• 한국어병학회지
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• 제15권2호
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• pp.77-82
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• 2002

Effects of stress-induced suppression of humoral immunity on scuticociliate killing activity of olive flounder plasma were investigated. Changes in glucose level. alternative complement activity and Iysozyme activity of plasma by handling stress were analysed in relation to in vitri parasiticidal activity of plasma. The plasma glucose level was about two times higher in fish after a handling stress than in control fish. Plasma lysozyme activity and natural haemolytic activity were decreased in suessed fish.The scuticociliate killing activity of plasma was significantly lower in stressed fish than in non-stressed control fish. The present results indicated that stress-induced immunodepression could be a cause of scuticociliatosis occurrence in olive flounder.

• Fisheries and Aquatic Sciences
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• 제26권10호
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• pp.593-604
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• 2023

Post-harvest handling and hygienic level of aquatic products significantly affect the quality and level of safety. Cold chain control is one of the determining factors for the quality of fish and the bacterial community that grows on the fish. Identification of spoilage bacteria and pathogens in aquatic products must be made because it will determine the physical and chemical quality. A molecular identification method with high sensitivity is the solution. This study aims to identify the quality of fish and bacterial communities that grow. The research procedures included sample collection, pH measurement, drip loss measurement, transportation and cold storage treatment, DNA extraction, DNA sequencing, sequence analysis, and bioinformatics analysis. The conclusion obtained from this study is that the simulation of the cold chain system applied to eastern little tuna does not significantly affect changes in the water activity value, pH, and drip loss. The insignificant change indicates that the eastern little tuna samples are still in good quality. The bioinformatics analysis showed the highest diversity and abundance of the bacterial community came from the Gammaproteobacterial class.

• 한국수산과학회지
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• 제33권2호
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• pp.115-118
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• 2000

은연어는 국내에서도 양식되고 있는 고급어종으로 생산량도 매년 증가추세에 있다. 스몰트까지 담수에서 사육한 은연어는 이후에 해수로 옮겨 사육하는데, 육상에서 해상으로의 운반과정에서 그물작업이나 가두기는 피할 수 없는 과정이다. 이로 인해 어류는 상당한 스트레스를 받아 해상사육 과정에서 폐사하기도 한다. 본 연구는 그물작업이 은연어의 스트레스에 미치는 영향을 살펴보고자 2시간의 그물작업을 한 전후에 1차 스트레스 반응의 지표로 코티졸의 농도를, 그리고 2차 반응지표로 혈당, 중성지방, 콜레스테롤, 젖산 및 K Na, Cl 등의 전해질 농도와 함께 ALT, AST와 LDH의 활성을 조사하였다. 그 결과, 이들 그물작업으로 인해 연어의 코티졸, 혈당 농도 및 LDH 활성은 유의적 (p<0.05)으로 증가하였기에 은연어가 상당한 스트레스를 받는다는 것을 알 수 있었다.

• Fisheries and Aquatic Sciences
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• 제14권3호
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• pp.218-225
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• 2011

Dual frequency identification sonar (DIDSON) is an imaging sonar that has been used for numerous fisheries investigations in a diverse range of freshwater and marine environments. The main purpose of DIDSON is fish counting, fish sizing, and fish behavioral studies. DIDSON records video-quality data, so processing power for handling the vast amount of data with high speed is a priority. Therefore, a semiautomated analysis of DIDSON data for fish counting, sizing, and fish behavior in Echoview (fisheries acoustic data analysis software) was accomplished using testing data collected on the Rakaia River, New Zealand. Using this data, the methods and algorithms for background noise subtraction, image smoothing, target (fish) detection, and conversion to single targets were precisely illustrated. Verification by visualization identified the resulting targets. As a result, not only fish counts but also fish sizing information such as length, thickness, perimeter, compactness, and orientation were obtained. The alpha-beta fish tracking algorithm was employed to extract the speed, change in depth, and the distributed depth relating to fish behavior. Tail-beat pattern was depicted using the maximum intensity of all beams. This methodology can be used as a template and applied to data from BlueView two-dimensional imaging sonar.

• Fisheries and Aquatic Sciences
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• 제23권9호
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• pp.25.1-25.9
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• 2020

Fish is an extremely perishable food product which requires proper handling soon after harvest. The present study was aimed at assessing post-harvest fish losses and preservation practices in Siavonga district, Southern Zambia. Structured and semi-structured questionnaires were used to collect data on post-harvest fish losses and preservation practices from aquaculture producers, artisanal, and commercial fishers. All the fishers who landed on the lakeshore were interviewed, while aquaculture producers were randomly selected based on the information provided by the local department of fisheries. The results of the study revealed that all the fishers experienced post-harvest fish losses at varying degrees with those losing up to 10% of the total catch being in the majority. In contrast, aquaculture producers did not report any post-harvest fish losses. Most aquaculture producers commonly used chilling as preservation practice contrary to artisanal and commercial fishers who commonly used smoking and sun sun-drying respectively. Furthermore, fish product safety and quality control were poorly practiced in the district. Lack of cold storage facilities and fluctuating weather conditions were the major challenges impacting fish post-harvest activities. Therefore, to curb the loss of revenue due to post-harvest fish losses, we propose the introduction of new technology, self-development skills for fishing communities, and enhanced access to refrigeration facilities.

• 한국어병학회지
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• 제7권2호
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• pp.161-171
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• 1994

뱀장어의 울혈증 발병 원인구명을 위하여 서해안 지역 5 개 양만장을 대상으로 아가미 울혈증 발병현황과 수질등 역학조사를 실시하였고, 한편으로는 스트레스(handling 과 수온차) 및 병어에서 분리한 아가미 마쇄액을 건강어의 복강에 주사하여 울혈증 발병률과 CHSE-214 에 접종하여 세포변성을 조사하였다. 조사한 양만장의 아가미 울혈증 발병률은 30-80%로서 사육시의 수온과 선별시의 수온차가 클수록 발병률이 높았으며, 수질환경과 본증의 발병과는 뚜렷한 상관관계가 없었다. 또한 발병률이 높은 양만장의 뱀장어는 Ht, Hb, Tp, Alb, Mg 및 Glu 치등이 낮은 반면 GOT, GPT, Ca 및 Met-Hb 치등은 높게 나타나는 경향을 보였으나, 반드시 아가미 울혈증에 비례하여 증감되지는 않았다. 스트레스(handling 과 수온차)를 가함에 따라 아가미 울혈증이 실험적으로 유발되어졌으며, 발병률은 50-70% 이었다. 이러한 스트레스 조건하의 어류의 혈액학적인 성상은 울혈증 발병빈도에 비례하여 Ht, GOT, GPT, Met-Hb, Alb 및 Glu 치등은 증가되었으나, Tp, Hb 및 Mg 은 감소하는 경향을 보였으며, 온도차가 클수록 cortisol 량이 증가되는 경향을 보였다. 그러나, 병어의 아가미 마쇄액을 복강주사 및 CHSE-214 에 접종하였던 바 각각 울혈증의 발병 및 세포변성이 전혀 관찰되지 않았다. 이러한 결과는 선별시 handling 과 수온의 급변이 혈중 cortisol을 상승시켜 혈액의 전해질 변화를 초래케하므로써 혈액의 흐름을 완만하게 되고 동정맥계로의 혈액유입량이 증가하게 되어 중심정맥동이 확장되므로써 울혈이 형성되는 것임을 시사한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4866-4888
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• 2020

One major and time-consuming task in fish production is obtaining an accurate estimate of the number of fish produced. In most Nigerian farms, fish counting is performed manually. Digital image processing (DIP) is an inexpensive solution, but its accuracy is affected by noise, overlapping fish, and interfering objects. This study developed a catfish recognition and counting algorithm that introduces detection before counting and consists of six steps: image acquisition, pre-processing, segmentation, feature extraction, recognition, and counting. Images were acquired and pre-processed. The segmentation was performed by applying three methods: image binarization using Otsu thresholding, morphological operations using fill hole, dilation, and opening operations, and boundary segmentation using edge detection. The boundary features were extracted using a chain code algorithm and Fourier descriptors (CH-FD), which were used to train an artificial neural network (ANN) to perform the recognition. The new counting approach, based on the geometry of the fish, was applied to determine the number of fish and was found to be suitable for counting fish of any size and handling overlap. The accuracies of the segmentation algorithm, boundary pixel and Fourier descriptors (BD-FD), and the proposed CH-FD method were 90.34%, 96.6%, and 100% respectively. The proposed counting algorithm demonstrated 100% accuracy.

• 한국어류학회지
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• 제19권2호
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• pp.88-92
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• 2007

Marine birnavirus (MABV)에 무증상적으로 감염된 넙치 (Paralichthys olivaceus) 치어에 면역억제제의 일종인 Dexamathasone을 투여하였을 때 MABV의 감염강도에 영향을 미치는가를 조사하였다. Real time PCR 분석결과 dexamethasone을 투여한 그룹이 생리식염수를 주사한 그룹 및 no handling 그룹에 비해 유의적으로 낮은 Ct 값을 나타냈으며, 또한 semi-quantitative RT-PCR 분석결과에 있어서도 dexamethasone을 주사한 그룹이 대조구 그룹들에 비해 MABV 유전자가 유의적으로 높게 증폭되는 것으로 나타났다. 이러한 결과로부터 dexamethasone 투여가 넙치 치어에 감염된 MABV의 복제를 증가시킴을 확인하였다.

• 한국어병학회지
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• 제8권2호
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• pp.111-118
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• 1995

뱀장어에 인위적으로 스트레스를 가하여 아가미 울혈증을 발생시킨 후에 NaCl 처리에 따른 CVS의 울혈증의 치료효과 및 혈액성상의 변화에 미치는 영향을 조사하였다. 스트레스 직후에 고빈도의 발병율을 보였던 아가미 및 간의 울혈증은 염처리 후 3일째 까지는 감소되었으나, 4일 이후에는 별 영향이 없었다. 혈액성분중 스트레스 후 증가되었던 Ht, Met-Hb, $Ca^{++}$, GOT, GPT, LDH 및 glucose치 등과 감소되었던 $Mg^{++}$ 및 Hb치 등은 염처리 3일까지는 회복율이 촉진되었으나, 그 이후에는 큰 차이를 보이지 않았다. 그러나 알부민 및 총단백치는 염처리 기간동안 별 변화가 없었다. 이상의 결과는 스트레스에 의해 발병된 아가미 울혈증에 대한 염처리법은 초기 3일까지는 효과가 있으나, 그 이상의 기간에는 전혀 효과적이지 못함을 보여준다.

• Fisheries and Aquatic Sciences
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• 제5권2호
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• pp.141-143
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• 2002

The treatment efficacy of oral administration of praziquantel against the blood-sucking monogenean Microcotyle sebastis under the commercial rockfish-culture conditions was evaluated. The quantity of praziquantel added to the food was calculated so that the amount of praziquantel ingested daily by fish was 200mg or 400mg/kg body weight (bw). The fish were fed a moist-pelleted fish meal supplemented with praziquantel at an rate of 0 (control), 200 or 400 mg of praziquantel per kg bw, respectively, for 3 times at an interval of 24 h. On 1 day to 8 days after the treatment, 10 fish were taken randomly from each net-pen daily (80 fish in each group in total), and the efficacy of each treatment was confirmed. Abundance of worms were significantly reduced in groups fed praziquantel-supplemented diets. The results clearly demonstrated that feeding the praziquantel-supplemented diet was effective for controlling M. sebastis infestation in practical commercial rockfish-culture systems without imposing any handling stress.