• 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.

• The Korean Journal of Malacology
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• v.28 no.1
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• pp.45-54
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• 2012

We investigated environmental characteristics of the tidal flat oyster aquafarms to clarifyeffects of the tidal flat environmental factors on growth and mortality of the tidal flat oyster Crassostrea gigas by the Net Bag Rack Culture System in two districts in Western Korea. In this study, we have carried out the basic environmental investigation on growth of the single tidal flat, water quality and sediments, etc. in Taean and Seosan districts, Choongcheongnam-do, where the single tidal flat oyster aquaculture have been performed by the net bag rack culture system. In June 2011 when the final survey carried out at the two districts in western Korea, the mortality in Seosan district was higher than that in Tae-an district. Judging from the results of growth and mortality of the single tidal flat oysters investigated at two sites of Jinsan-ri in Taean and Chang-ri in Seosan districts, two results of Taean district showed higher growth and lower mortality than those of Seosan district. It is assumed that the proper acceptable density possible for growth of the tidal flat seeds and the secure of economics, in case of plastic cultivate net with the size of $50{\times}80cm$, are about 200 individuals. In this study, It was clarified that selection of the suitable sites, the input into the net bag of high quality oyster seeds and selective dispersion in the optimal density of the single tidal flat oyster have an effect on growth and mortality of the tidal flat oyster.

• Journal of Life Science
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• v.17 no.10
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• pp.1309-1314
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• 2007

Investigation on health conditions of Thai koi (Anabas testudineus) were carried out through clinical and histopathological observations from different farms of Mymensingh district for seven months during August 2006 to February 2007. Fish sampling and water quality parameters (temperature, dissolved oxygen and pH) were monitored on a monthly basis. Clinical examination of fishes was also carried out for any kind of abnormalities at monthly intervals. Samples of skin, muscle, gill, liver and kidney were observed by histological technique. Among the water quality parameters the values of water temperature, dissolved oxygen were found to be at unfavorable level for fish during the colder months in the farms. Clinically it was observed that fishes were more affected from December to January and almost normal in appearance during August to September and February. Different clinical symptoms like scale loss, dermal lesion, ulcer and loss of caudal fin were noticed in December and January. In histopathological study, structures of fish organs were normal from August to September. In the months of October and November, minor pathologies were found to be started. Marked pathological changes like necrosis, pyknosis, inflammation, hemorrhage, hypertrophy, hyperplasia, missing of primary and secondary gill lamellae were observed in the months of December and January. Whereas, in the month of February the pathological condition of fish gradually reduced. Again when considered individual fish farm, fishes of Reliance Aqua Farm were more affected than Sotota Matshya Hatchery. The study showed that severity of clinical and pathological changes were increased in December and January. During the period EUS and protozoan diseases were noticed in A. testudineus of the investigated farms.

• Korean Journal of Ichthyology
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• v.31 no.1
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• pp.7-15
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• 2019

The present study aimed to investigate the influence of starvation on growth, survival and swimming ability of Pacific cod Gadus macrocephalus larvae. Notochord length, musculature height, body depth, gut height and volume of yolk of reared larvae were measured to determine the growth parameters. A significant difference was observed in all morphometric characteristics before 15 DAH (days after hatching). Body depth and volume of yolk of unfed larvae were significantly smaller than those of fed larvae from 9 DAH (P<0.05). Almost all yolk in fed group was consumed at 11 DAH. Survival and growth of larvae were observed to determine the effect of delayed initial feeding (2 DAH, 3 DAH, 4 DAH, unfed). All larvae in the unfed group died by 15 DAH and the larvae in other experimental groups survived until the end of the experiment to 21 DAH. Survival rate was not significantly different between the 2 DAH group ($17.5{\pm}4.27%$) and the 3 DAH group ($20.5{\pm}1.5%$) at 21 DAH (P>0.05). However, there was a significant difference in survival rate between the 3 DAH group and the 4 DAH group ($11.7{\pm}1.52%$) (P<0.05). There was no significant difference in notochord length among the groups fed from 2 DAH, 3 DAH and 4 DAH at 21 DAH (P>0.05). The swimming ability in fed group gradually increased in both cruising and burst swimming speeds, while those abilities in unfed group gradually decreased after reaching the peak at 6 DAH in both cruise ($18.7{\pm}6.56mm/s$) and burst swimming speed ($43.5{\pm}12.65mm/s$).

• Journal of Life Science
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• v.30 no.1
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• pp.26-31
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• 2020

Heterosigma akashiwo is a globally distributed raphidophyte that forms blooms and causes significant losses to the aquaculture industry in many coastal countries. The development of a fast and sensitive detection method is therefore required to facilitate the appropriate warning of harmful algal blooms. In this study, a nuclease protection integrated with sandwich hybridization (NPA-SH) assay was developed to both qualitatively and quantitatively detect H. akashiwo. The NPA, capture and signal probes were designed by nucleotide sequencing of H. akashiwo. The applicability of NPA-SH was evaluated using cultured H. akashiwo cells and field samples collected at Goseong Bay, Korea. The results show that this method has good applicability and effectiveness in analyzing cultured cells and field samples. A linear regression equation for the quantitative analysis of H. akashiwo was obtained, and the lower detection limit of the assay was 1×10⁴ cells/ml. There was no statistically significant difference in the results of H. akashiwo quantitation using NPA-SH compared to those obtained using a microscope. These results indicate that NPA-SH can be a good alternative to the traditional microscopic method used to monitor H. akashiwo.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.6
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• pp.563-570
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• 2019

Red tide has caused massive fish kills in Korean coastal waters with devastating economic loss in the aquaculture industry since 1995. Remote sensing technique has shown to be effective for the detection of red tide in wide areas, where the absorption property of red tide water plays a central role in understanding the red tide reflectance. This study analyzed the optical absorption property of sea waters dominated by the dinoflagellate specie of Alexandirum affine, off the Tongyeong area in August, 2017. Water samples collected from 20 stations in the ship-based campaign were measured for absorption by pigment, suspended solid, and dissolved organic matter, with the corresponding water quality variables such as chlorophyll concentration and total suspended solid. The analysis showed that Alexandrium-dominated water exhibits strong absorption in the spectral range below 400 nm unlike that of diatom-dominated waters, and greater fluctuations in the range of 400 nm - 500 nm. The packaging effect in pigment absorption was stronger in Alexandrium-dominated waters, and the exponent in the absorption by detritus and gelbstoff is disparate for diatom and Alexandrium. In the model for the detritus and gelbstoff absorption (a_dg(λ)=a_dg(λ₀)e^-s(λ-λ₀)), the optimal exponent coefficient(s) for the Alexandrium was close to 0.01 rather than to 0.015, which was commonly use for modelling diatom waters.

• 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 fish pathology
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• v.23 no.1
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• pp.85-98
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• 2010

Ministry of Agriculture, Fisheries and Food (MAFF) and National Fisheries Research and Development Institute (NFRDI) have inspected the hatchery-reared seeds of 22 marine species and 11 freshwater species for aquatic animal diseases in stock enhancement program in 2009. Results showed that total 12 local selfgovernments have been restocking the sea with cultured juveniles. Gyeongsangnam-do, Jeollanam-do, Jejudo and Chungcheongnam-do have a preference for marine species seeds to freshwater species. On the contrary, freshwater species were released mostly in Gyeonggi-do, Jeollabuk-do and Chungcheongbuk-do. In the marine species group, abalone was the most abundant as 24.5%, and then sea cucumber (15.2%), olive flounder (11.5%), swimming crab (5.6%), black sea bream and rockfish (6.8%), rock bream (5.1%), black rockfish (4.6%) and scorpionfish (4.5%) were followed. Crucian carp was the most abundant as 19.4%, and then eel (17.0%), Korean bullhead (12.3%), melanian snail (12.0%), catfish (8.4%) were followed in the freshwater species group. The total number of inspection cases in this study were 1,080 and disqualification cases were 19 by detection of aquatic animals pathogens such as red sea bream iridovirus (RSIV), koi herpesvirus (KHV) or white spot syndrome virus (WSSV).

• 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.

• Development and Reproduction
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• v.15 no.2
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• pp.121-131
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• 2011

The aim of this study was to investigate the egg development and the color change of Amphiprion melanopus, by the live food and thyroid hormone. After fertilizing, it took 168 h until hatching. The size of hatching larvae were $3.5{\pm}0.3$ mm, and some individuals had small yolk sac. As reaching the particular age, they underwent the color change (metamorphosis) - Days after hatching (DAH) 10: black, DAH 15~20: the 3 white stripes appear, DAH 30: the dorsal & the caudal white stripe begin to disappear. DAH 90: body color become red and orange, adult: cinnamon body color and a white stripe on head. - The group fed enriched Artemia with Tigriopus japonicus grew the faster than with only Artemia. The fin coloration of the one fed the only T. japonicus has a vivid red and orange color. $T_3$-treated group (4 ppm) grew the faster than the others (0, 2, 6 ppm). The size of the 6 ppm group was the smallest. The results suggest T. japonicus can be used as a supplement with rotifer and Artemia for the juvenile development and coloration. $T_3$ is considered to be involved in the metamorphosis and color formation of Amphipirion sp.