This study examined the functional efficiency through hydraulic model test for wave energy transmission coefficient, wave energy reflection coefficient, wave overtopping, and stability of new-type wave dissipating block SEALOCK ADVANCE 61. The applied experiment time was about 2 h~4 h 30 min on prototype model on the basis of 1,000 waves, and the weight of the corresponding block was 20 ton (model: 741 g). The incident wave was experimented for total of 18 cases. As the result, wave energy reflection coefficient was 0.24∼0.57, and wave energy transmission coefficient was analyzed to be 0.15∼0.16 in case of wave overtopping occurrence. Also, wave dissipating block(SEALOCK ADVANCE 61) showed no destruction aspect, showing stable and excellent solidity aspects in general.

The fish (fish eggs, larval fish, and adult fish), caught by RN 80 net and gape net between coastal waters off Jeung island and Saok island, in January and April of 2016 were assessed for species composition in their abundance. Fish eggs and larval fish studied at three stations and were composed of 5 and 11 taxa, respectively. The adult fish were studied at one station and were composed of 20 species, 18 families, and 8 orders. The dominant species were Engraulis japonicus and Nuchequula nuchalis which were caught at all of the fish stages. Larval fish and adult fish were assessed for their richness, evenness, diversity, and dominance to gain a measure of the biodiversity. The richness index was the highest in April at adult fish (R=2.102), the evenness index was the highest in January at larval fish (E=0.953), the diversity index was the highest in April at adult fish (H’=2.010), and the dominance index was the highest in April at larval fish.

In this study, re-analysis wind fields of KMA, JMA, and NOAA were collected for the estimation of waves during typhoon MAYSAK (2009). The wind field data of KMA, JMA, and NOAA were used as input conditions, and the significant wave height, peak period, and representative wave direction were estimated using SWAN (Simulating Waves Nearshore, version 41.31) numerical modeling. Calculation ranges of the typhoon wave estimation range from 20° to 50°N and 117° to 147°E, and the latitude and longitude were composed of grid size at 0.05° (about 5 km resolution). Experimental conditions were 0~360° 60 division for direction division, and 40 division for frequency division 0.04~1.0 Hz, and JONSWAP spectrum was used. In order to verify the reproducibility of the typhoon wave estimation results, quality-controlled wave observation data provided by WINK in the typhoon MAYSAK best track were collected, and the reproducibility of wave estimation data using KMA, JMA, and NOAA wind fields was compared and reviewed.

In this study, an experiment was conducted to investigate the engine performance, combustion characteristics, and emission characteristics, according to the operating conditions of the engine and the mixture ratio of diesel oil and butanol in a diesel engine. Combustion pressure, fuel consumption, smoke concentration, excess air ratio, intake and exhaust temperature were measured during this experiment. Using these data, the coefficient of variation of IMEP (indicated mean effective pressure) and the indicated fuel conversion efficiency were calculated for investigating the engine performance. The cylinder pressure was analyzed for pressure increasing rate and heat release rate. The experimental results of butanol blending oil were compared with the those of diesel oil. The optimum operating condition of engine and proper range of butanol blending rate could be identified without bad effect to the engine performance and the soot emission in this study.

In Korea, coastal erosion in Korea gradually increases the intensity of typhoons and high waves such as swells on the coast due to climate changes such as sea level rises and sea water temperature rises. In addition, due to maintenance projects such as dam, dike and river embankment construction, the amount of sand that flows from river to coast is decreasing. Coastal erosion is accelerating due to imbalances in sand budget. Therefore, this study aims to analyze the current situation and outcomes of coastal erosion response. In particular, detailed current status, problems and improvement plans were reviewed for each stage of coastal maintenance project planning, design and construction, and monitoring, feedback management, and effective erosion countermeasures were suggested.

This study was carried out to understand the seawater flow characteristics of the waters near the Yulchon Industrial Complex in Gwangyang Bay as a basic data for understanding the habitat environment of marine ecosystems, plant plankton, shellfish, fish and algae. Numerical experiments were conducted using field observation and EFDC in the target area. As a result of field observation, half-day casting showed the dominant tidal phase, and the average flow rate of flood was 14.14 cm/s~16.09 cm/s, and the average flow rate of ebb was 11.67 cm/s~15.31 cm/s. At the time of flood tide, NW and NNW directions and at ebb tide SE and SSE directions were observed. And half-day casting (M2, S2) is the predominant algae form than one casting (K1, O1). As a result of the numerical experiment, the flow around the target area appeared in southwest direction at the time of flood tide, and the flow in the northeast direction at the time of ebb tide was strong. The flow rate of the survey area was up to 75 cm/s at the time of spring tide flood, and up to 54 cm/s at the time of ebb. At the time of neap tide flood, it appeared up to 26 cm/s, and at the time of ebb up to 21 cm/s. Therefore, systematic and continuous monitoring is needed to understand the marine ecosystem habitat in the area around Yulchon Industrial Complex in Gwangyang Bay. This study will be used as basic data.

Species composition of fish larvae in coastal waters off Wan island port were investigated in May and August, 2019. During the study period, the fish larvae were identified as belonging to 24 taxa, 19 families, and 9 orders. The dominant species of fish larvae were Engraulis japonicus, Nuchequula nuchalis, and Ammodytes japonicus. These three species accounted for 56.4% of the total number of individuals collected. The evenness index of the fish larvae was the highest in St. 4 (E=0.88) and the lowest in St. 1 (E=0.74). The richness index of the fish larvae was the highest in St. 2 (E=3.49) and the lowest in St. 4 (E=2.89). The diversity index of the fish larvae was the highest in St. 4 (H′=2.53) and the lowest in St. 1 (H′=2.19). The dominance index was the highest in St. 1 (D=51.12%) and the lowest in St. 4 (D=34.76%). The similarity index was the highest between St. 5 and St. 2 by 92.14%.

해양환경 특성 조사에서 수온은 13.54~24.80℃, 염분 30.23~32.00 psu, pH는 7.85~7.98, 용존산소는 7.38~8.26 mg/L의 범위로 나타났다. 갯벌 노출 시간 및 고도 조사에서 지반고는 248.85~278.88 cm의 범위로 나타났으며, 노출 시간은 5시간 5분에서 6시간의 범위로 나타났다. 본 연구에서 채집된 낙지는 총 345개체였으며, 외투장은 2.25~9.72 cm ML의 범위로 나타났으며, 평균 6.09 cm ML로 나타났다. 생체량은 7.40~293.20g의 범위로 나타났으며, 평균 82.78 g으로 나타났다. 외투장 7.00~7.99 cm의 개체군이 전체의 89개체 (24.1%)로 가장 많이 출현하였다. 낙지의 주 먹이생물은 게류로 나타났으며, 다음으로 새우류, 이매패류, 갯지렁이류로 나타났다. 낙지 인공 산란장 적지 기준은 수질환경, 퇴적환경 및 생물학적 요인으로 구분되었다. 수질환경은 수온 10.0~20.0℃ (최적 범위 10.0~16.0℃), 염분은 27.0~35.0 psu, 염분의 변화에 민감함으로 주변에 하천이 없어야 한다. 용존산소는 5.0 mg/L 이상을 유지하여야 한다. 퇴적환경은 사니질성분의 갯벌조간대가 알맞으며, 노출시간은 6시간 이내, 지반고는 280 cm 이내여야 했다. 생물학적 요인은 생물학적 최소형인 7.0 cm ML 이상의 낙지를 사용하여야 하며, 산란기인 5~6월, 10~11월이 조성적기였다. 또한 주변에 풍부한 낙지 먹이생물이 서식하여야 한다. 인공산란장 조성은 암수낙지를 3일간 어두운 환경에서 교접을 시킨 후 이를 10 m당 1개체씩 (1 ha에 100개체) 조성된 인공산란장에 방류한다. 이러한 인공산란장이 조성되면, 자율관리어업공동체를 구성하고 지자체 및 유관기관의 기술지원 및 행정지원을 통한 유기적인 연대관계를 유지하여야 할 것이다.

This study was conducted to investigated the morphology comparison of cranium, orbital bone, and jaw bone skeletons of nine species of Scorpaenidae fish; Sebastes inermis, Sebastes thompsoni, Sebastes schlegelii, Sebastes vulpes, Helicolenus hilgendorfi, Inimicus japonicus, Sebasticus marmoratus, Sebasticus tertius, and Inimicus japonicus. Samples were collected from December, 2012 to May, 2013 in fisheries market in Yeosu, Korea and were applied to analyzes such as morphology of skeleton. As a result, taxonomic characteristics of skeleton were vomer, frontal, sphenotic, parietal, the second suborbital bone, dentary, articular, and angular.

At the center of the Noryang waterway, there is the Gwangyang Bay, the Yeosu Strait is located at the west, and the Jinju Bay, the Gangjin Bay and the Sacheon Bay is located at the east. The freshwater from several rivers is coming into the study area. Especially in the event of flood, the freshwater of the Seomjingang is flowing into the Gwangyang Bay area (including the Yeosu Strait) and freshwater of the Gahwacheon (discharge of Namgang Dam) is flowing into the Jinju Bay area (including the Gangjin Bay and the Sacheon Bay) in great quantities. The Gwangyang Bay area and the Jinju Bay area are connected with the Noryang waterway. In addition, the freshwater out of the Seomjingang and the Gahwacheon also affect through the Noryang waterway. In this study, we elucidated the characteristics of seawater exchange rate and residence time seasonally, with a consideration of the freshwater out of 51 rivers, including the Seomjingang and the Gaghwacheon, using a particle tracking method. The result showed that the particles released from the Gwangyang Bay area moved to the Jinju Bay area through the Noryang waterway. However, the particles moved from Jinju Bay area to Gwangyang Bay area appeared comparatively small. Seasonal seawater exchange rate ranged from 41.2 to 51.3% for the Gwangyang Bay area and from 58.0 to 62.1% for the Jinju Bay area. In addition, seawater exchange rates in summer turned out to be larger than those in any other season. The residence time appeared to be 13.3 to 14.7 days in the Gwangyang Bay area and 9.2 to 10.1 days in the Jinju Bay area. As a result, residence time of the Jinju Bay area turned out to be a little bit smaller than those of the Gwangyang Bay area.

Species composition and community structure of fish eggs and larval fishes in coastal waters off Geoje island were investigated from November, 2018 to August, 2019. Durng the study period, the fish eggs were identified as belonging to 9 taxa. The dominant species of fish eggs were Engrauils japonicus, Nuchequula nuchalis, and Sillago japonica. These three species accounted for 73.2% of the total number of individuals collected. The collected larval fishes were identified into 16 taxa, 15 families, and 4 orders. The dominant species of larval fish were E. japonicus, N. nuchalis, and Sebastes schlegelii. These three species accounted for 61.4% of the total number of individuals collected. The diversity index of the larval fishes was the highest in summer by 1.92 and the lowest in winter by 1.30. The community similarity of each season was the highest between spring and summer by 54.6%.

For morphological and osteological studies of Plectorhinchus cinctus, samples were collected in Yeosu fisheries market and analyzed. The differences of covariance were presented in following characteristics: body color, body shape, black bands, and spots ranging from back to tail. P. cinctus had 12 dorsal fin spines, 15~16 fin rays, 16~19 pectoral fin rays, 1 ventral fin spines, 5 ventral fin rays, 3 anal spines, and 6~9 fin rays. The taxonomic characteristics of skeleton were supra-occipital bone, the basisphenoid bone in the skull, the maxillary bone, the angular bone in the jaw bone, existence and nonexistence of the supra-temporal bone in the shoulder, and the number of the branchiostegal ray bones.

전남 무안군 갯벌 조간대의 수온은 13.54~24.80℃의 범위로 나타났으며, 염분은 30.23~32.00 psu, pH는 7.85~7.98, 용존산소는 7.38~8.26 mg/L의 범위로 나타났다. 퇴적물의 입도조성은 3개 지역 모두 모래가 50.0% 이상으로 나타났다. 갯벌조간대에서 출현한 식물플랑크톤은 규조류가 종조성의 90% 이상으로 나타났으며, 주요 우점종은 Paralia sulcata로 나타났다. 동물플랑크톤은 절지동물문이 종조성의 90% 이상으로 나타났으며, 주요 우점종은 게류 유생 (brachyura larvae)으로 나타났다. 식물 및 동물플랑크톤의 종조성은 우리나라 연안의 전형적인 출현양상이었다. 대형저서동물은 환형동물문이 80% 이상으로 나타났으며, 주요 우점종은 털보집갯지렁이 (Diopatra sugokai)로 나타났다. 칠게와 낙지의 출현량은 정점 2에서 가장 높게 나타났으며, 낙지의 주 먹이 생물인 칠게의 출현량이 높은 곳에서 낙지의 출현량이 높게 나타난 것으로 판단되었다.

The fluctuation in the abundance and species composition of fishes were investigated using shrimp beam trawl in the south coastal water off Namhae-gun, Gyungsangnam-do, Korea, from October, 2008 to September, 2009. A total of 3,519 fishes (341,413 g) were sampled and classified into 57 Species, 47 genera, 36 families and 8 orders. The dominant orders were Perciformes including 26 species, 23 genera and 16 families followed by Scorpaeniformes including 16 species, 12 genera and 9 families, Pleuronectiformes including 7 species, 5 genera and 7 families, Anguilliformes including 2 species, 2 genera and 2 families, Tetraodontiformes including 2 species, 1 genra and 1 family, Mugiliforms and Lophiiformes 1 species, 1 genera and 1 family. Among the appeared 57 species, Platycephalus indicus was the dominant species by 11.11%, followed by Hemitripterus villosus (10.66%), Hexagrammos otakii (6.59%), Istigobius hoshinonis (6.08%), and Mugil cephalus (5.54%). The diversity was the highest in October (3.083), while the lowest in March (1.910). The evenness was the highest in February (0.938), while the lowest in March (0.649). The dominance was the highest in March (0.607), while the lowest in October (0.189). The richness wast the highest May (5.563), while the lowest in February (1.993). The similarity of community structure was 62.79% between January and December.

In the framework of “The Comprehensive Data Analysis for Areas under the National Jurisdiction” Project, the Korea Hydrographic and Oceanographic Agency first checks data for missing or wrong values, then provides the data to the public. For stationary observation points, removing wrong or missing values entails temporal discontinuity which may not be best restored with interpolation. Manual correction is time-consuming and the decision criteria may differ among employees. The less is the quality of the data, the more specialists are to be involved, and the less objective are the models’ outcomes that use the data as an input. The focus of the current study is to overcome this by a temporal and spatial interpolation of marine data using neural networks. The experiments were done in two cases: an interpolation based on the single observation point data, and an interpolation based on the neighborhood observation points’ data. Then, each case was further subdivided into an interpolation based on six and twelve-hours time horizons. This is because, the variation in data is not large for the data within an hour timeframe, so simple nearest interpolation or linear interpolation models are sufficient. On the basis of this, the feasibility of interpolation of missing marine data was verified.

In order to study osteology on the family Platycephalidae 3 species (Platycephalus indicus; Cociella crocodila; Inegocia japonica) were collected in Yeosu city Namsan fish market and Goheung Nokdong fish market from January 2014 to October 2014, and were applied to analyzes such as osteological charcteristic. The family Platycephalidae 3 species were the same vertebrae number as 26, but P. indicus was different from C. crocodila and I. japonica by having 11~12 abodominal vertebrae and 14~15 caudal vertebrae. Both of C. crocodila and I. japonica were the same by having 10 abodominal vertebrae and 16 caudal vertebrae. Dorsal pterygiophores of P. indicus was 22 and formula of pterygiophores was 2*12111111112111111111. Anal pterygiophores which is ventral pterygiophores was 13 and it started from 11th vertebrae. C. crocodila’s dorsal pterygiophores was 19 and the formula of pterygiophores showed 2*111111111211111111. Anal pterygiophores was 11 and started from 11th vertebrae. The dorsal pterygiophores of I. japonica was 22 and the formula of pterygiophores was 2*12111111121111111111. Anal pterygiophores was counted 13 and it started from 11th vertebrae. Therefore, the pterygiophores formula on the family Platycephalidae 3 species were distinguished one another.

We discussed current situations in relation to developments and utilizations of artificial reefs (ARs) in Korea. ARs have been introduced since the first project officially started in 1971. Afterwards, comprehensive projects have been implemented to boost the fishing industry, such as a seedling release of fish, constructions of marine ranch and sea forests by using technologies of the design and deployment of ARs from 1998 to 2015. It proved that catch of fish fairly increased, and accordingly fishermen’s earnings were also improved, compared to the past when those projects were not executed yet. In addition, local governments and communities are closely collaborating to rehabilitate the fishing industry by means of improving marine environments, complementary plantings of algae, organizing a self-ruled fishing community, and a post management of marine ranch. In recent years, however, the fishing industry is challenging due to climate change, rise of sea level, and coastal pollutions almost all around the world. Therefore, we will have to share our knowledge of ARs and collaborate in order to overcome the current crisis of fishing industry.

Seagrass plays an important role and functions in coastal and estuarine ecosystems such as water quality improvement and coastal purification, coastal ecosystem feeding, spawning and growing place of fish. Recently, the changes of seawater flow and marine environment have occurred due to coastal reclamation and construction of artificial structures in Seomjin River estuary. Therefore, it is expected to affect the distribution of seagrass in the Seomjin River estuary. In order to reconstruct and manage the seagrass habitat in Seomjin River estuary, we investigated the spatial variation of seagrass habitat according to the coastal topographic changes using remote sensing data. We tried to extract coastline and boundaries of seagrass habitat from the satellite images and aerial photographs, and conduct overlay analysis to identify the changes in location and area of coastal topography and seagrass habitat.

Species composition and yearly variation of fish in coastal waters off Heuksan island were investigated using seasonal samples collected by fish pots from 2015 to 2017. A total of 269 fishes were sampled and classified into 25 species, 16 families, and 6 orders. The dominant species were Sebastes schlegelii (44 individuals, 11,790 g), followed by Conger myriaster (38 individuals, 5,240 g), and Hexagrammos agrammus (24 individuals, 2,650 g). By year, the highest number of individuals was found in 2015 (97 individuals, 15,107 g), while the lowest in 2017 (76 individuals, 11,364 g). The diversity index was the highest in 2015 (Hʹ=2.66) and the lowest in 2017 (Hʹ=2.42). The richness index was the highest in 2015 (RI=4.15) and the lowest in 2017 (RI=3.23). The evenness index was the highest in 2016 (J=0.90) and the lowest in 2015 (J=0.89). The dominance index was the highest in 2017 (D=34.2%) and the lowest in 2015 (D=29.9%). Highly economic species, such as Muraenesox cinereus, Conger myriaster, Sebastes schlegelii, Liparis tanakai, Pleuronichthys cornutus, and Takifugu rubripes, were caught.

Eight temperate seagrass species have been previously reported in coastal waters off the Korean Peninsula. Recently, the species, Halophila, which are mainly predominant in tropical and subtropical areas, have been discovered in the southern coast of Korea for the first time. This species were identified as Halophila nipponica. H. nipponica has been distributed in a warm temperate region of Japan where is under the influence by Tushima Warm Current, and was not previously found outside the Japanese archipelago. In this study, we carried out some numerical experiments to understand the process how the spores of H. nipponica disperse under the influence of the flow in coastal waters of Korea. For this, we used the EFDC to reproduce the dispersion process of the spores in terms of a particle tracking method. The numerical results represented a clockwise circulation of the flow at ebb tide with a velocity of roughly 3 cm/s. However, the particles did not move away too far from the spores site because the flow is fairly weak. In addition, the flow patterns had no significant difference from season to season.