• Journal of Environmental Impact Assessment
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• v.28 no.2
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• pp.129-140
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• 2019

Majangcheon is a small agricultural stream which is located in Chuncheon-si, Gangwon-do. To understand ecological characteristics of Majangcheon as biological habitats, we surveyed its physical environment and fishes from June 2016 to September 2016. The altitudinal difference between lowest and highest point of the stream was 3 meters and the first-order stream under a map drawn on a scale of 1:25,000. The flow rate of stream was slow in overall with $0.09-0.48m{\cdot}s^{-1}$. More than 50% of clay were found in all points except for the point St. 3 in the riverbed structure surveyed. A total of 2,532 individuals of 22 species in nine families were collected from Majangcheon. Of them, stillwater-living species (Acheilognathinae and Carassius auratus) and floating species (Zacco platypus and Oryzias sinensis) were mainly collected. In Majangcheon, thus, both of stillwater-living and floating fishes were specifically coexisted. The correspondence analysis, based on fishes collected from Majangcheon and past research, showed that Majangcheon is closer to the flat streams in Gyeonggi-do rather than the mountainous streams in Gangwon-do but it appeared as an independent group from those of two regions. As a result, Majangcheon is a stream with specificity of fish community.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.403-411
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• 2012

Acoustic telemetry is used to obtain a relatively continuous record of fish movement. This method has several advantages for studying migrating fish populations that are moving from large rivers. The Nakdong River is the longest river in South Korea and the main stream has faced a change, which consists of the installation of the large weirs. In this study, we applied acoustic telemetry to monitor the movement pattern of Erythroculter erythropterus (family Cyprinidae) and identified home range and movement distance in the Nakdong River. A total of fourteen individuals were released at three different locations and around 80 km section from the estuary barrage was investigated. Eight individuals were tagged and released at estuary barrage (N02) utilized up to 15.9 km (home range) upstream from the release site as home range. Four individuals were tagged and released at Samrangjin (N07), most fish moved and stayed within 9.7 km (home range) downstream area, except E12, which did not show any movement. Two individuals were tagged and released at Changnyeong-Haman weir (N10), and all individuals migrated downstream from the release site. Especially, E14 recorded the longest accumulated detected distance, 36.7 km downstream during 32 days after release. There was no correlation identified between movement (accumulated detected distance and home range) and standard length (Spearman rank correlation, p>0.05). Although, this technique could be an available method to monitor behavior and ecology of freshwater fish effectively, increment of number of receivers and tags are required for more detailed results of fish migration.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.168-178
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• 2010

Fish assemblages associated with rock reef and non-rock reef were studied using specimens collected at three sites in Geomun Island waters of the Southern Sea, Korea, in February, May, August and October, 2006. Two survey methods for the study were followed: collection by a gill net, and video observation by scuba diving. The gill-net survey was conducted during the night, the scuba-diving observations were conducted during the day. From the gill-net survey, a total of 40 species, 380 inds. and 71,426.9 g was caught at the three sites. The dominant species was Trachurus japonicus; other species were Raja kenojei, Dasyatis akajei, Stephanolepis cirrhifer, Narke japonica, Pagrus major, Sebastes inermis, and Sphyraena pinguis. At the rock-reef site, a total of 26 species, 264 inds. and 46,776.7 g was caught by gill net, and the dominant species was T. japonicus. A total of 17 species, 45 inds., 10,535.1 g was caught at the flat-bottom 1 site, and 19 species, 71 inds. and 14,115.1 g were caught at the flat-bottom 2 site. The scuba-diving survey resulted in 13 species and 1,749 inds. observed at the three sites through the survey period. The main observed fishes were rock-dwelling species such as Chromis notatus, Microcanthus strigatus, S. cirrhifer, Ditrema temmincki, Evistias acutriostris, Girella punctata, Halichoeres poecilopterus, Hexagrammos agrammus, Prionurus scalprum, Sebastes inermis, and Semicossyphus reticulatus. Seven species and 1,739 inds. observed at the rock-reef site comprised 99.4% of the inds. of the three sites. Therefore, the fish community in Geomun Island waters included many rock-reef. species, but a few were migratory species like T. japonicus and Scomber japonicus. The abundance of fish at the rock-reef site was high in comparison with those at two non-rock reefs. The dominant species were very different between the day and the night, although rock-reef species comprised the main part of the fish community. We conclude that the high abundance of fish in Geomun Island waters is most closely related to physical structure, such as rock reefs, which is the main habitat of many fishes.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.7-7
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• 2017

범람파동 개념에 따르면 하도와 홍수터의 횡적 연결성은 하천 생태계의 생물다양성과 생산성 증대에 중요한 역할을 한다. 제방에 의하여 제내지 홍수터가 하도와 차단된 우리나라 하천에서 생태적 서비스를 증대하기 위해서 횡적 연결성을 복원하는 기술 개발이 필요하다. 횡적 연결성의 복원 기술을 개발하기 위해서는 우선 하도와 홍수터 사이에 생태적 연결성의 현황을 파악하고 연결성을 저해하는 요인을 진단하는 평가 기술 개발이 시급히 요청되고 있다. 따라서 본 연구에서는 제방에 의하여 차단된 제내지 하천환경에서 수리적, 생태적 횡적 연결성을 평가하고 진단하는 기술을 개발하고 연결성 회복 방안을 제안하고자 한다. 차단된 제내지 하천환경 평가는 1) 지리정보시스템을 이용하여 차단된 하천공간을 탐색하고, 2) 탐색된 전체 재내지에서 원격평가에 의하여 간편하게 횡적 연결성 평가를 실시하고, 3) 선정된 특정 제내지 대상지에서 현장평가에 의하여 상세하게 연결성을 평가하는 순서로 수행된다. 차단된 하천공간의 획정은 홍수가 범람할 수 있는 제내지 공간을 잠재적 하천공간으로 정의하고 수치표고모델 (DEM)과 하천기본계획의 30년 빈도 홍수위 자료를 이용하여 제내지 홍수터를 탐색하였다. 제내지 홍수터의 원격 연결성평가는 지리정보시스템에서 수치지도와 토지피복도 등 공간자료를 이용하여 수리 및 서식처 환경성, 제방 차단성과 하도 및 육상 연결성을 평가하고 원격평가 결과를 토대로 현장평가 대상지를 선정하였다. 횡적 연결성의 현장평가를 위하여 크게 하도-홍수터 연결성과 제내지 서식처 보존성으로 평가 항목을 선정하였다. 또한 연결성 평가는 수리연결성과 생물연결성으로, 서식처 보존성 평가는 습지유지율, 습지보존성, 육역지보존성을 세부항목으로 구성하였다. 평가 항목별로 5 등급의 평가 기준에 따라서 평가 점수를 부여하고 평가 총점을 산출하여 최종 연결성 평가 등급을 5 단계로 구분하였다. 현장평가를 위한 MS Access 기반 소프트웨어를 개발하여, 데이터 입력과 관리 및 평가 결과 산출과 비교를 편리하게 하였다. 개발된 제내지 하천환경 평가법을 청미천과 만경강에 적용하여 검증하였다. 개발된 평가법을 바탕으로 차단된 제내지 하천환경에서 연결성 회복에 따른 어류와 식생의 분포를 예측하는 수리생태 결합모델을 개발하였다. 먼저 차단된 제내지에서 연결 수로를 복원하여 유속, 수심 분포를 준이차 수리수문 모델로 예측하였다. 예측된 수리 환경에 따라서 지표어종의 서식처 적합도 지수 (HSI)를 이용하여 서식 분포 확률을 모의하였다. 또한 일반화가법모델 (GAM)을 이용하여 환경구배에 의한 우점식생의 분포를 예측하였다. 차단된 제내지 하천환경의 생태적 연계성 평가 기술을 기반으로 제방제거, 제방후퇴, 제방고 하강, 수문 및 연결수로 개선, 생물이동 저해 장벽 제거 등의 다양한 복원기술이 개발되어야 할 것으로 생각된다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.67-79
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• 1995

Temporal variation of demersal fish in Asan Bay was determined by analyzing seasonal samples collected by an otter tyawl from November 1990 to August 1993. Of 49 species identified, Cynogiossus joyneri, Thrissa koreans and Johnius belengerii predominated in abundance, consisting of $84.7\%$ in fish numbers and $70.5\%$ in biomass. The number of species did not show any significant seasonal variation. Fish numbers and biomass were comparatively high 3n spring, summer and tall, and low in winter. Community structure, analyzed by principal component analysis using rank correlation, showed a clear seasonal trend, which seems to be related to the seasonal effects such as temperature. The number of species and their abundance in the study area were lower than those in other embayments of Korean peninsula. It seems that unstability of the sediments by tidal mixing caused this phenomenon. The total number of species decreased annually. The species of which the frequency of occurrence tends to diminish as time were mainly composed of the species which rarely occurred with low abundance.

• Korean Journal of Ecology and Environment
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• v.53 no.2
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• pp.148-155
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• 2020

In this study, we analyzed the effects of the presence or absence of weirs on fish assemblages in wadeable streams (Stream order 1^st~4^th). More specifically, we investigated these effects by evaluating the differences in stream size. The results showed differences in the fish assemblages in third or higher order streams (PERMANOVA, P<0.005). The presence or absence of weirs mainly affected variables such as the number of species the individuals, and species richness index, whereas no difference was observed in the populations of exotic, endemic, and endangered species. A SIMPER analysis showed that the common species Zacco platypus, Zacco koreanus, and Pungtungia herzi are dominant in their corresponding streams (contribution>5%), and that these are the main contributors to differences among the fish assemblages. All these species showed high relative abundances at the sites with weirs. Altered environments by the presence of weirs provided these species with concentrated habitats. In summary, this study analyzed the effects of weirs on fish assemblages on a broad, nationwide, scale, and these results can effectively aid future studies on the specific effects of weirs.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.116-116
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• 2022

현재 인공지능은 공학적 문제 해결 외에도 다양한 분야에 적용되어 매우 친숙하게 활용되고 있다. 특히 하천 분야에서는 시설물 주위 국부세굴 또는 어류 서식처 분석과 같이 관련 변수들의 복잡성으로 적절한 결과를 쉽게 얻어내기 어려운 것들에 적용되고 있다. 그 외에도 인공지능 기법을 적용할 수 있는 분야로 하천에서의 수위를 이용하여 유량을 예측하는 것이 있다. 기존에는 수위-유량 관계 곡선을 만들어 수위를 이용하여 유량을 예측하였으나, 관계곡선 제작에 활용된 수위와 유량 범위에서 벗어나는 경우 과다한 유량으로 계산되는 경우가 있다. 본 연구에서는 인공지능 기법 중 하나인 인공신경망 기법을 사용하여 하천의 유량 예측을 수행하였다. 기존 국가수자원관리종합정보시스템에 기록된 자료를 활용하여 수위와 유량 자료를ANN에 학습시키고 학습에 활용하지 않은 시기의 자료를 이용하여 전반적인 유량 예측 성능과 루프형 수위-유량 관계 곡선을 생성할 수 있는지를 검토하였다. 또한 학습 범위를 벗어난 홍수량에 대한 측정 결과를 검토하고, 기존 수위-유량 관계곡선과 비교하여 그 성능을 검토하였다.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.391-400
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• 2015

In order to investigate the distribution and species composition of fish in shallow wetlands that might be affected by environmental factors, we investigated the physicochemical parameters, macrophytes biomass, and fish assemblage in 24 shallow wetlands in South Korea from May to June, 2012. In this study, a total of 20 fish species were identified, and Cypinidae were found to be the most dominant species. Physicochemical parameters and macrophyte biomass were different in the survey sites, and macrophytes biomass, in particular, showed a positive relationship with fish abundance in stepwise multiple regression (df=1, F=32.00, P=0.001). According to the result of the cluster analysis between survey sites, the survey sites were divided into three groups in accordance with species composition of fish in relation to macrophytes biomass. In the wetlands of the first group, Lepomis macrochirus which belongs to Centrarchidae was found to be dominant and other fish assemblages were hardly seen. In the second group, unlike the first group, Carassius auratus that belongs to Cypinidae was found to be dominant. In the third group, Lepomis macrochirus was found to be as dominant as the first group but various other fish species appeared. Where there was abundance of the main food sources (i. e. zooplankton) of fish in the survey sites, there were more diverse macrophyte biomass. Consequently, it is proven that macrophytes strongly affect the species composition and abundance of fish, and high biomass of macrophytes support high assemblage of fish. Based on these results, we recommend establishing diverse aquatic macrophytes communities when restoring or creating wetlands to assure high diversity of fish species that use macrophytes as their habitat.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.310-321
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• 2014

Change in fish species composition after the Hebei Spirit oil spill in December 2007 off Taean were determined by analysis of samples collected in Mailpo beach, 10 km south from the oil spill site and polluted by the crude oil. Fish samples were collected by a beach seine in the shallow water at Malipo beach during the low tide of the new moon from February 2008 to December 2009. Five seine hauls were made during the day and the night in each sampling time. Monthly day and night samples did not show the significant differences in species composition. A total of 21 species, 1,032 individuals and 6,544 g of fish were collected in 2008, and 31 species, 4,206 individuals and 35,659 g of fish in 2009. The species collected were composed of the small-sized fish or juveniles. Abundant fishes were the resident species in coastal water, and the migrants were low in abundance. Among the fish occurred, Chelon haematochelius, Sebastes schlegelii, Takifugu niphobles and Pleuronectes yokohamae were predominated in abundance of both years. Monthly fish abundance and species diversity in 2008 were significantly lower than those in 2009. A few number of resident fish were collected from February to June 2008 showing the lowest in May 2008, and fish abundance increased from July 2008. The number of species and abundance of fish in 2009 were increased in spring as the temperature raised, showed a peak in summer and decreased in autumn. This monthly variation in fish species composition and abundance was similar to those in the non-polluted water in other temperate waters. Low fish abundance during several months after oil spill was considered to be related to the residual oil in the water and habitat disturbance due to oil cleaning activity in the beach. Monthly fish species compositions after September 2008 were similar to those of 2009 suggested that the impact on the shallow water fish by the oil residuals was not too significant at least to the fish species composition after September 2008.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.462-468
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• 2004

Most of the surveys of periphyton carried out for environmental and ecosystem health assessment of streams have considered the impact made on their fixative substrates (stones, rocks, sand, silt, clay and other abiotic matters), but there has been virtually no research that considered moving substrates. This study attempted to make an analysis and assessment of the habitat environments of the microalgae attached to the skin surfaces of fish living in small streams, with a focus on their species composition and community structure. The dominant fish in the this survey were Zacco temmincki and Zacco platypus, which are usually found in the streams, and rivers, and they accounted for 62% and 19%, respectively, in relative abundance. Substrates of fish, a representative organism with the trait of moving a long distance, show a marked contrast with those of organisms fixed at a certain place. Characteristics of both the upstream and the downstream reach well reflected in the microalgae attached to the skin surface of fishes, of which diatoms took the major composition. The result of this observation is considered to be useful to provide basic data in assessment of stream health. Also it may be suggested as a biological tool for the assessment of aquatic environment in the future.