• Korean System Dynamics Review
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• v.11 no.1
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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.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.369-375
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• 2004

This experiment was studied to obtain basic environmental effects and biological information on the early growth of larval mitten crab (Eriocheir sinensis). Mitten crabs were maintained for each larval stage with solutions containing 0.1, 0.2, and 0.3 ppm of cadmium (Cd) and mercury (Hg). The relationship between survival rate of mitten crabs and metal content in the growth chamber showed a positive correlations. However, it showed a significant difference in the 96 $hr- LC^{50}$ values of Cd and Hg for the E. sinensis larvae from the first zoea larva to juvenile. Hg was more toxic to E. sinensis larval than Cd. When Cd and Hg are released into the water, they enter E. sinensis larval and are biological magnified. These results of survival rate and bioaccumulation are very important when considering the survival of the mitten crab.

• Korean System Dynamics Review
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• v.12 no.1
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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.

• Journal of Aquaculture
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• v.11 no.2
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• pp.125-132
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• 1998

The results of experimental culture for Koran mitten crab, Eriocheir japonicus at different outdoor culture methods such as rice field, pond, and vinyl house from July 21, 1994 to October 23, 1995 were summaried as fellows. 1. The water temperature was 2${\circ}C$~32${\circ}C$ during the culture periods from July 21, 1994 to October 23, 1995, and it ranged from 15${\circ}C$ to 30${\circ}C$ during the terms showing the intake habit of feed with these temperature maintained for 281 days of 460days of the total cultur periods. 2. The gain weight of Korean mitten crabs was 1,711.3g at the rice field, and 1,565.4g at the pond, and 1.220.0g at the vinyl house. The survial rate was 22.7% at the pond, and 18.7% at the rice field, and 18.3% at the vinyl house with the average survial rate of 19.9%. The daily growth rate of cauapace width was 0.64% at the rice field, and 0.61% at the pond, and 0.59% at the vinyl house. And the gain weight and the daily growth rate were the best at the rice field. 3. When the culture was finished, the frequency of carapace width of 4.0~4.9cm was 57.1% at the rice field, and 33.3% at the vinyl house. Therefore, culture at the rice field for the cultur of mitten card was considered to be the best outdoor culture method from the point of view in the fast growth and polyculture feasibility with paddy rice.

• Korean Journal of Environmental Biology
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• v.30 no.1
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• pp.26-30
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• 2012

We investigated the effect of the Geum river Estuary Barrage, on the migration and spawning of the Chinese mitten crab from May 2007 to January 2009. The larvae were caught on May in the lower reachs of the estuary barrage, but the juveniles were not collected in the upper reaches of the estuary barrage. Adult crabs arrived at the Geum river estuary for spawning in early September, and spawned between March and April. Therefor if there are corridors which let the juveniles move to the upper stream, the crab population might be restored to the former state that they grow up to adults in the freshwater, and could be migrated easily to marine habitat for spawning.

• Ocean and Polar Research
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• v.31 no.3
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• pp.257-264
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• 2009

Seventeen females of the mud crab Scylla serrata, from the State of Kosrae, Micronesia, were transported to the Fisheries Resources Research Institute, Gyeongsangnam-do, in oxygen-filled plastic bags. After acclimatization to a $30^{\circ}C$ holding temperature, nine females were selected for seed production trials. Spawning was hastened using eyestalk ablations; however, this may not be required in commercialscale mud crab seed production. Primary spawning produced an average of 2.4 million hatched larvae, whereas secondary spawning produced 0.4 million. About 10 days elapsed between spawning and hatching and 30 days between hatching and crablet. Mass mortalities up to 90% were observed between stages zoea 1 and zoea 2 in every trial. The highest survival rate from zoea 1 to crablet was estimated at 0.25%. Most commercial shrimp hatcheries in Korea are equipped with almost all necessary facilities and could be converted easily to mud crab hatcheries, able to run three to four times per year using hatchery technologies developed for blue crabs and Chinese mitten crabs.

• Development and Reproduction
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• v.12 no.3
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• pp.231-241
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• 2008

The present study was designed to clarify aspects of the annual reproductive cycle of the fresh water mitten crab, Eriocheir japonicus inhabiting Sumjin river, and to determine the adequate conditions of temperature, photoperiod and salinity on the gonadal maturation and breeding of adult female crabs. Based on the seasonal changes of GSIs and gonadal histology of adult crabs, the annual reproductive cycle could be divided into 4 periods as follows: previtellogenesis period (from September to October) when GSIs were low value and ovaries had oocytes in previtellogenesis stage and meiotic prophase stage; maturing period (from November to March of the next year) when GSIs increased gradually and ovarian oocytes accumulated yolk globules; spawning period (from April to June) when high value of GSI of female was kept and ovigerous female appeared; resting period (from July to August) when GSIs decreased rapidly, and vitellogenic oocytes degenerated. Gonadal maturation was influenced by water temperature, but not photoperiod and salinity. GSI more increased in experimental regime of $18^{\circ}C$ than that of $10^{\circ}C$ regardless of photoperiod conditions (12L12D and 15L9D). However, in $26^{\circ}C$ regime of both photoperiod conditions, the value of GSI was not changed, and vitellogenic oocytes were not observed. Spawning was considerably influenced by water temperatures and salinities regardless of photoperiods. Vitellogenic female crabs did not spawn at $10^{\circ}C$ in any salinity conditions. However, at $18^{\circ}C$ and $26^{\circ}C$, over a half of rearing female crabs spawned in condition of 30% sea water (salinity 9.6%o) and 60% sea water (salinity 19.2%o), while no female spawned in freshwater condition (salinity 0.0%o).

• The Journal of Fisheries Business Administration
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• v.53 no.2
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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.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.2
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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.