• Korean Journal of Ecology and Environment
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• v.36 no.1 s.102
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• pp.21-28
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• 2003

Community composition and functional feeding groups of aquatic insects according to stream order were investigated from the Gapyeong Creek, a typical mid-sized Korean stream in Gyeonggi -do, Korea, in April 2000. For field investigations, the main watercourse and three major tributaries of the stream that belong to stream order ll to Vll were divided into reaches (ca. $1{\sim}4$ km in distance). Aquatic insects were sampled from one or two sites each reach (total 30 sites) using a Surber sampler ($50{\times}50$cm, mesh 0.75 mm). As a result of the quantitative samplings(two Surber samplings at riffle and pool/run per site; total $2{\times}30$=60 Surber samplings) and additional qualitative samplings, a total of 164 species of aquatic insects in 103 genera, 54 families, and 8 orders were collected from the stream. Those aquatic insects were composed of Trichoptera (56spp.: 34.1%), Ephemeroptera (43 spp.: 26.2%), Diptera (25spp.: 15.2%), Plecoptera (23 spp.: 14.0%), Coleoptera (6 spp.: 3.7%), Odonata (6 spp.:3.7%), Hemiptera (3 spp.: 1.8%), and Megaloptera (2 spp.: 1.2%); EPT-group (122 spp.:74.4%) or EPT-group plus Diptera (147 spp.: 89.6%) occupied most of the aquatic insect community; relatively larger number of species occurred in the mid-stream reaches (order III-Vl). The quantitative samplings throughout the study sites yielded a total of 26,286 individuals of aquatic insects ($136{\sim}2522$ inds./0.5 $m^2$, mean 906.4inds./0.5 $m^2$) that belongs to Ephemeroptera (11,994 inds.: 45.6%), Diptera (8730 inds.:33.2%), Trichoptera (4123 inds.: 15.7%), Plecoptera (1213 inds.: 4.6%), Coleoptera (204 inds.: 0.8%), Odonata (13 inds.: 0.05%), Megaloptera (5 inds.: 0.02%), and Hemiptera (4inds.: inds.: 0.02%); average number of individuals of aquatic insects increased as the stream order increased: average numbers of individuals of Bllecoptera and Trichoptera decreased and increased, respectively, as the stream order increased. Tolerant species such as Chironomidae spp., Uracanthella rufa and Hydropsychidae spp. were particularly abundant in the down stream reaches (order Vll) . Species diversity indices (H`) and dominance indices (Dl) were relatively higher and lower, respectively, in the mid-stream reaches (order $IV{\sim}VI$). Shredders occupied the smallest partand collector-gatherers were most abundant among the functional feeding groups(FFGs); collector-filterers considerably increased in the down stream reaches (orders Vl and VII); scrappers were relatively evenly distributed throughout the stream reaches: predators were relatively more abundant in the uppermost stream reaches(order ll) . Overall, the characteristics of aquatic insect comminity and FFGs in the Gapyeong Creek are largely similar to those in the normal streams of temperate deciduous forest in the northern hemisphere that is explained by the river confineum concept.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.374-383
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• 2021

In 2020, the diversity of benthic macroinvertebrate communities was investigated in the Sohan stream, an ecological and landscape conservation area, and the results were compared with the previous research conducted in 2011. In total, 42 species (two phyla, three classes, and seven orders) were found in the Sohan stream. Species richness and abundance sharply decreased at all sampling sites because of Typhoons Haishen and Maysak in 2020, which had a direct impact on the stream. In the functional feeding group, the ratio of collector-gatherers was the highest at all sampling sites. However, during the autumn season, the shredder ratio increased from 13.4% to 42.4% in the uppermost stream site. Compared with the diversity of benthic macroinvertebrates surveyed in 2011, a total of 53 species (two phyla, three classes, and eight orders) were found. The percentage of species richness and abundance of Ephemeroptera, Plecoptera, and Trichoptera was more than 50% both in 2011 and 2020. Only the richness of Ephemeroptera was significantly different between them (2011: 2.9 and 2020: 6.7). In this study, the abrupt changes of species richness and abundance in benthic macroinvertebrate were not observed before and after the designation of an ecological and landscape conservation area. However, it is necessary to monitor benthic macroinvertebrates in order to confirm that biodiversity is continuously maintained long after the designation of the ecological and landscape conservation area.

• Animal Systematics, Evolution and Diversity
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• v.20 no.2
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• pp.215-223
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• 2004

Two species of the heptageniid mayfly genus Thalerosphyrus Eaton, T. vietnamensis (Dang) and T. separatus n. sp., are described from Vietnam. Thalerosphyrus separatus can be distinguished by the basally detached posterolateral expansions of pronotum in larva and by the Y -shaped penes in male adult. Their larval and adult stages are described with line-drawings of diagnostic characters. Their diagnoses, distributions, habitat and ecological data, and taxonomic remarks are provided.

• Korean Journal of Ichthyology
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• v.19 no.3
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• pp.236-245
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• 2007

Feeding habits of Liobagrus andersoni were investigated in a tributary of the Namhan river from October 2005 to October 2006. L. andersoni was considered as an entirely bottom-feeding carnivore based on it's stomach contents. Because, the diet of L. andersoni was mainly aquatic insect such as Ephemeroptera, Trichoptera, Diptera. The most important prey was Ephemeroptera species. Small sized individuals (<50 mm SL) fed mainly on small prey organisms such as Baetis. However, larger Ephemeroptera and Trichoptera were heavily selected with increasing fish size. The relative proportion of food items was changed with season. The prey materials were more various at summer and autumn than winter. L. andersoni eaten Ephemeroptera intensively in spring and summer but eaten Trichoptera and Chironomidae in winter. Feeding activity of L. andersoni was started after sunset and was most active at midnight, but the activity was reduced after sunrise and during day period. So it was considered that L. andersoni was a nocturnal stalkers.

• Journal of Wetlands Research
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• v.2 no.2
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• pp.133-146
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• 2000

An ecological survey was performed in Miryang dam water system during the period of June 5~6, 2000. The fauna collected from 7 sites consisted of total 67 species, 49 genus, 25 families, in 7 orders of aquatic insects. These included 29 species of Ephemeroptera, 22 species of Trichoptera, 7 species of plecoptera, 6 species of Diptera, 1 species of Megaloptera, Odonata and Coleoptera repectively. The relative abundance of Ephemeroptera, Trichoptera, Plecoptera, Diptera, and Coleoptera was 71 %, 11.2%, 5.1%. 11.9% and 0.6% respectively. The primary dominant species of tatal level was Epeorus aesculus, and second dominant species was Epeorus latifolium. The primary dominant species were Heptagenia kihada at site 1, Ecdyonurus dracon at site 2,3,4 and Epeorus aesculus at site 5, Epeorus latifolium at site 6,7. Dominance indices were ranged from 0.30 to 0.55, and species diversity indices from 3.11 to 4.25(mean=3.71). Saprobic system based on species diversity indicated that whole sites were oligosaprobic.

• Korean Journal of Ichthyology
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• v.31 no.1
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• pp.54-61
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• 2019

A study on the diel activities and feeding habits of Pseudobagrus brevicorpus living in the Daegacheon Stream of Nakdonggang River was conducted in September 2017. Diel activity took place during the night, just after sunset and just before sunrise. Pseudobagrus brevicorpus swam in the middle depths, and when they found prey organisms, approached and consumed them immediately. Fish were divided by age into three groups. Prey organisms whose index of relative importance in the stomach contents exceeded 1% belonged to the orders Ephemeroptera (80.8%), Diptera (8.6%), and Trichoptera (8.5%). An index of relative importance by age showed that the Ephemeroptera are very important prey organisms, and the sizes of prey organisms increase with fish growth.

• Korean Journal of Ichthyology
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• v.20 no.4
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• pp.279-284
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• 2008

The feeding ecology of endangered Cottus hangiongensis was studied in the Hosan stream from September 2006 to August 2007 by collecting them seasonally. The stomach contents of C. hangiongensis consisted mainly of aquatic insects and Nematoda, small fish, fish eggs, snails (Semisulcospira libertina), and small stones were also observed. The main aquatic insects in the order of relative importance were Diptera, Trichoptera, Ephemeroptera and Plecoptera. The most important prey items were Chironomidae sp.1 and Hydropsyche kozhantschikovi. Change in the main prey organisms by season were Trichoptera in the spring and the summer, Diptera in the autumn, and Plecoptera in the winter by ratio of dry weight.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.118-124
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• 2014

As part of researching the feeding habit of Liobagrus somjinensis, the study of its stomach contents and benthic aquatic macroinvertebrates fauna at the waters the fish was collected were carried out monthly from January to December 2010 in Yo stream, Somjin River Sikjeong-dong, Namwon-si, Jeollabuk-do, Korea. In the survey of the stomach contents, the prey organisms are all aquatic insects consisting of 5 orders, 14 classes and 16 species. They fed mainly on Trichoptera and Ephemeroptera including dominant insects such as Hydropsyche kozhantschikovi (79.1%), Chironomidae spp. (48.7%), Baetiella tuberculata (34.2%) at the occurrence rate. Based the result, L. somjinensis appeared to be an aquatic insect feeder that consumes only benthic aquatic insects. The feeding rate of L. somjinensis was the highest in November, whereas it was the lowest in December to next February when they did not feed in the winter season. A survey of the benthic aquatic macroinvertebrates fauna was accompanied for prey preference at the waters. They have 7 orders, 20 classes and 27 species, and among them, two species, Hydropsyche kozhantschikovi (39.0%) and Epeorus pellucidus (18.1%), were aquatic dominant insects. Among 7 orders interestingly, Odonata and Megaloptera, known as having a larger size than other aquatic insects, were not found at the stomach contents. As a result, Liobagrus somjinensis most prefer Hydropsyche kozhantscikovi which is the most dominant species with relatively a smaller size at the waters the study was performed.

• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.90-105
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• 2013

This study was performed to find out stomach contents of cold water fish such as Manchurian trout (Brachymystax lenok tsinlingensis) and River salmon (Oncorhynchus masou masou) in the Odae mountain area. Field survey was carried out 3 times by each season from May to October 2012 along the Gyebang stream and the Yangyang-Namdae stream at north-west mountain slope and north-east mountain slope of the Odae mountain area respectively. The result of digestive track analysis showed that food species of Manchurian trout were total individuals of 645 including 5 orders, 23 families, 39 species of benthic macroinvertebrates and 11 taxa of terrestial insects. And each IRI (Index of Relative Importance, %) value of food species by Manchurian trout was terrestial insects 37.0%, Trichoptera 36.4%, Ephemeroptera 20.0%, Diptera 3.9%, Plecoptera 2.7%, and Gordea <0.1%. While the River salmon fed on 1,186 individuals covering 4 orders, 20 families, 33 species of benthic macroinvertebrates and 6 taxa of terrestial insects including arachnid. Also IRI values by River salmon were terrestial insects including arachnid 2.7%, Ephemeroptera 52.9%, Trichoptera 27.9%, Diptera 9.4%, and Plecoptera 7.0% respectively. With these results, we might say that both Manchurian trout and River salmon is carnivorous fish which display the feeding preference to terrestial insects and benthic macroinvertebrates. As a results we could find out that the two kinds of cold water fish preferred similar habitat types and liked same order of food species in same season, however the compositions of food species for Manchurian trout and River salmon were considerably different.

• Korean Journal of Environmental Biology
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• v.41 no.3
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• pp.247-255
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• 2023

The occurrence of sudden strike pest events in urban areas is increasing as global warming intensifies, consequently, re causing harmful impacts. Studies on these incidents are fewer in number and insufficient compared to research on other nuisances such as mosquitoes and flies. Therefore, we conducted a study on the development of a selective collection method, using a filter layer to establish a monitoring system for Ephemera orientalis (Ephemeroptera: Ephemeridae), a species frequently identified as a sudden strike pest. Three sampling points were selected along the Hangang River in Namyangju, where E. orientalis outbreaks occur. Prototypes, consisting of four layers and with a light source attached to attract insects, were installed at each sampling point. Sampling was performed every 30 minutes between 19:00 and 22:30 in the month of June. The filter interval of each layer was adjusted so that the collected mayflies were distributed into specific layers. To evaluate the collection efficiency in line with the materials and the filter intervals, the optimal collection efficiency was investigated by combining two types of layer materials (stainless and acrylic) and filter intervals (1-5 mm). The optimal conditions were as follows: The selective collection efficiency was found to be highest at 96.5% when the interval of the selective target filter was 2.0 mm and there was one upper filter.