• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.450-455
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• 2018

We examined correlations of the density of fish farms with the distributions of indicator bacteria (Escherichia coli, fecal streptococci) and a bacterial fish pathogen (Streptococcus parauberis) off the coastline of Jeju Island. Seawater samples were collected at four coastal sites on the Island [Aewol (control), Gujwa, Pyoseon and Daejeong] in June, August and October 2016. The indicator bacteria were generally more frequently isolated from samples taken in August when water temperatures and human activities on nearby beaches were highest. Although fish farms were least common at Daejeong, the numbers of isolated fecal indicator bacteria were highest in the seawater and effluent water collected from this site. Hence, fish farms were not likely major contributors of indicator bacteria at Daejeong. We found discrepancies between the isolated bacterial counts and the predicted bacterial copy numbers deduced from our qPCR results, indicating that this pathogen may exist in a viable but non-culturable (VBNC) state in seawater. Thus, livestock wastewater and chemical fertilizer loading off Jeju Island may negatively impact seawater quality more than the effluent released from fish farms does.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.1
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• pp.91-94
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• 2018

We develop a time-temperature indicator (TTI) that can determine whether thawing of fish and other fishery products has occurred during frozen storage. A polypropylene tube with an internal diameter of 3 mm was prepared and cut to a length of 14 to 20 mm. One end of the tube was thermally sealed and 0.1% acetic acid was injected into the other end; the tube was then frozen at $20^{\circ}C$. Then the open side of the frozen tube was blocked by sinking the tube into a 10% gelatin solution. The tube was attached to a polyvinyl packaging bag along blue litmus paper and the bag was put into a freezer at $-20^{\circ}C$. After freezing, the bag was removed to an ambient temperature of $20^{\circ}C$, and the time dependence of the color change of the litmus paper was observed. The color changed from blue to red, with the length of the red region increasing with time. Our TTI can be used as a part of a visible detection system and the detection program can conduct the elapsed time analysis on the length of the red region of the litmus paper indicating the degree of thawing. Thus, the TTI is a useful tool in the temperature management of frozen fish and fishery products.

• Journal of Food Hygiene and Safety
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• v.11 no.1
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• pp.57-70
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• 1996

This paper intends to investigate commercial fish and shellfish 25 species (fish 8 species, shellfish 7 species, crustacean 3 species, moluse 4 species and echinodermata) for the distribution of sanitary indicator organisms (total viable counts, coliforms, staphylococci, vibrios, and enterococci) and distributional change of indicator organisms accordion to storage temperature and period. The logarithmic mean of total viable counts for total commercial fish and shellfish 25 species was 5.41$\pm$.026 CFU/g, and in accordance with fish and shellfishes, crustacean 6.76$\pm$0.67 CFU/g, shellfish 5.67$\pm$0.56 CFU/g, echinodermata 5.47$\pm$1.50 CFU/g, fish 5.02$\pm$0.38 CFU/g, and mollusc 5.03$\pm$0.65 CFU/g. The logarithmic mean of enterococci was 2.36$\pm$0.37 CFU/g, and in accordane with fish and shellfish, crustacean 3.44$\pm$2.12 CFU/g, shellfish 3.87$\pm$0.45 CFU/g, echinodermata 3.38$\pm$0.0 CFU/g, fish 2.16$\pm$0.41 CFU/g and mollusc 0.01$\pm$0.0 CFU/g. The logarithmic mean of vibrios was 1.60$\pm$1.59 CFU/g, and in accordance with fish and shellfish, crustacean 4.23$\pm$1.11 CFU/g, shellfish 3.58$\pm$0.90 CFU/g, echinodermata 1.64$\pm$0.34 CFU/g, fish 1.79$\pm$0.67 CFU/g and mollusc 1.07$\pm$0.61 CFU/g. The logarithmic mean of staphylococci was 1.60$\pm$1.59 CFU/g, and in accordance with fish and shellfish, shellfish 0.01$\pm$0.00 CFU/g, echinodermata 3.51$\pm$0.60 CFU/g, fish 1.68$\pm$0.64 CFU/g, crustacean 0.34$\pm$0.33 and mollusc 3.90$\pm$0.11 CFU/g. The logarithmic mean of coliformas was 2.52$\pm$0.32 CFU/g, and in accordance with fish and shellfish, echinodermata 3.58$\pm$1.89 CFU/g was highest, shellfish 3.25$\pm$0.30 CFU/g, crustacean 3.23$\pm$0.49 CFU/g, fish 2.18$\pm$0.63 CFU/g, peeled shellfish 1.80$\pm$0.51 CFU/g and mollusc 1.55$\pm$0.95 CFU/g. As the results of research of the change of the contaminate indicator microflora in working with storage period at 1$0^{\circ}C$, 2$0^{\circ}C$ and 3$0^{\circ}C$, total viable counts was increased without storage temperature and enterococci were decreased slowly at 1$0^{\circ}C$, but increased at 20 and 3$0^{\circ}C$. Vibrios were decreased slowly at 1$0^{\circ}C$, decreased at 2$0^{\circ}C$ and 3$0^{\circ}C$in 2 days after increased rapidly. Staphylococci were increased promptly without storage temperature in 2 days, then the total viable counts were maintained. Coliforms were increased at 1$0^{\circ}C$ by 7 days, then decreased or maintained after 14 days, changed at 2$0^{\circ}C$ in accordance with fish species in 2 days, then returned to the initial total viable count, and decreased rapidly at 3$0^{\circ}C$ on 2 days. By the way, there were no difference among the species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.6
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• pp.697-703
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• 2018

In 2017, total coliform (TC), fecal coliform (FC) and fecal Streptococci (FS) bacteria were examined in seawater samples collected at coastal sites on Jeju Island (Aewol as a control, Namwon, and Daejeong) and at Pohang (Yeongil as a control, Guryongpo-North, and Guryongpo-South) to examine the correlations between the density of fish farms and distributions of the indicator bacteria. Only a few TC, FC, and FS colonies were detected in all of the samples obtained from Jeju Island. Of note, 2,000 and 1,000 CFU of FS $100mL^{-1}$ were detected in samples from Guryongpo-South in June and August, respectively. Although the total area of approved fish farms located within 5 km of the sampling point at Guryongpo-South is 5-16 times smaller than in other regions, the number of indicator bacteria was highest in this region. Therefore, microbiological pollution in the Guryongpo-South region might be due to sources other than the effluent released from nearby fish farms.

• Journal of Environmental Health Sciences
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• v.36 no.3
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• pp.199-207
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• 2010

In this study, breast milk levels of indicator polychlorinated biphenyls (PCBs) were estimated, and statistics drawn, for 22 Koreans in the general population, aged 26-38, who had resided in metropolitan areas for more than 5 years without occupational exposure to organochlorine pollutants. Concentrations of indicator PCBs were measured using the isotope dilution method with a high resolution gas chromatograph/high resolution mass detector, which provided accurate and precise data for investigation of trends, and international comparisons. The geometric mean of total indicator PCB levels was 22.3 ng/g lipid, which is significantly lower than the level in individuals from European countries. Overall, the geometric mean and 95th percentile of the most abundant congener PCB 153 were 8.04 ng/g lipid and 16.4 ng/g lipid, respectively. PCB congeners 138, 153 and 180 together accounted for about 75% of the indicator congeners analyzed. Breast milk total indicator PCB concentrations were significantly associated with age and parity, but not with body mass index (BMI), rate of body weight increase, or smoking habits. The geometric mean level of PCB 153 in breast milk from mothers with a pre-pregnant BMI < $21\;kg/m^2$ was significantly higher than in pre-pregnant women with a BMI of ${\geqslant}\;21\;kg/m^2$ (p<0.05). Women who ate more fish, meat, and milk products did not have significantly higher total indicator PCB levels than those who ate less of these products, but a significant difference in PCB 153 levels was demonstrated between the subjects consuming higher (11.45 ng/g lipid) and lower (6.79 ng/g lipid) amounts of fish (p<0.05), after adjusting for confounders. These results suggest that age, parity and fish intake are the important factors affecting the concentrations of indicator PCBs in these subjects.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.3 no.2
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• pp.84-96
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• 2022

Most of the islands of Korea are distributed in the South and West Sea, and it consists of independent small stream. As a result, the fish community that inhabits the island's stream is isolated from the mainland and other island. This study utilized a Self-Organizing Map (SOM) and a random forest model to analyze the relationship between environmental variables and fish communities inhabiting islands in South Korea. Through the SOM analysis, the fish communities were divided into three clusters, and there were differences in biotic and abiotic factors between these groups. Cluster I consisted of sites with relatively larger island areas and a higher number of species and population. It was found that 15 out of 16 indicator species were included. Meanwhile, the remaining clusters had fewer species and populations. Cluster II, especially, showed the lowest impact from physical variables such as water width and depth. As a result of predicting the species richness using the random forest model, physical variables in habitats, such as stream width and water depth, had a relatively higher importance on species richness. On the other hand, forest area was the most important variables for predicting Shannon diversity, followed by maximum water depth, and gravel. The results suggest that this study can be used as basic data for establishing a stream ecosystem management strategy in terms of conservation and protection of biological resources in streams of islands.

• International Journal of Advanced Culture Technology
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• v.11 no.2
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• pp.375-380
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• 2023

The study was conducted in Manu-stream, located in Paju, Gyeonggi-do, from January 2021 to December 2021. The survey points were selected in the upper and lower streams based on where thermal discharged to investigate water temperature and fish species and biological community analysis and growth rate were analyzed. The average annual water temperature difference between the upper and lower stream is about 11.0℃, and in the case of the lower stream area, the water temperature is maintained at 20.0℃ or more per year. Fish that appeared during the survey period decreased lower stream compared to the upper stream, which is believed to be the result of a decrease in temperature-sensitive species as the simple riverbed structure and water temperature increased compared to the upper stream. As a result of biological community analysis, it showed a relatively stable community state at the upper stream. The growth rate of fish has a high regression coefficient b value in lower streams throughout the four seasons. It showed relatively good growth lower stream, with a high water temperature. However, the results of each survey point are similar from season to season. The indicator species is a resistant intermediate species, and the range of resistance to water temperature is wide, so it is judged that water temperature's effect on the indicator species' growth is low.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.1
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• pp.24-30
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• 2007

We developed an ecosystem indicator (EI) for the coastal and offshore areas of Korean waters. One of the major scientific challenges of this undertaking was to translate broad policy statements for ecosystem-based fisheries management (EBFM) into practical terms. Fish reproduction potential (FRP) was defined as an EI to describe the reproductive probability of adult fisheries resources in Korean waters. The FRP was estimated as the ratio of adult fish composition to total catch, catches (in metric tons) by species and by ecosystem, and fishery effort (in horse power per metric ton). The FRP indices of the East/japan Sea Ecosystem (EJSE), Yellow Sea Ecosystem (YSE), and East China Sea Ecosystem (ECSE) began to decrease after the mid-1980s, and the current indices have decreased further, at 0.63 (EJSE), 1.22 (YSE), and 0.68 (ECSE) index points compared to the indices of 1975, when similar catch amounts were recorded. Lower FRPs in the Korean marine ecosystems were the result of higher proportion of immature fisheries resources in the total catch. Because this kind of ecosystem-level indicator is thought to reflect scientific approaches to EBFM and to provide an important tool for assessing the current status of marine ecosystems with respect to both quantity and quality, more EIs should be developed for Korean waters.

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.212-220
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• 2009

In this study, we analyzed fish compositions and ecological characteristics such as trophic guilds and tolerance guilds in association with water quality characteristics in Masan Reservoir during November 2008. Total number of species were 12 species (6 families) and the dominant species were Zacco platypus, Hemiculter eigenmanni, and Pseudorasbora parva. We found three Korean endemic species and one exotic species, Carassius cuvieri. According to the analysis of ecological indicator characteristics, relative proportion of tolerant and omnivore species was 98% of the total indicating that probably, the fauna was influenced by physical habitat disturbance and physicochemical degradations. Fish distribution analysis along with littoral zone showed that the most fishes (${\sim}$95%) were observed in the littoral zone where emerged macrophytes were well developed. Also, substrate analysis indicated that the most species were found near silt area (11 species, 91.7%), so that the significant differences were found between the substrate types. Analysis of water quality indicated that concentrations of total phosphorus (TP) and chlorophyll-a (ChI-a) as a lake trophic indicator were judged as eutrophic states, respectively and COD as an indicator of organic matter pollution averaged 10.9 mg $L^{-1}$. Based on the water quality, this system were influenced by the nutrient enrichments and organic matter. The degradations of water quality in Masan Reservoir resulted in trophic compositions of fish (increase of omnivore species) and the dominance of tolerant fish. This Monitoring data may contribute changes of fish fauna and compositions in relation to habitat modifications and chemical water quality degradations in the future.

• Journal of Fisheries and Marine Sciences Education
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• v.21 no.3
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• pp.451-458
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• 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.