• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.689-692
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• 1999

Proximate compositions of muscles and eggs between wild sweet smelt which were caught in Seomjin river and Miryang river, and cultured sweet smelt which were purchased from certain cultured farms in Hadong and Miryang, were compared. Proximate compositions of wild sweet smelt muscles were $76.7\~77.5\%$ for moisture, $18.4\~19.9\%$ for protein, $2.41\~3.47\%$ for lipid, and $1.04\~1.33\%$ for ash content and there were almost no differences between the fishes from Seomjin and Miryang river. Protein and ash content in the cultured fish muscles were similar to those of the wild fish muscles, while the former contained much more lipid and carbohydrate, and less moisture than the latter, especially lipid content differed greatly according to their cultured farms. This might be the result of their different diet compositions. Lipid, protein and carbohydrate content in eggs of the wild and cultured fishes were much higher than those in their muscles. There was a negative correlation between moisture and lipid content in all samples; y= -0.2715x+24.903 (r= -0.7253, p<0.001).

• Korean Journal of Ecology and Environment
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• v.33 no.2 s.90
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• pp.162-175
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• 2000

The present study was carried out to clarify the distribution of rotifera with salinity variation during the period from February 1998 to July 1999. Rotifera consists of 27 genera and 88 species, from the maximum occurrence of 39 species in November, 1998 to the minimum of 21 species March, 1998. With 32 dominant species, Keratella cochlearis cochlearis, K. cochlearis f. tecta, Ascomorpha saltans saltans and Asplanchna (s. str.) priodonta priodonta occurred predominantly. Distribution of Rotifera related to salinity showed that 36 species occurred in the freshwater zone, 3 species in the mixo-oligohaline zone ($0.5{\sim}5.0%_o$) and mixo-mesohaline zone ($5.1{\sim}28.0%_o$) respectively, on the other hand 2 species (Asplanhna (s. str.) priodonta priodonta, Synchaeta oblonga) in all zones. Average abundance by salinity ranged from $1,273\;ind./m^3$ ($25.0{\sim}28.0%_o$ to $16,259\;ind./m^3$ ($15.1{\sim}20.0%_o$. The percentage composition calculated effect by stepwise multiple regression of the pearson correlation coefficient value of environmental factors and Rotifera abundance (station $1{\sim}4$) revealed that it was 74.32% in BOD, 72.15% in COD, 69.77% in conductivity, 65.87% in $Cl^-$ and 58.27% in chlorophyll a. Also, (Station $5{\sim}12$) revealed 9.11% in $Cl^-$, 7.67% in TP and 6.20% in chlorophyll a.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1031-1040
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• 2015

Ultrstructural studies of germ cell differentiation and vitellogenesis in the oocytes of the female Rapana venosa in the brackish water area of Seomjin River were investigated by transmission electron microscope observations. In the early vitellogenic oocytes, the Golgi complex and mitochondria were involved in the formation of glycogen particle, lipid droplets, and yolk granules. In the late vitellogenic oocytes, the rough endoplasmic reticulum and multivesicular bodies were involved in the formation of proteid yolk granules in the cytoplasm. However, heterosynthetic vitellogenesis in this species were not observed in vitellogenic oocytes during oogenesis. A mature yolk granule was composed of three components: crystalline core, electron lucent cortex and the limiting membrane. As shown in some large gastropods, vitellogenesis in R. venosa occurred by way of endogenous autosynthesis without heterosythetic vitellogenesis (exogeneous endocytosis), which are found in the oocytes in bivalves. The mating period and spawning activity were related with the increases of seawater temperatures and salinities.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.5
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• pp.335-344
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• 2012

Hexachlorobenzene (HCB) and Dichloro-Diphenyl-Trichloroethane (DDT) were determined in surface sediments collected from main rivers of Korea. Concentration of HCB in sediments ranged from 0.41 to 3.82 (average 1.58) ng/g, 0.08 to 6.09 (average 0.90) ng/g, 0.02 to 0.97 (average 0.30) ng/g, 0.28 to 0.59 (average 0.42) ng/g and 0.23 to 0.48 (average 0.32) ng/g in Han river, Nakdong river, Geum river, Yeongsan and Seomjin river respectively. The DDTs concentration was ranged from 0.67 to 14.20 (average 4.76) ng/g, N.D. to 10.36 (average 1.81) ng/g, N.D. to 7.26 (average 1.87) ng/g, N.D. to 3.12 (average 1.08) ng/g and 0.02 to 2.04 (average 0.56) ng/g in Han river, Nakdong river, Geum river, Yeongsan and Seomjin river respectively. In comparison with the concentration of HCB and DDTs in other studies, the values in sediments of this study were lower than those of other countries. Comparison with that Sediment quality guideline (SQG) of National Oceanic and Atmospheric Administration (NOAA), the HCB levels of this study were very lower than Effect Range Low (ERL) value. In the case of DDTs, the concentrations of 46 points were higher than ERL (1.58 ng/g). It have not harmful effect on ecosystem of the sediment, however ongoing monitoring of sediments is deemed necessary.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.669-680
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• 2017

This study evaluated the consistency of the standard flow to forecast low-flow based on various drought indices. The data used in this study were streamflow data at the Gurye2 station located in the Seomjin River and the Angang station located in the Hyeongsan River, as well as rainfall data of nearby weather stations (Namwon and Pohang). Using streamflow data, the streamflow accumulation drought index (SADI) was developed in this study to represent the hydrological drought condition. For SADI calculations, the threshold of drought was determined by a Change-Point analysis of the flow pattern and a reduction factor was estimated based on the kernel density function. Standardized runoff index (SRI) and standardized precipitation index (SPI) were also calculated to compared with the SADI. SRI and SPI were calculated for the 30-, 90-, 180-, and 270-day period and then an ROC curve analysis was performed to determine the appropriate time-period which has the highest consistency with the standard flow. The result of ROC curve analysis indicated that for the Seomjin River-Gurye2 station SADI_C3, SRI30, SADI_C1, SADI_C2, and SPI90 were confirmed in oder of having high consistency with standard flow under the attention stage and for the Hyeongsan River-Angang station, SADI_C3, SADI_C1, SPI270, SRI30, and SADI_C2 have order of high consistency with standard flow under the attention stage.

• Journal of the Korean Geophysical Society
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• v.2 no.3
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• pp.209-216
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• 1999

In order to get geologic information necessary for underground installation of water pipe, seismic refraction profiling was applied to the southwest side of the Seomjin River which flows between Namwon-gun, Cholabuk-do and Gokseong-gun, Cholanam-do. Before obtaining the in-line refraction data, walkaway data were recorded with 1 m geophone interval and -36∼+36 m offset range. From the walkaway data, it is interpreted that a dry soil layer with the average velocity of 585 m/s covers wet sediments with the average velocity of 1,326 m/s. The second layer overlies basements nearly horizontally with the average velocity of 4,218 m/s. Refraction profiling of 220 m long with the geophone interval of 2 m is interpreted with the Generalized Reciprocal Method (GRM). Three layers are identified with average velocities of 688 m/s, 1,473 m/s, and 3,776 m/s, respectively. The depth to the bedrock impossible for ripping ranges between two extremes, 1.51∼2.43 m and 2.25∼3.54 m, depending upon thickness of the hidden layer. A typical shortcoming of refraction method, the hidden layer problem, prevents accurate estimation in depth of the second layer.

• Korean Journal of Ichthyology
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• v.25 no.4
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• pp.189-199
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• 2013

The distribution status and habitat characteristics of the endangered species, Lethenteron reissneri were investigated in 2011~2012 in Korea. During the study period, L. reissneri were collected 60 stations among 755 sampling stations investigated. The total numbers of ammocoetes and adults were 208 and 435, respectively from eight stations of the Han River drainage system, four stations of Geum River drainage system, 32 stations of Seomjin and Yeongsan River drainage systems, and 16 stations of Nakdong River drainage system. The Han and Geum river drainage systems, the Sapkyo Stream and independent streams running toward the East Sea were estimated to have suffered sudden reductions of population density, whereas the Seomjin River drainage system showed increased population density compared with historic occurrence records. L. reissneri inhabited the middle-upper stream of clean water with well-developed rapids and lots of aquatic organisms. According to IUCN Red List categories and criteria L. reissneri was assessed to be vulnerable (VU) [B2ab (ii,iii,iv,v);D1] because of the rapid reduction of the occupying areas and the small number of mature individuals. Besides the distribution status and habitat characteristics we discussed the conservation strategies of L. reissneri.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.32-38
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• 2011

In this study, the correlations of concentrations in sediment heavy metals between two pretreatment methods, total digestion and aqua regia digestion, have been investigated. Total 43 samples had been collected from streams and lakes in Yeongsan and Seomjin watersheds. They were decomposed in two pretreatment methods and five metal components (Cd, Cr, Ni, Pb, Zn) were analyzed. Overall average concentrations of heavy metals were Zn>Cr>Pb>Ni>Cd in the order. The concentrations of aqua regia digestion were 35.0% (Cd), 53.8% (Cr), 66.2% (Ni), 64.4% (Pb) and 76.4% (Zn) of the concentrations of total digestion and heavy metal concentrations of total digestion were higher. Heavy metal concentrations in sediments from lakes were higher than those from streams. The correlation equations between the concentrations of total digestion and aqua regia digestion were obtained. The concentrations of Zn and Ni, which showed strong linear correlations, increased in aqua regia digestion as the concentration in total digestion increased. The linear correlation coefficients between two digestion methods for most analyzed metals were above the average correlation. However, these results can be applied with limitations due to heterogeneity of sediments.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.151-163
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• 2003

In this study, we investigated the physiochemical characteristics of temporal estuarine environment formed during the summer flood season (consecutive rainy days with average 50 mm day$^{-1}$ precipitation) in the coastal area of South Sea of Korea. The freshwater from the Seomjin River was characterized by lower temperature, salinity and pH, and high concentrations of COD and nutrients. In the summer flood season, such peculiar Somejin-River freshwater was dispersed southward along the coast of Yeosubando-Dolsando-Geumodo, form-ing temporal estuarine environment (defined as "Coastal Pseudo-Estuary" in this study) throughout the entire study area (as far as 60 km from the Seomjin River mouth). Compared to the winter dry season, the DIN/DIP ratio was almost doubled (16-36) during the summer flood season. This excessive nitrate supply during the summer flood season was probably due to nitrogenous fertilizer. Distribution and behaviors of physiochemical factors in this coastal pseudo-estuarine environment were controlled not only by the runoff of the Seomjun River (physical mixing of river water with seawater) but also by the biogeochemical estuarine processes which are mostly similar to those of the river estuary.r estuary.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.221-230
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• 2019

Barbel steed (Hemibarbus labeo) is a small freshwater fish species as semi-bottom dwellers distributed in eastern Asia. We carried out characterization of the cytochrome c oxidase subunit I (COI) gene from the mitochondrial DNA of H. labeo in the Sumjin River to identify the phylogenetic location of H. labeo in the genus Hemibarbus and Cyprinidae. Multiple alignment of the 577 bp COI sequence revealed high sequence homology (99~100%) between Seomjin River H. labeo. The nucleotide sequence similarity between H. labeo (HD1) and H. mylodon was 88.91% and that of H. longirostis was 88.81% among the three species found in Korea. In addition, the nucleotide sequence similarities of H. maculatus, H. meditus, H. umbrifer and H. barbus showed 98.97%, 97.20%, 96.87% and 98.85%, respectively. Phylogenetic analysis on seven species of the genus Hemibarbus showed that the H. labeo collected in this study formed two clades. One of which consisted of Hadong, Imsil, Kangjin. The other one formed a step with HD2, HD8 and HD9 of Hadong and the H. labeo reported in Busan, Asan and Seoul, Korea. Phylogenetic position of the H. labeo among Cyprinidae showed 0.143 for the evolutionary distance from Zacco platypus and 0.006 for the H. maculatus. In addition, the genetic position of the H. labeo among 28 species of Cyprinidae was found to be located in Group I, including Gobioninae fishes. The results of this study will provide key genetic information for the taxonomic comparison in Cyprinidae and study of model fish for pollution monitoring in freshwater environments.