• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.873-883
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• 2015

From August 2012 to April 2013, the ichthyofauna and post-restoration properties of Yangjae stream were investigated. A total of 1,503 fish of 2 forms, 16 species and 5 families were studied during the survey period. A survey of the distribution of freshwater fish inhabiting Yangjae stream after restoration of the stream showed large populations of Zacco platypus and Rhynchocypris oxycephalus. From the frequency distribution of the total length for the Zacco platypus population inhabiting Yangjae stream, it was estimated that there are 4 distinct age groups, with an abundance of the 27-63 mm (Age $0^+$) category accounting for 51.3% of the population. The regression coefficient (b) for the length-weight relationship in Zacco platypus was 3.27, while the slope of the condition factor was positive, demonstrating that stable growth conditions are being maintained. Analysis of tolerance and trophic guilds showed a decrease in the numbers of sensitive species and insectivore species further downstream, and an increase in tolerant species and omnivore species. Principal component analysis using community indices and indices of biotic integrity (IBI) showed that there were differences according to the survey time: the first and second surveys showed major changes on certain single species populations while during the third survey, it was analyzed that the populations of various types of fish had established balance.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.48-54
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• 2011

Risk assessments of pesticides detected in six major rivers during peak season were estimated for algae, Daphnia, and fish using hazard quotient (HQ) indexes. The eight pesticides (isoprothiolane, hexaconazole, diazinon, chlorpyrifos, prothiofos, alachlor, butachlor, molinate) were detected within the range of 0.027~12.871 ${\mu}g/L$. Detection frequency of isoprothiolate was estimated to be high at 67.5%, and those of the others varied from 15.0 to 37.5%, Hazard Quotients (HQ) indexes varied by freshwater organisms (algae, Daphnia, and fish). Overall, the ecological risk probability due to exposure of pesticides detected in major rivers did not reveal based on HQ indexes below 1.0. Particularly, butachlor and molinate for algae, chlorpyrifos, diazinon, prothiofos for Daphnia, and chlorpyrifos for fish acted as dominant contributors in increasing the ecological risk in six major rivers. This implied that integrated ecological risk assessment is required using various biological species, reflecting toxicity sensitivity. This study may provide the essential data in establishing the priority for pesticides management in major rivers, Korea.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.27-41
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• 2016

This study was performed to investigate the community structure and health assessment of macrobenthic assemblages in Geoje-Hansan Bay, Southern Coast of Korea. Macrobenthos were collected by van Veen grab sampler at May (spring) and August (summer) 2013. The total species number and mean density were 300 species $7.6m^{-2}$ and $1,994ind.\;m^{-2}$, respectively. The major dominant species were the polychaetes Lumbrineris longifolia ($299{\pm}164ind.\;m^{-2}$), Aphelochaeta monilaris ($100{\pm}57ind.\;m^{-2}$), the bivalve Musculista senhousia ($91{\pm}96ind.\;m^{-2}$) and the polychaete Praxillella affinis ($80{\pm}66ind.\;m^{-2}$). From the community statistics [cluster analysis and nonmetric multidimentional scaling (NMDS) ordination], the macrobenthic community was distinguished into two groups of inner bay (farming ground of near Sandal Island) and channel station(from Hansan Island to Chubong Island) group. In this study, the ecological status was assessed by four biotic indices Shannon's H', the ATZI Marine Biotic Index (AMBI), multivariate-AMBI (M-AMBI) and the Environment Conservation Index (ECI). The ecological status of the macrobenthic community in Geoje-Hansan Bay were poorer in the inner bay station than in the channel station. The results of the present study showed that three biotic indices (Shannon's H', M-AMBI and ECI) were valid as an index for evaluating the ecological status than the AMBI.

• Korean Journal of Environmental Biology
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• v.36 no.3
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• pp.400-411
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• 2018

This study was a survey of the Wonju stream in Wonju city from May 2015 to September 2016. A total of three sites were selected from the upstream area Gwanseol-dong to the downstream area Hojeo-myeon. Physicochemical analysis, aquatic insect changes, cluster analysis, functional group analysis, rarefaction curve, and statistical analysis were compared between 2004 and 2016. A total of 19 species (38.78%) in 2004 and 22 species (36.67%) in 2016 were analyzed, with the largest number belonging to ephemeroptera. The individual ratio ranged from 27,759.2 (ind. $m^{-2}$, 84.30%) in 2004 to 4,573.2 (ind. $m^{-2}$, 41.64%) in 2016, with the highest number involving diptera. As a result of the community analysis, significant differences were detected in the indices of dominance, diversity, evenness, and richness in 2004 and 2016 (p<0.05). Burrowers of the habitat orientation groups showed the greatest variation with an average of -68.00% (${\pm}2.15$) and the collector-gatherers of the functional feeding groups showed the highest variation of -40.12% (${\pm}1.77$). The rarefaction curve analysis suggested that the species was the poorest in the midstream regions in 2004 and 2016. Physical factors and water quality showed a significant correlation with diversity index, evenness index, and the number of individuals. MDS analysis of the similarity of upstream and downstream regions was high in 2004, and low in 2016. The differences were attributed to physicochemical changes such as increase in flow velocity due to improvement of small dams and changes in bottom structure.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.179-185
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• 2010

This is a study of the fish assemblages in eelgrass beds of Geoje Bay on Geoje Island, Korea. Samples were collected by surf net monthly from June 2006 to May 2007. A total 26 species, 1,825 individuals, and 4,483.1 g of fishes were collected. The dominant species were Acentrogobius pflaumii, Aulichthys japonicus, Gymnogobius heptacanthus, Rudarius ercodes, Chaenogobius annularis, Gymnogobius urotaenia, Syngnathus schlegeli, Pterogobius elapoides, Zoarchias glaber, Takifugu niphobles, Zoarchia suchidai. These species accounted for 90.6% of the total number of individuals and 76.2% of the biomass of the fishes collected. The fish assemblages in the eelgrass beds showed clear seasonal changes; the number of fish species and individuals increased in March and were highest in September, whereas the biomass attained its highest level in May and subsequently decreased. Meanwhile the species diversity indices showed their highest value in December.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.35 no.2
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• pp.178-195
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• 1999

The species composition and seasonal variation in abundance of fishes in the Nakdong River estuary were investigated monthly from February 1987 to January 1988. During the study period, 23,008 specimens belonging to 100 species were collected. The most abundant fish species were Repomucenus valenciennei, Pholis fangi, Leiognathus nuchalis, Trachurus japonicus, and Sardinella zunasi. These five species comprised 63.0% of total fishes and 47.8% of total biomass collected. The seasonal dominant fish species were P. fangi and R. valenciennei in spring, R. valenciennei and Cynoglossus joyneri in summer, Thryssa kammalensis and Apogon lineatus in fall, and R. valenciennei, L. nuchalis and S. zunasi in winter. The number of fish species, number of individuals collected, and species diversity indices fluctuated with the seasons. The number of species and number of individuals decreased significantly in the upper estuary. While temperature was an important factor which influenced on seasonal fluctuation of the fish community, salinity determined the spatial distribution of fishes.

• Korean Journal of Agricultural Science
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• v.29 no.2
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• pp.10-19
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• 2002

This study was conducted to investigate the avifauna of Gap stream in Daejeon metropolitan city from September in 2001 to August in 2002. For the monthly change of bird community, survey was carried at study area per each month, the obtained results could be summarized as follows. 1. The observed birds were 12 orders 31 families 83 species and 15900 individuals, 38 species are water bird as Herons, Dabbling ducks, Diving ducks, Rails, Sandpipers & Plovers and 45 species are land bird as Raptors, Woodpeckers, Wagtails, Thrushes, Warblers, Tits, Buntings, Crows. 2. These birds could be divided 29 residents, 29 summer visitors, 18 winter visitors, 7 passage migrants. 3. Among the birds, Chinese Sparrowhawk Accipiter soloensis, Eurasian Sparrowhawk Accipiter nisus, Kestrel Falco tinnunculus are legally protected species as natural monuments in Korea. 4. The major dominant species were Common Teal Anas crecca, Spot-billed Duck Anas poecilorhyncha, Mallard Anas platyrhynchos, Grey Heron Ardea cinerea, Magpie Pica pica, Little Egret Egretta garzetta in order, Gap stream should be appropriate habitats for dabbling ducks and herons. 5. Among the total number of 83 species, the highest number of species was 37 species in February and the lowest number of species was 27 species in June. 6. Among the total number of 15900 individuals, the highest number of individuals was 2899 individuals in December and the lowest number of individuals was 385 individuals in May. 7. Among the monthly species diversity index, the highest number of species diversity index was 2.6207 in September and the lowest number of species diversity index was 2.0716 in January.

• Korean Journal of Environment and Ecology
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• v.25 no.2
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• pp.123-131
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• 2011

Seabird distribution in the East Sea was studied from April to May 2007 using line transect counts. We observed a total of 1,379 individuals of 23 species including 14 species of seabird. The overall seabird sighting rate was 2.5 birds $km^{-2}$. The Streaked shearwater(Calonectris leucomelas)(74.5%) was the numerically dominant species. Ancient murrelets(Synthliboramphus antiquus)(8.3%), red-throated divers(Gavia stellata)(5.0%), common terns(Sterna hirundo)(2.1%), Pacific divers(Gavia pacifica)(2.0%), and black-tailed gulls (Larus crassirostris)(1.1%) were also frequently observed. The sightings of seabirds was highest between $36^{\circ}N$ and $37^{\circ}N$ of the coastal area of the Korean peninsular. However, the index of species diversity(H') was higher between $35^{\circ}N$ and $36^{\circ}N$. The sighting rates of most observed species decreased with distance from the coastline. The distribution patterns of Streaked shearwater were linked to the variation in the distribution pattern of minke whales(Balaenoptera acutorostrata). Also, spatial segregation was found in the distributions of the two species of divers(Gavia spp.).

• Korean Journal of Ichthyology
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• v.23 no.1
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• pp.37-45
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• 2011

Seasonal variation in species composition and abundance of fish larvae assemblages in the south-western Jinhae Bay were investigated monthly in 2009. During the study period, 49 larvae species belonging to 24 families were collected. The dominant species were Clupea pallasii, Hexagrammos otakii, Konosirus punctatus, Engraulis japonicus, Parablennius yatabei, and Omobranchus elegansei. These six species accounted for 92.7% of the total number of individuals collected. The number of species, number of individuals, and species diversity indices fluctuated with the seasons. The peak number of species and individuals occurred in July and January, respectively. Principal component analysis(PCA) and correlation analysis showed that variation in monthly water temperature could act as an indicator of seasonal variation in community structure and abundance of the dominant species; in particular, those of C. pallasii, H. otakii, E. japonicus and P. yatabei corresponded with the water temperature.

• Korean Journal of Ichthyology
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• v.22 no.3
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• pp.186-194
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• 2010

Seasonal variation in species composition and abundance of fish assemblage in the coastal waters off Gori were determined using monthly samples collected by a three-side fyke net in 2006. Of a total of 59 fishes collected, the dominant species were Trachurus japonicus, Mugil cephaIus, Konosirus punctatus, Apogon lineatus, Chelidonichthys spinosus, Ditrema temmincki, Sebastes schlegeli and Apogon semilineatus. These 8 fishes accounted for 92.7% of the total number of individuals collected. The number of fish species, number of individuals, biomass and species diversity indices fluctuated with the seasons. The peak number of fishes occurred in December, whereas biomass of fishes was the highest in March. The number and biomass of fishes were lower in January corresponded with the low temperatures, and the diversity indices were lower in December than in any other month.