• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.167-177
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• 2006

Both fish community and water quality in Lake Doam were investigated from September 2004 to August 2005. The turbidity of Lake Doam located in the upper region of the Songchun River in the South River system, Korea was high whole year due to the effects of distributed non point source pollutions in the watersheds. During the experimental periods, mean concentration of chlorophyll-a in epilimnetic layer (0 ${\sim}$ 5 m) was 18.5 ${\mu}g\;L^{-1}$ and transparency ranged from 0.3 m to 2.4 m. Average TP and TN concentrations were 111 ${\mu}g\;L^{-1}$ and 4.1 $mg\;L^{-1}$, respectively. Lake was classified as eutrophic state based on the nutrient concentrations suggested by U.S.EPA (1976). Total number of fish collected in Lake Doam was 9,600 individuals in 26 species of 6 family. Both dominant and subdominant species in the lake were P. herzi (34.9%) and Z. platypus (22.5%), respectively. Occurrence of water column species was high at upper region of the lake, whereas benthic type of species highly ,appeared in downstream area. The different fish assemblage between upper and lower area would be considered as the difference of bottom substrate and concentrations of suspended solids. In addition high appearance of Comat type of fish that is hybrid between gold fish (C, auratus) and C. auratus was found in the lake. It was unclear the reasons that high proportion of mutant species appeared in the lake. More researches are required in this area in future.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.255-262
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• 2010

This study was conducted at 5 sites of Bocheong Stream basin in May and September 2009 for the evaluate of fish assemblage and chemical water quality. For the study, the models of Index of Biological Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) were modified as 8 and 11 metric attributes, respectively. We also analyzed patterns of chemical water quality at the sampling site over the period of 2005~2009, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. The survey showed that total sampled fishes were 34 species and the most dominant species was Zacco platypus (24.3%). In Bocheong Stream basin, values of IBI averaged 28 (n=5), which is judged as a "Good". IBI score at B1, B4 and B5 indicating a "Good" condition whereas, B2 and B3 were as 21 and 22, indicating "Fair" condition, respectively. QHEI was 152 (n=5), judged as "Fair" habitat condition. Values of BOD and COD averaged 1.0 $mgL^{-1}$ (scope: 0.3~4.0 $mgL^{-1}$) and 2.3 $mgL^{-1}$ (scope: 0.3~18.7 $mgL^{-1}$), respectively. Total nitrogen (TN), total phosphorus (TP) and suspended solid (SS) were distinct spatial variation. Based on the IBI, QHEI and chemical water quality dataset, ecological health of Bocheong Stream basin was evaluated that generally good.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.403-411
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• 2007

The purpose of the study was to evaluate fish community, based on conventional at Shannon-Weaver diversity index (H'), and ecological health, based on the Index of Biological Integrity (IBI) using fish assemblage in the eight sites of Nakdong River during June${\sim}$August 1999. Total number of species sampled was 19 species, and two sensitive species of Zacco temminckii (51%) and Rhynchocypris oxycephalus (28%) dominated the fish community. Also, trophic guild analyses showed that insectivore was 87% of the total and omnivore was rare, indicating that the ecological health is well maintained in the system. The pattern of spatial variation in the diversity index(H') was very similar to patterns of the species number and individual number, whereas the pattern of H' was not matched with the tolerance and trophic guild data. The diversity index (H') showed highest (1.56) in Site 6 where the proportion of sensitive species and tolerant species was minimum and maximum, respectively, and where the insectivore and omnivore were minimum and maximum. In other words, the diversity index was not matched at all with the trophic and tolerant guilds, indicating that the conventional index did not reflect the ecological characteristics of fish community in the system. In the mean time, the ecological health (IBI) averaged 33.5 (n=8), indicating "good${\sim}$fair condition" and the IBI values matched with trophic and tolerance guilds. Maximum IBI occurred in Site 2 where the sensitive and msectivore species were nearly maximum, and the tolerant and omnivore species were almost minima, indicating that IBI values were closely associated with the ecological functions and health conditions. Overall data suggest that the conventional diversity index may not effective for a evaluation of fish community, and that in contrast the IBI approach may be a useful tool for diagnosis of stream community.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.5
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• pp.499-505
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• 2011

The fishing grounds of Korean large-pair trawlers have shifted since exclusive economic zones (EEZs) were established in a fisheries agreement involving countries neighboring Korean waters. The distributions of marine ecosystems and fisheries resources have been changing with environmental changes such as global warming and with the shift in species targeted as a result of changes in fishing technology and fishing gear. This study analyzed variation in the species assemblages caught in Korean waters by large-pair trawlers as a result of these geopolitical and environmental changes. The data used in this study were obtained from the Fishery Production Statistics of Korea and the Port Sample Survey of the National Fisheries Research and Development Institute (NFRDI) from 1990 to 2007. Hierarchical clustering analysis (HCA) and correspondence analysis (CA) were used to explore the characteristics of the catch-species composition. The overall variation in the species composition of the catch of Korean large-pair trawlers showed that the proportions of croaker Johnius grypotus, small yellow croaker Larimichthys polyactis, eel Anguilla japonica, and blue crab Portunus trituberculatus decreased, whereas those of hairtail Trichiurus lepturus, Spanish mackerel Scomberomorus niphonius, anchovy Engraulis japonicus, and common squid Todarodes pacificus increased in Korean waters over the 18-year period. The results of the HCA of the annual catch data by species showed four different distributions of fish species according to year. Results of the CA showed that the species assemblages differed between the 1990s and 2000s.

• Korean Journal of Ecology and Environment
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• v.52 no.3
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• pp.231-244
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• 2019

Zooplankton is essential biological assemblage in understanding the structure and function of aquatic ecosystems, since it plays as a linkage between primary producers and higher trophic level organisms such as fish. Although zooplankton has planktonic characteristics, the sampling and treatment methods for its community analyses are more complicated and variable compared with phytoplankton due to its high diversity in body size and species-specific depth selection behaviors. In the present paper, we reviewed representative classical methods for field sampling and treatments of freshwater zooplankton in relation with quantification of its community structure, and suggested appropriate methods depending on various research objectives.

• 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 Marine Life Science
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• v.2 no.2
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• pp.62-69
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• 2017

In order to assess the potential environmental factors in the vicinity of a fish cage farm, we investigated the biotic and abiotic factors during a short-term period in summer 2016 in two inner stations of Tongyeong Obi. High water temperature on August 10^th was apparent among the full depth of up to 29℃, which might have been related to the abnormally high temperatures of large amounts of the Changjiang River discharge along the Tongyeong coast. The concentration of nitrate+nitrite, ammonium, phosphate, and silicate ranged from 0.08 to 5.11 μM, 0.08 to 34.62 μM, 0.01 to 1.15 μM, and 1.46 to 31.79 μM, respectively. The nutrients were mainly supplied by precipitation and leaching from the bottom sediments in the fish culture farm area. It was not retained for a long duration because of the phytoplankton consumption and diffusion by water currents. The chlorophyll a concentration varied from 0.49 ㎍ l^-1 to 7.39 ㎍ l^-1. At that time, Chaetoceros debilis, C. pseudocurvisetus, and Pseudo-nitzschia delicatissima were rapidly proliferated and reached the level of 4.74 × 10⁹ cells l^-1. In particular, the lowest dissolved oxygen was recorded at 4.52 ㎍ l^-1 at the bottom layer after bloom. Therefore, even though phytoplankton blooms in summer have frequently occurred in a fish culture farm area, the oxygen-deficient environments were not found in neither the surface nor bottom layers, which implied that the water masses might be well exchanged from the mouth of the northwest and southeast between Obi and Mireuk Island in the study area.

• Korean Journal of Ecology and Environment
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• v.43 no.3
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• pp.356-368
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• 2010

In this study, we applied approach of integrative star-plot area (SPA), chemical water quality and habitat conditions (QHEI) to diagnoze ecological conditions at the eight sampling sites of Sapkyo Stream. These outcomes were compared with biological health based on the Index of Biological Integrity (IBI) using fish assemblage. And then, we evaluated the integrative ecological health condition using the star-plot method. This approach based on the sum of all the star-plot areas over these water and habitat characteristics. It was developed to reflect an integrative assessment of the ecological health in the stream. The biological health, based on the model values of IBI indicating "fair-poor" condition according to the criteria. Physical habitat health, based on the QHEI, averaged 123 indicating a "good-fair" condition. Also, chemical health, based on simply BOD values indicating "poor grade" according to the criteria of the Ministry of Environment Korea (MEK). The SPA indicating that 50% of the all was impaired condition and the most sampling sites were downstream sites influenced by the point and non-point sources. Overall our results suggest that the ecological health impact was a combined effect of eutrophication and habitat degradations in the stream. The approach of SPA can be used as a tool to evaluate the integrative health of stream environment and to identify possible causes of observed effects.

• Korean Journal of Ecology and Environment
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• v.40 no.3
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• pp.370-378
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• 2007

The objective of this research was to diagnose integrative ecological health in Bansuk Stream, one of the tributaries of Gap Stream, using the fish assemblage during July 2006${\sim}$April 2006. For this research, we selected six sampling sites and applied some approaches such as the Index of Biological Integrity (IBI), Qualitative Habitat Evaluation Index (QHEI), and necropsy-based Health Assessment Index (HAI). The stream health condition, based on the IBI values, averaged 24 (n= 18, range: $10{\sim}46$), indicating "poor${\sim}$fair" condition according to the criteria of US EPA (1993). Physical habitat condition, based on the QHEI, averaged 116 (n=6, range: $77{\sim}139$), indicating "fair${\sim}$good" condition. Values of IBI were more correlated with 3 metrics of instream cover ($M_1$, r=0.553, p=0.017, n=18), flow/velocity ($M_3$, r=0.627, p=0.005, n=18), and riffes/bends ($M_7$, r=0.631, p=0.005, n=18) than other metrics. Value of HAI in the control was zero (i.e., excellent condition), while the values in the T1 and T2 treatments were 5 (range: 0${\sim}$30) and 50 (range: 40${\sim}$80), respectively. The maximum values of IBI (46) were coincided with zero of HAI. Thus, these approaches seem to be a good tool for a diagnosis and evaluations of stream ecosystem health.

• Korean Journal of Environmental Biology
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• v.36 no.1
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• pp.73-81
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• 2018

This study was conducted to understand the current status of the translocated species using a precede study and a model to evaluate the potential invasiveness that could adversely affect the aquatic ecosystem in the Gangneungnamdae Stream. A total of 12 translocated species were investigated and identified from 9 sites in a precede study, and steadily increased since 1982. For the study, which utilized research based on the total FISK (Fish Invasivenss Screening Kit) scores, all of the non-native fishes in Gangneungnamdae Stream were classified into two groups: namely as a high and a medium risk of becoming invasive. It was determined that there were two species (Zacco platypus and Pseudorasbora parva) that were determined to have posed the highest risk. The study determined that the mean scores were shown to have ranged from $3.06({\pm}0.16)-3.42({\pm}0.13)$. Consequently, the habitat analysis showed that the determined QHEI (Qualitative Habitat Evaluation Index) values in the stream averaged 146 (88-171), indicating that an optimal habitat condition did exist in that locale. It can be inferred that compared to land use in the surrounding watersheds, the QHEI values and frequency of translocated species showed the lower the altitude of stream, the QHEI values were decreased and in case of land use pattern, a noted decreased forest and grassland area, and gradually increased urbanized area was seen to exist in the region. The correlation between the fish assemblage, QHEI, land use pattern of surrounding watershed and number of translocated species was identified and analyzed when the stream altitude decreased, and the number of species was increased (r= - 0.782, p=0.0127), the number of species was decreased (r= - 0.737, p=0.0234), and finally when the QHEI values were decreased, it was noted that the urbanized area was increased (r=0.292, p=0.446). In the case of the number of translocated species, when the number of translocated species was increased, the associated urbanized area was increased.