared to the control (p < 0.05). The concentrations of plasma $Na^+$ and $Cl^-$ were significantly lower in fish exposed at 3.8 psu compared to the control (p < 0.05). The results of this study provide evidence that S. schlegelii exposed to concentrations below 23.9 psu show significant physiological responses to tolerate salinity changes under the experimental conditions we established.

• The Journal of Engineering Geology
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• v.18 no.3
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• pp.321-330
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• 2008

This study, geological survey was carried out in order to study on the geology, geological structure and volcanic activity of the Ulleung-do volcano body. Ulleung-do is the volcano body of about 3,000m heights from the East Sea seabed. The geology of Ulleung-do is divided into basaltic agglomerate, trachytic agglomerate, trachyte, trachytic pumice and trachyandesite in ascending orders. The faults in caldera of Nari Basin came to make the reverse triangle style in compliance with sinking. The faults in circumference of Nari Basin are ranging with northeast-southwest direction and northwest-southeast direction. The Quaternary volcanic activities in the Ulleung-do are divided into 5 activity period. The engineering geologists and the applied geologists were not easy to apply because complicated geology of Ulleung-do. Therefore, this study supplied simple geology of Ulleung-do for them.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.191-199
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• 2009

Fisheries resources collected by set net in the Mizo fishing ground off Namhae Island were studied from March to December 2004 to determine species composition and catch variation. The water temperature of the fishing ground ranged $10.9{\sim}25.1^{\circ}C$ A total of 69,147.5 kg comprising 39 species was caught during the survey period. Most of the catch was fishes (33 species); others included cephalopods (5 species) and crustaceans (1 species). The dominant species were migratory, such as Trichiurus lepturus, Ammodytes personatus, Engraulis japonicus, and Scomberomorus niphonius, and accounted for 81.2% of the total catch. Sub-dominant species were Sardinops melanostictus, Acanthopagrus schlegeli, shrimps, and Todarodes pacificus, but they accounted for only 12.1% of the total. The catch by set net during the fishing period was much higher in spring and in autumn than in summer, relating to the recruitment of dominant species. Although the number of species had a tendency to decreased after summer, the catch in autumn was also higher than that in spring due to high temperatures (>$17^{\circ}C$ and seasonal variation of dominant species. The dominant species in spring were A. personatus and E. japonicus and in autumn were T. lepturus, S. niphonius, and E. japonicus.

• Environmental Analysis Health and Toxicology
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• v.22 no.1 s.56
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• pp.83-90
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• 2007

This study was investigated the effort of growth and gonadal development in olive flounder, Paralichthys olivaceus exposed to PCBs Effluent Allowance Concentration, 3.0 ppb in Korea. Total length, body weight and weight gam of fish were no significant differences between two treatments (control: T.L.-110.0 mm, T.W.-9.61 g: treatment: T.L.-112.8 mm, T.W.-9.68 g), however, weight gain of fish unexposed to PCBs wat observed to increase gradually from 100 days after hatching (30 days after treatment). In the indifferentiated gonad to the juvenile stage, the differentiation of the ovary occured at 60 days after hatching (20 days after treatment) and that of the testis occured at 70 days after hatching (30 days after treatment) in two groups. In the ovary, the oogonia and ovarian lamellar appeared 130 days after hatching (50 days after treatment). The spermatogonia and resticular lobule of the testis were observed at 130 days after hatching (50 days after treatment). Testicular cyst appeared 140 days after hatching (60 days After treatment). There was no difference on the development of ovary and testis. There was no obvious difference of sex ratios. Therefore, These results considerate that PCBs have any effect for growth and gonadal development, but a little act for early growth in olive flounder.

• Journal of Conservation Science
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• v.20
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• pp.105-117
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• 2007

This study is examined the beads excavated in the Sacheon Neukdo ruins to investigate the features of archaeological chemistry and to compare those of the same type of beads excavated within the Gyeongsang-do area by means of scientific analysis. The samples have been observed the micro-structures by an optical microscope and SEM and confirmed the physical property by density measurement. Chemical property have been analyzed main components such as flux, stabilizers, and colorants by SEM-EDS. Besides, XRD was used to identified the characteristic materials of beads. The white opaque beads, which was initially estimated as sea-shell beads, confirm as amorphous silica material. The glass beads, which are blue type as a result of compositional analysis, it is revealed potash glass group and LCA(Low-CaO, $Al_2O_3$) system. gB ones are revealed only in LCA-A(LCA-CaO<$Al_2O_3$), while purple blue ones in LCA-B(LCA-CaO>$Al_2O_3$).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.3
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• pp.359-371
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• 1998

The cold water event near Gampo-Ulgi coast in summers between 1987 and 1994 are studied using sea surface temperature records at the coastal stations, ocean winds measured by SSM/I and AVHRR SST images. The response time of the cold water events by upwelling is less than two days and surface cold water expands up to the Ulleung Island. An analysis of 61 upwelling favorable winds indicates that the surface water temperature drops more than $1^{\circ}C\;in\;80\%$ of the south-westerly wind events. The linear correlation coefficient between wind impulses and the maximum temperature drops is good (0.6). It is found that the major cause of the cold water events is the along-shore wind in summer. The bottom topography and off-shore direction of the East Korean Warm Current by the potential vorticity conservation near Gampo coast also contribute the formation of the cold water along the southeast coast of Korea.

• Journal of Aquaculture
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• v.9 no.2
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• pp.179-186
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• 1996

Zoeal stage's larvae of pandalid shrimp Pandalus hypsinotus, is distributed off the East sea and esteemed as a valuable shrimp resource in Korea, were reared in $10^{\circ}C$ temperature-controlled chambers and inverstigated the energy budget. The total energy intake per larva of zoea I to VI stages fed on Artemia nauplii was 140.88 J. The energy loss by respiration, molting, and excretion were 16.22 J, 1.19 J, and 106,40 J, respectively. The amount of energy used by growth was 17.07 J. Pandalid larvae assimilated $24.47\%$ of the ingested food. The gross efficiency ($K_1$) calculated by the equation of (growth+exuviae)/ingestion $rate{\times}100$ was $12.96\%$, and the net growth rate ($K_2$) calculated by the equation of (growth rate + exuviae)/(growth rate+ exuviae+ respiration rate)${\times}100$ was $52.96\%$. The percentage used for somatic growth and maintenance among the assimilated energy were $49.51\%$ and $47.04\%$ respectively.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.127-135
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• 2015

The aim of this study was to investigate the antioxidant activity of thermal treatment yam (Dioscorea batatas DECNE.) in Korea. Thermal treatment yam was extracted by different solvents including 70% methanol, 70% ethanol and chloroform-methanol mixture (CM, 2:1, v/v). Then color property, total phenol content and antioxidant activity were analyzed. Yam possessed high $L^*$ value and $H\limits^{\circ}$ value, which were $54.92{\pm}2.18$ and $73.20{\pm}0.77$, respectively. Thermal treatment yam exhibited great antioxidant activity evaluated by ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt] radical scavenging activity, DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, reducing power, and ferric reducing antioxidant power. Total phenol contents of various extracts from thermal treatment yam increased in the following order: 70% methanol extract ($63.53{\pm}0.33mg\;CAE/g$), 70% ethanol extract ($69.47{\pm}1.00mg\;CAE/g$) and CM extract ($97.49{\pm}0.66mg\;CAE/g$), respectively. The same trend was also could be found in antioxidant activity assays except for reducing power assay. These results implied that these extracts from thermal treatment yam might be useful to take a good part in prevention of human diseases and aging.

• Korean Journal of Microbiology
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• v.51 no.1
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• pp.75-80
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• 2015

Pseudoalteromonas donghaensis HJ51, isolated from the East Sea, has been reported as a novel strain to produce extracellular protease. Crude supernatant was used to determine optimal activity and optimal production conditions for the enzyme. It was found that the optimal temperature and pH of the protease were $40^{\circ}C$ and pH 7.5-10.5, respectively. The enzyme activity was kept to 88% at the pH 11. In metal requirement analysis, the enzyme exhibited the highest activity when 10 mM $Fe^{3+}$ was supplied. While supplementation of additional carbon sources used in study showed no positive effect on cell growth and enzyme activity, the addition of beef extract, tryptone, or casamino acids instead of peptone of PY-ASW containing 1% glucose increased enzyme production to 21, 7, 4%, respectively. Taken together these properties, the enzyme produced from P. donghaensis HJ51 can be applied to the industries that require protease activity under alkaline pH and low temperature.

• Journal of Aquaculture
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• v.10 no.2
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• pp.213-218
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• 1997

Experiments on the feeding activity and environmental tolerance of geoduck clam, Panope japonica caught at the coastal water of Kangwon province located in the East Sea of Korea were performed from January to December, 1994. Twenty genera and 33 species of plankton were found in the digestive tract, and most of them are phytoplankton. In spring, 21 species of planktonic foods were indentified, but in sumer, only 11 species were identified. Nitzschia longissima and Rizosolenia alata were present evey month. Weight of the digestive tract was fluctuate seasonally : higher winter and spring, and lower summer. Adult geoduck clams could be tolerated within the range of 5 to $20^{\circ}C$ water temperature, and they could tolerated considerably well temperature than higher temperature within the range.