• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.454-459
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• 2006

A simultaneous high-performance liquid chromatography assay method for amoxicillin and ampicillin in fish products was developed, evaluated, and validated by monitoring these antibiotics in fish samples obtained from aquaculture and distribution. The recovery rate of this method was higher than those of conventional methods and was 95.3-106.6% for amoxicillin and 81.4-92.4% for ampicillin. Our pretreatment procedure sufficiently removed or reduced materials affecting HPLC analysis, such as low-molecular-weight substances. The performance limit of this method was evaluated as 0.01 ppm of amoxicillin and ampicillin in fish muscle. Finally, 171 fish samples, including olive flounder (Paralichthys olivaceus), common sea bass (Lateolabrax japonicus), and black rock fish (Sebastes schlegeli) collected from fish farms in the coastal area between April and September 2005 were analyzed to evaluate the overall efficiency of the method and to monitor the actual of amoxicillin and ampicillin usage in fish farms. The results indicated that the developed method was suitable for analyzing amoxicillin and ampicillin in fish muscle, and determined that those antibiotics were being used for fish farming but were not detected in fish samples during the shipping and distribution stages.

• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.364-370
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• 2011

Water quality criteria for human health protection are derived based on the human health risk assessment. Water quality criteria in Korean freshwater bodies have been derived according to the equations developed by the US Environmental Protection Agency. The equations include the fish intake parameter, which is very important factor that significantly influences on the criteria derivation. So far, several fish intake values were used in human health risk assessment for water quality standards and effluent standards. However, these values are not consistent and they refer to various sources. Therefore, there is a need to suggest the most appropriate value of fish intake parameter to derive freshwater quality criteria in Korea. In this study, national and international fish intake values were widely collected and evaluated to select the adequate value of fish intake parameter that can be applied in Korea. The USEPA presented fish intake parameter as the 17.5 g/day for general adults and sport fishers and 142.4 g/day for subsistence fishers. In Korean reports, wide range values of 2 to 67.7 g/day were suggested as fish intake value. These values included finfish and shellfish intakes in common but had various habits. This study found that the 52.4 g/day suggested in Korean Exposure Factors Handbook published by the Ministry of Environment in 2007 seemed to be the suitable fish intake parameter to derive the freshwater quality criteria in Korea. The value is based on water corrected intakes of finfish and shellfish present in freshwater and coastal areas. We expect that this report can be useful to select suitable fish intake value in human health risk assessment for establishing freshwater quality standard in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.16-25
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• 2015

Visual census and hydro-acoustic survey was carried out at Ulju small scale marine ranching area (MRA) to estimate demersal fish aggregations on September and November 2013. In this hydro-acoustic survey, the authors combined an image sonar with a scientific echo sounder to monitor an underwater situation and compare two acoustic data. Consequently, visual census survey was useful to estimate fish species composition for hydro-acoustic survey, because it is easy to identify aggregated fish species and overcome limits on a fishing depth and ability of an conventional fishing gear like a bottom gill-net or a fish trap at marine ranching area. Mean fish density was estimated as $0.757g/m^2$ on September and $0.219g/m^2$ on November and Fish abundance was finally calculated as 1.51ton (coefficient of variation, CV=13.1%) on September and 0.44ton (CV=47.7%) on November, respectively. Hydro-acoustic survey combined with the image sonar was useful to monitor fish aggregations and estimate fish stocks around artificial reefs at shallow coastal MRA. We were able to easily identify the underwater structures like an artificial reef and a fishing rope as well as fish aggregations from image sonar data. Therefore, the method was effective to separate unwanted echo signals in acoustic data of scientific echo sounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.693-704
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• 2010

Seasonal variation in species composition around Dokdo, East Sea of Korea, was investigated using trammel-net catches, from 2006 to 2009. A total of 53 fish species belonging to 23 families in 12 orders were captured; the orders Perciformes (12 families, 22 species) and Scorpaeniformes (four families, 22 species) were dominant. Between 2008 and 2009, 43 species were collected by trammel net. The number of species was highest in August 2009 (25 species) and lowest in February 2009 (11 species). The number of individuals and total biomass peaked in November 2009. Diversity indices for fish catches were highest in August 2008 (2.4368) and lowest in November 2009 (0.4253). The dominant species were Thamnaconus modestus and Sebastes schlegeli. Hierarchical clustering analysis showed five fish groups, with frequency and number of individuals similar to results of correspondence analysis (CA), which showed a closer relationship to the year term than the season term. CA showed that temperature was an important factor influencing fish species richness and abundance. Three main fish assemblage types coexisted around Dokdo: an East Sea coastal fish assemblage, a subtropical fish assemblage, and a cold water fish assemblage.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.1184-1193
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• 2015

Monitoring for megalocytivirus infection was conducted for ten months from March to December in 2013 in 15 aquatic farms culturing, red sea bream, rock bream, rock fish and black sea bream around Tongyoung coastal area in Korea, to assess spatial and temporal variability of detection prevalence, and to explore possible links with seawater temperature. In nested-PCR targeted major capsid protein (MCP) gene, asymptomatic megalocytivirus infection was detected in the externally healthy farmed fish with a significant prevalence in range from 0 to 58.3% for ten months. Higher prevalence of megalocytivirus (46.7% - 57.1%) was observed in high water temperature season from September to November than that in other months with lower prevalence of 0.0% to 20.0%. Even though an acute infection of megalocytivirus was occurred in rock bream (positive in the first PCR) with high mortality in one of fifteen farms, there was no expansion or transmission of the disease to the rock fish and red sea bream culturing in net cage just proximal to the rock bream cage in which disease outbreaked. Nucleotide sequence analysis of the cloned MCP gene isolated asymptomatically infected rock fish revealed that the megalocytivirus in this study was clustered together with the rock bream iridovirus (RBIV) under the subgroup II of the genus megalocytivirus (Iridoviridae), which is known to be the major megalocytivirus strain in Korea. The typical histopathological signs were not found in the spleen of rock fish asymptomatically infected by megalocytivirus. Experimental infection of rock bream with the spleen homogenate of the rock fish infected asymptomatically did not induce any mortality unlike the homogenate of infected rock bream with hih mortlity. However, these results may suggest that the asymptomatic infection of megalocytivirus in other fish species can be a potential risk threatening aquaculture industries as a transmission factor of megalocytivirus to susceptible fish species, especially rock bream.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.475-482
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• 2011

In this research, we have attempted to estimate the water quality of fish farms in terms of parameters such as water temperature, dissolved oxygen, pH, and salinity by employing observational data obtained from a coastal ocean observatory of a national institution located close to the fish farm. We requested and received marine data comprising nine factors including water temperature from Korea Hydrographic and Oceanographic Administration. For verifying our results, we also established an experimental fish farm in which we directly placed the sensor module of an optical mode, YSI-6920V2, used for self-cleaning inside fish tanks and used the data measured and recorded by a environment monitoring system that was communicating serially with the sensor module. We investigated the differences in water temperature and salinity among three areas - Goheung Balpo, Yeosu Odongdo, and the experimental fish farm, Keumho. Water temperature did not exhibit significant differences but there was a difference in salinity (significance <5%). Further, multiple regression analysis was performed to estimate the water quality of the fish farm at Keumho based on the data of Goheung Balpo. The water temperature and dissolved-oxygen estimations had multiple regression linear relationships with coefficients of determination of 98% and 89%, respectively. However, in the case of the pH and salinity estimated using the oceanic environment with nine factors, the adjusted coefficient of determination was very low at less than 10%, and it was therefore difficult to predict the values. We plotted the predicted and measured values by employing the estimated regression equation and found them to fit very well; the values were close to the regression line. We have demonstrated that if statistical model equations that fit well are used, the expense of fish-farm sensor and system installations, maintenances, and repairs, which is a major issue with existing environmental information monitoring systems of marine farming areas, can be reduced, thereby making it easier for fish farmers to monitor aquaculture and mariculture environments.

• Ocean and Polar Research
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• v.40 no.1
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• pp.37-48
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• 2018

The purpose of this study is to assess the climate change vulnerability of coastal and offshore fisheries in the South Sea of Korea using the RCP scenarios. Based on the vulnerability defined by IPCC, the indicator-based method was applied. Exposure indicator was calculated through weighted sum of the sea temperature and salinity forecasted by National Institute of Fisheries Science, and the weights were obtained from the time-space distribution of each fisheries. Sensitivity indicator was determined by applying the catch proportion of fisheries to the sensitivity of fish species. The adaptive capacity was measured by survey of fisheries which represent the ability of the fishermen well. As a result of summarizing the above indicators, vulnerability of coastal fisheries is higher than offshore fisheries. This shows that measures against coastal fisheries are needed. In addition, the results of each scenario are somewhat different, so it is considered that accurate prediction of climate change is important for adaptation measures.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.1
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• pp.59-67
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• 2022

This study assessed the levels of water qualities and microbials contamination of inland olive flounder farms in Jeju in the summers from 2015 to 2017. Three farms (A-C) located in a concentrated area using mixing coastal seawater and underground seawater and one farm (D) located in an independent area using only coastal seawater were selected. Total ammonia nitrogen (TAN) reached a maximum of 0.898 ± 1.024 mg/L as N in the coastal seawater of A-C, which was close to the limit of the water quality management goal of the fish farm. TAN in the influent from A-C was up to three times higher than that of D, so that the discharged water did not spread to a wide range area along the coast and continued to affect the influent. TAN of the effluent in A-C increased by 2.7-4.6 times compared to the influent, resulting in serious self-pollution in the flounder farm. Heterotrophic marine bacteria in the influent of A-C was about 600 times higher than D, and the discharge of A-C was increased by about 30 times compared to the influent.

• Ocean and Polar Research
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• v.27 no.3
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• pp.323-333
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• 2005

The paper is to serve as a guide for deciding on a desirable direction for the vessel buyback program, reviewing their performance and economic effects from fish harvest reduction due to not reaching MSY. Compared with maximum willingness to pay for vessel buyback programs designed to avoid economic losses occurring as a result of overfishing, the portions of investment costs for buyback program are so small comparatively to the range of 0.32% to 12.19% at the annual base. The economic loss effects occurred in terms of the reduction of fishing harvest are comprehensively estimated at the present value of 30,877 billion won since 1971, and exceeded the revenues for fish harvests from 1999. In order to resole fish stocks through a vessel buyback program, this paper recommends that the yield should be reduced to less than the intrinsic growth rate. Otherwise, the buyback program policy eventually fails regardless of the temporal effect of benefits. This paper further argues that technical policy tools such as fishing grounds, fishing seasons, size of fish and minimum size of meshes should be effectively utilized.

• Journal of the korean society of oceanography
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• v.37 no.2
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• pp.82-89
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• 2002

Butyltins (BTs) were measured in 2 species of shellfish and 16 species of fish collected along the Korean coast. Tributyltin (TBT) was detected in the mussels and oysters of sentinel organisms (20 to 940 ng Sn/g dry wt), indicating widespread contamination of TBT in the Korean coast. The elevated concentrations of TBT in the shellfish found in the sites near harbors or shipyards suggested that antifouling paints are probable major sources of butyltins in these areas. The TBT compound was detected in 12 out of 16 fish samples. The concentrations of TBT in fish muscles wee between 7 and 151 ng Sn/g dry wt, while the level in whole body of anchovy was very high (793 ng Sn/g dry wt). Exposure doses to Korean people via consumption of these marine products wee evaluated. The results suggested that the environmental levels of TBT were below the level of concern.