• Journal of Food Hygiene and Safety
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• v.27 no.3
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• pp.285-289
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• 2012

In this study, the veridical efficacy of an aquatic disinfectant tablet composed to calcium hypochlorite against red sea bream iridovirus (RBIV). A veridical efficacy was determined with the viability of RBIV contacted with the disinfectant in viral stock cultured in fat head minnow cell line. An aquatic disinfectant tablet and RBIV were reacted on the distilled water (DW), hard water (HW) or organic matter suspension (OM) condition. On DW and HW condition, RBIV was inactivated with 25,000 fold dilutions of an aquatic disinfectant tablet. With the investigation of the antiviral effect of the disinfectant on OM condition, RBIV was inactivated on 22,000 fold dilutions of an aquatic disinfectant tablet. As an aquatic disinfectant tablet possesses veridical efficacy against RBIV, the disinfectant solution can be used to limit the spread of cultured marine fish viral disease.

• Journal of fish pathology
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• v.34 no.2
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• pp.149-159
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• 2021

Genus Megalocytivirus cause red sea bream iridoviral disease (RSIVD) and scale drop disease (SDD). Based on the phylogeny of the major capsid protein (MCP) and adenosine triphosphatase (ATPase) genes, megalocytiviruses except for SDD virus (SDDV) could be three different genotypes, red sea bream iridovirus (RSIV), infectious spleen and kidney necrosis (ISKNV), and turbot reddish body iridovirus (TRBIV). In this study, primary cells derived from the caudal fin of rock bream (Oplegnathus fasciatus) grew at 25℃ in Leibovitz's medium supplemented with 10% (v/v) fetal bovine serum and primocin (100 ㎍/mL). Rock bream fin (RBF) cells exhibited susceptibility to infections by different genotypes of megalocytiviruses (RSIV, ISKNV and TRBIV) with the appearance of cytopathic effects with an increase in the viral genome copy number. Furthermore, compared to grunt fin (GF) cells, even though 10 times lower number of RSIV genome copies were inoculated in RBF cells, viral genome copy number produced on RBF cells were 44 times higher than that of GF cells at 7 d post-inoculation. As the isolated RBF cells are sensitive to different genotypes of megalocytiviruses (RSIV, ISKNV and TRBIV), they can be used for future studies regarding in vitro viral infection and subsequent diagnosis.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.139-144
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• 2022

This study aims to investigate egg quality changes and free amino acid composition. Factors that can affect egg quality about farming conditions were investigated through biochemical analysis of egg by red spotted grouper, Epinephelus akaara. As a result, the buoyant, fertilization embryonic survival and hatching rate were better when reared in sea cage than in tank. And the content of free amino acid in fertilized eggs reared in sea cage was higher then in tank. In conclusion, fertilized eggs with good egg quality can be produced when farming sea cage, and contained more free amino acid.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.9
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• pp.624-628
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• 2014

Reverse electrodialysis (RED) is a technique to produce electricity from two feed water that has different salinity. Recently, RED has been considered the attractive technology because this new process has large global potential and possibility to generate energy from abundant but largely unused resources. To make RED an economically attractive technology, the optimization of operation condition should be developed. In this study, we investigate the relation of internal resistance to power density of RED. And the effect of sea water and fresh water flow rate on power density was confirmed. To minimize the internal resistance and to increase power density of RED, the ratio of sea water and fresh water flow rate was optimized. Experimental result show the best performance with $1.30W/m^2$ of power density at 1.7 flow ratio of seawater/freshwater.

• Development and Reproduction
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• v.22 no.4
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• pp.369-378
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• 2018

We determined the morphologic characteristics (body weight and degree of abdomen inflation) of the red spotted grouper, Epinephelus akaara, mother fish producing healthy eggs. Experimental fish were chosen from fish reared in a sea cage. The fish were divided into four size groups by body weight: 400~600, 600~800, 800~1,000, and 1,000~1,200 g and four stages (I~IV) of the degree of abdomen inflation. After hormone treatment, we observed the amount of ovulation-induced eggs, and rates of buoyancy, fertilization, embryonic survival, and hatching. As a result, mother fish with a body weight of 600 g or more spawned, and the fertilization rate, embryonic survival rate, and hatching rate were high in the 800~1,000 g range, thus showing effective ovulation induction. As a result of dividing the degree of abdomen inflation based on the anal fin of the mother fish into I-IV stages and determining hormone treatment time, the GSI was $0.9{\pm}0.2%$ at stage I, $2.3{\pm}0.2%$ at stage II, $5.6{\pm0.2%$ at stage III, and $7.9{\pm}0.9%$ at stage IV. The flotation rate and hatching rate were highest at stage III, and the fertilization rate and embryonic survival rate were highest at stage IV. Therefore, in terms of egg quality, the amount of eggs collected per mother fish, maturation, and histology were different depending on the degree of abdomen inflation. At stage III, where the abdomen inflation degree of the mother fish was based on the basal part of the dorsal fin relative to the height of the anal fin was 1, the egg quality was highest.

• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.75-78
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• 2002

The effects of Coehlodinium polykrikoides on the gill of red sea bream, Pagrus major, were examined to clarify the ichthyotoxic mechanisms of this plankton species. The gill of fish exposed to dense blooms over 3,000 cells/mL for 24 h showed severe epithelial separation: a severe edema was found in the secondary lamellar epithelium and interlamellar regions of primary filament. In addition, lipid peroxidation of gill tissue in Coehlodinium-exposed fish was about 2.5 times higher than that of control. The composition of glycoproteins in the gill mucus of Coehlodinium-exposed fish was also changed. These results suggest that the loss of structural integrity of cell membranes in fish gill may be deeply involved in fish death by C. polykrikoides.

• ALGAE
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• v.28 no.1
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• pp.53-62
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• 2013

Actinotrichia is a calcified galaxauracean red algal genus with temperate and tropical distributions in the Indian and Pacific Oceans. Morphological characteristics, along with rbcL and cox1 sequences, were analyzed from specimens collected in the western Pacific and the Indian Oceans. Both rbcL and cox1 data confirmed the occurrence of A. fragilis, A. robusta, and Actinotrichia sp. in this region. The presence of A. fragilis was verified in tropical Indo-Pacific and temperate northeast Asian waters and was characterized by high genetic diversity. Although A. robusta commonly occurs in the East China Sea, we confirmed its presence on rocks and crustose algae in the subtidal zone of three islands in the Andaman Sea. Actinotrichia sp. was similar to A. calcea in morphology and distribution, but with sufficiently different sequences, thus, additional sampling over the range will enable a more realistic evaluation of its taxonomic status.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.17 no.1
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• pp.1-6
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• 1981

The selective response of the sea bass, Lateolabrax japonieus and the gray rock cod, Sebastes inermis to the colored twines was studied in a white tiled aquarium C400LX60WX70H em), by use of Y -maze made of gray plastic plate. Anyone of the different colored twines, white, black, blue, yellow and red, was strung crosswise on a rectangular frame which was mounted to one of the two outlet ends of Y -maze, and another colored twine was used to the other end of the Y -maze. In each trial, a fish was guided toward the inlet of the Y -maze to let the fish select either one of the two different colored twines. The results obtained are aS follows: 1. Sea bass preferably selected the colored twines in a order of white, blue, yellow, black and red with significant difference. 2. Gray rock cod showed little difference in selecting colored twines even though the fish selected white one a little more frequently.

• Korean Journal of Remote Sensing
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• v.32 no.2
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• pp.87-96
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• 2016

Red tide, causes aquaculture industry the damages in Korea every summer, was usually detected by using satellite, aquaculture information was difficult to detect by using satellite. Therefore, we suggests the method for detecting the red tide using the coastal observation and the product from the unmanned aerial Vehicle. As a result, we obtained the high resolution unmanned aerial Vehicle images, detected the red tide by using the unsupervised classification from the true color images and the simple algorithm from the RGB color images. Compared the previous color images, unmanned aerial Vehicle images were clearly classified the ocean color, we were able to identify the red tide distribution in sea surface. These methods were determined to accurately monitor the red tide distribution on the aquaculture fields in the coastal waters where is established the aquaculture.

• Korean Journal of Remote Sensing
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• v.24 no.4
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• pp.325-331
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• 2008

We propose an algorithm to detect large Cochlodinium polykrikoides red tide event that was appeared in Korean coastal waters. This algorithm is based on two-stage filtering using MODIS chlorophyll information. Most of the red tide detection studies generally use assumption that sea water having high chlorophyll concentration is red tide events because of high correlation and red tide. However, these methods generate many commission errors such as turbid water by detecting inactive sea water of red tide. Therefore, we eliminated commission errors by applying two stage filtering and verified the algorithm's effectiveness by detecting large Cochlodinium polykrikoides red tide event that was appeared in Korean coastal waters.