• Journal of Aquaculture
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• v.19 no.3
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• pp.205-209
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• 2006

Genetic change from broodstock to hatchery stock of the olive flounder Paralichthys olivaceus and effective number of breeders (Ne) were investigated by the different fertilized-egg collecting methods; E1 (eggs collected one day after spawning) and E2 (eggs collected two days after spawning) using seven microsatellite loci (Kop2, Kop22, Kop18, Kop3, Kop21, Kop9 and Kop26) for the better understanding of stock enhancement. Observed heterozygosity in three stocks ranged from 0.651 at Kop3 to 0.928 at Kop22, with offspring being slightly higher heterozygous over their parents. However, the genetic reduction of offspring was significant. The offspring allele number per locus was reduced to 23.5% for E1 and 17.6% for E2 of their maternal number. Ne to the hatchery stock was estimated to be 21.9 for E1 and 34.3 for E2. The inbreeding coefficients of populations El and E2 were 0.023 and 0.015, respectively. The present study suggests the extension of the egg collection period for a recovery of the genetic diversity in artificially produced offspring.

• Microbiology and Biotechnology Letters
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• v.38 no.3
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• pp.322-328
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• 2010

Fermented skate is a traditional Korean food popular in Southwestern area of Korea. It has a characteristic flavor and alkaline pH. In this study we tried to determine the microbial flora in fermented skate using two different approaches. In culture-independent method, we amplified V2 region of 16S rRNA gene by PCR and cloned them into pUC18 plasmid to construct 16S rDNA fragment library. BLAST searches for the sequences obtained from this library revealed that uncultured bacterium clone 054E11.b was the most dominant flora in this fermented fish. In culture-dependent method, we diluted suspension of skate and spreaded on MRS, PCA, and MacConkey plates. We identified colonies grown on those plates by using PCR amplification of V2 region of 16S rRNA and DNA sequencing. BLAST searches of those DNA sequences resulted in totally different species with the observations from the 16S rDNA library analysis. Discrepancies of results obtained from both approaches suggest that the agar plates used in culture-dependent method may be different from the real condition of fermented skate. Therefore, results from culture-independent approach using 16S rDNA fragment library analysis may reflect real microbial flora in fermented skate.

• Korean journal of applied entomology
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• v.59 no.4
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• pp.433-441
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• 2020

This study was conducted to understand the distribution characteristics of aquatic insects in ecologically different ponds in terms of the disruption. We investigated the fauna of aquatic insects in three artificial ponds (pond 1, 2 and 3) and two natural ponds (pond 4 and 5) located within 1 km each other around Gungdaeoreum in Jeju Island, from March 2018 to June 2020. A total of 50 species belonging to 15 families were found in the surveyed ponds: total 850 individuals with 14 species in 4 families of the order Odonata, total 4,391 individuals with 14 species in 6 families of the order Hemiptera, and total 2,014 individuals with 22 species in 4 families of the order Coleoptera. In overall, total abundance and species numbers were relatively higher than those of artificial pond in natural ponds in which animal and plant ecosystems were well established. In the case of artificial ponds, the number of individuals and species recovered rapidly when reconstituted by introducing aquatic plants, etc. (Pond 1). The nymphs of Odonata were observed largely in ponds without natural enemies such as large fish, and where adults could freely access without interception by artificial structure. Phytophagous Corixidae of the order Hemiptera were abundant, and Haliplidae populations of the order Coleoptera were affected by the distribution of the plants. Accordingly, the major factors affecting aquatic insect abundance were identified as the presence of refuges such as the topography and aquatic plants and presence of predators. Species of the order, Odonata were vulnerable based on these factors. Our results can be useful as basic information for the restoration of wetlands and construction of artificial wetlands or for conservation of species diversity in the future.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.287-296
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• 2021

This study was conducted to investigate the species composition collected by fyke net and characteristics of the Erythroculter erythropterus population in the Asan Lake and Chungju Lake from June to September, 2021. The collected fish in Asan lake were identified as 4,977 individuals of 13 species from a total of six families and in Chungju lake were identified as 2,436 individuals of 18 species from a total of eight families. The dominant species in Asan lake, both the individuals and biomass were E. erythropterus with 4,470 (89.8%) and 498,424g (84.5%). The dominant species in Chungju lake, both the individuals and biomass were E. erythropterus with 1,327 (54.5%) and 301,818 g (77.5%). The results of the community analysis showed that a dominant index value of Asan lake was 0.93, higher than 0.71 of Chungju lake, and a diversity, evenness, and richness index value of Chungju lake were higher than of Asan lake. The frequency distribution of the total length analysis of the E. erythropterus population showed the appearance rate of 1~2 year olds was high in Asan lake, and the appearance rate of more than 2 years old were high in Chungju lake. The length-weight analysis of E. erythropterus in Asan Lake and Chungju Lake showed a regression coefficient b of 3.06 and 3.04, a condition factor (K) of 0.000128 and 0.000051 with a positive slope. This study could be served as baseline data for assessing habitat characteristics based on the species composition of fishes, and identifying health conditions of E. erythropterus in Asan Lake and Chungju Lake, artificial lakes.

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.64-72
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• 2005

The data for the present study were collected from the both-sides fyke net fishery in coastal Dolsan, Korea, from March 2003 to February 2004 A total of 2,402 individuals (432,42 kg) were collected and identified to 11 orders, 34 families, and 48 species. The most dominant order was the Perciformes, comprising 21 species in 15 families, followed by Scorpaeniformes, 8 species in 5 families, and Pleuronectiformes, 5 species in 3 families, These three orders constituted 67.9% of the total collected fish. The most dominant species, Acanthopagrus schlegeli, accounted for 279 individuals (20.26 kg), followed by Mugil cephalus with 187 individuals (99.61 kg), and Konosirus punctatus with 178 individuals (8.89 kg). The diversity index of the fish catches was 1.6823~2.9105 and was the highest in September 2003 and the lowest in December 2003. The evenness index was 0.6585~0.8872 it was the highest in August 2003 and the lowest in December 2003. The dominance index was 0.2000~0.6852, with the highest in December and the lowest in August 2003.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.82-92
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• 2007

In 2003, we evaluated biological water quality at twelve sites of Youngsan River using community analysis, fish compositions, and the Index of Biological Integrity (IBI). Of the twelve, four sites were the controls, which have no point sources in the upstream and the remaining eight sites were the impacted sites, which are influenced by wastewater treatment plant (WTP) and agro-industrial complex. Model values of the IBI, based on 12 sites data, averaged 28 (n=12, range: $18{\sim}44$), indicating fair poor condition according to the criteria of US EP A (1993). In the mean time, mean IBI in the control sites (S3, S5, S6, S11) was 42 (n=4, range: $38{\sim}44$), indicating a good condition, whereas mean IBI in the impacted sites was 21, indicating a poor condition. Mean IBI value in the control, thus, was greater by 2 fold than that in the WTP sites. The spatial pattern of IBI values was similar to the patterns of species diversity index and species richness index, except for Site 11, which was 1st order stream. Similarity analysis indicated that three groups were divided at the similarity level of 80%. One group was the streams influenced by wastewater and the other two groups were the pristine streams as the control, indicating that the stream health conditions are directly influenced by presence or absence of the point sources. Also, Pearson's correlation analysis showed that IBI values had negative correlation (r=0.899, p<0.001) with relative abundance of tolerance species, and had positive relation (r=0.890, p<0.001) with sensitive species. Overall, outcomes suggest that the point sources of the WTP might impact the species composition and ecological health, resulting in degradation of biological water quality.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.127-136
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• 2020

This study was conducted to investigate the population characteristics of Nile tilapia (Oreochromis niloticus) in the Daegu Metropolitan City thermal effluent stream (Dalseo Stream) from January to November 2019. The collected fish were identified as 4,247 individuals of 20 species from a total of eight families. The dominant species was O. niloticus with 1,306 individuals and a high relative abundance (30.75%). The water temperature of Dalseo Stream was maintained above 10℃ throughout the year, which means that O. niloticus could inhabit it even in winter. The length-weight analysis showed a regression coefficient b of 3.1496, and a condition factor (k) of 0.0025 with a positive slope. Comparing the water temperature of Dalseo Stream and the total length of O. niloticus per investigation period, the 0-age individuals appeared May 29 when the water temperature was maintained above 22℃. In conclusion, the thermal effluent of Dalseo Stream allowed O. niloticus to survive in winter and maintain stable growth conditions and life cycles. The results of this study will inform ecological information on O. niloticus, which suggests that river management efforts should consider the management of O. niloticus populations for the conservation of fish species diversity.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.145-156
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• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.

• Journal of Wetlands Research
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• v.8 no.2
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• pp.53-64
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• 2006

A study on the restoration process of a stream ecosystem and the water quality renovation technique by removing algae, vegetation and fish monitoring as evaluating the removal of the algae by dietetic characteristics of fishes were performed on Sangdong stream in the B city after stream restoration it to the artificial stream as the cases, restoring urban stream into close-to-nature stream are being increased domestically with the aim of ecological city. As a result, restoration and rehabilitation of the fundamental stream ecosystem was well maintained 4 years later the reclamation at the moment and total 93 diagnosis which were all vascular plant phylum including 44 families, 73 genuses, 79 species and 14 varieties in flora and vegetation community were observed. 3 families, 8 species and 354 populations in total among Fishes were found and Pseudorasbora Parva, Cyprinus Carpic and Carassius Auratus strongly resistant to water pollution were dominantly appeared in order of 50.5% of Pseudorasbora Parva 21.2% of Cyprinus Carpic, 20.9% of Carassius Auratus, 7.1% of Macropodus chinensis and 0.3% of Misqurnus anguillicaudatus according to relative richness index. It turned out to be that Cyprinus Carpic ingests algae over 90% and Carassius Auratus takes it over 30% according to the analysis about the alimentary object of the fishes as a consequences of algae's excrescent from characteristics of the tested experimental stream. It is reported that a Cyprinus Carpic, about 34 cm in length, ingested wet-weight 43.2g algae on the rough analysis toward the sample which makes us recognize how effective a macro community Cyprinus Carpic is for removing algae.As a consequence of this research, the effect of stream ecosystem characteristics and water quality purification could not be expected by aquatic plants and trees which were eliminated at experimental stream. From now on, a close-to-nature stream should be formed of ecological hydraulic and hydrologic engineered modeling from the beginning so that it can perform the water quality purifying function. It is determined that the structure of food chain will be abundantly influenced by the induction of oversized macro community like Cyprinus Carpic because a biomass of a consumer of higher order is increased. It is estimated that the removal algae by fishes is not effective despite in some cases of dietetic characteristics so much more studies should be executed in the future.