• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.2
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• pp.180-194
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• 1985

The author investigated the history of oyster culture in Korea through examining old books and reports dealing with the fishery. Oysters have been produced in the all coastal areas in Korea, especially the center areas of production were the Hwangupo (Hamkyongbuk-do), Younghungman (Hamkyongnam-do), the estuary of Nakdonggang (Kyongsangnam-do), Kwangyangman, Haechangman, the estuary of Yongsangang (Chollanam-do), Yonghoto (Hwanghae-do) and the estuary of Uprockgang, where the large size oyster (more than 40cm in shell height) inhabited in form of groups. It was called by nine different names in the old times, Gul, Seukhwa and Moryeo were the most common names. The oyster was used as 46 kinds of medicinal stuff. The habitat forms of natural oyster can be distinguished to two types; one is that oyster is exposed to the air during the period of low tide (A-type), another is that oyster is not (B-type). The first oyster culture by the old books in Korea was started about 530 years ago as the bottom culture method derived from the A-type of oyster. After long years, the hanging culture method might have been started from the hint of the habitat form of B-type. The oyster culture in Korea developed based on the habitat forms of natural oyster at the biginning of 1900s. After World War II, the Korean government strongly recommded the laver farmers to culture oyster as relief measures. At that time, the stone culture method was mainly adopted. The quantity of oyster production is now about $15{\times}10^6{\sim}19{\times}10^6\;\frac{M}{T}$, and the half of oyster production including seed oyster is exported to the foreign countries.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.619-626
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• 2014

In this paper, it was constructed the halophyte Mesocosm experimental which was used tidal flat and dredged sediment as a substrate material. Depending on the vegetation and substrate material of Mesocosm, Mesocosm A(tidal flat sediment + Salicornia herbacea), Mesocosm B (only dredged sediment), Mesocosm C(dredged sediment + Salicornia herbacea). Monitoring was carried out of Warter quality factots(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P), water temperature, salinity), Sediment factors(Chemical Oxygen Demand(COD), Total Nitrogen(T-N), Total Phosphorus(T-P)) and growth of Salricornia herbacea. Habitat Stability Index of vegetation was calculating by using the monitoring results. HSI of Mesocosm C was calculated from 0.87 to 0.95 as compared to the relatively high HSI in Mesocosm A, it was evaluated to be able to be used in the restoration and construction of the coastal salt marsh with dredged sediment.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.615-625
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• 2021

The coastal areas around Palau Island and Tonga Island, near the Pacific equator, consist of coral reefs, mangrove and seaweed. In particular, understanding the optical properties of sea surface water in coral reef habitats helps improve the accuracy of remote sensing based habitat mapping and identify tropical ecosystem characteristics. Here, we collected spectral characteristics of sea surface water of Palau Island and Tonga Island and analyzed the concentration of suspended matters, absorption coefficient, and remote sensing reflectance to understand the seawater characteristics of the coral reef habitats. Based on the results of the suspended matter concentration analysis, we developed and verified an empirical algorithm to derive the concentration from satellite data using remote sensing reflectance of three bands, 555, 625, 660 nm, showed a high determinant coefficient, 0.98. In conclusion, coral reef habitats in tropical regions are characterized by CASE-I water in terms of the marine optics with oligotrophic properties, and require monitoring using continuous collection and analysis of field data.

• Journal of Ecology and Environment
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• v.44 no.1
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• pp.54-61
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• 2020

Background: Most fish undergo prey switch from juvenile to adult. It is thought that slightly different feeding habits occur among adult fishes due to growth, spawning, habitat change, and so on. Therefore, the diet of the John Dory Zeus faber (≥ 24 cm TL) was studied in the coastal waters of Korea by analysis of stomach contents, with comparison by season and size class of diet composition and prey diversity. Monthly samples were taken from February 2017 to January 2018. Results: The results showed that the John Dory was a piscivorous predator, and pisces had occupied 82.3% of IRI%. Trichiurus lepturus and Trachurus japonicus were important preys in all size classes and seasons. Diet composition differed among the size classes and seasons (Chi-square test, P < 0.05). As body size of Z. faber increased, the occurrence of benthic fish (Glyptocephalus stelleri) tended to increase. The seasonal prey composition also changed depending on the abundant species of each season. Conclusions: Z. faber is a piscivorous predator. The consumption habits of Z. faber appear to different results by their size and seasons. This study suggests that Z. faber could be considered an opportunistic predator.

• Journal of Ecology and Environment
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• v.29 no.2
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• pp.125-141
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• 2006

Insect fauna in adjacent areas of Demilitarized Zone (DMZ) in Korea was surveyed seasonally in $2001{\sim}2003$. The survey area was divided into 3 regions (eastern mountain, middle inland, and western coastal regions) in accordance with administrative districts and topography. Sampling methods such as sweeping, sieving, beating, brushing and suction were used depending on the environmental and military conditions. Total 361 genera and 437 species of 116 families belonging to 14 orders were identified. Among these, 46 species were new to insect fauna of DMZ areas. Species richness was the highest in the eastern mountain region. Numbers of habitat-common and -specific species were 96 (22%) and 195 (47.2%), respectively. The insect species community similarity was highest (0.64) between eastern mountain region and western coastal region. Insect orders showing high species richness were Coleoptera (38.9%), Lepidoptera (19.2%), Orthoptera (9.4%), and Hemiptera (9.2%). These results will be useful information for study of history on the change of insect fauna and future conservation in DMZ areas.

• Journal of Environmental Impact Assessment
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• v.21 no.1
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• pp.171-184
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• 2012

하천 수위를 유지하거나 농업용수를 취수 할 목적으로 조성되는 크고 작은 보는 용수공급 시설로 이용되고 있으나, 하천 생물이동의 차단, 보 상류부의 수질악화, 수변 생물서식처의 변화, 하천경관 훼손과 같은 환경적 문제를 초래하고 있다. 더욱이 도시화가 진행됨에 따라 토지이용의 변화, 시설의 노후화 등으로 매년 50~150개 정도의 보가 폐기되고 있는 현실이다. 본 연구는 하천에 설치되었으나 용도와 기능이 상실된 보를 철거하여 생태적 연속성을 확보하고 하천 본래의 모습으로 되돌려 주며, 하천의 생태적 건강성을 회복 및 향상 시키고자 하였다. 보 철거 시범사업으로 공릉천에 설치된 길이 76m, 높이 1.5m의 공릉2보와, 한탄강에 설치된 길이 190m, 높이 2.8m의 고탄보를 철거하였고, 각 시범사업 대상지의 물리/화학/생태특성 모니터링 분석을 수행하였다. 그 결과 철거 직후 보의 직 상류부에 전체적으로 침식이 발생하고, 보 하류부는 여울, 하중도, 사주, 침식 등 다양한 지형으로 변모되었다. 본 연구를 통하여 하천복원의 취지에 맞는 하천 본래의 모습에 가까운 하천으로 복원하기 위해서는 기능 및 용도가 상실된 보의 경우는 기존의 보체를 개량하거나 어도를 설치하여 주는 것 보다 구조물 자체의 완전철거를 통한 생물 이동통로 조성이 바람직하다고 판단된다.

• Ocean Systems Engineering
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• v.14 no.2
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• pp.101-114
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• 2024

Seafloor sediment mapping is an essential research topic in shallow coastal waters, especially in port development, benthic habitat mapping, and underwater communications. The seafloor sediments can be interpreted by collecting sediment samples directly in the field using a grab sampler or corer. Another method is optical, especially using underwater cameras and videos. Both methods each have weaknesses in terms of area coverage (mechanic) and accurate positioning (optic). The latest technology used to overcome it is the acoustic method (echosounder) with Global Navigation Satellite System (GNSS) Real Time Kinematic (RTK) positioning. Therefore, in this study will propose the classification of seafloor sediments in coastal waters using acoustic method that is Multibeam Echosounder (MBES) multi-frequency with five frequency (200 kHz, 250 kHz, 300 kHz, 350 kHz, and 400 kHz). In this study, the deep neural network (DNN) used the bathymetric multi frequency, bathymetric difference inters frequencies, and bathymetric features from 5 (five) frequencies as input layer and 4 (four) sediment types in 74 (seventy-four) sample sediment as output layer to make a seafloor sediment map. Results of sediment mapping using the DNN method show an overall accuracy of 71.6% (significant) and a kappa coefficient of 0.59 (moderate). The distribution of seafloor sediment in the study area is mainly silt (41.6%), followed by clayey sand (36.6%), sandy silt (14.2%), and silty sand (7.5%).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.3
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• pp.129-138
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• 2017

The coastal wave environment is a very important factor that directly affects the change of coastal topography, the habitat of marine life, and the design of offshore structures. In recent years, changes in the wave environment due to climate change are expected, and a trend analysis of the wave environment using available data sets is required. In this paper, significant wave heights which are measured at six ocean buoys (Deokjeokdo, Oeyeondo, Chibaldo, Marado, Pohang, Ullengdo) have been used to analyze long-term trend of normal waves. In advance, the outlier of measured data by Korea Meteorological Administration have been removed using Rosner test. And Pearson correlation analysis between the measured data and ECMWF reanalysis data has been conducted. As a results, correlation coefficient between two data were 0.849~0.938. Meanwhile, Mann-Kendall test has been used to analyze the long-term trend of normal waves. As a results, it was found that there were no trend at Deokjeokdo, Oeyeondo and Chibaldo. However, Marado, Pohang and Ullengdo showed an increasing tendency.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.5
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• pp.312-317
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• 2016

The submersion and emersion patterns are key factors that directly influence the habitat environment of the coastal plants and animals. In this study, the coasts are divided into five zones (zones 1, 2, 3, 4, and 5 - not flooded, flooded once, flooded and exposed to air twice, exposed to air once, continuously flooded in the day, respectively) based on the patterns using tidal elevation data at the major eight stations and the domestic and international reference tidal levels, i.e., AHHW, ALLW, HAT and LAT, are also estimated to analyse the characteristics of the five distinct zones. Based on the results, the frequency of the zone 3 are dominant and forms from 87.2% to 88.2% (nearly constant) irrelevant with the tidal ranges at all stations. The taking-up percentages of the zones 2 and 4 show nearly constant, below 4% and over 8%, respectively. In Pohang station classified as the mainly diurnal tide, the percentages are decreased to 1.4% in zone 2 and increased to 10.8% due to the effects of the annual and semi-annual tidal components.

• Journal of the Korean Geographical Society
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• v.50 no.4
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• pp.375-391
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• 2015

Trees to arrest sand-shifting have been planted on most of coastal dunes in Korea and considered as conservative objects. However, we reconsider that the simplicity of these trees have hindered ecological roles of coastal dunes; geochemical cycle and habitats of endemic species in coastal ecosystem. We examined geochemical properties of sediments on Byunsuran dune field where is planted with pine trees. There are significant difference in properties between embryo dune sediments and foredune sediments, but there are not between foredune and secondary dune. There are no significant difference between pine forest sediments and mixed forest sediments. It is also not showed the difference between dune ridge sediments and swale sediments. Despite spatial diversity from appearance, geochemical properties are not linked with geomorphic and vegetational conditions because of dense planted trees on foredune. To recover natural properties of coastal dunes, we need to change the conservation scheme to increase geomorphic and ecological diversity.