• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.389-398
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• 2008

The regional characteristics of crackdown on illegal fisheries in Korea Waters are investigated using data from the Ministry of Maritime Affairs and Fisheries, local cities and Provincial governments, and the Korea Coast Guard from 1996 to 2006, focusing on the relationship between the crackdown on illegal fisheries, catches within the affected regions, and characteristics of similar crackdown in Chinese fishing vessels. Illegal fisheries in the South Sea were all strongly affected within each region, and a relationship between the crackdown and subsequent catches showed a relatively good correlation in the South Sea. As a monthly variation, a strong correlation appeared during the autumn season, but this strong correlation was not evident during the spring. This paper suggests that a relationship exists between the crackdown on illegal fisheries and subsequent catch rates, suggesting that an intensification of these efforts in the South Sea and the Yellow Sea, and attendant increases in manpower and equipment would result in a significant decrease in illegal fishing by Chinese fishing vessels from year to year.

• Journal of the Korean association of regional geographers
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• v.22 no.4
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• pp.875-886
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• 2016

The eastern coast of Seopo-myeon, Sancheon-si in the South Coast is a bay almost completely separated from open sea by Changseon and Namhae Islands. Marine terraces in this area can be classified into geomorphic surfaces with elevations of 10~12m, 15~18m, 20~24m, 25~28m, 30~33m, 35~38m, 40~45m, 45~50m and 54m. This marine terrace system is similar to the Boryeong area in the West Coast. The geomorphic surfaces distribute along ridges and show relatively small areas. The young and old surfaces show a mixed distributional pattern. This distributional pattern contrasts to the East Coast where the oldest surface farthest from the coastline is parallel to the coast and age of the surfaces increases with a distance from the coast. These seem to result in high energy waves by typhoon that developed wave-cut platform on hill areas with relatively complex relief in a short time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.239-252
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• 1981

The East China Sea is an important region as nursery and spawning grounds for pelagic fishes such as jack mackerel, common mackerel etc. , and thus constitutes a major fishing area for purse-seine fishery. The environment surrounding in this region is under the influence of the Yellow Sea Cold Water, China Coastal Water and Kuroshio Current. The purpose of this study was to clarify the effects of oceanographic conditions and thermal fronts on the formation of the fishing grounds for the mackerels in the East China Sea. Through the analyses of fisheries statistics during 1968-1976 and temperature data, the following facts are found: 1) Approximately $70\%$ of the total mackerel(common) catches appeared to be come from the Tsushima Current region which includes Sakai coast of the Japan Sea, eastern Tsushima and Shirase Island, and Jeju Island of Korea. This area covers only about $8\%$ of the East China Sea. 2) Main fishing grounds for the jack mackerel are also centered around the area of southwestern Goto, Shirase and eastern Tsushima Island where the catches accounted for about $54\%$ of the total jack mackerel catches. 3) Fluctuations in annual catches are relatively small in the Tsushima Current region, compared to other regions such as Yellow Sea, southwestern coast of Kyushu and mid-western part of the East China Sea, where the fisheries yields varied considerably due to unstable fishing conditions. 4) It appears that the fishing grounds for the jack mackerel are mainly distributed along the warmer region ($15-20^{\circ}C$) of the thermal front, and those for the common mackerel are in somewhat colder region ($13-16^{\circ}C$) in the Tsushima Current.

• 한국해양학회지
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• v.18 no.1
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• pp.1-9
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• 1983

The northern boundary of the Tsusgima Current and its fluctuations are divcussed in the Japan Sea in summer. This current was characterized with high slinity, and its path was traced by following the salinity maximum on the basis of oceanographical data collected during the period from 1963 to 1979. The salinity maxima (34.45-34.85 ) of the Tsushima Current in the areas between 29 N in the East China Sea and northern part of the Japan Sea were found at depths between 46m and 135m. The representative thermosteric anomaly corresponding to the salinity maximum eas examined in order to analyze the advection of this currint. In the Tsushima Current region in the Japan Sen, the thermosteric anomaly values in the layer of salinity maximum during the period of 1970 to 1979 was beween 220 cl/t and 260 cl/t. In general, as the current moves northward its salinity decreascs, its thermosteric anomaly decreases and the depth of salinity maximum becomes shallower. The northern boundary of this current, which is indicated by 34.4 isohaline on 240 cl/t isanosteric surface during the study period of ten years, was confined to south of 40 N of the Japan Sea. The 34.4 isohaline edvealed two types of flow; one of them flows northward along the eastern coast of South Korea and then meanders eastward, while the oter flows basically northeastward along the coast of Japan. The meanders of northern boundary of this currint idrntified th isohaline in this word were nearly similar to those studied by others on the bases of isotherm analysis.

• Journal of the Korean earth science society
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• v.28 no.3
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• pp.367-373
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• 2007

A geoacoustic modeling has been developed to predict sound transmission through the submarine layers of sediment and rock. It demands a geoacoustic model with the measured, extrapolated, and predicted values of geoacoustic parameters controlling acoustic propagation. In the coastal areas of Okgye and Bukpyeong, the East Sea, the marine succession consists of Quaternary/Tertiary deposits and acoustic basement. The basement of Okgye coastal area is indicative of siliciclastics of the Pyeongan Group in Paleozoic, and the average velocities of P-wave and S-wave are 4276 m/s and 2400 m/s, respectively. The basement of Bukpyeong coastal area is indicative of limestone of the Joseon Supergroup in early Paleozoic, and the average velocities of P-wave and S-wave are 5542 m/s and 2742 m/s, respectively.

• Ocean and Polar Research
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• v.26 no.4
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• pp.595-606
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• 2004

Hydrographic survey in the Korea Strait has long history that has begun in August 1917 at the Busan - Tsushima cross section, still continues to date. However, chemical properties of bottom cold water found exclusively in the western channel of the Korea Strait during summer did not receive much scientific attention. The aim of the study is to decipher the enigmatic origin of the Korea Strait Bottom Cold Water (KSBCW) in terms of chemical properties. The physicochemical properties of the KSBCW are extracted from the CREAHS II hydrographic data. OMP method was applied to analyze origin of the KSBCW quantitatively. The KSBCW is well defined by low temperature below $10^{\circ}C$. The cold waters exhibited the local presence near the coast at about 120m depth with a thickness of 20m to 30m. The cold water was characterized by relatively cold, saline and higher chemical concentrations than adjacent waters. The KSBCW seems to have different origin kom that of the coastal upwelled waters at the Ulgi-Gampo because it is saline, denser and contains considerably less dissolved oxygen than upwelled waters. The physicochemical properties are reported to have noticeable annual variations which suggest the complex origin of the KSBCW. OMP analysis show that the KSBCW is a mixture of three water types; TMW (24%), ESIW (36%) and ESPW (40%). Relationship between the KSBCW and the east Sea circulation is traced by mapping the water masses that have similar T, S and DO of KSBCW. The result showed that the KSBCW is most possibly an extension of southward flowing coastal intermediate waters. Front these results, we expect that the monitoring KSBCW will provide us valuable information about the East Sea circulation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.1
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• pp.45-49
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• 2015

Disturbance to marine wildlife is a serious negative impact of marine debris. In this study, the percentages of Black-faced Spoonbill nests that included plastic marine debris were calculated from surveys conducted on an islet named Suhaam off the western coast of South Korea. The percentages of nests including plastic decreased from 71% in 2010 to 37% in 2011 to 33% in 2012. The total number of nests increased from 28 in 2010 to 38 in 2011 to 43 in 2012. These differences in nests and nesting materials were possibly due to natural nesting materials such as tree branches and rice straws that were provided at the breeding site as a protective action in 2011 and 2012. Additional conservation efforts should be made to prevent further negative impacts from marine debris.

• Journal of the korean society of oceanography
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• v.33 no.4
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• pp.146-156
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• 1998

Hydrographic data retrieved in the southwestern part of the East Sea in 1992-1993 were analyzed to investigate the probability of southward intrusion of the East Sea Intermediate Water (ESIW) into the Ulleung Basin. The ESIW showed the ranges of 1 to 4$^{\circ}$C in potential temperature, 33.80-34.06 psu in salinity, and 26.9-27.3 kg/m$^3$ in potential density (${\sigma}$$_{\theta}$). The mean depth occupied by the ESIW was 170 m, where the characteristic values of the above three were 2.64$^{\circ}$C , 34.02 psu, and 27.13 kg/m$^3$, respectively. One of the most prominent features of the ESIW was that its salinity changed not only seasonally but also interannually. It was low in summer and high in winter. The salinity within the isopycnal layer of 26.9-27.3 kg/m$^3$ was closely related with the potential vorticity (${\rho}$$_{\theta}^{-1}$ f ${\varrho}$${\rho}_{\theta}$/${\varrho}$z), being in direct proportion to the salinity. This implies that the low-salinity water was thicker than the high-salinity water. The flow path of the ESIW was investigated by tracking the low-salinity or the low-potential vorticity water and by referring to acceleration potential. Careful analysis of the flow path proves that the ESIW intrudes from the north between the Korean coast and Ulleung Island into the Ulleung Basin in summer. Existence of the high-potential vorticity water in the Ulleung Basin is associated with the interruption of the inflow of low-salinity water.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.3
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• pp.367-375
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• 2016

Marbled flounder Pseudopleuronectes yokohamae is a commercially important flatfish in the coastal waters of the East Sea off Pohang, Korea. Maturity and spawning dynamics of P. yokohamae were investigated based on samples collected by gill net and long line in the coastal waters off Pohang from January 2013 to December 2014. We analyzed monthly changes in maturity stage, gonadosomatic index (GSI), egg diameter, fecundity, and total length at 50% group maturity. We found that the spawning period was December to February, wherein fecundity ranged from 55,760 eggs at 20.40 cm total length (TL) to 1,559,007 eggs at 46.6 cm TL. The relationship between TL and fecundity (F) was F = 0.0017 TL^3.5604 (R² = 0.6984), and F increased with increasing TL. We estimated the TL at 50% group maturity as 27.4 cm for female and 23.5 cm for male P. yokohamae, respectively. The results from this research will aid in the development of policies on season and minimum catch length for sustainable production of P. yokohamae. We propose that it is necessary to conduct long-term ecological monitoring for this species because biological properties such as spawning ecology and growth performance are being affected by climate change.

• Journal of fish pathology
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• v.18 no.3
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• pp.205-214
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• 2005

The isolates, which has caused considerable damage to the olive flounder farm located in the eastern coast of Korea showed 99% sequence homology in the comparison of 16s rRNA gene of P. damselae subsp. damselae ATCC 33539. The present P. damselae was identical to the biotype No.8 in Pedersen et al. (1997) and the same LPS protein pattern as P. damselac subsp. damselae ATCC 33539. The comparison of infection rates among present P. damselae and Vibrio spp. showed that isolated P. damselae was the highest, followed by V. anguillarium, V. harveyi. and V. ordalii.