• 한국시스템다이내믹스연구
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• 제11권1호
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• pp.27-57
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• 2010

This article deals with an ecological-economic analysis of the 'Pasture Project of Kum River', which is the farming plan of mitten crabs using Jichun, a stream of the River Kum where the natural propagation of mitten crabs are blocked because of the estuary dam constructed in 1990. Toward analyzing the ecological and economic effects of the crab releasing and harvesting activities in Jichun, a two-stage cohort model of population dynamics with cannibalistic behaviors and density restrictions in biomathematics is adopted, despite of the current infertility in Kum, considering the opportunity of establishing dam fishways in the near future. This study moreover presents a method of parameter estimation especially with assuming a steady state of the ecosystem, and performs various analyses such as the risk measurement of climate change and the economic value of such fishways.

• Journal of Ecology and Environment
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• 제43권1호
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• pp.31-42
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• 2019

Background: Han River estuary is a national wetland reserve near the Demilitarized Zone (DMZ) between South Korea and North Korea. This trans-boundary estuary area has been well preserved and shows distinctive plant communities along the salinity gradient. To elucidate energy flows and nutrient cycling in this area, we studied trophic relations between the dominant sesarmid crab, Sesarma dehaani, and food sources in three wetlands with different environments along the estuarine gradients. Results: Stable isotope signatures (${\delta}^{13}C$ and ${\delta}^{15}N$) of the crabs were significantly different among the sites and body size classes. Seasonal changes in ${\delta}^{13}C$ of small crabs were distinct from those of large individuals at all the sites. The isotopic values and fatty acid profiles of the crabs were more different among the sites in September than in May. In May, large-sized crabs utilized more plant materials compared to other dietary sources in contrast to small-sized crabs as revealed by a stable isotope mixing modeling, whereas contributions to diets of crabs were not dominated by a specific diet for different body size in September except at site 1. Based on PCA loadings, fatty acid content of $18:3{\omega}3$, known as a biomarker of plant materials, was the main factor to separate size groups of crabs in May and September. The ${\delta}^{13}C$ value of sediment had high correlation with those of small-sized crabs at site 1 and 2 when 1-month time lag was applied to the value for crabs during the surveyed period. Conclusions: Based on the stable isotope and fatty acid results, the consumption habits of S. dehaani appear to be distinguished by sites and their size. In particular, smaller size of S. dehaani appears to be more dependent on fewer food sources and is influenced more by the diet sources from the sediments in Han River estuary.

• 한국시스템다이내믹스연구
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• 제7권2호
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• pp.97-120
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• 2006

This paper deals with the extension of and discussion on the System Dynamics model (Jeong & Jeon, 2005) of river crabs in Korea. The previous model has been elaborated to empirically search for the optimal restoration and harvest rates of crabs in the Imjin River, on the basis of theoretical models of population dynamics in the field of bio-mathematics and environmental economics. In this paper, the authors tries to couple a series of new feedback loops related to density restrictions and cannibalistic behaviors with a stage-structured model of the crab ecosystem, and also to endogenize the parameter of baby crabs' survival that is caused by water quality improvement and income increase. Through these extensions and relaxations, the authors are able to argue about the strategic decision of the optimal rates additional considerations as well as the properties of the integrated system that was not covered in the previous paper.

• Parasites, Hosts and Diseases
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• 제27권3호
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• pp.225-227
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• 1989

1986년 11월과 1987년 2월에 경상남도 하동군의 섬진강 하구에서 말똥게(Sesarsnndehanni)를 채집하여 이락촌폐홉충(P. itektsuenensis)의 피낭유충 감염상을 조사하였다. 피낭유충은 대부분 게(crab)의 간 조직에서 검출되었으며 조사한 말똥게 74마리 중 47마리(63.8%)에서 1∼102개(평균 18개)의 피낭유충이 검출되었고, 게의 크기에 따라 피낭유충 양성률 및 감염량이 증가하는 경향을 나타내었다. 이 연구 결과 최근에도 섬진강 하구에 이락촌폐흡충의 생태학적 환경이 잘 유지되고 있음을 알 수 있었다.

• 한국시스템다이내믹스연구
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• 제12권1호
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• pp.59-74
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• 2011

This article deals with an economic evalutation of the 'Pasture Project of Kum River', which is the farming plan of mitten crabs in a stream of it. An augmented model of social capital is based on the past ecological-economic system dynamics model and elaborated further with suggestions of social capital literature. During the modeling process a chain diagram of causal relations and its relevant mathematical equations are presented for simulating the project performance, and the simulation results are provided to contrast the dynamic behaviors of the former ecological-economic model with ones of the new model incorporating social capital. The results indicate that an increase in the economic benefit of the project could happen in case of considering the process of social capital accumulation around the case area, which can be regarded as a remarkable trial to approve the common confidence in the role of social capital to enhance an economic achievement.

• 수산경영론집
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• 제53권2호
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• pp.1-20
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• 2022

This study is aimed to analyze fishermen's perception and the economic feasibility of inland waters ranching project on the branches of Geum River. Analysis of fishermen's perception on the branches of Geum River showed that fishermen had an affirmative response on the inland freshwater ranching project related issues such as fisheries resources enhancement, necessity of project, economic achievement as so on. The model of inland waters ranching project on the branches of Geum River is designed to fisheries resources enhancement, habitat compositiom, ecology tours, use and management of resources. The results of the economic feasibility of inland waters ranching project on the branches of Geum River were internal rate of return (IRR) was 18.43%, a benefit-cost ratio was shown to be 1.54, net present value (NPV) was 4,929 thousand won, which indicates the economic feasibility of inland waters ranching project.

• 한국환경복원기술학회지
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• 제11권2호
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• pp.40-54
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• 2008

Small and large dams are installed in the course of a stream for maintaining the water level of the stream or obtaining agricultural water. Currently about 18,000 of them are installed in Korea to supply water. However, the environmental problems of small dams are well known : the interruption of stream eco-corridors, deterioration of water quality in the upper reaches of the small dam, changes in the habitats of riparian organisms, damages to the stream scenery. In a very few of these small dams artificial eco-corridors like fishways are installed, but the number is very minimal.Accordingly, to efficiently restore stream eco-corridors by removing these small dams, it will be necessary to closely examine physical impacts, such as changes in the riverbed and changes in the shape of the stream caused by the removal, chemical impacts, such as changes in water quality, and transport and accumulation of contaminated sediments and biological impacts, such as changes in the habitats of organisms, and develop related technologies in advance, and have these technologies verified through demonstration application in the sites. In this study, we analyzed the physical, chemical and ecological impacts of the removal of the above-mentioned small dams, and conducted a research on the demonstration small dam removal project for a spot investigation. As a result, the small dam removal will restore the eco-corridor, there by improving the habitat of fishes and crustaceans. The number of major underwater organisms inhabiting the Gokreungcheon, such as Korean spotted sleepers, Chinese minnows, Microphysogobio yaluensis, Abbottina rivularis, stone morokos, striped shinners, long-nosed barbels, and Chinese mitten crabs, is expected to increase, and the food chain in the ecosystem will improve so that species diversity will improve as well.

• 환경생물
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• 제30권1호
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• pp.26-30
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• 2012

본 연구는 금강하구둑과 관련하여 금강에 서식하는 참게($Eriocheir$ $sinensis$)의 이동과 산란을 알아보기 위해 2007년 5월부터 2009년 1월까지 금강 수계에서 조사하였다. 참게의 유생은 5월에 기수역에서 채집되었으나, 이후 치해로 변태하여 소상하는 개체들은 채집되지 않았다. 산란을 위해 참게들이 금강하구에 도달하는 시기는 9월 초순이었고, 3월부터 4월 사이에 산란을 하는 것으로 확인되었다. 연구 결과 기수에서 부화한 참게의 유생이 치해로 변태하여 담수로 이동하는 통로를 만들어 준다면, 금강 수계의 자연산 참게 복원이 제한적이나마 가능할 것으로 판단된다.

• Animal Systematics, Evolution and Diversity
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• 제38권1호
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• pp.42-45
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• 2022

The varunid crab, Varuna yui Hwang & Takeda, 1986, is known as widely distributed in the Southeast Asian region. Three specimens of varunid crabs were collected near the estuary of the river from Korea and identified as V. yui. Varuna yui could be distinguished from the other congeneric species, V. litterata (Fabricius, 1798), by having a more extended mesial lobe on the distal region of the male first gonopod. In this paper, morphological diagnosis and illustrations of the newly collected V. yui are provided. The specimens examined herein were deposited in the National Marine Biodiversity Institute of Korea and Nakdonggang National Institute of Biological Resources.

• 한국발생생물학회지:발생과생식
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• 제12권3호
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• pp.231-241
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• 2008

본 실험은 동남참게, Eriocheir japonicus의 명확한 생식년주기를 밝히기 위하여, 그들의 자연 서식처인 섬진강에서 채집한 성체 참게의 생식소 조직의 계절적인 변화 그리고, 암 참게 생식소의 성숙과 산란에 미치는 환경요인 즉, 온도, 광주기 그리고, 염분 농도에 대하여 조사하였다. 암 참게의 생식소 발달과 GSI의 계절적 변화를 기초로하여 생식년주기를 다음과 같이 4단계로 구분하였다: 난황형성전기$9{\sim}10$월), GSI는 낮았으며, 난소내에는 난황형성전기와 감수분열전기의 난모세포들을 가지고 있었다; 성숙기(11월$\sim$다음해 3월), GSI는 점차적로 증가하여 난모세포내에는 난황구들이 축적되었다;에는 영향을 받지 않았다. 광주기 조건(12L12D, 9L15D)에 관계없이, $10^{\circ}C$ 실험군의 암 참게보다, $18^{\circ}C$ 실험군의 암 참게의 GSI가 더욱더 증가하였다. 그리고, $26^{\circ}C$ 실험군에서 두 개의 광주기 조건(12L12D, 9L15D)에서 암 참게의 GSI는 변화하지 않았으며, 난소내에는 난황이 축적되고 있는 난모세포들은 없었다. 산란은 수온과 염분 농도에 의하여 많은 영향을 받으며, 난황형성중인 암 참게는 두 달간 사육하여도, $10^{\circ}C$에서는 전혀 산란을 하지 않았으며, $18^{\circ}C$와 $26^{\circ}C$에서 사육한 암 참게의 반 이상은 염분 농도 9.6%o와 19.2%o의 조건하에서 산란하였다. 그러나, 염분 농도 0.0%o의 조건에서는 산란한 암 참게가 한 마리도 없었다.