• Korean Journal of Ichthyology
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• v.28 no.1
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• pp.52-56
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• 2016

A single specimen (700 mm in disc length) of Plesiobatis daviesi, belonging to the family Plesiobatididae, was firstly collected in the north-eastern coastal waters of Jejudo Island, Korea by using a bottom trawl on 24 October 2010. This species was characterized by having five pairs of gill openings, tail with one to three large spines, long snout length, long caudal fin, and pleated margin of nasal curtain. It is morphologically similar to Urolophus aurantiacus, but the former is distinguished from the latter by having longer caudal fin and snout length. We add P. daviesi to the Korean fish fauna and suggest the new Korean names, "Gin-kko-ri-huin-ga-o-ri-gwa", "Gin-kko-ri-huin-ga-o-ri-sok" and "Gin-kko-ri-huin-ga-o-ri" for the family, genus and species, respectively.

• Fisheries and Aquatic Sciences
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• v.23 no.8
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• pp.23.1-23.10
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• 2020

This study was conducted to evaluate the acute effects of waterborne cadmium exposure on bioaccumulation and antioxidant enzymes in eels (Anguilla japonica) and to determine the median lethal concentration (LC₅₀). Fish were exposed to different cadmium concentrations (0, 0.15, 0.30, 0.61, 1.83, 3.08, 3.67, 4.29, and 5.51 mg L^-1) for 96 h. The LC₅₀ of A. japonica to cadmium was 3.61 mg L^-1. Cadmium accumulation generally increased in tissues with increasing waterborne cadmium concentrations. At ≥ 1.83 mg L^-1 exposure, all tissues accumulated significant cadmium concentrations compared with the control group, in the order of kidney > liver > gill > spleen > muscle. Measurements of variation in actual cadmium concentrations showed that a reduction of the metal in experimental water was related to cadmium accumulation in tissues. As activity alteration of antioxidant enzymes for reactive oxygen species, superoxide dismutase and catalase activities increased at ≥ 0.61 mg L^-1 significantly, glutathione peroxidase and glutathione S-transferase activities were not significantly changed. The results of this study suggest that acute exposure to waterborne cadmium is potentially fatal to A. japonica due to the metal's major accumulation in various tissues and the effect of antioxidant enzyme activity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.83-88
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• 1994

For the purpose of genetic stock indentification of three species of salmonid fishs and their hybrid, lactate dehydrogenase(LDH), malate dehydrogenase(MDH), isocitrate dehydrogenase(IDH), a-gylycerophosphate dehydrogenase(a-GPDH), malic enzyme(ME), 6-phospho-gluconate dehydrogenase(6-PGD), phosphoglucose isomerase(PGI) and phospho-glucomutase(PGM) from skeletal muscle, liver, heart and gill tissues in all three species were analyzed. Chum and masu salmon showed no polymorphic patterns in all isozyme loci, however rainbow trout were found to have polymorphic patterns at MDH-B, LDH and IDH loci. Especially, significant differences were found at MDH-B loci between the three species and the IDH patterns of rainbow trout were also different from the other two species. These loci therefore can be utilized as efficient genetic markers for the identification of hybrids and improve the efficiency of fish breeding. There was no difference except PGI between diploid and triploid isozyme patterns but PGI showed some potential as a marker for triploid in masu salmon.

• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.111-117
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• 2000

There were observed the histomorphological alterations such as chloride cell hyperplasia, branchial lamellar epithelial separation, the increased cellular turnover of chloride cells, glomerular shrinkage and blood congestion in rainbow trout (Oncorhynchus mykiss) during the seawater adaptation. The ultrastructure by scanning electron microscope (SEM) indicated that the gill secondary lamella of rainbow trout exposed to seawater, were characterized by rough convoluted surfaces during the adaptation. There were observed a large number of mitochondria with the elongate and well-developed cristae in chloride cells exposed to seawater by transmission electron microscope (TEM). The presence of two mitochondria- rich cell types is discussed with regard to their possible role in the hypoosmoregulatory changes which occur during seawater-adaptation. Glomerulus shrinkage and blood congestion were occurred higher in nephrons of seawater-adapted fish than those living in freshwater. Our findings demonstrated that rainbow trout tolerated moderately saline environment and the increased body weight living in seawater was relatively higher than that living in freshwater in spite of histopathological changes.

• Korean Journal of Ichthyology
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• v.28 no.4
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• pp.283-286
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• 2016

A single specimen (276.9 mm standard length) of the scorpaenid Sebastes glaucus was collected by a gill net from Dokdo, East Sea, Korea. The specimen is characterized by yellowish brown body color, deep body, convex frontal region and nape, board occipital region, 14 spines at dorsal fin, and no scales at maxilla. This is the first record of S. glaucus in Korea; we therefore add the species to the Korean fish fauna. According to the NFRDI (1999), we propose the Korean name, "Cheong-hoebol-rak" for this species.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.6
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• pp.757-762
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• 2010

Korean fishing boats have had appropriate hull forms for the safety, stability and convenience of fishing ability. However, Korean fishermen are recently concerned about the resistance performance and speed of Korean fishing boats, because the prices of fuel oil are gradually risen, also the exhausting of fish resources and the demand of high speed fishing boats are increased. Therefore, the necessity of the study on the improvement of resistance performance for Korean small coastal fishing boats is gradually increased. This study compares the hull form characteristics of Korean fishing boats with those of Japanese fishing boats, and the hull form of a representative Korean fishing boat is modified. From the modification of the hull form parameters for the Korean fishing boat, the improvement of resistance performances is evaluated. Moreover, the increase of resistance performances is also achieved from the modification of local characteristics for the hull form of the Korean fishing boat. A computational method and ship model tests in towing tank are used for the conformations of the improvement of resistance performance.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.2
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• pp.103-114
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• 2010

For an effective management of fisheries resources, we need fisheries informations necessary for the establishment of reasonable fishing effort and TAC distribution. To study the present state of by-catch and discard of gill-net fishery in the East Sea, we carried out fishing research using trammel nets in the coastal sea of Susan-port (Yangyang), Jangho-port (Samcheok) and Hupo-port (Uljin). As a result, a total of catch of Susan was 259,172g and that of Hopo was 577,638g. Thus Catch of Susan was 1.49 times more than that of Hupo considering the number of used fishing gear. And catch of Janho was 7.4 times more than that of Susan considering the number of experiment. Two methods of by-catch analysis in this study were used, one method is standardizing of listed species catching possible in fishing license, another method is regarding catch species under 1% of total catch as by-catch. As a result of by-catch analysis of two method, by-catch rate of Susan was 6.55% and 5.87% respectively, that of Hupo was 44.70% and 5.24% and that of Jangho was 0.96% and 2.31%. Discard rate of fish in Susan, Hupo and Jangho were 1.59%, 3.42%, 2.23% respectively.

• Korean Journal of Ichthyology
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• v.31 no.3
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• pp.178-182
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• 2019

This is the first report of Brachirus annularis (Pleuronectiformes: Soleidae) from Korea. A specimen of B. annularis (229.0 mm standard length) was firstly collected by drift gill net at a fishing ground locating between Jejudo and Geomundo Islands, the southern coast of Korea on 31 March, 2019. This species was characterized by having five large, deep colored patches on the ocular side of body, each patch outlined by dark brown ring, united dorsal and anal fins jointed with caudal fin, and short pectoral fin. We add this species to the Korean fish fauna and propose its new Korean names, "Eol-luk-seo-dae-sok" and "Eol-luk-seo-dae" for the genus and species, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.57 no.4
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• pp.389-396
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• 2024

Reactive oxygen species (ROS) generated by harmful algal blooms (HABs) exert detrimental effects on aquaculture systems. Fish gill cells deteriorate upon exposure to HABs, suggesting that internally generated ROS in HABs influences the external environment. Therefore, we investigated the internal and external changes in ROS concentrations during growth using fluorescence staining of four representative HABs: Alexandrium affine, Chattonella marina, Karenia mikimotoi, and Margalefidinium polykrikoides. The concentrations of H₂O₂ and O₂^- produced by A. affine were low; H₂O₂ from M. polykrikoides was primarily detected internally throughout the experiments, and O₂^- was not detected. High H₂O₂ and O₂^- concentrations were observed in K. mikimotoi during the death phase, with weak external O₂^- concentrations. Regarding C. marina, which produces large amounts of ROS, H₂O₂ was observed internally during the exponential phase, whereas weak O₂^- concentrations were measured externally in the stationary phases. Collectively, our results highlight that ROS concentrations and internal/external distributions are functions of HABs and growth stage. These differences indicate the potential allelopathic mechanisms of proliferating HABs and suggest a possible impact of ROS on aquaculture organisms.

• Journal of fish pathology
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• v.3 no.1
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• pp.21-25
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• 1990

In inland aquaculture, a lot of fishes often died cause of touch of L. carteri which is attached on the net cage. In this works, the experiment were carried out on classification of species, toxin test, and extermination with some chemicals. A bryozoa from net cage in lake Okjeong is classified into the Phylactolaemata, Lophopodella carteri Hyatt. A bryozoa broke out firstly on the 30th of June with water temperature up to $31^{\circ}C$ and it reattached on the net with water temperature below $30^{\circ}C$. Size of bryozoa colony is about $0.8{\times}0.6{\sim}1.7{\times}1.5cm$. Water column of attachment was 0~5m and the peak is 2~3m. In toxin test on the israeli carp, goldfish and catfish touched with bryozoa for 1 minute at $25^{\circ}C$ of water temperature, a dead fish appeared at 20 minutes after touched. Mortality was 90% for israeli carp and 100% for goldfish at 100 minuties after touched, but catfish was not died at all. It was supposed that the toxin is from nematocyst being around tentacles and this toxin act a deadly poison on a israeli carp and goldfish. In extermination test, the bryozoa treated with 300ppm of formalin, 5% of sodium chloride, 5ppm of malachite green, 200ppm of potassium permanganate, 1000ppm of potassium iodide, 10ppm of DDVP for minute respectively, all of them were not effected.