• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.855-863
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• 2019

The efficiency of fishway installed in rivers can be directly evaluated by means of fish monitoring. On the other hand, when it is difficult to monitor the fish in certain conditions, or when planning a fishway, the efficiency can be evaluated indirectly through the hydraulic analysis. In this study, the hydraulic analysis technique for evaluating the efficiency of a fishway was presented. The River-2D model with the fish physical habitat module was used for the analysis of the attraction efficiency, and the weighted usable area was proposed as an index of the efficiency. In the analysis of passage efficiency, the three-dimensional model, Flow-3D, was used as an evaluation tool to describe the fluid behavior on a hydraulic structure with free surface. The ice-harbor type fishway at Baekgok weir in the Deokcheon River was selected as a test-site, and the efficiency was estimated using the hydraulic analysis. And then it was compared with fish monitoring data acquired from the river. As a result, it is difficult to replace the hydraulic analysis results with the efficiency quantitatively, but it can help to grasp the general tendency.

• Parasites, Hosts and Diseases
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• v.59 no.5
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• pp.523-529
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• 2021

The endemicity of zoonotic trematode metacercariae (ZTM) was investigated with total 871 freshwater fishes (19 species) from Deokcheon-gang (a branch stream of Gyeongho-gang) in Sancheong-gun, Gyeongsangnam-do, Korea for 3 years (2018-2020). All fishes were examined with the artificial digestion method. The metacercariae of Clonorchis sinensis (CsMc) were detected in 233 (36.3%) out of 642 fish in 11 positive fish species (PFS), and their infection intensity was 27 per fish infected (PFI). Especially, in index fish, Puntungia herzi, of CsMc infection, prevalence was 64.2% and infection intensity was 37 PFI. Metagonimus spp. metacercariae (MsMc) were found in 760 (87.5%) out of 869 fish in 18 PFS and their infection intensity was 228 PFI. In sweet smelt, Plecoglossus altivelis, the prevalence of MsMc was 97.6% and their infection intensity was 3,570 PFI. Centrocestus armatus metacercariae were detected in 209 (29.4%) out of 710 fish in 8 PFS and their infection intensity was 1,361 PFI. Echinostoma spp. metacercariae were found in 293 (42.6%) out of 688 fish in 15 PFS and their infection intensity was 5 PFI. Metacercariae of Clinostomum complanatum and Metorchis orientalis were also detected in 2.7% and 21.2% fish in 4 PFS and their infection intensities were 3.1 and 3.4 PFI respectively. By the present study, it was confirmed that some species of ZTM including CsMc and MsMc are more or less prevalent in fishes from Deokcheon-gang in Sancheong-gun, Gyeongsangnam-do, Korea.

• Korean Journal of Ichthyology
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• v.18 no.4
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• pp.329-338
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• 2006

Phylogenetic relationships and DNA polymorphism among local populations of the Korean native catfish species, Liobagrus mediadiposalis, have been investigated based on mitochondrial cytochrome b DNA sequences. As a result, three genetically distinct groups of local populations were recognized based on the phylogenetic tree constructed. The first group was called "Nakdong-river group" that included the local populations from Geumho-river, Gyeongho-river, and Deokcheon-river; the second one was "Geum-river group"; the third one was represented as "Seomjin-river group" that included the samples from Seomjin-river, Dongjin-river and Geokum-do. The phylogeny also implied that the ancestral group of L. mediadiposalis have first evolved to Nakdong-river group, and later two local populations (Geum-river and Seomjinriver group) were diverged from the other lineage. DNA polymorphisms we observed were 4.4~4.7% between Geum-river group and Seomjin-river group, 5.1~5.5% between Seomjinriver group and Nakdong-river group, and 5.5~5.7% between Nakdong-river group and Geumriver group. These results indicated the long period of geographic isolation due to the river system in Korea caused such high degrees of DNA polymorphisms between local populations of L. mediadiposalis.

• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.179-195
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• 2013

The study area, which is located in the southeastern part of the Jirisan province, Yeongnam massif, Korea, is mainly composed of the Precambrian Hadong southern anorthosite complex (HSAC), the Jirisan metamorphic rock complex (JMRC) and Cretaceous sedimentary rock which unconformably covers them. Lithofacies distribution of the Precambrian constituent rocks mainly shows NS and partly NE trends. This paper researched deformational phased structural characteristics of HSAC and JMRC based on the geometric and kinematic features and the forming sequence of multi-deformed rock structures, and suggests that the geological structures of this area was formed through at least three phases of ductile deformation. The first phase ($D_1$) of deformation happened due to the large-scale top-to-the SE shearing, and formed the sheath or "A"-type fold and the regional tectonic frame of NE trend in the HSAC and JMRC. The second phase ($D_2$) of deformation, like the $D_1$ deformation, regionally occurred under the EW-directed tectonic compression, and most of the NE-trending $D_1$ tectonic frame was reoriented into NS trend by the active and passive folding, and the persistent and extensive ductile shear zone (Hadong shear zone) with no less than 2.3~1.4 km width was formed along the eastern boundary of HSAC and JMRC through the mylonitization process. The third phase ($D_3$) of deformation occurred under the NS-directed tectonic compression, and partially reoriented the pre-$D_3$ structural elements into ENE or WNW direction. It means that the distribution of Precambrian lithofacies showing NE trend locally and NS trend widely in this area is closely associated with the $D_1$ and $D_2$ deformations, respectively, and the NS-trending Hadong shear zone in the eastern part of Hadong northern anorthosite complex, which is located in the north of Deokcheon River, also extends into the HSAC with continuity.