• Korean Journal of Ichthyology
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• v.35 no.1
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• pp.39-43
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• 2023

The water temperature and salinity have an important effect on the growth and survival of rearing fish. This study investigates the effect of water temperature and salinity on larvae and juveniles of Platycephalus indicus. The experimental water temperature was set to 13, 16, 19, 22, and 25℃, respectively, and the salinity was set to 7, 14, 21, 28, and 32 psu, respectively. Ten individuals were randomly collected daily and measured the total length using a stereo microscope. The growth rate was the highest at 25℃ (21.62±0.14 mm), 28 psu (15.02±0.05 mm) and the lowest at 13℃ (7.04±0.05 mm), 7 psu. The survival rate was the highest at 22℃ (69.2%), 32 psu (84.1%) and the lowest at 13℃ (15.1%), 7 psu. This study demonstrates that the water temperature and salinity affected the survival and growth of Platycephalus indicus larvae and the juvenile.

• Journal of the Korean earth science society
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• v.44 no.6
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• pp.611-628
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• 2023

This study aimed to explore the geo-educational value of Deokmyeong-ri in Goseong-gun, Gyeongsangnamdo, through field research. The study area comprises well-exposed outcrops, which can be used as field sites during field trip for studying sedimentary structures (normal grading bedding, cross bedding, ripple, and desiccation crack), coastal depositional environments (coastal cliff, shore platform, and gravel beach), basic principles of relative dating (unconformity, fault, intrusion, and xenolith), and columnar joints. This study evaluated the field sites based on the achievement standards and textbooks used in the science curriculum. The field sites have a high educational value because they exhibit typicality, as mentioned in the textbook, and provide study materials for enrichment learning. Furthermore, Deokmyeong-ri Area has well-developed tourist and educational infrastructures; thus, it is a safe place for geological education.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.129-138
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• 2024

This study examines the osteological development of the Pike gudgeon, Pseudogobio esocinus in the cranial, vertebral, caudal, pelvic and pectoral girdle for the purpose of taxonomic and aquacultural studies. Adult Pike gudgeon collected from the Boseonggang River were reared at 18.5~19.5℃ (average 19.0℃). At 5 days after hatching (total length (TL) 4.25 mm), the parasphenoid, dentary, centrum of vertebrae and clavicle began to ossify. At 22 days after hatching (TL 6.33 mm), 36 to 38 vertebrae had ossified. At 42 days after hatching (TL 16.71 mm), the majority of the skeleton had ossified. Pike gudgeon exhibited comparable characteristics to other fishes of Gobionidae throughout its development, although it displayed differences in some areas, such as the caudal skeleton and fin supports.

• Korean Journal of Ichthyology
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• v.36 no.3
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• pp.263-272
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• 2024

The genus Rhinogobius fishes, collected from a stream in the Geumodo Island of Yeosusi, Jeollanam-do, Korea, were identified as Rhinogobius nagoyae Jordan and Seale, 1906. The specimen from Geumodo Island exhibited the following morphological characteristics, which were consistent with the original description of R. nagoyae and other literatures: I, 7~8 second dorsal fin rays; I, 7~8 anal fin rays; 18~19 pectoral fin rays; 31~36 longitudinal scales; 8~9 transverse scales; first dorsal fin elongate in male, its distal tip reaching to base of second or third branched ray of second dorsal fin in males when adpressed; pectoral fin base with 1~3 crescent-like reddish brown line; abdomen blue when mature; when alive or freshly-collected, cheek with vermiculate reddish brown line; caudal fin 6~7 distinct rows of dark dots; a bow-shaped dark brown blotches at caudal-fin base. Detailed specimen-based descriptions were reported here.

• Journal of Fisheries and Marine Sciences Education
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• v.7 no.1
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• pp.14-30
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• 1995

한국(韓國)의 연근해어업(沿近海漁業)은 국내외 여건의 변화로 경쟁력(競爭力)을 잃어가고 있다. 따라서 구조개선(構造改善)을 통한 활로개척의 필요성이 강하게 대두되고 있으나, 중앙정부(中央政府) 차원의 어업여건(漁業與件) 개선은 장기간이 소요될 것으로 예상된다. 따라서 지방화시대(地方化時代)를 맞이하여 수산정책(水産政策)도 지방정책(地方政策)에 의한 지역적 특성을 가진 정책으로 발전시켜나갈 필요가 있다. 여기에서는 그런 차원에서 본토(本土)와는 지리적(地理的), 사회적(社會的), 경제적(經濟的)으로 상당히 독립된 특성을 가지고 있는 제주도(濟州道)에 있어서의 연근해어업(沿近海漁業)에 관한 각종 자료를 이용하여 어업의 현황을 분석하고, 나아가 생산성(生産性)을 보다 향상시킬 수 있는 어업구조(漁業構造)의 개선방향(改善方向)에 관하여 연구하였다. 그 연구결과(硏究結果)는 다음과 같다. 1. 제주도(濟州道) 연근해어업(沿近海漁業)의 실태(實態) 1) 어업인구(漁業人口)는 계속 감소하고 있으며 부녀자(婦女子) 비율이 뚜렷하게 높다. 2) 어선세력(漁船勢力)은 10톤이하의 소형선(小型船)이 꾸준히 증가되고 있으며, 10~50톤급의 증가률(增加率)도 매우 높다. 3) 어항(漁港)은 107개가 있으나 그중 80%는 비법정(非法定)의 소규모(小規模) 어항(漁港)이었다. 4) 어선어업(漁船漁業)은 연승(延繩) 유자망(流刺網) 채낚기 분기초망어업(焚寄抄網漁業) 등을 중심으로 이루어지고 있다. 5) 생산물(生産物)의 종류는 어류(魚類)가 주축을 이루고 있고, 대부분 고급(高級) 어종(魚種)이며, 가격은 상당히 높다. 6) 어선어업(漁船漁業)의 한어기(閑漁期)에 관광산업(觀光産業)과 연계하여 운영하고 있는 유어어업(遊漁漁業)은 상당히 발전할 소지를 가지 고 있다. 2. 문제점(問題點) 1) 어업인구(漁業人口)는 감소하는 반면 부녀자(婦女子)의 참여율은 높아 어선어업(漁船漁業)에 종사할 인력의 수급이 어려우며, 이것이 조업규모(操業規模)를 지속적으로 확대하지 못하는 요인이 되고 있다. 2) 어항시설(漁港施設)이 미비하여 어선어업(漁船漁業)의 규모를 확대시키기가 곤란하다. 3) 연근해어업(沿近海漁業) 어획물(漁獲物)의 판매를 위한 제도 및 시설이 소비환경(消費環境) 및 기호변화(嗜好變化)에 적절히 대응하지 못하고 있다. 4) 유어어선(遊漁漁船)의 운영기반(運營基盤)이 취약하여 활성화되지 못하고 있다. 5) 어업의 경쟁력 확보를 위한 기술교육(技術敎育) 및 연구(硏究) 지도체제(指導體制)가 취약하다. 3. 구조개선(構造改善)의 방향(方向) 1) 어업인력(漁業人力)의 안정적인 수급(需給)을 위하여 어민(漁民)의 정주환경(定住環境)을 개선하고, 어민후계자(漁民後繼者) 육성사업(育成事業)의 자금지원 수준을 향상시켜야 하며, 수산고등학교(水産高等學校) 졸업자(卒業者)를 수산계대학(水産系大學)에 일정 비율 정원외(定員外) 특예입학(特例入學) 시킴으로써 기술(技術)의 고도화(高度化)와 어촌 정착 동기를 높여 주어야 한다. 2) 어업인력(漁業人力) 감소에 대비하여 어선의 장비를 현대화, 생력화(省力化)하여 적은 인력으로도 운영이 가능하도록 유도하여야 한다. 3) 어업의 경쟁력 확보를 위해 어항시설(漁港施設)을 확충하고, 소비자(消費者)의 기호변화(嗜好變化)에 대응하여 위탁판매(委託販賣) 장소를 중심으로 종합어시장(綜合魚市場)을 개설해야 하며, 이와는 별도로 활어위판장(活魚委販場)을 시설하여 어획물(漁獲物) 부가가치제고(附加價値提高) 및 유통개선(流通改善)을 이루어야 할 것이다. 4) 유어어선(遊漁漁船)의 운영도 편의시설(便宜施設)을 확충하고 인공어장(人工漁場)의 조성을 추진하여 안정적인 부업으로 정착될 수 있도록 하는 노력이 필요하다. 5) 연구(硏究) 지도(指導)의 강화를 위하여 제주도(濟州道)에 소재하고 있는 연구(硏究) 지도기관(指導機關)을 적극적으로 활용함은 물론, 필요하다면 기관을 개편 증설하고, 어업인력(漁業人力)의 질적 향상을 위한 어민교육원(漁民敎育院)의 설립도 검토해 볼 필요가 있다.

• Economic and Environmental Geology
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• v.47 no.5
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• pp.533-540
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• 2014

The Wangdol-cho area, in the Hupo Bank, plays a very important role in main fishing grounds, leisure tourism and marine environmental researches of the East Sea. We analyzed the detailed bathymetry and classified the seabed characteristics of the Wangdol-cho area, based on seafloor backscattering images and sediment grain size. The Hupo Bank is developed in parallel with the eastern coastal line of Korean peninsula, and the shallowest area (Wangdol-cho) of the Hupo Bank is located along the eastern part of Hupo Port. The Wangdol-cho comprises three summits; north summit, middle summit, and south summit. The middle summit area among the three summits has the most shallow water depth with minimum about 6 m. The north summit shows about 8 m minimum depth and the south summit about 9 m. The bathymetry data around three summits represent undulating seabeds with many scattered underwater reefs and shallow water depth. The area between the underwater reefs, the flat seafloor in the northeastern part of the survey site, and the western steep slope area have relatively coarse sediments such as sandy gravel and gravelly sand. The bathymetry in the western side of the Wangdol-cho shows steep slope seabed, extending to the Hupo Basin. Fine sediments including mud and silty sand occur in the Hupo Basin area of the survey site. The submarine detailed topography and the analysis of the seafloor characteristics of the survey area are expected to contribute to management for marine environmental researches and sustainable use of ecosystems in the Wangdol-cho.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.1-6
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• 2011

The underlying principle of environmental conservation and restoration is to receive continuous services from nature. In this context, the basic objective of oil spill response and recovery activities is to allow affected residents to retain sustainability of their daily livelihood and productive environment. Hence, monitoring the status of socio-economic impact and the extent of restoration is an important parameter in the restoration effort to repair the damaged functions of environmental services with oil spill accident. However, assessment of socio-economic impact poses investigators with much difficulties in selecting the most appropriate approaches because the process often involves various stakeholders, directly and indirectly. Moreover, the analyses and interpretation of the results also pose a great challenge. The present study monitored fisheries and tourism numbers which were considered as major local socio-economic indicators of living and production environment affected by M/T Hebei Spirit oil-spill accident. This monitoring was conducted by examining the published papers and statistical reports. This was supplemented by surveying how the local residents actually felt about the damage and recovery for the first time in Korea. The results showed that the rate of the recovery was about 40~50 %, and the rate of the recovery seemed to be slowed or decreased. However, what the local residents actually felt was 2~10 points less than the literature surveys and statistical reports. These results suggested limits to using only the literature and statistical surveys for the traditional socio-economic impact assessment. The study also showed the need to include in the impact assessment process what and how the local residents actual feel about the oil spill damage and recovery process.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.2
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• pp.3-18
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• 2002

This study has been carried out to find the water Quality in coastal sea of fungmun area, southern Jeju Island. In-situ observations and water sampling had been made every month from July 1997 to June 2000. The distributions of water temperature and salinity over the study area have been 13.8~27.0℃ and 30.0~34.7‰, respectively. Salinity is showed low salinity from June to September (rainy season) because of rain. Tsushima Warm Waters (TWW) as ≥15℃ and ≥34‰ influence the adjacent sea around Jeju Island all year round. Yangtse Coastal Waters (YCW) influence the surface layer around Jeju from June to September and so strong stratification (termocline, halocline) resulted at the depth of between 20~30m at outer-sea. However the stratification does not happen even in summer at inner-sea, which seem to be caused due to vertical mixing by wind, waves and tides. A water mass of high value of water temperature and salinity (respectively 14.1~17.7℃, 33.9~34.1‰) stayed at the lower layer in outer-sea all the year round. It is probably formed by mixing between TWW and YSBCW(Yellow Sea Bottom Cold Water). The mean value of DO was the lowest in summer and the highest in winter. COD and TH were the highest in summer and the lowest in winter. However, TP showed the lowest value in summer season, because the mean value of N/P ratio was over 16. The mean of N/P ratio was under 16 in other seasons. The phosphate would be a limiting factor in the growth of phytoplanHon in summer. Nitrate would be a limiting factor in other seasons. Distribution of chlorophyll a did not show any seasonal change in the study period, but especially increased during April and May in the first year(1998) and the second year(1999) all over the study area, which suggested that phytoplankton inhabitation distributed widely in the study area. The space averaged values were the highest for TIN in rainy season and lower for TP in rainy season than in other seasons. It suggests that river runoff influences the inner-sea.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.24 no.6
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• pp.373-380
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• 2012

The sandy beach along the east coast of Korea offers beautiful scenery with high-quality sand for leisure, and is also famous for the white-sand and pine-tree which is an important scenic resource. Furthermore, the sandy beach helps to maintain natural environment of the costal area and functionates as a disaster prevention system against high waves. There are two major value evaluation methods, Travel Cost Method and Contingent Valuation Method, to assess the value of coastal sandy beach. Contingent Valuation Method is considered to be more appropriate for simultaneous evaluation on the usefulness and the uselessness of the beach. But in order to apply Contingent Valuation Method to coastal sandy beach evaluation, close examination and investigation on the potential bias, such as on questionnaires, surveys and replies, are required. In this study, the characteristic of primary amenity of sandy beach users is investigated, in prior to evaluating the usefulness and the uselessness of the beach measured by contingent valuation method. The characteristic of amenity on major sandy beaches on the east coast of Korea is studied and compared by diverse value evaluation methods.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.6
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• pp.408-415
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• 2016

Small fishing ports and coastal structures installed in a relatively low sea water depth disturb the wave induced current and cause the collapse of equilibrium state of sediment transport. These structures creates diffracted waves and matter the concentration of waves to cause the beach erosion. In order to mitigate these eroding problems on the beach, many counter measurements were proposed such as detached breakwater, groin or headland; however, these methods interrupt the aesthetic view of sandy beach due to the exposed structures above the sea level and have difficulty of applying to those beaches with the good scenery. Furthermore, some of these methods create secondary environmental problems after the installations. To eliminate these problems, one of the countermeasures, artificial reefs have been selected and used worldwide to minimize the disturbance of the scenery and secondary effects on the environment. Meanwhile, it is important to set the design elements for installing the artificial reefs such as that of length, opening width, clearing distances from the shoreline and more. Nevertheless, there are no construction manuals or standards for designing the artificial reefs with these important design elements yet. In this study, different conditions of artificial reefs were used with various cases throughout hydraulic model test to precisely analyze the changes of waves and currents to propose the standards of design elements to install the artificial reefs.