• Title/Summary/Keyword: Southern waters

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Maturation of Blackthroat Seaperch Doederleinia berycoides in Waters of Southern Korea (한국 남해 연근해에 서식하는 눈볼대(Doederleinia berycoides)의 성숙)

  • Kim, Hyeon Ji;Kwon, Dae-Hyeon;Park, Jeong-Ho;Kim, Yeonghye
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.53 no.1
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    • pp.103-106
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    • 2020
  • We investigated the biological maturation of blackthroat seaperch Doederleinia berycoides in southern Korea waters, based on samples collected from March 2018 to February 2019. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI) and total length (TL) at 50%, 75% and 97.5% group maturity. The spawning period was May to October in 2018. We estimated the TL at 50% group maturity as 27.0 cm for females in 2018. We estimated the TL of females at 75% and 97.5% group maturity as 28.7 cm and 32.7 cm, respectively, in 2018.

Faunal Analysis and Oceanic Environment of the Recent Benthonic Foraminifera from the West and South Sea of korea (한국 서남해에서 산출된 현생저서 유공충의 동물군 분석 및 해양환경 연구)

  • CHEONG, HAE-KYUNG;PAIK, KWANG-HO;PARK, BYONG-KWON
    • 한국해양학회지
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    • v.27 no.2
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    • pp.123-136
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    • 1992
  • As a result of faunal analysis on 50 bottom samples bearing a total of 183 species of the Recent benthonic foraminifers from the West and South Sea of korea, five bioassociations (groups of species) and five biotopes (groups of samples) were discriminated. From the areal distribution of biotopes in combination with bioassociations and the available ecological data of foraminiferal species, five biofacies are recognized: (1) Southern Inner Shelf Biofacies; (2) Southern Coast Biofacies; (3) Northern Middle Shelf Biofacies; (4) Central Middle Shelf Biofacies; and (5) Southern Outer Shelf and Upper Slope Biofacies. The biofacies are defined by a group of sampling stations containing a diagnostic species association and can be related to the major current pasterns and water masses in the West and South Sea of Korea: Southern Inner Shelf Biofacies is related to the Coastal Waters and drainage from China; Southern Coast Biofacies is related to the Coastal Waters and drainage from Korea; Northern Middle Shelf Biofacies is related to the Coastal Waters and Yellow Sea Cold Water, Central Middle Shelf Biofacies is related to the Yellow Sea Warm Current; and Southern Outer Shelf and Upper Slope Biofacies is related to the Tsushima Warm Current.

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Effect of Typhoons on Contaminants Released from the Southern Sea around Fukushima of Japan (일본 후쿠시마 근해에서 방출된 오염물질에 미치는 태풍의 영향)

  • Hong, Chul-Hoon;Kim, Jinpyo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.49 no.2
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    • pp.234-240
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    • 2016
  • We examined the diffusion of contaminants released from the southern coast around Fukushima, Japan, during the passage of typhoons using a three-dimensional numerical model (POM) to track diffusing radioactivity (RA) released from the nuclear power plant at Fukushima following the accident caused by the giant tsunami event in March 2011. Radioactive contaminants released during the passage of typhoons may have significantly affected not only Japanese but also Korean coastal waters. The model domain covered most of the northwestern Pacific including marginal seas such as the East/Japan Sea and the Yellow Sea. Several numerical experiments were conducted case studies focusing on the westward diffusion from the southern coast of Japan of contaminants derived from the source site (Fukushima) according to various attributes of the typhoons, such as intensity, track, etc. The model produced the following results 1) significant amounts of contaminants were transported in a westward direction by easterly winds favorable for generating a coastal air stream along the southern Japanese coast, 2) the contaminants reached as far as Osaka Bay with the passage of typhoons, forced by a 5-day positive sinusoidal form with a (right-) northward track east of Fukushima, and 3) the range of contamination was significant, extending to the interior of the East/Japan Sea around the Tsugaru Strait. The model suggests that contaminants and/or radioactivity released from Fukushima with the passage of typhoons can affect Korean waters including the northeastern East/Japan Sea around the Tsugaru Strait, especially when the typhoon tracks are favorable for generating a westward coastal air stream along the southern Japanese coast.

137Cs, 40K and 210Po in abiotic components of aquatic ecosystems two rivers in the Can Gio biosphere reserve, Vietnam

  • Ilya G. Sidorov ;Nataliya N. Tereshchenko ;Andrey A. Korotkov;Olga D. Chuzhikova-Proskurnina;Nguyen Trong Hiep ;Aleksandr V. Trapeznikov
    • Nuclear Engineering and Technology
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    • v.54 no.11
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    • pp.4265-4271
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    • 2022
  • Determination of 137Cs, 40K and 210Po in water, bottom sediments and suspended matter of river systems of the Can Gio Biosphere Reserve, Vietnam was carried out. The average activity concentration of 137Cs in waters of Ca Gau and Long Tau was 0.89 ± 0.14 and 1.08 ± 0.15 Bq m-3 and was comparable to the levels of this radioisotope in waters of the East Sea. The activity concentration of 137Cs in bottom sediments was 2.23 ± 0.81 and 3.63 ± 1.24 Bq kg-1. The activity concentration of 137Cs in water and bottom sediments could be characterized as low. So, the water areas of the Ca Gau and Long Tau rivers could be attributed to areas with insignificant pollution by technogenic radionuclides. The 210Po activity concentration in bottom sediments of the Ca Gau and Long Tau rivers ranged from 9.2 ± 1.2 to 25.5 ± 2.1 Bq kg-1, which is typical for river bottom sediments. Such values indicate the absence of anthropogenic enhancement of the entry of this radionuclide into the Can Gio river systems. The 40K activity concentration varied within 467 ± 42-651 ± 39 Bq kg-1 and represented typical values of potassium content in the bottom sediments of coastal water bodies, subject to a significant influence of the lithogenic component of suspended matter.

Five species of the Genus Prionospio (Polychaeta: Spionidae) in Kwangyang Bay, Korea

  • Jung Rae-Hong;Choi Byoung-Mi;Hong Jae-Sang
    • Fisheries and Aquatic Sciences
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    • v.1 no.2
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    • pp.216-226
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    • 1998
  • Specimens of the spionid polychaetes (Polychaeta: Spionidae) were collected and examined in the subtidal shallow waters of Kwangyang Bay, southern coast of Korea, from April 1990 to November 1994. Five species of the genus Prionospio are described and illustrated: Prionospio (Minuspio) multibranchiata Berkeley, 1927, P. (Prionospio) saccifera Mackie and Hartley, 1990, P. (P.) bocki Soderstrom, 1920, P. (P.) membranacea Imajima, 1990, and P. (P.) paradisea Imajima, 1990. These five species of spionid polychaetes are reported for the first time in Korean waters.

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Reproductive ecology of the sharp toothed eel in the southern Korean waters (한국 남해에 서식하는 갯장어, Muraenesox cinereus (Forsskal)의 생식생태)

  • Cha, Hyung Kee;Seo, Young Il;Oh, Taeg Yun;Kim, Heeyong;Lee, Sun Gil;Choi, Mun Sung
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.3
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    • pp.217-226
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    • 2012
  • Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity ($AL_{50}$), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

Quantitative Assessment of Micropollutants in the Southern Coastal Waters of Korea (남해 연안 해역에 있어서 미량유기오염물질의 정량적 평가)

  • Han, Sang-Kuk;Park, Ji-Young;Lee, Jong-Sam
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.8 no.4
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    • pp.213-219
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    • 2005
  • In this study, we try to Quantitatively assess the micropollutants in Gwangyang bay, Gamag bay and Yeoa bay, using simultaneous analytical method fir 310 chemicals. In the results, several dozen organic pollutants were detected in sampling sites, and the major chemicals detected were CH type chemicals, such as aliphatic and polycyclic compounds, and CHN(O) type chemicals, such as aromatic ammines and nitro compounds. The concentration of organic pollutants was higher in summer than in winter. However, there was no association of species of organic pollutants with season. The total concentration of pesticides at each sampling site was measured within the range of $ND{\sim}9.11{\mu}g/L$. Insecticides and fungicides of pesticide type were detected in Gwangyang bay and Gamag bay, while six kinds of endocrine disrupter were detected in southern coastal waters. From the results of this study, we should estimated that the insecticides, the fungicides, and a few of the endocrine disrupters are major pollutant factors in southern coastal waters.

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Distribution of Fish Larvae in the Southern Coastal Waters (Yeosu, Namhae and Tongyoung) of Korea in Spring and Summer (한국 남해안(여수, 남해, 통영) 연안해역 춘·하계 어류 자치어 분포 특성)

  • Choi, Hee Chan;Yoo, Man Ho;Youn, Seok Hyun;Oh, Hyun Ju
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.23 no.6
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    • pp.759-766
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    • 2017
  • In order to identify the species composition and distribution pattern of larval fish assemblages in the southern coastal waters of Korea, monthly samples were taken using an RN80 net which was towed horizontally in three different regions (Yeosu, Namhae and Tongyoung) between May to September 2016. A total of fifty taxa were collected during the study. Among these, Engraulis japonicus, which accounted for 56.8 % of the total population, was the most dominant species, followed by Sillago japonicus, Parablennius yatabei, Gobiidae Type A, Parablennidae sp., and Omobranchus elegans as dominant taxa, that accounted for 87.5% of the total number of individuals. ANOSIM results revealed that regional groups were not separated, but seasonal groups were clearly divided with statistical significance, and these differences were caused mainly by water temperature variations identified by canonical analysis.