• 수산해양기술연구
• /
• 제50권4호
• /
• pp.427-434
• /
• 2014

Although ex situ target strength (TS) measurements using dual- and split-beam systems have become the primary approach of estimating fish abundance, theoretical model estimation is a powerful tool for verifying the measurements, as well as for providing values when making direct measurements is difficult. TS values for 20 samples of live bambooleaf wrasse (Pseudolabrus japonicus) whose target length (TL) ranged between 13.7 and 21.3 cm were estimated theoretically using the Kirchhoff-ray mode model, and the TS values for 18 live fish samples were additionally measured at ${\sim}0^{\circ}$ tilt angle to the swimming aspect using a tethered method at a frequency of 120 kHz to verify the theoretical values. The digitizing intervals used to extract the fish body and swim bladder morphology in the X-ray photographs significantly affected the calculated TS patterns, but variations based on the speed of sound and density ratio values for the general range of fish flesh were relatively small (within 1 dB). Close agreement was observed between the measured and theoretical TS values, and the correlation between the average TS and body length of the fish could be calculated accurately as <$TS_{120kHz}$>= 20logTL (cm) -71.6 using the theoretical method.

• 수산해양교육연구
• /
• 제21권3호
• /
• pp.451-458
• /
• 2009

The purpose of this study is to analyze the nutrition composition and physiological changes, and to evaluate the food quality of live fish in cultured and wild fishes which have been kept in an aquarium tank. The moisture and lipid content of wild and cultured fishes when kept in an aquarium tank for seven-days storage was found to be lower than those of the initial stage storage(zero day). The breaking strength was also rapidly decreased in all of live fishes tested in this study as the periods of storage extended. The protein content did not differ significantly. However, the content of cortisol, which is a indicator indicating a stress reaction in tissues, was apt to increasing as the periods of storage extended. The cortisol content of wild fishes were higher than those of cultured fishes. On the other hand, the activity of activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which is also a indicator indicating a stress reaction, were not changed in the serum of wild and cultured fish, suggesting the ALT and AST activity dose not directly related with a healthy loss originated from stress. The death ratio of wild fishes were higher than cultured ones due to limited activity and stress during the storage in a aquarium tank.

• 한국잠사곤충학회지
• /
• 제51권2호
• /
• pp.95-98
• /
• 2013

본 시험은 붕어에 대하여 동애동에의 살아있는 유충과 건조된 유충 및 번데기의 공급 사육시 성장에 미치는 영향을 조사하기 위하여 약 16주간 사육하면서 어체의 증체율 및 길이성장을 비교 조사하였다. 사료로 사용하기 위한 성분분석에서 건조 유충과 번데기의 조단백질 함량은 43% 이상 수준으로 나타났으며, 지방산 분석결과에서 불포화 지방산의 함량이 상대적으로 높게 나타났다. 이는 양어사료의 단백질 및 필수 지방산 공급원으로 좋은 원료로 사용 가능 할 것으로 사료된다. 약 16주간 동애등에를 붕어먹이로 공급하여 어체의 증체율과 길이에 미치는 영향을 조사한 결과는 살아있는 동애등에 유충을 공급한 실험구에서 증체율과 길이의 증가가 가장 크게 나타났다. 양어사료만을 공급한 실험구와 양어사료에 건조한 유충과 번데기를 50% 혼합하여 공급한 실험구의 증체율 및 길이의 증가를 비교해 보았을 때 건조한 유충과 번데기를 혼합하여 공급하는 것이 효과적인 것으로 나타났다.

• Fisheries and Aquatic Sciences
• /
• 제7권4호
• /
• pp.192-203
• /
• 2004

The effects of temperatures, starvation, and kind of foods on growth, RNA/DNA ratio and protein contents during metamorphosis and early juvenile stage of olive flounder (Paralichthys olivaceus) were examined. During metamorphosis, warm-acclimated fish showed higher RNA and DNA content than those of the cold-acclimated fish, excepting H stage (28 DAH) at which the ratio was higher at cold temperature. RNA/DNA ratio during metamorphosis showed similar values at two temperatures tested. However, after 42 DAH warm-acclimated juveniles had higher DNA content compared with cold-acclimated fish, resulted in marked decreases in RNA/DNA ratios. Higher RNA content at H stage of cold-acclimated fish was consistent with an increase in protein content. Growth of fish rearing at warm temperature was higher than those of fish at cold temperature during all experiments. In starvation experiment, contents of DNA, RNA and protein significantly decreased. Even though there were no significant differences in total length (TL) and body weight between the live mysid-fed and artificial pellet-fed fish at 35 mm TL, both RNA/DNA and protein/DNA ratios of the former group was significantly higher than those of the latter due primarily to lower DNA content of the live mysid-fed group. The results from this study suggest that temperature, starvation and kind of foods should be considered when RNA/DNA ratio applied to assessing the cultured larval and juvenile fish condition.

• 수산경영론집
• /
• 제45권3호
• /
• pp.99-110
• /
• 2014

Flounder was selected as one of the 10 strategic export aquaculture products for seafood export expansion in 2013. The flounder aquaculture industry has promoted export market diversification and product diversification from live to processed goods as a it's main strategy. The purpose of this study is to find an improvement plan for export expansion to the United States, as it emerged as a new target export market for the flounder. A summary of the key findings is as follows. First, the western region of the United States prefers to consume live and fresh flounder, whereas the eastern region prefers to consume fresh flounder. Second, because of it's high quality, Korean flounder is favored in the western region of the United States despite it's high price, whereas in the eastern region of the United States, where production volume is high, Korean flounder has to compete with US flounders because of it's high price. Third, according to the survey results, US consumers tend to enjoy seafood, as well as flounder cuisines. Fourth, the main consumption place of flounders by US consumers are restaurants, and they prefer to consume them in the form of sashimi and sushi. Fifth, 70% of US consumers expressed willingness to consume flounder when eating out. which shows great market potential. However, the high price of Korean flounder and limited size of the live fish market act as major obstacles to expanding export volume. To expand exporting Korean flounder, continuos efforts such as price reduction, exporting highly fresh fish, the co-development of processed food with the US are needed.

• 한국수산과학회지
• /
• 제50권2호
• /
• pp.195-206
• /
• 2017

Joint time-frequency images of the broadband echo signals of six fish species were obtained using the smoothed pseudo-Wigner-Ville distribution in controlled environments. Affine transformation and principal component analysis were used to obtain eigenimages that provided species-specific acoustic features for each of the six fish species. The echo images of an unknown fish species, acquired in real time and in a fully automated fashion, were identified by finding the smallest Euclidean or Mahalanobis distance between each combination of weight matrices of the test image of the fish species to be identified and of the eigenimage classes of each of six fish species in the training set. The experimental results showed that the Mahalanobis classifier performed better than the Euclidean classifier in identifying both single- and mixed-species groups of all species assessed.

• 한국식품위생안전성학회지
• /
• 제16권3호
• /
• pp.241-246
• /
• 2001

서울시를 비롯한 6개 도시의 음식점과 활어를 판매하는 어시장 등에서 활어조에 사용하는 해수에 대하여 병원성 비브리오균의 분포, 이화학적특성 및 위생지표세균 등 환경인자와의 관계를 비교하였다. 시험해수에서 전염병균인 Vibrio cholerae O1은 전혀 검출되지 않았고, V. parahaemolyticus는 가장 빈번한 검출되었는데 검출율은 69.2%이었다. 그리고 V. vulnificus 및 V. cholerae non-O1 등 병원성 비브리오균이 검출된 활어조의 해수는 그렇지 않은 해수에 비하여 수온과 탁도는 높았고, 염분과 pH는 낮았으며 생균수, 대장균군 및 분변계 대장균이 휠씬 높게 검출되어 이러한 환경인자들과의 관련성이 시사되었다.

• 한국어병학회지
• /
• 제31권2호
• /
• pp.93-99
• /
• 2018

Edwardsiella tarda predominantly causes edwardsiellosis in fish at high temperature, but is rarely isolated from water when water temperature is low. However, E. tarda is viable but nonculturable (VBNC) in low water temperature, but it can be revived when water temperature rises and cause disease to fish. Therefore, in order to prevent disease, it is very important to identify pathogens that are in the VBNC state in environmental water. In this study, E. tarda cells in the VBNC state were detected by the ethidium monoazide (EMA)-PCR method using the low-temperature oligotrophic sea water microcosm obtained by inoculation of E. tarda at a concentration of $10^8CFU/ml$. In order to distinguish between live and dead bacteria in E. tarda, each sample was treated with EMA at different concentrations, photoactivated with a 500 W halogen lamp, and PCR was performed with E. tarda specific primer. At the concentration of $10^7CFU/ml$ bacterium, DNA amplification was observed only in the live cells when treated with $60{\mu}g/ml$ of EMA, and smaller amounts of live cells could be distinguished from dead cells by adjusting the EMA concentration. In addition, the VBNC cells of E. tarda in the oligotrophic low temperature seawater microcosm were estimated to be in the range of $10^4{\sim}10^5CFU/ml$ by EMA-PCR. Therefore, it is possible to detect VBNC cells that will act as potential pathogens in environmental water using EMA-PCR method, and quantitative confirmation using concentration change is also possible.

• 산업기술연구
• /
• 제26권B호
• /
• pp.63-71
• /
• 2006

The concerned object of the construction industry is environment. It is one of the main purposes of today's construction that human can live reasonably in nature. This study is about the fish-road connecting hydraulic structure in the river with nature. Chapter 2, starting with the general investigation about fish-road and helps comprehension for relatively general fish-road such as necessity, establishment purpose, history, study example, relating domestic law, design condition, consideration and form of fish-road. Chapter 3, containing the present condition of fish-road facilities in Gangwon-Do and thoughts of the problems and general countermeasures of existing fish-road. Chapter 4, Having Examined compatibility by amount of flowing water through hydraulic model test in the Ice harbor I-type model. chapter 5, Analyzation and arrangement to efficient establishment plan of fish-road and the result of the hydraulic model experiment to be beaconed a little in forward fish-road study. In the hydraulic model test result, when we suppose establishment of 1~3 in slope of 1/20, could know that applicable drought flow of the river is $0.06{\sim}3.0m^3/sec$ in case of Ice harbor I-type which transforming Ice harbor that was invented as studying project of the Ministry of Environment.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권6호
• /
• pp.1324-1329
• /
• 2001

The depression of the external situation like the departure of WTO system and the plan of EEZ proclaim is forcing fishery into improving their fishing condition. By this international and domestic circumstance, development of the sea water cooling apparatus for fish hold storage is demanded sincerely. This study represents the thermal characteristics of the fish hold storage during transportation. The numerical analysis in this study is the finite volume method with the SIMPLE computational algorithm to study the seawater flow behavior in the fish hold storage. The computation were carried out with the variations of the circulating flow velocity and depth of fish hold storage. As the result of the three dimensional simulations, the mean temperature doesn't almost change by the circulating flow rate. find the mean temperature is suddenly changed by the ratio of depth of fish hold storage.