• The Journal of the Acoustical Society of Korea
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• v.41 no.4
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• pp.435-445
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• 2022

In this study, the reverberation of a bistatic sonar operated in southeastern coast in the East Sea in July 2020 was analyzed. The reverberation sensor data were collected through an LFM sound source towed by a research vessel and a horizontal line array receiver 1 km to 5 km away from it. The reverberation sensor data was analyzed by various methods including geo-plot after signal processing. Through this, it was confirmed that the angle reflected from the sound source through the scatterer to the receiver has a dominant influence on the distribution of the reverberation sound, and the probability distribution characteristics of bistatic sonar reverberation varies for each beam. In addition, parametric factors of K distribution and Rayleigh distribution were estimated from the sample through moment method estimation. Using the Kolmogorov-Smirnov test at the confidence level of 0.05, the distribution probability of the data was analyzed. As a result, it could be observed that the reverberation follows a Rayleigh probability distribution, and it could be estimated that this was the effect of a low reverberation to noise ratio.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.4
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• pp.625-633
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• 1994

In this study, processing of dried products of adcidian , Haocynthia roretzi, were investigated, which has been cultured in the south and east coast of Korea in recent years. Raw ascidians were shucked , gutted, soaked and then drained. Seven kinds of dried ascidian meats were prepared : boiled in 5% slat solution for 10 min and hot-air dried (A)-sun dried (B) or hot-air dried (C) after soaking for 1 min in 0.2% NaHSO3 solution , sun dried (D) or hot -air dried (G) after treating for 15 sec in 5% liquid smoke solution, and sun dried (E) or hot -air dried (F) after blanching for 30 sec in boiling 5% salt solution added with 0.2% NaHSO3. The moisture contents, water activity of the products showed little change and VBN gradually increased during storage at 25 $\pm$2$^{\circ}C$. The TBA and POV values of the liquid smoked dried ascidian (product D, G0 were considerably lower than those of others, In fatty acid composition 22 : 6 , 20 : 5 : 16: 0 and 18 : 1 acid were predominant. Conditions adopted in products D and G had a good antioxidative effect on highly unsatuated fatty acids during the storage. The contents of inosine and AMP of products were higher than those of other nucleotide and their related compounds. Judging from the results of chemical experiments and sensory evaluation, the sample A, D and G were most desirable and they could be preserved more than 120 days at room temperature(25$\pm$2$^{\circ}C$).

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.953-968
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• 2018

In order to understand the change of surface water temperature in the East China Sea (ECS), this study analyzed the relationship between sea surface temperature (SST), air temperature (AT) and heat flux using satellite and model reanalysis data from 2003 to 2017. SST in the ECS showed the lowest (average : $13.72^{\circ}C$) in March and the highest (average : $28.12^{\circ}C$) in August. AT is highly correlated with SST and shows a similar seasonal change. In August, SST is higher than AT and then continuously higher than AT until winter. To analyze the change of the summer SST in the ECS, we used the SST anomaly value in August to classify the periods with positive (04', 06', 07', 13', 16', 17') and negative (03', 05', 08', 09', 10', 11', 12', 14', 15') values. Spatial similarity between the two periods indicates that SSTs are relatively larger variations in the northern part than in the southern part, and in the western part than in the eastern part in the study area. AT and net heat flux values also show similar changes with SST. However, the periods of the positive SST anomaly have the relatively increasing SST, AT and heat flux values compared to the periods of the negative SST anomaly in the summer season of the ECS. Although the change of SST in the summer season generally well correlates with AT, there were the periods when it was different from general trends between SST and AT (10', 12', 15', 16'). SST in August 2010 and 2012 decreased by $0.5^{\circ}C$ from AT. It suggests that the decreasing SST was considered to be caused by the effects of the typhoon passing through the study area. In August 2015, AT was relatively lower than SST (> $0.5^{\circ}C$), which is might be weakening of the East Asian Summer Monsoon. In August 2016, SST and AT show the highest values during the whole study periods, but SST is higher than AT (> $1^{\circ}C$). From satellite and heat flux data, the variations of SST have been shown to be relatively higher in the area of the expansion Changjiang Diluted Water (CDW) originated from the China coast. More research is needed to analyze this phenomenon, it is believed as not only the effect of rising AT but also the expansion of the low-salinity water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.5
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• pp.259-268
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• 2007

To measure the proximate composition of fisheries products and to evaluate their nutritional value, we collected individuals from 101 species from the east (Pohang), west (Gunsan), and south (Tongyeong) coasts of Korea: 51 fish species, 32 species of molluscan shellfish (Gastropoda and Bivalvia), 6 species of Cephalopoda, 8 species of Crustacea, and 4 other species. The proximate composition of fish was $75.3{\pm}5.0%\;moisture,\;19.1{\pm}2.7%\;protein,\;3.8{\pm}4.1%\;lipids,\;0.4{\pm}0.3%$ carbohydrates, and $1.4{\pm}0.3%$ ash. The proximate composition of molluscan shellfish was $79.1{\pm}3.2%\;moisture,\;14.2{\pm}3.2%\;protein,\;0.7{\pm}0.6%\;lipids,\;3.9{\pm}1.9%$ carbohydrates, and $2.1{\pm}0.4%$ ash. We observed clear regional variation in the lipid content of some fish species. Specifically, the lipid content of gizzard shad (Clupanodon punctatus) was highest in the autumn, while the lipid contents of red seabream (Pagrus major) and purple pike conger (Muraenesox cinereus) were highest in the winter. The daily average intake of the proximate composition through fisheries products consisted of 11.7 g of protein, 1.9 g of lipids, 1.1 g of carbohydrates, and 1.1 g of ash. The respective intakes of protein, lipids, and carbohydrates from fisheries products were about 19.3, 3.6, and 0.3% of the nutrient reference values set by the Korean Food & Drug Administration. Therefore, fisheries products playa very important role as a source of protein.

• Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.26.1-26.8
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• 2016

Background: The nematode species belonging to genus Anisakis occur at their third larval stage in numerous marine teleost fish species worldwide and known to cause accidental human infection through the ingestion of raw or undercooked fish or squids. They may also draw the attention of consumers because of the visual impact of both alive and dead worms. Therefore, the information on their geographical distribution and clear species identification is important for epidemiological survey and further prevention of human infection. Results: For identification of anisakid nematodes species isolated from largehead hairtail (Trichiurus japonicus), polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of internal transcribed spacers of ribosomal DNA were conducted. Mitochondrial cytochrome c oxidase subunit 2 gene was also sequenced, and phylogenetic analysis was conducted. From the largehead hairtail (n = 9), 1259 nematodes were isolated in total. Most of the nematodes were found encapsulated throughout the viscera (56.2 %, 708/1259) or moving freely in the body cavity (41.5 %, 523/1259), and only 0.3 % (4/1259) was found in the muscles. By PCR-RFLP, three different nematode species were identified. Anisakis pegreffii was the most dominantly found (98.7 %, 1243/1259) from the largehead hairtail, occupying 98.7 % (699/708) of the nematodes in the mesenteries and 98.1 % (513/523) in the body cavity. Hybrid genotype (Anisakis simplex ${\times}$ A. pegreffii) occupied 0.5 %, and Hysterothylacium sp. occupied 0.2 % of the nematodes isolated in this study. Conclusions: The largehead hairtail may not significantly contribute accidental human infection of anisakid nematode third stage larvae because most of the nematodes were found from the viscera or body cavity, which are not consumed raw. But, a high prevalence of anisakid nematode larvae in the largehead hairtail is still in concern because they may raise food safety problems to consumers. Immediate evisceration or freezing of fish after catch will be necessary before consumption.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.227-237
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• 1993

Lineaments in the Kyungsang basin most intensely develop in the East coast domain including the Yangsan fault, which dominantly run in NNE direction. The geometry of small fault population near or along the Yangsan fault represents the dominant strikes of N35E, high angle dips and shallowly plunging rakes with dextral movement sense. Stereographic solution on the Yangsan fault geometry gives the dip of 88SE, the slip direction of 17,024 and the slip rake of 18, which were determined from the strike (N23E) of the fault measured on map, and the average attitude (N35E, 84SE) and fault striation (16, 037) of small fault population considered as Riedel shears. It is judged from the geometry of small fault population to the main Yangsan fault and dragging features of bedding attitude near the fault that the Yangsan fault was produced from dextrally strike-slip movement. The movement of the Yangsan and the adjacent parallel faults is thought to be taken place much later than the other fault sets in the Kyungsang basin. It might occur during the geologic age from Eocence to early Miocene according to the consideration of K-Ar ages of the igneous rocks near the fault. The estimated paleostress state indicates ENE shortening and NNW extension. The displacement of the Yangsan fault in the study area is not constant along the fault but decreases from the south to the north. Taking the northern end of the study area as a separating point the whole extension of the Yangsan fault may be divided into southern and northern segments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.3
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• pp.340-348
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• 2003

Sedimentological investigations on surface and suspended sediments were performed in Kwangyang Bay of the middle South Sea in order to reveal recent changes in depositional environments concerning anthropogenic influence. A variety of coastal developments caused the texture of the surface sediments to become distinctively finer, particularly in the southwestern part of the bay. Accordingly, the westward lining sedimentary facies was somewhat simplified from triple-mode distribution to the dual-mode one by the construction of POSCO. This east-west distribution to the sedimentary facies has recently graded into the north-south distribution by further construction of other industrial complexes including Kwangyang Port. The prominent textural changes in surface sediments are most likely associated with weakening of tidal currents related to the developments which is anticipated to be .still continued. The distribution and flux estimation of suspended sediments suggest a noticeable import of fine particles into the bay predominantly through a northern entrance rather than the southern entrance. The movements of suspended sediments in the water level near the seabed prevailed over those of the mid and surficial levels.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.42 no.2
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• pp.78-85
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• 2006

A survey on the fishing gear for octopus drift-line fishing was done in Gangwon-do, Sacheon, Gyeongnam and Hokkaido, Japan, while a survey on the environments of fishing grounds used data from January to August from the Korea east coast farming forecast system of Donghae Fisheries Research and Development Institute. The present situation of fishing was examined with boats engaging in drift-line fishing from March to August in the coastal waters along Gangneung. The fishing tackle for octopus drift-line fishing was made manually, and the size, shape, and weight of the hook and number of shooting used vary according to the fishing time and region. Lead is used as the material for sinkers. As bait, pork fat with skin is mostly used in Gangwon-do. The temperature of the bottom water layer in the coastal fishing ground of Gangneung from April to June ranges from $3.2-12.4^{\circ}C$, which is the optimal temperature for octopuses. During July and August, the temperature ranges from $5.0-20.6^{\circ}C$. The maximum difference between day and night temperatures reached up to $9.2^{\circ}C$. Salinity is generally stable at $33.2-35.324.6%_{\circ}$, which does not affect the inhabitation of octopuses. The octopus catch reached its peak from May to July, while most octopuses weighed less than 1 kg (76.7%). The results show that it is effective to carry out octopus drift-line fishing up to a depth of 40 meters; and that the maximum number of octopuses per line is obtained with an operation time of six hours.

• Bulletin of the Korean Chemical Society
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• v.32 no.12
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• pp.4258-4264
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• 2011

The total mercury concentration ($Hg_T$) of surface snow samples collected along a ~1500 km transect in east Queen Maud Land was determined using inductively coupled plasma sector field mass spectrometry to address the behavior of Hg on the Antarctic Plateau. Due to the volatile nature of mercury, measures were taken against Hg loss from standard solutions by choosing appropriate container material and stabilizing agents. Glass bottles with Teflon-lined caps were superior to Teflon and polyethylene containers in protecting against Hg loss, but addition of gold chloride ($AuCl_3$) or bromine chloride (BrCl) was necessary to ensure preservation of Hg. As Hg loss was also observed in snowmelt samples, our analysis may underestimate the actual amount of HgT in the snow. Even so, the measured HgT was still very low (< 0.4-10.8 pg $g^{-1}$, n = 44) without a signal of depositional enhancement accompanying photo-oxidation of atmospheric elemental mercury in austral midsummer. Moreover, the dynamic variation along the traverse implies spatial and temporal heterogeneity in its source processes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.315-323
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• 2008

To measure the mineral content of fishes, we collected 177 individuals from 53 fish species from the east (Pohang), west (Gunsan), and south (Tongyeong) coasts of Korea. The mean content of the macro mineral in a 100 g sample taken from the edible portion of each fish was (in descending order): P(207.4 mg), K(169.7 mg), Na(101.6 mg), Ca(44.4 mg), and Mg(30.4 mg). In comparison, the mean content of micro mineral in the fishes was (in descending order): Zn ($8.98{\mu}g/g$), Fe ($5.03{\mu}g/g$), Cu ($0.76{\mu}g/g$), Mn ($0.43{\mu}g/g$), and Ni ($0.08{\mu}g/g$). We could not observe clear regional variation in the mineral content of fish species. With regard to minerals considered essential for humans, the amount of Ca per sample (100 g) was the highest in the Scyliorhinus torazame (465.4 mg), and than followed by Ammodytes personatus (338.0 mg), Dasyatis akajei (267.4 mg), Raja kenojei (248.1 mg), Conger myriaster (174.1 mg), Clupanodon punctatus (86.8 mg), Muraenesox cinereus (81.2 mg), and Engraulis japonica (70.4 mg). The daily average intake of the mineral through the fishes consisted of P (100.6 mg), K (82.3 mg), Na (49.3 mg), Mg (14.8 mg), Zn (0.44 mg), Fe (0.24 mg), Cu (0.04 mg) and Mn (0.02 mg). The respective intakes of macro mineral (P, Mg, Na, Ca, K) from the fishes were about 14.4, 4.2, 3.3, 3.1 and 1.8% of the dietary reference intakes for Koreans (KDRIs) set by the Korean Nutrition Society. In comparison, the respective intakes of micro mineral (Cu, Zn, Fe, Mn) from the fishes were about 4.6, 4.4, 2.4, and 0.6% of the KDRIs.