• 현장농수산연구지
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• 제23권1호
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• pp.81-87
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• 2021

2020년 11월, 국내의 넙치 양식장에서 양식 중이던 넙치가 이상 유영 소견을 보이다가, 지속적으로 폐사하였다. 질병 진단 과정 중, 폐사어의 신장에서 세균(KNCFKW-PN1)이 분리되었다. gyrase B subunit 유전자의 시퀀스 분석 결과, KNCFKW-PN1 분리주는 기존에 보고된 LMG 2227^T 균주의 해당 유전자 시퀀스와 99.59% 유사도를 보여 Pseudoalteromonas nigrifaciens 로 동정이 되었다. 항생제 감수성 실험 결과에 따르면, KNCFKW-PN1 분리주는 ciprofloxacin에 대하여 중등도의 내성을 나타내었고, ampicillin, cefepime, cefotaxime, ceftazidime, amikacin에 내성을 나타내었다. 본 사례는 다제 내성 Pseudoalteromonas nigrifaciens 세균이 넙치로부터 분리된 최고의 보고이다.

• 한국음향학회지
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• 제25권1호
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• pp.7-13
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• 2006

잡는 어업에서 기르는 어업으로 전환하는 수산정책 과정에서 바다목장사업은 바다목장을 설치한 해역에서 육상에서 식이음으로 순치시킨 치어를 방류하여 사료투입시, 또는 성장한 어류들을 모이게 하는 수단으로 순치음을 해양에 방사하기 위해서는 수중 스피커의 개발이 필요하다. 본 연구에서는 수중에서 어류의 발생음과 인공적으로 음을 방성했을 때 어류반응에 대한 연구문헌을 조사하였다. 그 결과, 민감하게 반응하는 주파수는 $150Hz\~2kHz$이고 음압레벨은 $100dB\~150dB$ ($1{{\mu}$ Pa를 0dB)로 조사되었다. 따라서 수중 스피커 설계 제작시 주파수대역과 출력레벨의 사양은 $150Hz\~3kHz,\;100dB\~145dB$로 설정하였다. 그리고 설계사양 등가회로에 의한 전기임피던스 곡선과 반공진주파수를 등가회로법으로 구하고 수중 스피커를 제작하였다. 설계 제작된 수중 스피커를 수압탱크에서 안정성 평가와 최저 사용 주파수 범위를 결정하는 전기임피던스 특성실험을 실시하였으며 수심 10m에서 수중 스피커를 설치하여 해상실험을 한 결과를 정리하고, 제반 음향특성의 실험결과를 기술하였다.

• 수산경영론집
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• 제40권3호
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• pp.189-205
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• 2009

This study is aimed to analyze the economic feasibility comparison of the extruded pellets and moist pellets on the Oliver flounder culture farms in Jeju Island. In order to do this, we selected 2 farms (M and S farms) in Jeju Island as a sample. In the study, various analyses including productivity analysis, cost structure analysis, profitability and economic feasibility analysis by feed type were conducted for two sample farms of Oliver flounder culture. The results of economic analysis by feed type on the Oliver flounder culture can be summarized as follows; First, there were not significant differences in productivity by feed type. Second, results of the profitability analysis on farm M by feed type showed the profitability was estimated to be 15.52% and 9.83% in EP and MP, respectively. In addition, the profitability of farm S was estimated to be 28.37% and 33.72% in EP and MP, respectively. Third, results of the economic analysis on farm M by feed type indicated that an internal rate of return(IRR) was 8% and 7% and a benefit-cost ratio was shown to be 1.64 and 1.11 in EP and MP, respectively. Furthermore, the economic analysis of farm M by feed type showed that an IRR was 19% and 24% and a benefit-cost ratio was calculated to be 1.4 and 1.51 in EP and MP, respectively. In summary, it is especially emphasized that economic valuation is not related to feed types (EP and MP). Finally, in order to improve the economic feasibility, it should be more focused on the efficient business management of the Oliver flounder aquaculture.

• 한국수산과학회지
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• 제47권6호
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• pp.1026-1036
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• 2014

Real-time monitoring for environmental factors (temperature, salinity, chlorophyll-a, etc.) and fugacity of carbon dioxide ($fCO_2$) was conducted at an oyster Crassostrea gigas farm in Goseong Bay, south coast of Korea during 2-4th of November, 2011. Surface temperature and salinity were ranged from $17.9-18.7^{\circ}C$ and 32.7-33.8, respectively, with daily and inter-daily variations due to tidal currents. Surface $fCO_2$ showed a range of $390-510{\mu}atm$ and was higher than air $CO_2$ during the study period. Surface temperature, salinity and $fCO_2$ are showed significant correlations with chl.-a and nutrients, respectively. It means when chl.-a value is high in surface water of the oyster farm, active biological production consume $CO_2$ and nutrients from environments and produce oxygen, suggesting a tight feedback between biological processes and environmental reaction. Thus, factors affecting the surface $fCO_2$ were evaluated using a simple mass balance. Temperature and biological productions by phytoplankton are the main factors for $CO_2$ drawdown from afternoon to early night, while biological respiration increases seawater $CO_2$ at night. Air-sea exchange fraction acts as a $CO_2$ decreasing gear during the study period and is much effective when the wind speed is higher than $2-3m\;s^{-1}$. Future studies about organic carbon and biological production/respiration are required for evaluating the roles of oyster farms on carbon sink and coastal carbon cycle.

• 한국지리정보학회지
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• 제14권2호
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• pp.147-161
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• 2011

우리나라는 삼면이 바다로 둘러싸여 있기 때문에 수산물의 공급처인 연안에서 다양한 품목들을 양식하고 있다. 최근 연안 및 바다의 넓은 지역에 위치한 김, 전복, 어류 양식장의 정확한 위치와 시설량 파악을 위해 많은 연구들이 진행 중이며, 효율적인 어장관리를 위하여 지리정보시스템(Geographic Information System)과 원격탐사(Remote Sensing)를 이용한 양식장 시설량 판독이 필요하다. 본 연구는 보다 정밀하게 양식장 시설량을 판독하기 위하여 기존에 사용하던 해상도가 2~2.5m인 위성영상보다 고해상도인 항공영상(25cm)을 이용하였다. 김, 전복, 어류의 양식장이 모두 갖춰져 있는 완도군을 대상으로 항공영상 촬영 및 영상 보정, 어장 공간DB 구축, 시설량 판독을 수행하였다. 면허지 내/외의 시설량 분석 결과, 김, 전복 양식장의 면허지 외 시설량이 증가하였으며, 어류 양식장 시설량은 전복양식으로 전환했기 때문에 면허시설, 영상을 이용한 판독 시설량, 면허지 외 시설 모두 감소하였다. 김, 전복 양식장의 면허지 내/외 시설량 증가에 대해서는 이탈시설 및 무면허 시설에 대한 지속적인 단속과 관리가 필요할 것이다. 이처럼 양식장 시설량은 넓은 지역에 분포해 있기 때문에 고해상 항공영상을 이용하여 판독하는 것이 직접 현장조사를 통해 시설량을 산출하는 것보다 효과적이다. 본 연구는 어류 양식장의 효과적인 관리를 위하여 양식장의 정확한 위치와 시설량 산출에 항공영상을 이용하는 방안을 제시하였다.

• 한국어병학회지
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• 제32권2호
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• pp.81-89
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• 2019

As an epidemiological survey, mortality of marbled rockfish, Sebastiscus tertius observed from a fish farm in Gyeongnam province of South Korea. The major macroscopic sign of the diseased fish was severe multifocal dermal ulceration. Histological observation revealed inflammation, necrosis and colonization of bacteria in various tissues (gill, liver, spleen and kidney). Bacteria was isolated from spleen and kidney in moribund and mortality fish. Seven bacterial isolates from the diseased fish were identified as Aeromonas salmonicida subsp. salmonicida using API 20E and 20NE, API 50CH API ZYM system. Under light microscopy, infected marbled rockfish showed the lifting of the lamella epidermal layer, edematous changes and hypertrophy of epithelial cell in the gill filament. The atrophy of the mucosal fold, erythema in the intestine, and the necrosis of hematopoietic tissue and renal tubule cells with karyolysis were observed in the kidney. In this study was demonstrated the histological reaction of red marbled rockfish infected by Aeromonas salmonicida. Furthermore, this is the first account of extensive dermatitis in Sebastiscus tertius due to atypical A. salmonicida infection, which has high potential in aquaculture among native fish species.

• 수산해양기술연구
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• 제35권3호
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• pp.328-334
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• 1999

A fish pump makes very important roles in an automation system of an aquaculture farm, thus it has been used widely in order to transfer fishes from one place to the other place automatically. In spite of its significant roles, the efforts for developing performance and promoting efficiency of the fish pump are not sufficient yet. In this paper, a method which makes the fish pump automation system is suggested. Automation of the fish pump can be accomplished by using variable voltage and variable frequency inverter system including induction motors. Especially, very simple logic to generate Pulse width Modulation(PWM) wave to control induction motor efficiently and three steps speed control method to regulate liquid quantity of the fish pump simply are suggested. Owing to the simplifies speed control and PWM wave generation technique, a cheaper microprocessor, 80C196KC, than a digital signal Processor(DSP) can be used to operate control algorithm in induction motor systems for real time control Also, a new idea of remote control for the simplifies novel inverter system by Programmable logic Controller(PLC) without special output unit, digital to analog converter(D/A), is suggested in this paper. Consequently the function of reliability, availability and serviceability of the fish pump system are developed. It will be expected to contribute expanding of application of the fish pump in aquaculture farms because the system can reduce energy consumption and some difficulties according to manual operation prominently.

• 한국전자통신학회논문지
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• 제9권3호
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• pp.369-376
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• 2014

최근 기후변화와 각 나라의 해양확보로 인하여 수산자원의 급감을 해결하기 위한 친환경 양식업이 부각되고 있다. 해양 양식업 작업의 편이성을 제공하기 위해 어업용 선박 크레인을 사용한다. 본 논문에서는 영상처리기를 이용하여 기본의 선박 크레인의 작업환경을 개선하고 영상장비를 통해 입력받은 작업영역의 영상정보를 모니터링 및 분석하여 영상을 최적화하고, 작업자에게 편리하고 높은 가시성을 갖도록 하는 실시간 영상 가이드 시스템을 제안한다.

• ALGAE
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• 제17권3호
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• pp.187-194
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• 2002

A seaweed biofilter/production system of being developed to reduce the environmental impact of marine fish farm effluent in coastal ecosystems as a part of an integrated aquaculture system. Several known seaweed taxa and their cultivars have been considered as candidate biofilter organisms based on their species-specific physiological properties such as nutrient uptake kinetics and their economic value. Porphyra is an excellent cadidate and shows efficient nutrient extraction properties. Rates of ammonium uptake were maintained at around 3 ${\mu}moles{\cdot}g{\cdot}dw^{-1}{\cdot}min^{-1}$ at 150 ${\mu}M$ inorganic nitrogen at $10^{\circ}C$. Ulva is another possible biofilter candidate with an uptake rate of 1.9 ${\mu}moles{\cdot}g{\cdot}dw^{-1}{\cdot}min^{-1}$ under same conditions. A simple uptake/growth and harvest model was applied to estimate the efficiency of the biofilter/production system. The model was deterministic and used a compartment model structure based on difference equations. The efficiency of Porpyra filter was estimated over 17% of ${NH_4}^+$ removal from the contimuous supply of 100 ${\mu}mole{\cdot}l^{-1}\;{NH_4}^+\;at\;100l{\cdot}sec^{-1}$ flow rate.

• Fisheries and Aquatic Sciences
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• 제22권1호
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• pp.4.1-4.10
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• 2019

Russian sturgeon (Acipenser gueldenstaedtii) is commercially important in Korea because its caviar is highly prized. Although the early ontogeny of the species has been described, behavioral modifications in response to various light intensities or diel photoperiodicity patterns have not been studied extensively. The objective of the present study was to examine the behavioral characteristics of hatchery-produced A. gueldenstaedtii prelarvae over a diel photoperiodic cycle. During a diel light cycle comprising 16 h of daylight (450 lx), 4 h of dim light (10 lx), and 4 h of darkness (< 1 lx), newly hatched A. gueldenstaedtii prelarvae exhibited negative phototaxis in daylight (day 0-day 2), and this early behavior was not significantly affected by changes of light intensities. Rheotactic and non-rheotactic aggregation into schools was typical between days 3 and 6. Under the diel light cycle conditions described, rheotaxis was not influenced by environmental light intensity as much as non-rheotactic schooling behavior. Post-schooling behavior, which progressed from day 7 to day 8, did not change significantly during the diel light cycle. The data from the present study could be of practical value in developing a visual guide for assessing the fitness and quality of Russian sturgeon prelarvae under diel light cycle conditions in hatcheries.