• Development and Reproduction
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• v.19 no.4
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• pp.181-187
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• 2015

Early life stage mortality in fish is one of the problems faced by loach aquaculture. However, our understanding of immune system in early life stage fish is still incomplete, and the information available is restricted to a few fish species. In the present work, we investigated the expression of immune-related transcripts in loach during early development. In fishes, recombination-activating gene 1 (RAG-1) and sacsin (SACS) have been considered as immunological function. In this study, the expression of the both genes was assessed throughout the early developmental stages of loach using real-time PCR method. maRAG-1 mRNA was first detected in 0 dph, observed the increased mostly until 40 dph. Significant expression of maRAG-1 was detected in 0 to 40 dph. These patterns of expression may suggest that the loach start to develop its function after hatching. On the other hand, maSACS was detected in unfertilized oocyte to molura stages and 0 to 40 dph. maSACS mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.4
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• pp.387-398
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• 2023

Conventional aquaculture faces declining productivity, shifting to recirculating aquaculture system (RAS), known for minimizing water usage and maintaining consistent water temperatures for year-round fish growth. Rainbow trout (Oncorhynchus mykiss), a globally important cold-water species and the third most farmed fish in inland waters of Korea, valued for its fecundity and rapid growth. Dissolved oxygen, an important environmental factor affecting fish production and economics, highlights the need for smart aquaculture practices. Since 2018, the rise of intelligent aquaculture platforms, incorporating information and communications technology (ICT), emphasizes the essential role of RAS implementation. This eight-week study aimed to determine the optimal dissolved oxygen concentration for rainbow trout in RAS, utilizing a device for continuous monitoring, control and record. Dissolved oxygen concentrations were set at 5-6 mg/L, 9-10 mg/L, 14-15 mg/L and 17-18 mg/L. The growth rate significantly decreased at 5-6 mg/L, with no significant differences in other experimental groups. In hematological analysis, growth hormone (GH) was significantly highest at 5-6 mg/L, followed by 9-10 mg/L while Insulin-like growth factor-1 (IGF-1) was significantly lowest at 5-6 mg/L. In conclusion, the optimal dissolved oxygen concentration for rainbow trout in RAS is approximately 9-10 mg/L. Higher concentrations do not contribute to further growth or profitability.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.745-753
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• 2010

Many studies using RFID which can identify the movement of targeted objects has been conducted actively. In this paper, we propose improved tagging method to check exactly the amount of fish feed by the aquaculture tank in a land-based aquaculture farm and design the RFID feeding system to perform auto feeding history. Also, we implement the prototype system which it includes development program for auto-identification and auto-recording and self-made RFID feeding cart equipped the weight device, RFID reader, control module and display device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.2
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• pp.173-181
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• 2014

The Economist was implied most of the major fisheries are procured by aquaculture in 2030 affected by the Aquaculture Revolution. William Hallal was also predicted that amount of aquatic products will be about 50% of the total fishery in 2015. Various organizations had been conducted various u-farm researches and demonstration projects due to changing environment. This study aims to propose an ICT-based technologies and policies for the ICT-based smart system by identifying results and problems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.730-733
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• 2010

The Green Lamp Fixture (GLF) of LED prepared with thin panel structure was investigated for illumination of street lamps and other lighting system uses, which was also very useful to aquaculture and aquafarm lighting uses, or fish luring lights and marine aquanautics of aquamarinautics (aquamarine+aquanautics) uses, etc. In the case of fish luring lights, it was verified that the fish luring of Green Lamp Fixture of LED was very effective for phototaxis movement and ecological community promotion to the micro-living things of organisms and the small fries and fishes, like as 'crowding together'. For the aquaculture lightings, it was also very excellent in waterproof and heat-sink properties, photosynthetic growing of algae and micro-organisms, water-weeds and seaweeds living underwater.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.39-39
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• 2003

Antioxidant enzyme genes play a key role in cell defense against the lethal effects of oxidative stresses in animals and have an essential function which has allowed the evolution of aerobic respiration starting from an ancient form of oxygen-insensitive life. Piscine antioxidant enzymes are also involved in the rapid response to various toxic chemicals as well as many biological stresses, indicating that they could be used as biomarkers for health and aquatic environment. With the purpose for developing fine molecular probing tool to assess the stresses in marine fish, we identified three major antioxidant enzyme genes (superoxide dismutase, catalase and glutathione-S-transferase) from Korean rock bream using expressed sequence tag analysis and/or high density filter screening. Here we report the molecular information on these gene transcripts including complete sequence data and expression profiles.

• Fisheries and Aquatic Sciences
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• v.12 no.1
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• pp.35-43
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• 2009

Sturgeons and paddlefishes are frequently referred to as 'living fossils' among the actionpterygian lineage. They are increasingly facing threats to their existence because of various anthropogenic pressures. In this study, we present the complete mitogenome sequence of the Russian sturgeon Acipenser gueldenstaedtii (Acipenseriformes; Acipenseridae). The mitogenome showed highly homogeneous molecular features compared to previously known vertebrate mitogenomes. Phylogenetic tree inferred from concatenated protein-coding and tRNA genes unambiguously revealed the monophyly of A. gueldenstaedtii, Acipenser stellatus, and Huso huso. Genetic information of the endangered A. gueldenstaedtii will provide baseline data needed to develop molecular markers for stock identification and assessment of population diversity and also to develop future conservation strategies.

• Ocean and Polar Research
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• v.26 no.1
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• pp.102-111
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• 2004

Recirculating aquaculture system (RAS) consists of different treatment compartments that maintain water quality within the ranges commonly recommended for fish cultures. However, common RASs still exert considerable environmental impact since concentrations of organic matter and nutrients in their effluents are high. Compared with the traditional RAS, the model RAS developed here use a sedimentation basin for digestion purposes and then use the released volatile organic matter to stimulate a denitrification process. Different treatment compartments for solids, total ammonia nitrogen, and nitrate removal have been reviewed. This paper provides the basic information on designing different treatment compartments as well as the engineering criteria in closed seawater RAS, consisting of circular tanks for fish cultures; dual drain systems, sedimentation basins and foam fractionators for removal of solids; nitrification biofilters for TAN removal; denitrification biofilters for nitrate removal; and aerators for aeration. The main purpose is to outline a common procedure in designing of closed RAS for marine fish culture with an emphasis on easy management and low expense, as well as reduction of the environmental impact.

• Fisheries and Aquatic Sciences
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• v.20 no.10
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• pp.24.1-24.8
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• 2017

The experiment was conducted to investigate the effects of different algae in diet on growth, survival, and interleukin-10 productions of sea cucumber. At first, a 9-week feeding trail was conducted to evaluate the growth performance and survival of the sea cucumber fed one of the six experimental diets containing ST (Sargassum thunbergii), UL (Ulva lactuca), UP (Undaria pinnatifida), LJ (Laminaria japonica), SS (Schizochytrium sp.), and NO (Nannochloropsis oculata) in a recirculating aquaculture system. The result showed that survival was not significantly different among the dietary treatments, and the specific growth rate (SGR) of sea cucumber fed the UL diet ($1.58%d^{-1}$) was significantly higher than that of sea cucumber fed the other diets (P < 0.05), except for the LJ and NO diets. Secondly, interleukin (IL)-10 gene expression was determined where mice splenocytes were stimulated with $10{\mu}g\;ml^{-1}$ of sea cucumber extracts for 2 h. The result showed that IL-10 gene expression levels were significantly increased in UL, LJ, and NO diets fed sea cucumber extracts compared to other experimental diets. The results suggest that dietary inclusion with Ulva lactuca, Laminaria japonica, and Nannochloropsis oculata algae may improve the growth of juvenile sea cucumber and could upregulate IL-10 gene expression in mice splenocytes. Such detailed information could be helpful in further development of more appropriate diets for sea cucumber culture.

• Journal of Environmental Science International
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• v.19 no.11
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• pp.1397-1405
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• 2010

Mass mortalities of cultivated organisms have occurred frequently in Korean coastal waters causing enormous losses to cultivating industry. The preventive measures require continuous observation of farm environment and real-time provision of data. However, line hanging aquaculture farm are generally located far from monitoring buoys and has limitations on installation of heavy equipments. Substituting battery pack for solar panels and miniaturizing size of buoy, newly developed system can be attached to long line hanging aquaculture farm. This system could deliver measured data to users in real-time and contribute to damage mitigation and prevention from mass mortalities as well as finding their causes. The system was installed off Gijang and Yeongdeck in Korea, measuring and transmitting seawater temperature at the sea surface every 30 minutes. Short term variation of seawater temperature, less than one day, in Gijang from June to July 2009 corresponded tidal period of about 12 hours and long term variation seemed to be caused by cold water southeast coast of Korea, particularly northeast of Gijang. Seawater temperature differences between Gijang station and the other station that is about 500 m away from Gijang station were $1^{\circ}C$ on average. This fact indicates that it is need to be pay attention to use substitute data even if it is close to the station. Daily range of seawater temperature, one of crucial information to aquaculture, can be obtained from this system because temperature were measured every 30 minutes. Averages of daily range of temperature off Gijang and Yeongdeok during each observation periods were about $2.9^{\circ}C$ and $4.7^{\circ}C$ respectively. Dominant period of seawater temperature variation off Yeongdeok was one day with the lowest peak at 5 a.m. and the highest one at 5 p.m. generally, resulting from solar radiation.