• Journal of Navigation and Port Research
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• v.36 no.9
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• pp.741-751
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• 2012

This article analyzes the interdependency between nonrenewable marine sand resources and renewable fishery resources by the developed dynamic bioeconomic model. The developed bioeconomic model is applied to a case study of efficient sustainable management for marine sand mining, which adversely affects a valuable blue crab fishery and its habitat in Korea. The socially-efficient extraction plan for marine sand and the time-variant environmental external costs to society in terms of diminished harvest rate of blue crab are determined. To take into account long-term effects from destroyed fishery habitat, a Beverton-Holt age structure model is integrated into the bioeconomic model. The illustrative results reveal that the efficient sand extraction plan is dynamically constrained by the stock size of the blue crab fishery over time. Thus, the dynamic environmental external cost is more realistic resource policy option than the classical fixed external cost for determining socially optimal extraction plans. Additionally, the economic value of bottom habitat, which supports the on- and off-site commercial blue crab fishery is estimated. The empirical results are interpreted with emphasis on guidelines for management policy for marine sand mining.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.253-262
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• 2023

To identify sand crab Ovalipes punctatus populations and establish management units for each population, mtDNA COI regions were analyzed. As a result, the clade of O. punctatus in Korea were separated by two with a genetic distance of 0.17-2.08%, and there was no significant difference in the result of pairwise FST values representing genetic differentiation by sampling areas (p > 0.05). Also, no geographical separation found in the distribution of haplotypes and the results of the haplotype network. This result suggests that O. punctatus larvae were dispersed for a long time by the ocean current by suffering meroplanktonic period for 1 month, and increased the gene flow due to the development of the swimming legs for the increase in mobility. Therefore, in the results of mtDNA COI region analysis of O. punctatus in the East Sea, Yellow Sea, South Sea and East China Sea (Ieodo) of Korea, no clear intra-species differentiation was found.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.558-568
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• 2023

The spatio-temporal distribution of the sand crab Ovalipes punctatus larvae was investigated in the Korean waters in 2019. Sea surface temperature (SST) was the lowest in February and highest in September. Sea surface salinity (SSS) was the lowest in September and highest in March. Further, sea surface chlorophyll a (SSC) was the highest in September. Larvae were distributed in the South Sea and coastal area of Jeju Island from April to June, and the abundance was the highest in May. The spatio-temporal distribution analysis suggested that larval groups showed a tendency to be dispersed over a wider area as the larvae developed, due to the increase in their swimming ability. The correlation analysis between environmental factors and larval density suggested that larvae appeared in the SST range 11.8-20.9℃ and SSS range 31.5-35.3 psu. The Megalopal stage appeared in a wider range of SST and SSS than other larval stages, possibly due to the increased environmental tolerance before settlement. Results of redundancy analysis (RDA) and Spearman's rank correlation analysis between the larval density by developmental stages and the environmental factors suggested that SST showed a positive correlation and SSC showed a negative correlation in the later stage.

• Animal Systematics, Evolution and Diversity
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• v.5 no.2
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• pp.121-137
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• 1989

The larval stages of Scopimera longidactyla reared in the laboratory are described and illustrated in detail. The larval development consists of five zoeal and a megalopal stages. At 25$^{\circ}C$, the megalopa and the first crab instar were attained in 21 and 31 days after hatching, respectively. The larvae of Scopmera can be distinguished from those of other genera in the Scopimerinae and other sumbfamilies in the Ocypodidae by the relativelength of rostral carapace spines to carapace. The larvae of S. longidactyla are similar in morphology to those of S. globosa but distingished by the differences in larval , size, and appendage setation.

• The Korean Journal of Zoology
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• v.33 no.2
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• pp.200-216
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• 1990

The complete larval development of Scopimera bitympana Shen was descdbed and mustrated from the larvae reared in the lahoratory. S bItympana had five, or occasionally six, zoeal and one megalopal stages. At $25^{\circ}C$, the megalopa and the first crab instar were attained in 24 and 38 days (31 and 48 days in six zoeal series) after hatching respectively. S.bitympana zoeae can be distinguished from other described zoeae in the genus by the toothed carapace spines and the telson with a dorsal and two ventral spines. Megalopa of this species can be distinguished from other ScopimeTa spedes by the feature of carapace. Other minor morphological features of S. bitympana larvae are compared to the previous descripdons of larvae of the genus and the morphological differences are briefly discussed.

• Journal of Life Science
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• v.23 no.9
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• pp.1088-1095
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• 2013

The swimming crab, Portunus trituberculatus, inhabits seafloor habitats containing sand or pebbles and is widely distributed throughout the world. The present study investigated genetic polymorphisms of 10 microsatellites in 281 samples of P. trituberculatus collected from four locations along the coastal water of the Korean side of the Yellow Sea (Yeonggwang, Taean, Sorea, and Yeonpyeong-do Island). The number of alleles per locus ranged from 50 to 129, with a mean of 69.5. The observed and expected hetrozygosity varied from 0.111 to 1.000 and from 0.609 to 0.979, respectively. The inbreeding coefficients (Fis) varied among the loci from -0.0207 to 0.8175. The genetic differentiation (Fst) was less than 0.05 (range 0.0020-0.0124). Therefore, the four groups of P. trituberculatus appeared to exhibit little genetic differentiation. The lack of differentiation was confirmed in a phylogenetic tree constructed by the unweighted pair group method with the arithmetic average (UPGMA). The hypervariation between the populations and the lack of genetic differentiation may reflect active gene flow among the Yellow Sea populations and the absence of geographical boundaries. The highly polymorphic microsatellite loci will be useful for molecular and phylogenetic studies, as well as stock management, of swimming crab, which is an important fishery resource.

• Animal Systematics, Evolution and Diversity
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• v.30 no.4
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• pp.235-239
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• 2014

The first zoea of Camptandrium sexdentatum is described for the first time with a digital image of live zoeas. An ovigerous crab of C. sexdentatum was collected at the muddy sand flat in Namhaedo Island on 2 June 2012 and hatched in the laboratory on 6 June 2012. In Camptandriidae, the first zoea of C. sexdentatum is distinguished from the first zoeas of Cleistostoma dilatatum and Deiratonotus cristatum by having no dorsal and lateral carapace spines, an abdomen significantly broadened posteriorly, and a subovoid telson without forks. Especially, the finding of a subovoid telson without forks is the first report in brachyuran zoeas.

• Animal Systematics, Evolution and Diversity
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• v.26 no.3
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• pp.223-232
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• 2010

Actiniarians were collected from the rocks and sand bed of Jejudo Island, Ulleungdo Island, and Wangdolcho in Korean waters from 2004 to 2009. They were classified as two species of two families belonging to the suborders Endocoelantheainea and Nynantheae. Especially, suborder Endocoelantheainea, with distinct development of mesenteries, was firstly added to Korean athenarian fauna with the species, Halcurias carlgreni McMurrich, 1901. Calliactis polypus (Forsk$\aa$l, 1775) showing the commensalism with hermit crab, was easily distinguished from C. japonica by external features and the composition of cnidae. These two species were described in detail with tables and figures.

• Animal Systematics, Evolution and Diversity
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• v.24 no.1
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• pp.17-24
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• 2008

Three crab species, Macromedaeus orientalis, Eriphia smithi, and Ocypode cordimana, from Jejudo Island are recorded for the first time in Korea. M. orientalis was collected under the rocks by SCUBA diving in 20m and at low tidal mark. However, E. smithi and O. cordimana were collected in crevices of the rock at low tidal mark and in a burrow of sand beach at supra tidal mark, respectively. At present, E. smithi is the only species of the genus represented in Korean waters. Including the new records in this study, the established brachyuran fauna in Korea now comprises 203 species.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.509-515
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• 2010

In this paper, the mechanism that can walk efficiently in wet land or sand area is proposed. A vision camera is attached to the mechanism, which makes a kind of biologically inspired robot for coast guard. This visionary information enables the biologically inspired robot to react in peripheral environment by a soft-computing algorithm. In addition, the biologically inspired robot can achieve the mission appointed by a programmer connecting with outside, based on RF and Blue-tooth communication module. Therefore, the purpose of this research is the implementation of the biologically inspired robot that can operate most adaptively in sand and wet surface based on Theo Jansen mechanism.