• 한국환경과학회지
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• 제33권4호
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• pp.235-247
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• 2024

A total of 64 individuals of Acanthogobius flavimanus, which inhabit the coast of Korea, were collected from 8 regions from July to August 2023. A haplotype network and a phylogenetic tree were created. The genomic DNA of the target fish species was compared and analyzed with the genomic DNA of four regions in Japan downloaded from the National Center for Biotechnology Information (NCBI). In the haplotype network of Acanthogoboius flavimanus, Eocheong-do (EC) and Goseong (MAJ) exhibited low genetic similarity with other regions in Korea and Japan. The Phylogenetic tree showed that the population of MAJ exhibited differences in genetic structure compared to populations in other regions of Korea and Japan, indicating a distant relationship. Most marine organisms are known to migrate and spread via ocean currents, which is the most crucial factor promoting gene flow through larvae between populations. The haplotype of Acanthogobius flavimanus in MAJ differs from the haplotypes in Korea and Japan. The population in MAJ is believed to have limited genetic exchange due to the North Korea Cold Currents. We identified haplotype patterns based on the geographical distribution of Acanthogobius flavimanus off the coast of Korea and inferred that ocean currents have some influence on genetic distances.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.126-126
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• 2003

Performance of a laboratory scale closed seawater recirculating aquaculture system was evaluated. Twenty-kg Korean rockfish (130 fish) with an average body weight of 153.8 g was stocked. Over 107-day culture period, fish reached final density of 51.7 kg/m$^3$ (initial density, 33.3 kg/m$^3$) on the culture tank volume basis. On a daily basis, water addition was 3.4% of the total water volume in the system. Total ammonia nitrogen (TAN)concentrations were below 1 mg/L and nitrite nitrogen (NO$_2$-N) concentrations were within the range of 1-3 mg/L on most sampling days. TAN was removedin bead and sand filters and it was removed or produced in the sedimentation basin. Basically, NO$_2$-N was removed in the bead and sand filters while it was either removed or produced in the sedimentation basin. Nitrate nitrogen (NO$_3$-N) was produced in the bead filters and removed in the sand filter and sedimentation basin. Foam fractionator performed well in the recirculating system. The maximal daily removal values for total suspended solids (TSS) and protein were 10,9 g and 1.4 g, respectively. Whole water quality parameters were within the levels commonly recommendedfor fish culture on most of the sampling days. However, further studies are needed to evaluate the commercial feasibility of this system because of the small-scale system used in present experiment. At least, present study still provides some basic information for further studies of this kind of system.

• 수산해양기술연구
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• 제56권1호
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• pp.45-54
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• 2020

In this study, an automatic system for improving the working environment and increasing production efficiency of a laver aquaculture industry in Korea was developed by combining a hydraulic control system and a load cell in a current landing work of the laver. The improved gathering laver system allowed the automatic gathering process of the laver in the sea with the hydraulic control system connected to a cutting machine of the laver on the operating ship, which has been used for gathering the laver semi-automatically in a form of the traditional farming method. The transporting process of the laver from an operating ship to the land was improved as follows. A frame installed on the operating ship and the bag nets were designed and made to hold about 1,000 kg of the laver inside. The bag nets contain the laver on the improved operating ship were tied in knots and hooked on a crane using a load cell. The weight is measured immediately by lifting the bag nets through the load cell system. Weight information is communicated to the fishermen and successful bidders through the application. The advantages of the improved system can help fishermen to fish by improving their working environment and increasing production efficiency. The field survey to improve the landing operation of the laver aquaculture was conducted in Gangjin, Goheung, Shinan, Wando, Jindo, and Haenam in South Jeonnam Province. A total of 10 sites including Gunsan in Jeonbuk Province, Daebu Island in Ansan City, Jebu Island in Hwaseong City in Gyeonggi Province, and Seocheon in Chungnam Province were searched to collect data. Prototypes of the system were tested at the auction house of laver located in Goheung, where laver collection using hydraulic control and landing using road cell could be improved.

• Ocean and Polar Research
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• 제25권4호
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• pp.493-501
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• 2003

Performance of a laboratory scale closed seawater recirculating aquaculture system was evaluated. Twenty-kg of korean rockfish (130 fish) with an average body weight of 153.8g was stocked. Over a 107-day culture period, fish reached final density of $51.7kg/m^3$ (initial density, $33.3kg/m^3$) on the basis of the culture tank volume. On a daily basis, added water amounted to 3.4% of the total water volume in the system. Total ammonia nitrogen (TAN) concentrations were below 1mg/l and nitrite nitrogen $(NO_2-N)$ concentrations were within the range of 1-3mg/l on most sampling days. TAN was removed from bead and sand filters and it was removed or produced in the sedimentation basin. Basically, $NO_2-N$ was removed in the bead and sand filters, while it was either removed or produced in the sedimentation basin. Nitrate nitrogen $(NO_3-N)$ was produced in the bead filters and removed from the sand filter and sedimentation basin. The foam fractionator performed well in the recirculating system. The maximal daily removal values for total suspended solids (755) and protein were 10.9g and 1.4g, respectively. Whole water quality parameters were within the levels commonly recommended for fish culture on most of the sampling days. However, further studies are needed to evaluate the commercial feasibility of this system because of the smallscale system used in present experiment. At least, the present study still provides some basic information for further studies of this kind of system.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.432-439
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• 2021

Microbial community plays important roles in the culture environment of mud crab Scylla serrata. One of the environmental management efforts for the cultivation of S.serrata is by stabilizing microorganisms involved in nitrogen cycle process. The availability of dissolved inorganic nitrogen in its culture environment under a recirculating system closely relates to the nitrogen cycle, which involves both anaerobic and aerobic bacterial activities. Anaerobically, there are two major nitrogen compound degradation processes, i.e., denitrification and dissimilatory nitrate reduction to ammonium (DNRA). This study aimed to identify denitrifying and DNRA bacteria isolated from the recirculating cultivation of S. serrata. The water samples were collected from anaerobic filters called close filter system, which is anaerobically conditioned with the addition of varying physical filter materials in the recirculating mud crab cultures. The results showed that three denitrifying bacterial isolates and seven DNRA bacterial isolates were successfully identified. The phylogenetic analysis based on 16S rRNA gene of the denitrifying bacteria revealed that HIB_7a had the closest similarity to Stenotrophomonas daejeonensis strain MJ03. Meanwhile, DNRA bacterial isolate of HIB_92 showed a 100% similarity to Bacillus sonorensis strain N3, Bacillus vallismortis strain VITS-17, Bacillus tequlensis strain TY5, Geobacillus sp. strain DB24, Bacillus subtilis strain A1, and Bacillus mojavensis strain SSRAI21. This study provides basic information denitrifying and DNRA bacterial isolates identity which might have the potential to be applied as probiotics in aquaculture systems in order to maintain optimal environmental conditions.

• Fisheries and Aquatic Sciences
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• 제25권4호
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• pp.202-213
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• 2022

Antibiotic resistant Escherichia coli cases are increasing high especially in Southeast Asia. Illegal use of the antibiotic in the aquaculture farming may become the culprit of the outbreak and spread into environmental source. A study was conducted to: 1) detect the chloramphenicol (CAL)-resistant gene in E. coli isolated from three aquaculture farms and six rivers of northwestern Borneo and 2) investigate the correlation between cat gene with five common antibiotics used. Isolation of E. coli was done on Eosin methylene blue agar and characterized using indole, methyl red, Voges-Proskauer, citrate tests. E. coli isolates were subsequently tested for their susceptibility to five antibiotics commonly used in aqua-farming. The CAL-resistant E. coli were further analyzed for the presence of resistant genes (cat I, cat II, cat III, cat IV) using multiplex polymerase chain reaction. 42 bacterial colonies were isolated from a total of 80 individual water samples, 34 of which were identified as E. coli. Result showed 85.3% of the E. coli isolates were resistant to amoxicillin, 35.3% were resistant to tetracycline, 29.4% were resistant to CAL, 17.6% were resistant to nitrofurantoin and 8.8% were resistant to nalidixic acid. All of the 10 CAL resistant E. coli isolateswere detected with cat II genes; five isolates detected with cat IV genes; three isolates detected with cat III genes; and another two detected with cat I genes. Pearson correlation coefficient shows highly significant relationship between resistance pattern of CAL with amoxicillin; and CAL with tetracycline. Our findings provide the supplementary information of the CAL resistance gene distribution, thereby improving our understanding of the potential risk of antibiotic resistance underlying within this microbial ecosystem.

• 환경생물
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• 제20권3호
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• pp.245-255
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• 2002

한국산 살조개 (Protothaca jedoensis)의 새로운 산업화 양식품종으로 개발하기 위한 기초자료를 얻기 위하여 1998년 9월부터 1999년 8월까지 주로 조직학적 방법에 의해 생식소의 발달과정과 생식주기를 조사하였다. 살조개는 자웅이체로서, 생식소는 해부학적으로 소화맹낭과 족부근육 사이에 위치하였다. 난소와 정소는 각각 난자형성소낭과 정자형성소낭으로 구성되어 있었다. 비만도는 2월에 20.6로 가장 높았으며 8월에 최소값 (9.6)을 보였다. 군성숙도의 경우, 생물학적 최소형은 각 장 38.4 mm로 나타났다. 성숙한 난모세포의 크기는 $50-60\mu{m}$였으며, 성숙기의 정소에서 정소란이 관찰되었다. 살조개의 생식주기는 초기 활성기(12-2월), 후기 활성기 (1-4월), 완숙기 (3-7월), 부분 산란기 (6-8월), 퇴화 및 비활성기(7-l월)의 연속적인 5단계로 구분되었다.

• 한국지리정보학회지
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• 제16권3호
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• pp.81-90
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• 2013

본 연구는 GIS를 기반으로 한 미더덕 SFG를 이용하여 미더덕 양식장의 적지를 선정하는데 있다. 미더덕 양식은 2001년 15,084M/T의 생산량을 기록하였으나 2005년 1,412M/T로 생산량이 급격히 감소하였다. 이후 연간생산량은 조금씩 증가하여 2012년 2,484M/T를 나타냈으나 여전히 초기 생산물량에 미치지 못하고 있는 실정이다. SFG는 환경과 생물간의 상호연관성을 나타내고 양식생물의 성장도를 나타낸다. SFG 개념을 이용하여 GIS 기반의 적지선정이 가능하며, 양식장의 지속적인 생산성확보를 위한 어장관리시스템 구축에 활용할 수가 있다. 진동만 미더덕 양식장에 대한 GIS 기반의 미더덕 SFG를 이용한 적지 선정을 하여본 결과 해역 전체의 SFG는 0.054~0.57J/day의 범위를 보였으며, 대상해역과 중첩시킨 미더덕 양식장의 SFG 역시 0.054~0.57J/day로 분포하고 있다. 또한 미더덕 양식장의 SFG와 실제 생산량의 상관성 r=0.786, p<0.05 로 높은 상관성을 보이고 있다. GIS 기반 양식장의 서식지적합도 산정을 통한 어장관리시스템 구축은 양식장의 적지선정과 양식장의 지속가능한 생산량을 확보할 수 있으며, 환경의 변동과 양식생물성장의 인과관계를 객관화 할 수 있는 체계를 도입함으로서, 지속적인 어장관리를 위한 의사결정방안을 도출 할 수 있다.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2003년도 추계학술발표대회 논문요약집
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• pp.17-18
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• 2003

Although flounder is one of the most important marine fish for aquaculture in Korea, feeding the flounder in commercial farms depends mainly on moist pellet in which over 70% frozen fishes (e.g. frozen horse mackerel) are incorporated in its formulation. Therefore, for further expansion of flounder farming, it is essential to employ practical formulated feeds that can support reasonable growth. Development of nutritionally balanced and cost-effective feeds is dependant on the information about nutritional requirement and feed utilization of the species. Nutrient and energy source in feed are needed for the growth and maintenance of fish. Protein is probably the most important nutrient affecting fish growth and feed cost. Therefore, it is essential to determine the optimum dietary protein level for the growth of fish, both its high proportion in the feed and because it is the main factor in determining feed cost. Dietary energy level is also critical because protein source in the feed is utilized as an energy source when the feed deficient in energy is fed to fish, whereas when the feed excess in energy is fed to fish, feed consumption decreased and resulted in growth reduction due to lack of other necessary nutrients for normal growth. Improper dietary protein, energy levels and/or their ratio will lead to an increase of fish production cost and deterioration of water quality resulting from wasted feed; thus, they are important in formulating commercial feed. Dietary lipids play important roles in providing energy and essential fatty acid for normal growth and survival of fish. Although carbohydrates are not essential nutrients for carnivorous fish, these compounds play important roles as a low-cost energy source for protein sparing and also as a feed binder. Nutrition researches for flounder have identified its requirements of protein, lipid and essential fatty acid, vitamin, and minerals for normal growth. Other studies have also been carried out to investigate the utilization of the protein, lipid and carbohydrate sources. Based on these nutritional information obtained, practical feed formulations have been studied for improve aquaculture production of flounder. The results of the researches on utilization of dietary protein, lipid and carbohydrate by flounder are discussed in this review.

• 한국정보시스템학회지:정보시스템연구
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• 제32권4호
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• pp.137-147
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• 2023

Purpose The domestic aquaculture industry in South Korea utilizes both formulated feeds and live feeds for the cultivation of fish. While nutrient-rich live feeds, particularly using fry, have been preferred since the past, formulated feeds are gaining attention due to issues related to overfishing and environmental concerns. Formulated feeds are advantageous for storage and supply but require a sustained feeding regimen due to the comparatively slower growth rate compared to live feeds. As the aging population in rural areas leads to a shortage of labor, automated feeding systems are increasingly being adopted in aquaculture facilities. To enhance the efficiency of such systems, it is crucial to quantitatively analyze the behavioral changes in fish based on the presence or absence of feed. Design/methodology/approach In the study, RGB cameras and infrared cameras were used to analyze fish activity according to feeding, and an outline extraction algorithm was applied to analyze the differences resulting from this. Findings Unlike RGB cameras, infrared cameras are more suitable for analyzing underwater fish activity as they convert objects' thermal energy into images. It was observed that Canny, Sobel, and Prewitt filters showed the most distinct identification of fish activity.