• Journal of fish pathology
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• v.11 no.1
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• pp.83-86
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• 1998

The benedeniine monogenean Benedenia derzhabini (Layman, 1930) Meserve, 1938 from cultured Korean rockfish, Sebastes schlegeli, is described and reported for the first time in Korea. The parasite was recovered from the gills and inner wall of operculum. B. derzhavini is distinguished from B. seriolae and B. sebastodis by the relative shape and length between the accessory sclerites and the hamuli.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.309-311
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• 2002

A total of ten specimens of darkblotched rockfish, Sebastes crameri obtain-ed from Newport fish market were examined for parasites during February, 2002. Eight out of ten S. crameri were found to be infected with metazoan parasites. They were flatworm Trochopus australis, nematoda Anisakis simplex, and copepods Neobrachiella robusta and Chondracanthus triventricosus. Nine (30.0%) T. australis, seven (30.0%) N. robusta, one (10.0％) C. triventricosus and seven (60.0%) A. simplex were infected. Among them, A. simplex was the most abundant and prevalent metazoan parasites in S. crameri. T. australis and N. robsta were found in gills with moderate intensity (1.7 and 1.9, respectively), and C. triventricosus in dorsal fin with low intensity (0.3).

• Mycobiology
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• v.44 no.1
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• pp.7-13
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• 2016

The genets of Suillus granulatus in a Pinus strobus stand ($13m{\times}60m$) were identified using random amplified polymorphic DNA molecular markers and the DNA of mushrooms that fruited for two years, and variations in genet size and distribution were analyzed. From a total of 116 mushrooms, 73 genets were identified and were grouped into three locations. The genets of mushrooms in close proximity differed from each other. The genet sizes varied at any of the three locations. The lengths of the identified genets in the pine stand ranged from 0.09 to 2.90 m. The average number of mushrooms per genet was 1.2 to 2.3, and the percentage of genets that were represented by a single mushroom was 44% to 94%. This variation in the genets of mushrooms in close proximity suggests that the ectomycorrhizal mycelial bodies of S. granulatus propagated sexually by fusing haploid spores derived from the mushrooms gills with below-ground mycelia. Therefore, it is necessary further to investigate the formation of new genets through spores in ectomycorrhizal fungal colonies.

• Journal of Species Research
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• v.9 no.4
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• pp.443-447
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• 2020

A newly recorded species Caprella arimotoi Takeuchi, 1993, belonging to the family Caprellidae Leach, 1814, was collected from the South Sea, Korea. This species is morphologically very similar to Caprella verrucosa Boeck, 1871, with blunt dorsal projections on pereonites, oval-shaped propodus on gnathopod 2, and grasping spines on the pereopods 5-7. Caprella arimotoi originated from C. verrucosa and are difficult to distinguish because they have mixed characteristics. However, C. arimotoi was classified because of several morphological differences. The newly recorded species C. arimotoi is discernible from C. verrucosa by a forwardly curved anterodorsal projection on head, elongated gills, slender pereopod 7, and lacking ventrolateral projections on pereonites 2-7. To date, C. arimotoi has only been reported in Japanese waters. So, our record is the first record in Korean waters and outside of Japan. In this study, the Korean C. arimotoi is illustrated based on the mature male specimens with a brief description of the female, focusing on the sexually dimorphic characters.

• Environmental Analysis Health and Toxicology
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• v.13 no.1_2
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• pp.11-17
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• 1998

Cadmium, a major aquatic pollutant in many parts of the world, is toxic and readily accumulated in aquatic organisms. It mainly exists in water as complexes with organic ligands such as dissolved organic carbon and this complexation is known to have effects on the aquatic toxicities. In this study, acute toxicity, histology, and bioaccumulation were studied to evaluate effects of humic acid on cadmium toxicity and bioavailability to fish using Oryzias lalipes and Cyprinus carpio. 96h-LC$_{50}$ of cadmium was 6.38mg/L using Oryzias latipes. However, the mortality showed the dose-dependent decrease when humic acid was added to the test solution. When fish were exposed to 5 mg/L of cadmium, histological changes in the exposed organs (caudal fins, gills, kidney, liver, and gut) of C~lprinus carpio were decreased by humic acid, especially in kidney and liver. Bioaccumulation of cadmium also decreased by treatment of humic acid. It seems that the formation of complexes between cadmium and humic acid may decrease bioavailability of cadmium to fish, and thus reduce the toxic effects of cadmium.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.126-126
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• 2002

• Animal Systematics, Evolution and Diversity
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• v.35 no.1
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• pp.6-9
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• 2019

The genus Dendrodoris Ehrenberg, 1831 includes about 46 valid species worldwide, and is found in relatively shallow waters in the Indo-Pacific, Atlantic, and Australian regions. To date, five Dendrodoris species have been reported from Korea. In this study, we report D. guttata (Odhner, 1917) collected from Jeju Island. Morphology is distinguished from other Dendrodoris species by the shape of the black spots on the dorsal mantle and coloration of the gills. We determined mitochondrial cytochrome c oxidase I (cox1) partial sequences and combined them with publically available sequences of closely related congeneric species to examine its phylogenetic position among Dendrodoris species.

• Fisheries and Aquatic Sciences
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• v.26 no.7
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• pp.455-459
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• 2023

40 species of the family Caprellidae Leach, 1814 are recorded in Korean waters. Caprella aino Utinomi, 1943 was newly collected from seaweed farms from the southeastern waters of Korea. C. aino was firstly reported in Japanese waters in 1943. Adults of C. aino and Caprella mutica Schurin, 1935 are easily distinguished in that C. aino have pereonite II and gnathopod II without setae and two small tubercles of articulation of gills in pereonite III-IV, while C. mutica do pereonite II and gnathopod II covered with setae and those of pereonites III-VII with many tubercles. However, subadult C. mutica is hardly distinguishable from C. aino in that tubercles of pereonite III are less developed and they have inconspicuous setae of pereonite II and gnathopod II. Nevertheless, C. aino is distinguished from subadult C. mutica because adult C. aino have dorsal tubercles on pereonite IV, V, VI, VII unlike that of C. mutica. We report C. aino as a new record in Korean water with comparison of C. mutica.

• Computational Structural Engineering
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• v.7 no.3
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• pp.95-103
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• 1994

The safety related components in the nuclear power plant should be designed to withstand the seismic load. Among these components the integrity of reactor internals under earthquake load is important in stand points of safety and economics, because these are classified to Seismic Class I components. So far the modelling methods of reactor internals have been investigated by many authors. In this paper, the dynamic behaviour of reactor internals of Yong Gwang 1&2 nuclear power plants under SSE(Safe Shutdown Earthquake) load is analyzed by using of the simpled Global Beam Model. For this, as a first step, the characteristic analysis of reactor internal components are performed by using of the finite element code ANSYS. And the Global Beam Model for reactor internals which includes beam elements, nonlinear impact springs which have gaps in upper and lower positions, and hydrodynamical couplings which simulate the fluid-filled cylinders of reactor vessel and core barrel structures is established. And for the exciting external force the response spectrum which is applied to reactor support is converted to the time history input. With this excitation and the model the dynamic behaviour of reactor internals is obtained. As the results, the structural integrity of reactor internal components under seismic excitation is verified and the input for the detailed duel assembly series model could be obtained. And the simplicity and effectiveness of Global Beam Model and the economics of the explicit Runge-Kutta-Gills algorithm in impact problem of high frequency interface components are confirmed.

• Journal of fish pathology
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• v.33 no.1
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• pp.7-14
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• 2020

A disease that manifested severe anemia of the gills occurred in the olive flounder (Paralichthys olivaceus), which was cultured for 5-6 months with a recirculation water system in the laboratory. Microscopic observations showed immature parasite in the gills and mature adults in the oral cavity. The matured parasite was 5.60-9.32 (7.42) mm in total length, with 4 pairs of clamps on the pedunculated haptor, which was separated from the body proper by a long isthmus. From the morphological observations of the larvae, it was identified as Neoheterobothirum hirame belonging to the monogenea. The average hematocrite of infected fish was 10.3 ± 2.8%, significantly lower than that of normal flounder 31.4 ± 4.2%. Histopathologically, fish infected with N. hirame exhibited reduced numbers of erythrocytes in blood vessels of the gill filament and lamellae, reduced red pulp area of the spleen, and hepatocyte atrophy. From the above results, the cause of severe anemia in olive flounder was identified as N. hirame infection. This study shows an example where the growth of pathogens can be a problem in the recirculation system due to low water exchange rate.