• Korean Journal of Environment and Ecology
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• v.35 no.3
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• pp.265-276
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• 2021

This study investigated the characteristics of fish communities and river health in the Sincheon stream of Imgin River between April and October 2019. The survey collected 3,677 objects in 30 species belonging to 12 families from 23 survey stations. The dominant and subdominant species were Zacco platypus (28.4%) and Oryzias sinensis (13.6%), respectively, followed by Z. koreanus (11.8%), Rhynchocypris oxycephalus (11.7%), Carassius auratus (9.6%), and Pseudorasbora parva (7.9%) in that order. Among the fish species collected, 10 (33.3%) were endemic species in Korea. The exotic species were 5 (16.7%), including Micropterus salmoides, Lepomis macrochirus, Cyprinus carpio (Israeli type), Poecilia reticulata, and Xiphophorus maculatus. The land-locked species included Cottus koreanus and Rhinogobius brunneus, while C. koreanus was a climate change-sensitive species. The dominance of the fish community was low, and the diversity was high in the Sincheon mainstream, Sudongcheon and Cheongdamcheon, whereas Dongducheon and Sangpaecheon showed higher dominance and low diversity. The river health was very good and good in the uppermost and Sudongcheon areas, whereas the upper stream was normal, and the middle and lower streams were poor and very poor, respectively. The water quality was also mostly poor or very poor from the midstream to the downstream, and only Sudongcheon was very good. Therefore, the water quality had a great impact on fish habitat and eventually affected river health significantly. Although the water quality of Shincheon has improved each year, the introduction of several foreign species had a very negative effect. Improvement of river health in Shincheon requires water quality improvement and management of exotic fish species.

• Korean Journal of Environment and Ecology
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• v.32 no.3
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• pp.261-273
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• 2018

This study investigated the characteristics of fish communities in the streams flowing into the Han river in Seoul in May 2016 through April 2017. The investigated streams were Ui stream, Danghyeon stream, Cheonggye stream, Yangjae stream, Mokgam stream, Dorim stream, and Hongje stream, which were restored to their natural form. We collected 41 species of 10 families using skimming nets and cast nets from 21 points during the investigation period. There were 7 Korean endemic species, or 17.1% in collected species, such as Acheilognathus yamatsutae, Acheilognathus gracilis, Scrcocheilichthys nigripinnis morii, Squalidus japonicus coreanus, Zacco koreanus, Coreoperca herzi, and Odontobutis interruta. There were 5 (12.2%) exotic species: Cyprinus carpio (fancy type), Carassius auratus (goldfish), Carassius cuvieri, Lepomis macrochirus, and Micropterus salmoides. The dominant species were Zacco platypus, Carassius auratus, Acheilognathus lanceolatus, Acheilognathus gracilis, and Oryzias sinensis. The Yangjae stream showed more stable fish community than other streams as it showed higher species diversity, and evenness and richness indices. Regarding the fish tolerance guild according to water quality, there were 3 (7.3%) sensitive species, 16 (39.0%) intermediate species, and 22 (56.7%) tolerant species. Twelve (29.3%) were insectivore species, 23 (56.1%) were omnivore species, and 6 (14.6%) were carnivore species, indicating the dominating presence of omnivore fish species.

• Korean Journal of Ichthyology
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• v.21 no.1
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• pp.38-46
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• 2009

The ichthyofauna in certain reservoirs in Gyeongju-si, Gyeongsangbuk-do were studied from August 17 to September 22, 2005. During the study period, 22,747 individuals belonging to 25 species, 20 genera, 9 families and 4 orders were collected. Of these, 14 species were cyprinid fishes, and the dominant species was Pseudorasbora parva (relative abundance 52.28%). There were six Korean endemic species (8.51%), including Sarcocheilichthys variegatus wakiyae, Squalidus chankaensis tsuchigae, Squalidus mulimaculatus, Hemiculter eigenmanni, Pseudobagrus brevicorpus and Odontobutis platycephala the dominant species was Squalidus chankaensis tsuchigae (7.59%). There were six introduced species (25.00%), of which Hemiculter eigenmanni, Pseudobagrus fulvidraco and Hypomesus nipponensis were introduced from other native stream systems (20.99%), and Cyprinus carpio (Israeli), Carassius cuvieri and Lepomis macrochirus were exotic species (4.01%).

• Korean Journal of Ecology and Environment
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• v.42 no.2
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• pp.212-220
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• 2009

In this study, we analyzed fish compositions and ecological characteristics such as trophic guilds and tolerance guilds in association with water quality characteristics in Masan Reservoir during November 2008. Total number of species were 12 species (6 families) and the dominant species were Zacco platypus, Hemiculter eigenmanni, and Pseudorasbora parva. We found three Korean endemic species and one exotic species, Carassius cuvieri. According to the analysis of ecological indicator characteristics, relative proportion of tolerant and omnivore species was 98% of the total indicating that probably, the fauna was influenced by physical habitat disturbance and physicochemical degradations. Fish distribution analysis along with littoral zone showed that the most fishes (${\sim}$95%) were observed in the littoral zone where emerged macrophytes were well developed. Also, substrate analysis indicated that the most species were found near silt area (11 species, 91.7%), so that the significant differences were found between the substrate types. Analysis of water quality indicated that concentrations of total phosphorus (TP) and chlorophyll-a (ChI-a) as a lake trophic indicator were judged as eutrophic states, respectively and COD as an indicator of organic matter pollution averaged 10.9 mg $L^{-1}$. Based on the water quality, this system were influenced by the nutrient enrichments and organic matter. The degradations of water quality in Masan Reservoir resulted in trophic compositions of fish (increase of omnivore species) and the dominance of tolerant fish. This Monitoring data may contribute changes of fish fauna and compositions in relation to habitat modifications and chemical water quality degradations in the future.

• Korean Journal of Ecology and Environment
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• v.47 no.spc
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• pp.31-38
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• 2014

The fish community and upstream of glass eels (Anguilla japonica) in the Imjin River estuary Gyeonggi-do, Korea was investigated from 2008 to 2012. During the surveyed period 43 species belonging to 18 families were collected. Korean endemic species was Microphysogobio jeoni which showed a ration of 0.04% in collected species. Exotic fishes were Carassius cuvieri and Ctenophayngodon idellus, and comprised 0.06% of the total individual number. Among the fish species observed, 17 species of the freshwater fish (40.5%), 6 species of migration fish (14.2%), 8 species of the brackish water fish (19.1%) and 11 species of sea water fish (26.1%). In terms of composition ration, Anguilla japonica (glass eels, 49.8%), Coilia ectens (23.3%), Saurogobio dabryi (8.1%), Repomucenus olidus (3.3%), Lateolabrax maculata (2.9%) and Chelon haematocheilus (2.8%) were found to display high individual number. On the other hand, C. ectens (33.6%), C. haematocheilus (14.2%), Cyprinus carpio (10.5%), Mugil cephalus (9.1%) and S. dabryi (7.6%) were dominated of biomass. The dominant species of individual was A. japonica (glass eels), and subdomint species included C. ectens. The fish biomass catched of fisherman in the Imjin River (Paju-si) were 83.6~240.3 t by each year. The year 2011 and 2012 were decreased rapidly. Among these, M. cephalus (48.0~80.0%), C. carpio (6.7%), Carassius auratus (4.9%), Silurus asotus (3.9%), Takifugu obscurus (2.5%), Anguilla japonica (adult, 2.2%) and Pseudobagrus fulvidraco (2.1%) dominated of biomass. Body weight of glass eels at each year were 0.03~ 1.13 t, average 212.0 kg and 1,325,000 individual by 0.16 g each one individual.

• Korean Journal of Environmental Biology
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• v.33 no.3
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• pp.314-329
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• 2015

The fish fauna was investigated from 2010 and 2013 at main stream and tributaries in the Seomjin River which has no estuary dike. The collected fishes were identified into 37,751 individuals of 107 species of 81 genera belonging to 41 families. Among the collected fishes the primary freshwater fishes were 57 species (Relative Abundance: 53.3%), the secondary fishes were 10 species (RA: 9.3%) and the marine fishes were 40 species (RA: 37.4%). The dominant species was Zacco platypus (RA: 28.7%), and the subdominant species was Zacco koreanus (RA: 15.0%). The endemic species were 21 species (RA: 31.3%). The endangered fishes were Acheilognathus somjinensis (Level I), Lampetra reissneri (Level II) and Microphysogobio koreensis (Level II). The exotic species were Carassius cuvieri, Lepomis macrochirus and Micropterus salmoides. We supposed that Odontobutis interrupta in the Seomjin River is translocated species.

• Korean Journal of Environmental Biology
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• v.23 no.2 s.58
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• pp.173-183
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• 2005

The ichthyofauna and community structure in the Chuncheon Reservoir, Korea, were investigated from August 2003 to April 2004. The total number of fish caught from the period was 10,821 fish representing 41 species and 13 families. There were 16 Korean endemic species, including Hemibarbus mylodon, Acheilognathus yamatsutae and Odontobutis platycephala. Dominant species was Hypomesus olidus $(30.69\%) $ and subdominant species was Hemibarbus labeo $(14.70\%)$. Also, Zacco platypus $(10.57\%)$, Zacco temminckii $(9.66\%)$, Micropterus salmoides$(4.81\%)$, Rhinogobeus brunneus $(4.28\%)$ and Microphysogobio yaluensis $(3.10\%)$ were numerous. The biomass of collected fishes were Hemibarbus labeo (34.63 kg), Hypomesus olidus (19.01 kg), Cyprinus carpio (12.77 kg), Opsariichthys uncirostris amurensis (11.28 kg), Zacco platypus (8.04 kg). Among the 7 introduced fishes in Chuncheon Reservoir Carassius cuvieri, Hypophthalmichthys molitrix and Micropterus salmoides were originated from foreign countries, and others (Anguilla japonica, Hypomesus olidus, Oncorhynchus masou mason and Chaenogobius urotaenius) were introduced from other native river systems.

• Korean Journal of Ichthyology
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• v.31 no.2
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• pp.101-109
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• 2019

This study investigated the characteristics of fish communities at the Lake Yedang, in 2013 to 2014 and 2017. During the survey period, there were 29 species of 10 families collected from 3 survey stations. Of them, Cyprinidae occupied 34.5% (14 species), Bagridae, Gobiidae 10.3% (3 species), and Cobitidae, Centrachidae were 6.9% (2 species) in the number of species, respectively. Korean endemic species were 4 species (13.8%) Abbottina springeri, Cobitis nalbanti, Pseudobagrus koreanus, Odontobutis interrupta and accounted for a low rate. There were 3 species (10.3%) exotic species including Carassius cuvieri, Lepomis macrochirus, Micropterus salmoides. As a result of community analysis, dominant index was 0.45~1.00, diversity index was 0.19~2.30 and richness index was 0.41~1.94.

• Korean Journal of Environment and Ecology
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• v.26 no.6
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• pp.892-901
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• 2012

The purpose of this research was to analyze fish fauna, distribution patterns, and fish community structures in the Juksan-Weir regions of upper weir(R-UW) and lower weir(R-LW), which was constructed in 2011 on Yeongsan River watershed. Our outcomes will provide valuable information in the impact analysis of weir constructions next decades, even if the current research is limited to distributions and fauna studies of fishes. The fishes observed were 8 family and 30 species in all the sites, and the number of the species in the regions of R-UW and R-LW was 23(938 individuals) and 27(1,680 individuals), respectively, indicating greater abundance in the lower region of Juksan-Weir. Most dominant species was Opsarichthys uncirostris amurensis with relative abundance of 42%, and this species had greater abundance in the R-LW(49%) than in the R-UW(30%). Coilia nasus, was the migratory fish sampled in this region and had no differences of abundance between the two regions. The extic species observed were Carassius cuvieri, Lepomis macrochirus, and Micropterus salmoides. The two formers of Carassius cuvieri(1.2%) and Lepomis macrochirus(3.7%) dominated in the R-UW, whereas Micropterus salmoides had greater dominance in the region of R-LW. According to tolerance guild analysis, the proportion of sensitive species ranged from 0.4 to 0.5%, and that of tolerant species ranged from 65% to 70%, implying a severe pollution of nutrients and organic matters in the water body. In the mean time, according to trophic guild analysis, the proportion of carnivores(57 - 77%) was evidently higher than that of insectivores(10 - 20%), indicating a dominance of the carnivores. Especially, high abundance of the bass, exotic species, may disturb the fish overall food chain, so the efficient ecosystem management may be required for the conservation of endemic species. When we examined fish data files of last 60 years, the species of Culter brevicauda, designated as endangered species, was observed firstly in our research area and the total number was 5 individuals(0.2% of the total). So, this region observed should be conserved as a protection zone and further monitoring studies should be done in the future.

• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.264-271
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• 2011

At the Jangheung multipurpose dam, which is on the Tamjin River, a trapping and trucking operation was established to maintain continuous upstream migration of fish,. To facilitate fish gathering, installation of an effective fishing trap was required. In this study, we evaluated the fish trap, established at the Jangheung dam, using PIT (Passive Integrated Transponder) telemetry. A total of 254 individuals from 15 species were monitored. Among these tagged species, 36 individuals from 6 species (Carassius auratus, C. cuvieri, Zacco temminckii, Z. platypus, Pungtungia herzi, and Pseudobagrus koreanus) were detected; a 14.2% detection rate. C. auratus recorded the highest detection rate of 44.2% while P. herzi was 14.3%. Z. temminckii and Z. platypus showed relatively low detection, 5% and 7.7% respectively. Some of individuals from C. auratus and Z. platypus did not pass through the antenna at the first attempt but were continuously detected on multiple days. There were no statistical differences in body size (total length, standard length and body weight) of individuals that did or did not swim into the trap (Mann-Whitney U test, p>0.05). Fish mainly swam into the trap during outflow of water from the dam (Mann-Whitney U test, p<0.001) and showed a higher detection frequency in daytime than nighttime (Mann-Whitney U test, p<0.001). Thus, for fish movement into the trap, external factors such as outflow from dam and time of day have important roles. Based on detection rate, not all fishes showed upstream migration but represented selective migration. Consequently, the establishment of flexible outflow strategies that take into consideration ecological characteristics of fishes should required for improving the efficiency of fishway.