• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.3
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• pp.181-188
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• 2012

Despite the ecological importance of seagrass beds, their distributional information in Korean coastal waters is insufficient. Therefore, we used hydroacoustic system to collect accurate bathymetry and classification of seagrass, and Kompsat-2 (4 m spatial resolution) image for detection of seagrass beds at Deukryang Bay, Korea. The accuracy of Kompsat-2 image classification was evaluated using hydracoustic survey result using error matrix and Kappa value. The total area of seagrass beds from satellite image classification was underestimated compared to the hydroacoustic survey, estimated 3.9 and $4.5km^2$ from satellite image and hydroacoustic data, respectively. Nonetheless, the accuracy of Kompsat-2 image classification over hydroacoustic-based method showing 90% (Kappa=0.85) for the three class maps (seagrass, unvegetated seawater and aquaculture). The agreement between the satellite image classification and the hydroacoustic result was 77.1% (the seagrass presence/absence map). From our result of satellite image classification, Kompsat-2 image is suitable for mapping seagrass beds with high accuracy and non-destructive method. For more accurate information, more researches with a variety of high-resolution satellite image will be preceded.

• Korean Journal of Environmental Biology
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• v.39 no.1
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• pp.55-67
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• 2021

A 210-day experiment was conducted to examine the effects of starvation on survival, external morphometric traits, and sectioned morphometric traits in Far Eastern catfish(Silurus asotus). The survival rate decreased to 92.2±0.47% in the fed group and to 74.4±2.59% in the starved group. Eight dimensions of Ls, DALPO/Ls, DADOP/Ls, ED/Ls, CH/Ls, BDAA/Ls, BDMA/Ls, and BWAA/Ls showed significant differences (p<0.05), and 16 other dimensions of DALAD/Ls, DPDPL/Ls, HPLAA/Ls, HALAV/Ls, HALOP/Ls, DAUPO/Ls, DADAV/Ls, DADAA/Ls, Max BL/Ls, Man BL/Ls, LD/Ls, HWOP/Ls, DAUF/HL, DAUS/HL, IW/HL, and DAUE/HL were not significantly different among the initial, fed, and starved groups (p>0.05). The fed group showed higher total height (THX), wider width (WX), and larger area (AX) than those of the starved group in each body section. This research provides information on the morphometric traits and body sections of starved Far Eastern catfish. These results can be used as a basic guide to indicate nutritional status and assist in aquaculture methods for Far Eastern catfish. Moreover, the methods used in this study were considered helpful because the survey analysis method can be used to investigate information on the nutritional status of other fish species.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.128-130
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• 2021

This study aims to implement a Regression Analysis system for predicting the appropriate production of flatfish. Due to Korea's signing of FTAs with countries around the world and accelerating market opening, Korean flatfish farming businesses are experiencing many difficulties due to the specificity and uncertainty of the environment. In addition, there is a need for a solution to problems such as sluggish consumption and price drop due to the recent surge in imported seafood such as salmon and yellowtail and changes in people's dietary habits. in this study, Using the python module, xlwings, it was used to obtain for the production amount of flatfish and to predict the amount of flatfish to be produced later. was used to predict the amount of flatfish to be produced in the future. Therefore, based on the analysis results of this prediction of flatfish production, the flatfish aquaculture industry will be able to come up with a plan to achieve an appropriate production volume and control supply and demand, which will reduce unnecessary economic loss and promote new value creation based on data. In addition, through the data approach attempted in this study, various analysis techniques such as artificial neural networks and multiple regression analysis can be used in future research in various fields, which will become the foundation of basic data that can effectively analyze and utilize big data in various industries.

• Journal of Korea Water Resources Association
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• v.46 no.4
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• pp.401-412
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• 2013

Water footprint of a product and service is the volume of freshwater used to produce the product, measured in the life cycle or over the full supply chain. Since water footprint assessment helps us to understand how human activities and products relate to water scarcity and pollution, it can contribute to seek a sustainable way of water use in the consumption perspective. For the introduction of WFP scheme, it is indispensable to construct water inventory/accounting for the assessment, but there is no database in Korea to cover all industry sectors. Therefore, the aim of the study is to develop water footprint inventory within a nation at 403 industrial sectors using Input-Output Analysis. Water uses in the agricultural sector account for 79% of total water, and industrial sector have higher indirect water at most sectors, which is accounting for 82%. Most of the crop water is consumptive and direct water except rice. The greatest water use in the agricultural sectors is in rice paddy followed by aquaculture and fruit production, but the greatest water use intensity was not in the rice. The greatest water use intensity was 103,263 $m^3$/million KRW for other inedible crop production, which was attributed to the low economic value of the product with great water consumption in the cultivation. The next was timber tract followed by iron ores, raw timber, aquaculture, water supply and miscellaneous cereals like corn and other edible crops in terms of total water use intensity. In holistic view, water management considering indirect water in the industrial sector, i.e. supply chain management in the whole life cycle, is important to increase water use efficiency, since more than 56% of total water was indirect water by humanity. It is expected that the water use intensity data can be used for a water inventory to estimate water footprint of a product for the introduction of water footprint scheme in Korea.

• Journal of Life Science
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• v.22 no.7
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• pp.863-870
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• 2012

Rhodopsin, a dim light photoreceptor, has been regarded as one of the model systems for the structural and functional study of G protein-coupled receptors (GPCRs). Constitutively active mutant GPCRs leading to the activation of heterotrimeric GDP/GTP-binding protein signaling in the absence of ligand binding are of interest for the study of the activation mechanism in GPCRs. The present study focused on the opsin mutant E134Q/M257Y, which showed a moderate level of constitutive activity and the formation of two distinct rhodopsin chromophores with absorption maxima of 500 nm and 380 nm, depending on the presence of an inverse agonist, 11-cis-retinal, and an agonist, all-trans-retinal, respectively. Reconstitution of the mutant rhodopsin upon incubation with different ratios of 11-cis-retinal and the all-trans-retinal, as well as upon sequential binding of the two retinals, indicated its preferential binding to 11-cis-retinal. The thermal stability of the 11-cis-retinal-bound form of the E134Q/M257Y mutant was lower than that of the mutants containing a single replacement but higher than that of the all-trans-retinal-bound forms. The mutant also showed a lower stability in its opsin state as compared with that of the wild-type opsin but had little effects on the binding affinity to 11-cis-retinal. Information obtained in this study will be helpful for analyzing the structural changes associated with the activation of rhodopsin and GPCRs.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.243-251
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• 2012

Real-time monitoring for environmental factors(temperature, salinity, chlorophyll, etc.) and carbonate components( pH and $fCO_2$) was conducted during 5-6th of July, 2012 at a seaweeds farm in Gijang, Busan. Surface temperature and salinity were ranged from $12.5{\sim}17.6^{\circ}C$ and 33.7~34.0, respectively, with highly daily and inter-daily variations due to tide, light frequency(day and night) and currents. Surface $fCO_2$ and pH showed a range of $381{\sim}402{\mu}atm$ and 8.03~8.15, and chlorophyll-a concentration in surface seawater ranged 0.8~5.8 ${\mu}g\;L^{-1}$. Environmental and carbonate factors showed the highest/lowest values around 5 pm of 5th July when the lowest tidal height and strongest thermocline in the water column, suggesting that biological production resulted in decrease of $CO_2$ and increase of pH in the seaweed farm. Processes affecting the surface $fCO_2$ distribution were evaluated using a simple budget model. In day time, biological productions by phytoplankton and macro algae are the main factors for $CO_2$ drawdown and counteracted the amount of $CO_2$ increase by temperature and air-sea exchange. The model values were a little higher than observed values in night time due to the over-estimation of physical mixing. The model suggested that algal production accounted about 14-40% of total $CO_2$ variation in seaweed farm.

• Journal of fish pathology
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• v.20 no.3
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• pp.211-220
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• 2007

Red sea bream iridovirus disease (RSIVD) cause massive economic losses in marine aquaculture industry in Korea. The causative agent of this disease (RSIV) infects a wide range of fish species. The aims of this study were to monitor RSIV in wild marine fishes and to give critical information for controling the disease through prophylactic methods. Prevalence of the viral disease, geological distribution and reservoir of the virus were investigated using wild marine fishes captured in southern coast and east china sea for two years. (Polymerase Chain Reaction) PCR results showed that RSIV were detected in 39 (24.3%) out of 160 fish. MCP gene sequences of viral strains isolated in this study were closely related to that of a reference strain, red seabream-K, belonging to Megalocytivirus subgroup Ⅲ. The results suggest that some of wild marine fishes are RSIV carriers and may spread the pathogen directly to fish farmed in coastal area.

• Journal of Aquaculture
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• v.19 no.4
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• pp.225-230
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• 2006

A long-term (26 weeks) feeding experiment was conducted to examine the essentiality and requirement of inositol in diets for olive flounder because no information is available in the species. Five casein-gelatin based semi-purified diets were formulated to contain four different levels of myo-inositol (0, 0+antibiotic, 400, 800, and 1600 mg/kg, designated as M0, M0+, M400, M800, and M1600, respectively). One (M0+) of the control diets contained tetracycline hydrochloride (0.4%, wt/wt) as an antibiotic to inhibit biosynthesis of inositol by micro-organism in intestine of fish. Olive flounder at the early juvenile stage (initial body weight 1.22 g) were randomly distributed into fifteen 35 L tanks (48 fish/tank) and fed with one of the experimental diets (3 replicates per diet). At the end of the feeding trial, the weight gain, feed intake, specific growth rate, and protein efficiency ratio of fish fed diets containing higher levels of myo-inositol (M800 & M1600) were significantly higher than those of fish fed the other diets (P<0.05). Feed conversion ratio, survival, hematocrits, and hemoglobin of fish fed experimental diets were not significantly different among all the fish groups. Whole body compositions of fish were not different except for lipid content. The lipid content was significantly different between M0 and M400 diet groups. These results indicate that juvenile olive flounder requires dietary supplementation of myo-inositol in diets for normal growth and its optimum level seems to be approximately 800 mg myo-inositol/kg diet.

• Journal of fish pathology
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• v.5 no.1
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• pp.37-48
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• 1992

Antibiotics are chemical substances produced by various species of microorganisms that suppress the growth of other microorganisms or may destroy them. Among the more than 4000 antibiotics that has been identified, about 20s are using as the therapy of infectious fish diseases. There are several methods used to classify and group antibiotics, and the most common classification has been based on chemical structure and proposed mechanism of action. The effect of antibiotics may be determined by the kind of fish pathogens and by the external environment surrounded the infected fish. It implies that the kind of antibiotics and its application method should be decided after the determination of the reasons of fish disease. The uncontrolled usages of antibiotics may induce the selection of resistant mutants appeared spontaneously and present in any group of bacteria. The epidemic spread of such antibiotic resistant strains of fish pathogenic bacteria already has been reported in various districts of japan. Importantly, transferable drug resistant(R) plasmids were detected in strains of most of fish pathogens. Based on those reports, the antimicrobial resistance appears to be a rapidly emerging problem in the fish industry on the country. The expanding literatures on the pharmacokinetics, clinical trials, withdrawal periods and efficacy of environmental effect for the commonly using antibiotics have met the needs of data for the practical application of antibiotics. However, the most important thing for the treatment of fish diseases would be the communication and exchanging of information between the site of aquaculture and the diagnostic laboratory.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.148-152
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• 2000

To provide basic information on the integumentary system of the blenny, Pholis nebulosa, ultrastructures of epidermal and dermal layer were examined by means of the light and transmission electron microscope. The skin of the blenny consisted of epidermal and dermal layer. Epidermal layer consisted of supporting cell and unicellular gland. The supporting cells were classified into superficial cell, intermediated cell and basal cell, and the gland cells were classified into mucous secretory cell and club cell. The cytoplasm of supporting cells was divided into cortex and medullar part. In the cortex and medullar part, microfilaments and cell organelles were well developed, respectively. Superficial cell of epidermal layer was cuboidal and contained nucleus of horseshoe shape. Intermediated cell had a nucleus of irregular form and the electron density was higher than the other supporting cells, Basal cell was columnar, but nucleus was situated in the upper cytoplasm. Cell organelles of the basal cell were poor than the other supporting cells, but membrane interdigitations were well developed. The cytoplasm of mucous secretory cell had a well-developed ovoid secretory granules, which reacted to red with AB-PAS reaction. The club cell had a we31-developed round secretory granules and endoplasmic reticulum. figment cells were classified into two type. The one contained pigment granules of electron dense, and the other contained reflecting platelets. The cytoplasm of fibrocyte had n well developed rough endoplasmic reticulum.