• Development and Reproduction
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• v.19 no.4
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• pp.181-187
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• 2015

Early life stage mortality in fish is one of the problems faced by loach aquaculture. However, our understanding of immune system in early life stage fish is still incomplete, and the information available is restricted to a few fish species. In the present work, we investigated the expression of immune-related transcripts in loach during early development. In fishes, recombination-activating gene 1 (RAG-1) and sacsin (SACS) have been considered as immunological function. In this study, the expression of the both genes was assessed throughout the early developmental stages of loach using real-time PCR method. maRAG-1 mRNA was first detected in 0 dph, observed the increased mostly until 40 dph. Significant expression of maRAG-1 was detected in 0 to 40 dph. These patterns of expression may suggest that the loach start to develop its function after hatching. On the other hand, maSACS was detected in unfertilized oocyte to molura stages and 0 to 40 dph. maSACS mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.238-241
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• 2018

The purpose of this study was to investigate color pattern and growth in cross progenies between kois and red common carp (Cyprinus carpio). Coverage of red color patches in skin was investigated in $koi{\times}koi$ (KK), $koi{\times}red$ common carp (KR) and red common $carp{\times}koi$ (RK) progenies in 170 days post-hatching (DPH) by analysis of digital photographs. KR cross group had higher length (P<0.05) and the mean weight than in the KK but there were no significant difference between KR and RK. All groups consisted of three color pattern white, white-red and red. The percentage of red-area coverage in skin was 64% in KK progenies, 56% in KR and 36% in RK. The red coverage (30~50%) was highly in KR (15%) than in KK (10%) and RK (12%). The application of red-area body coverage analysis may suggest potentially useful tool for ornamental fish selection.

• The Journal of Fisheries Business Administration
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• v.46 no.1
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• pp.63-74
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• 2015

Due to red tide and abnormal currents that take place every year, the damage of inland fish farms that takes sea water is increasing frequently. Also, the households of inland fish farm due to the increase in the cost of fuel and electricity are struggling many hardships economically. In relation to underground seawater for it's farm analyzed economic effect based on the actual conditions for 1,700 inland fish farms, from this I have deduced policy implications for direction this project to be pursued from now on. The saving rate of costs of the fuel and electricity through the development of an underground seawater were approximately analyzed to decline about 3.4~9.7%, if utilizing only about 5% of the undeveloped farms, it was estimated effect of about 61 billion won, if 10%, it was estimated effect of about 122 billion won. Consideration in selecting the developer of underground seawater will be selected an character of farm method. It is expected this study will be helpful for business analysis related government in the fisheries.

• Development and Reproduction
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• v.24 no.4
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• pp.277-285
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• 2020

The disease-causing koi herpes virus (KHV), also known as cyprinid herpesvirus-3 (CyHV3), causes mass mortality of koi and carp. Koi (Cyprinus carpio) is a host for KHV, one of 12 virus species in the Alloherpesviridae family. We examined the effects of KHV disease koi (KK), and on koi×red common carp (KR) and red common carp×koi (RK) cross, using a virus challenge test. The infected fish had clinical signs that included gill necrosis and skin lesions. The RK and KR were highly more resistant (cumulative mortality: RK; 6% and KR; 8%) to KHV infection than KK fish (cumulative mortality: 28%). KHV DNA was confirmed in the tissues of all dead fish in groups by use of polymerase chain reaction (PCR), and the presence of the KHV protein in kidney was confirmed by immunohistochemistry. Histological analysis showed severe gill lesions and fusion of the lamellae in KK fish, but less severe damage in RK fish. In immunohistochemistry analysis, the KHV protein localized in the cytoplasm of infected kidney cells of KK, but the cross groups had lower levels of KHV antigen. Our data indicate that the cross groups had increased resistance to KHV disease.

• Fisheries and Aquatic Sciences
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• v.19 no.4
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• pp.17.1-17.9
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• 2016

The seasonal variation of fecal coliforms (FCs) and physicochemical factors was determined in seawaters of the Hansan-Geojeman area, including a designated area for oyster, and in inland pollution sources of its drainage basin. The mean daily loads of FCs in inland pollution sources ranged from $1.2{\times}10^9$ to $3.1{\times}10^{11}$ most probable number (MPN)/day; however, the pollutants could not be reached at the designated area. FC concentrations of seawaters were closely related to season, rainfall, and inland contaminants, however, within the regulation limit of various countries for shellfish. The highest concentrations for chemical oxygen demand (COD) and $chlorophyll-{\alpha}$ in seawaters were shown in the surface layer during August with high rainfall, whereas the lowest for dissolved oxygen (DO) in the bottom layer of the same month. Therefore, it indicates that the concentrations of FC, COD, DO, and $chlorophyll-{\alpha}$ of seawaters were closely related to season and rainfall.

• Korean Journal of Ichthyology
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• v.8 no.2
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• pp.68-73
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• 1996

This study was carried out to obtain the basic information on morphological and chromosomal charateristics in the three species of Chinese carps (grass carp; Ctenopharyngodon idellua, bighead carp; Aristichthys nobilis, and silver carp; Hypophthalmichthys molitrix) introduced to Korea from China. C. idellua was differ from A. nobilis and H. molitrix by the number of gill rakers, scales, fin rays, body proportion. A. nobilis and H. molitrix were similar in having ventral keel and many scale number, but H. molitrix was differ from A. nobilis by the connected gill rakers and body color pattern. Diploid chromosome and arm number (fundamental number, NF) of the three species were all the same to 2n=48 and NF=84. Diploid chromosome numbers in the three species are consisted of 10 pairs of metacentric chromosome, 8 pairs of submetacentric chromosome and 6 pairs of acro and/ or telocentric chromosome. Morphological and karyological relationship of the three Chinese carps are discussed.

• Korean Journal of Ecology and Environment
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• v.44 no.4
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• pp.364-372
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• 2011

The pale chub (Zacco platypus) is generally found in Asian countries, such as Korea, Japan, and China. Nevertheless, very little information exists about the genes involved in the metabolism of xenobiotics in this species. This species is useful in monitoring the environmental impact on various pollutants in freshwater as a sentinel fish species. We cloned the full-length cDNA sequence of xenobiotic metabolizing cytochrome P450 1A (CYP1A) gene from Z. platypus and characterized it. Tissue distribution and timedependent induction of CYP1A were studied by real-time RT-PCR. Induction pattern of CYP1A was studied by exposing the fish to an arylhydrocarbon receptor agonist, ${\beta}$-naphthoflavone (BNF). The liver showed the highest level of expression in basal state as well as BNF- treated fish. However, appreciable levels of expression were also recorded in Gill and kidney and the least level of expression was observed in the eye. The results of the time-course study revealed an induction in the liver, brain, and gills after 6 h and 12 h in most of the tissues. This study provides an insight into the xenobiotics metabolizing system of Z. platypus and offers baseline information for further research related to biomarker, stress, and adaptive response of this ecologically important fish species in the freshwater environment.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.49 no.5
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• pp.564-572
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• 2016

In this study, we isolated and characterized Escherichia coli from mussels and inland pollution sources in or in proximity to the Changseon area on the southern coast of Korea in 2014. A total of 147 strains of E. coli were isolated from 54 mussels and 32 pollution-source samples. The susceptibility of the isolates to 24 antimicrobial agents was analyzed. The resistance of E. coli isolates to rifampin was highest at 100%, followed by cephalothin (98.6%), tetracycline (91.8%), amikacin (81.0%), ampicillin (79.6%), cefazolin (79.6%), streptomycin (73.5%), piperacillin (70.7%), gentamicin (37.4%), cefoxitin (35.4%), cefamandole (34.7%), tobramycin (29.9%), amoxicillin/clavulanic acid (24.5%), nalidixic acid (21.8%), trimethoprim (19.0%), chloramphenicol (17.7%), cefotaxime (12.9%), trimethoprim (10.9%), ceftazidime (10.2%), aztreonam (7.5%), imipenem (2.7%), cefepime (2.0%), and cefotetan (0.0%). In addition, the antimicrobial resistance of E. coli isolates from inland pollution sources was slightly greater than or similar to that of isolates from mussels.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.4
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• pp.377-387
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• 2021

Fecal contamination levels of discharge water from inland pollution sources were investigated in Iwon-myeon (Taean-gun), South Korea. Gram-negative bacteria were isolated during the investigation and the antimicrobial resistance patterns of the isolates were examined to estimate their impact on the coastal environment. The ranges of total coliform and fecal coliform of 12 samples from four major inland pollution sources were 79-490,000 MPN/100 mL and 2.0-490,000 MPN/100 mL, respectively, with the highest level of fecal contamination at Station No. 3. A total of 137 strains (14 genus) were isolated, of which 86 strains (62.8%) were Enterobacteriaceae. The identified isolates were as follows: Pseudomonas spp. (35 strains), Klebsiella spp. (20 strains), Serratia spp. (20 strains), and Escherichia spp. (19 strains). The isolated Gram-negative bacteria showed the highest antimicrobial resistance to ampicillin (81.8%), followed by amoxicillin/clavulanic acid (64.2%), ceftiofur (61.3%), and cefoxitin (59.1%). Antimicrobials in which less than 10% of isolates showed antimicrobial resistance were ciprofloxacin (3.6%) and gentamicin (2.2%). Resistance to one or more antimicrobials was observed in 121 strains (88.3%) and 84 strains (61.3%) showed a tendency for multiple antimicrobial resistance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.615-625
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• 2023

This study evaluated the bacteriological safety of seawater and abalone produced in Uisin-myeon, Jindo-gun from September 2020 to December 2022 and calculated the effect of inland pollution sources on seawater and abalone. We surveyed 33 stations for seawater, 4 stations for abalone, and 7 stations for discharge water of major inland pollutants. We analyzed the coliform group, fecal coliform and Escherichia coli (E. coli) as bacteria indicators. In 924 seawater samples, the geometric mean of the coliform group and fecal coliform were <1.8-5.6 MPN/100 mL and <1.8-2.7 MPN/100 mL, respectively. The estimated 90^th percentile range for the coliform group and fecal coliform were <1.8-42 MPN/100 mL and <1.8-8.4 MPN/100 mL, respectively. The fecal coliform and E. coli levels for 107 abalone were <18-460 MPN/100 g and <18-78 MPN/100 g respectively. Moreover, the analyzed standard plate count was <30-7,700 CFU/g. The fecal coliform level and diffusion area in 7 inland pollutants were <1.8-3,300,000 MPN/100 mL and 2-2,500 m, respectively. The bacteriological safety of seawater and abalone in Uisin-myeon, Jindo-gun, was demonstrated to be a designated area according to Korean standards, a conditionally approved area per US standards, and Class A according to EU standards.