• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.1
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• pp.68-72
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• 1994

Six brands of encapsulated fishoil products and five fishes were analyzed for their contents of eicosapentaenoic acid (EPA 20 :5 n-3) , docosahexaenoic acid(DHA 22: 6 n-3) and tocopherols. In both of the fish oil products and the fishes, major fatty acids were palmitic acid, oleic acid, eicosapentaeoic acid and docosahexaenoic acid and fatty acid compositions were also similar pattern each other. EPA showed variable amounts from 19.2 to 50.3% in the oil products whereas DHA were 13.2% to 28.3% inthe fishes. Tocopherols were studied in relation to the oxidative stability of fish products no relation was observed. However the amount of tocopherols in fish oil proudcts were higher than that of fishes. Contents of EPA, DHA and tocopherols in encapsulated fishoil products oil products were variable comparing with manufactures' claimed contents.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.10a
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• pp.510-513
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• 2016

Detecting of the object in image processing is substantial but it depends on the object itself and the environment. An object can be detected either by its shape or color. Color is an essential for pattern recognition and computer vision. It is an attractive feature because of its simplicity and its robustness to scale changes and to detect the positions of the object. Generally, color of an object depends on its characteristics of the perceiving eye and brain. Physically, objects can be said to have color because of the light leaving their surfaces. Here, we conducted experiment in the aquarium fish tank. Different color of fish robots are mimic the natural swim of fish. Unfortunately, in the underwater medium, the colors are modified by attenuation and difficult to identify the color for moving objects. We consider the fish motion as a moving object and coordinates are found at every instinct of the aquarium to detect the position of the fish robot using OpenCV color detection. In this paper, we proposed to identify the position of the fish robot by their color and use the position data to control the fish robot gathering in one point in the fish tank through serial communication using RF module. It was verified by the performance test of detecting the position of the fish robot.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.1055-1062
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• 2014

Hydroacoustic surveys were conducted for spatio-temporal distribution and size estimation of fish in the Yongdam reservoir, Korea, from April to July 2014. Acoustic data were collected along acoustic transects using a 120 kHz scientific echosounder. The received acoustic data were the in situ acoustic target strength (dB) and nautical area scattering coefficient ($m^2/mile^2$). Data on fish behavioral patterns and size were collected using a DIDSON acoustic camera at stationary stations. Fish were mainly distributed in the center channel and close to the outer Yongdam reservoir. Acoustic density of fish in the summer season were higher than in the spring season. The seasonal vertical distribution pattern of fish aggregations may be strongly related to the vertical temperature structure. The size distribution of fish obtained from an acoustic camera correlated well with the acoustic size of fish from an echosounder.

• Fisheries and Aquatic Sciences
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• v.21 no.3
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• pp.12.1-12.15
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• 2018

A preliminary investigation of length-weight relationship, condition factor and reproductive ecology of African pike fish, Hepsetus odoe, was conducted between June to August 2010 in Lake Eleiyele. A total of 90 samples of the fish species were caught by fishermen using gill nets. The results obtained showed that fish species had isometric growth pattern (contrary to negative allometry expected) with the growth exponent, b value of 2.64, that is not statistically different from 3 and with high statistical power of 0.866 when tested. The mean condition factor, K, was found to be 2.6, indicating that the fish species were in good condition in the study area. For reproductive biology, mean fecundity and gonadosomatic index were found to be 1349 eggs and 3.53% respectively. This study was necessary to fill the knowledge gap and provide information for management and conservation of the investigated species in the lake system. This study recommended that further research needs to be conducted because the sampling was carried out in the rainy season period and within a quarter of a year.

• Fisheries and Aquatic Sciences
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• v.22 no.8
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• pp.18.1-18.5
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• 2019

The development of sex-specific genetic assays in a species provides both a method for identifying the system of sex determination and a valuable tool to address questions of conservation and management importance. In this study, we focused on the identification of single nucleotide polymorphisms (SNPs) that differentiate genetic sex in burbot Lota lota. Burbot are the only true freshwater representative of the cod family and a species of conservation and management importance throughout Eurasia and North America. To identify sex-specific SNPs, we utilized restriction site-associated DNA sequencing (RADseq) to interrogate thousands of SNPs in burbot samples of known phenotypic sex. We discovered 170,569 biallelic SNPs, none of which fit the pattern expected under female heterogamety. However, we identified 22 SNPs that fit the pattern expected under male heterogamety (males heterozygous XY, females fixed XX) and, from these, developed two genetic assays that robustly (~ 97% genotyping success) and accurately (> 99% correct) sexed burbot samples. These sex-specific genetic assays will benefit growing conservation aquaculture programs for this species and allow future assessments of sex-specific migration, growth, and mortality.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.34-44
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• 2016

Background: Little is known about how chemical water quality is associated with ecological stream health in relation to landuse patterns in a watershed. We evaluated spatial characteristics of water quality characteristics and the ecological health of Dongjin-River basin, Korea in relation to regional landuse pattern. The ecological health was assessed by the multi-metric model of Index of Biological Integrity (IBI), and the water chemistry data were compared with values obtained from the health model. Results: Nutrient and organic matter pollution in Dongjin-River basin, Korea was influenced by land use pattern and the major point sources, so nutrients of TN and TP increased abruptly in Site 4 (Jeongeup Stream), which is directly influenced by wastewater treatment plants along with values of electric conductivity (EC), bacterial number, and sestonic chlorophyll-a. Similar results are shown in the downstream (S7) of Dongjin River. The degradation of chemical water quality in the downstream resulted in greater impairment of the ecological health, and these were also closely associated with the landuse pattern. Forest region had low nutrients (N, P), organic matter, and ionic content (as the EC), whereas urban and agricultural regions had opposite in the parameters. Linear regression analysis of the landuse (arable land; $A_L$) on chemicals indicated that values of $A_L$ had positive linear relations with TP ($R^2=0.643$, p < 0.01), TN ($R^2=0.502$, p < 0.05), BOD ($R^2=0.739$, p < 0.01), and suspended solids (SS; ($R^2=0.866$, p < 0.01), and a negative relation with TDN:TDP ratios ($R^2=0.719$, p < 0.01). Conclusions: Chemical factors were closely associated with land use pattern in the watershed, and these factors influenced the ecological health, based on the multimetric fish IBI model. Overall, the impairments of water chemistry and the ecological health in Dongjin-River basin were mainly attributes to point-sources and land-use patterns.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1412-1419
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• 2023

Retroviral integration into ancient vertebrate genomes left traces that can shed light on the early history of viruses. In this study, we explored the early evolution of retroviruses by isolating nine Spuma endogenous retroviruses (ERVs) and one Epsilon ERV from the genomes of Agnatha and Chondrichthyes. Phylogenetic analysis of protein sequences revealed a striking pattern of co-evolution between jawless fish ERV and their host, while shark ERV underwent ancient cross-class viral transmission with jawless fish, ray-finned fish, and amphibians. Nucleotide sequence analysis showed that jawless fish ERV emerged in the Palaeozoic period, relatively later than ray-finned fish ERV. Moreover, codon analysis suggested that the jawless fish ERV employed an infection strategy that mimics the host codon. The genealogical diversity of ERVs in the jawless fish genome highlights the importance of studying different viral species. Overall, our findings provide valuable insights into the evolution of retroviruses and their interactions with their hosts.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.2
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• pp.103-110
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• 2016

This study aims to estimate the species, size and shape of fish using a non-contact 3 dimensional pattern laser so that this preliminary test was carried out to understand the structural feature and length of goldfish according to water turbidity and depth in the aquacultural tank. 3-D pattern laser could clearly detect its morphological shape except the caudal fin due to soft tissue. Since the sensing strength of line laser light according to depth has sufficient power, it is possible to measure its depth and structural feature in the detected range. The result showed that the measured error of individual's fork length was less than ${\pm}1%$ in the water using 3-D pattern laser, when compared with the measured value in the air.

• Journal of fish pathology
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• v.24 no.3
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• pp.279-287
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• 2011

Transcriptional response patterns of mud loach (Misgurnus mizolepis; Cypriniformes) hepcidin, a potential ortholog to human hamp1, in response to experimental challenges with non-pathogenic and pathogenic bacterial species were analyzed based on the semi-quantitative reverse transcription-PCR assay. Mud loach hepcidin transcripts were much more preferentially induced by pathogenic bacterial species (Edwardsiella tarda and Vibrio anguillarum) causing apparent pathological symptoms than by non-pathogenic species (Escherichia coli and Bacillus thuringiensis) displaying neither clinical signs nor mortality. However in overall, the induced amounts of hepcidin transcripts were positively related with the number of bacterial cells delivered in both pathogenic and non-pathogenic bacterial species. Inducibility of hepcidin transcripts were variable among three tissues examined (liver, kidney and spleen) in which kidney and spleen were more responsive to the bacterial challenge than liver. Time course expression patterns of hepcidin mRNAs after challenge were different between groups challenged with pathogenic and non-pathogenic species, although the overall pattern of hepcidin expression was in accordance with that generally observed in battery genes appeared during early phase of inflammation. Fish challenged with E. coli (non-pathogenic) showed the significant induction of hepcidin transcripts within 24 hr post injection (hpi) but the level was rapidly declined to the basal level either at 48 or 96 hpi. On the other hand, hepcidin transcript levels in E. tarda (pathogenic)-challenged fish were continuously elevated until 48 hpi, then downregulated at 96 hpi, although the level at 96 hpi was still significantly higher than control level observed in non-challenged fish. This expression pattern was consistent in all the three tissues examined. Taken together, our data indicate that hepcidin is tightly in relation with pathological and/or inflammation status during bacterial challenge, consequently providing useful basis to extend knowledge on the host defensive roles of hepcidin under infectious conditions in bony fish.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.6
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• pp.435-439
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• 2008

The antimicrobial resistance of 160 strains of Enterococcus faecalis and 173 strains of E. faecium to 12 antimicrobial agents was investigated. The test strains were isolated from 126 wild seawater and farmed fish, including olive flounder (Paralichthys olivaceus), black rock fish (Sebastes schlegeli), red sea bream (Pagrus major), and sea bass (Lateolabrax japonicus), in 2005 and 2006. Overall, 91.9% of the E. faecalis isolates and 88.4% of the E. faecium isolates showed antimicrobial resistance to at least one antimicrobial agent. The pattern of antimicrobial resistance of the isolates differed little according to the species of fish. The percentage of E. faecalis and E. faecium with specific antimicrobial resistance differed according to the sample source. For the isolates from farmed fish samples, 66.7% of E. faecalis were tetracycline resistant and 54.5% of E. faecium were erythromycin resistant. By contrast, in the wild fish seawater samples, 92.0% of E. faecalis were rifampin resistant and 88.5% of E. faecium were tetracycline resistant.