• 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.45 no.4
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• pp.392-402
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• 2012

In this study, to analyze the stream health using fish assemblage and make effective management, we conducted fish monitoring in the Hoeya River basin and neighboring streams. A total of 33 species classified into 12 families were collected from 29 sites in 2007. Dominant species was Zacco platypus (Relative abundance, RA: 24.8%), and subdominant species was Rhynchocypris oxycephalus (RA: 16.2%). Eight Korean endemic species and 4 exotic species were identified. Moreover, two species (Opsariichthys uncirostris amurensis and Hemiculter eigenmanni) were translocated from other basin. To evaluate stream health of the study sites, Index of Biological Integrity (IBI) was applied, based on fish assemblages. Overall, IBI values were "C (Fair)" or "D (Poor)" condition, according to the grade except two sites which recorded "B (Good)". The correlation between land use pattern of surrounding watershed and IBI was analyzed to verify impact of development on stream health using fish assemblage. As a result, when percentage of the developmental groups increased, IBI values were decreased (Pearson correlation, r=-0.425, p=0.022). In contrast, increment of percent forest and grass land was positively correlated with IBI (r=0.556, p=0.002). The agricultural group and IBI did not significantly correlate with each other (r=-0.231, p=0.333). In this study, we identified a relationship between land use of surrounding watershed and stream health using fish data (i.e. IBI). These results could be provided useful fundamental information to establish management and restoration plan in the Hoeya River basin and other rivers distributed in Korea.

• Korean Journal of Environmental Biology
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• v.31 no.3
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• pp.180-188
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• 2013

The objectives of the study were to analyze chemical water quality and fish community structures in the downstreams of Geum River during 2004~2005. Water quality parameters showed that ionic dilution was evident during July~August due to a rainfall and river runoff by Asian monsoon. Mean concentrations of BOD showed a seasonal variation and were greater in the downstream than in the midstream. The total number of fish species observed was 34 (11 families) and 30.3% of them was Korean endemic species. The dominant species with > 20% of the total were Zacco platypus (25.9%) and Microphysogobio jeoni (21.5%) in the river. Exotic species observed was only one species, Carassius cuvieri with relative abundance of 1.8%. According to the structure analysis of fish community, species richness index was highest (3.714) in S6 and lowest in S4 (1.961), while species diversity index was highest in S2 (1.01) and lowest in S5 (0.507). Tolerant species dominated the fish community (49%), and the sensitive species were rare (4.4%), indicating a biological degradation of ecosystem. In the mean time, omnivore species was composed of 49% in the fish community and insectivore species was nearly same with the proportion of the omnivores.

• Korean Journal of Ecology and Environment
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• v.37 no.2 s.107
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• pp.227-235
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• 2004

Fish fauna and community structure were surveyed in the Nakdong River, Gumi City, Kyeongpook province from April 2001 to July 2002. During the surveyed Period, 39 species, 32 genera belonging to 10 families were collected. Cyprinid fish occupied 64.1% (25 species) and cobitid fish had 7.7% (3 species). Fourteen species(35.9%) of observed species were known as endemic species. The exotic fish was Micropterus salmoides (2.5%) . The dominant species were Zacco platypus (relative abundance: 36.7%) and Opsariichthys uncirorstris amurensis (22.7%). Carassius aurafus and Microphysogobio rapidus were numerous (4.0${\sim}$4.3%). The rare species comprising less than 0.15% were Acheilognathus koreensis, Aphyocypris chinensis, Iksookimia longicorpus, Coreoleuciscus splendidus, Rhinogobius giurinus, Sarcocheilichthys variagatus wakiyae, Silurus asotus astus, and Channa argus. It was found that the population density of carnivorous Opsariichthys uncirostris amurensis increased drastically in the mid-reach of the Nakdong river since it had been introduced from the other native rivers in the middle 1990s. Gobiobotia nakdongensis inhabit riffle (water velocity : 0.43${\sim}$0.67 m $s^{-1}$) of which the river bed is mainly sand. This species is considered to be in need of conservation. As the result of analyzing fish community in the surveyed area, the species diversity, evenness and dominant indices were 1.008, 0.663 and 0.196 respectively. The findings showed that the tributary, which the waterside plants were abundant and had various habitats, had a higher species diversity (1.112) than the main river (0.787). Sand mining had been disturbing the river ecosystem of the study stations 3, 11, 13 & 14, and these stations showed a quite low species diversity (0.421 ${\sim}$0.574).

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.226-238
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• 2011

Ichthyological fauna and community structure were surveyed in the Naeseong Stream around the planed Yeongju Dam, Yeongju City, Gyeongsangbuk-do from April 2007 to October 2009, During the survey period, 27 species (25 genera, 10 families) were collected. Cyprinid fish comprised 63.0% (17 species) and cobitid fish comprised 7.4% (2 species). Ten of the 27 species (37.0%) were endemic species. The dominant and subdominant species based on the number of individuals was Zacco platypus (43.2%) and Zacco koreanus (15.8%), respectively. Introduced from the other native rivers and exotic fish were Opsariichthys uncirostris amurensis, Leiocassis ussuriensis, and Micropterus salmoides (11.1%). The declining population density of Zacco koreanus and its subdominant status represents a change, since, up until the mid 1990's, it was widely distributed throughout the area and was the dominant species. The distribution area of Zacco koreanus decreased in size; by 2009, it no longer inhabited the lower reaches of the Naeseong Stream. On the other hand, Zacco platypus remained the dominant species throughout the area, except for the upper-reaches of the water-course. Gobiobotia naktongensis inhabited all areas of Naeseong Stream, which mainly has a sandy bottom. Analyses of the fish community revealed species diversity, even-ness and dominant indices were 0.881, 0.615, and 0.230 respectively. These results showed that the main river, in which the water width and flow are abundant and which has various habitats, has a higher species diversity (0.829) than the tributary (0.735).

• Korean Journal of Environment and Ecology
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• v.32 no.2
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• pp.154-164
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• 2018

We investigated the ichthyofauna and fish community structure of the Mudeungsan National Park, Korea from 2014 to 2016 to prepare a conservation plan. We collected 21 species of 6 families collected from 8 survey stations through skimming nets and cast nets during the period. The dominant and subdominant species were Zacco temminckii (43.0%) and Rhynchocypris oxycephalus (15.1%), respectively. The other abundant species were Z. platypus (11.2%), Pungtungia herzi (10.1%), Squalidus gracilis majimae (8.9%), and Z. koreanus (4.5%). Among the fish collection, 13 species (61.9%) were Korean endemic species, but, endangered species and exotic species were not found. Similarity indices based on species composition and abundance showed the clear division of the fish community into two river systems (Yongsan River drainage system (St. 1-7) and Seomjin River drainage system (St. 8)). The Youngsan River system was further divided into the uppermost (St. 1, 2, 4, 6, and 7) and the upper-middle (St. 3 and 5) regions. The number of species appearing in a year was similar at 19 to 20 throughout the survey period. However, the individual number of fish in 2015 (2,670) was 20% less than that of 2014 (3,366) and 2016 (3,429), respectively. The probable reason for this decline is the rapid decline of stream level in 2015 compared to the other years. During the survey period, river works were undergoing at 3 out of 8 stations, having created disturbance in fish habitat and especially impacted on benthic fishes.

• 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.54 no.1
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• pp.12-23
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• 2021

As fish communities are sensitive to natural environmental changes as well as anthropogenic pressures, their composition and characteristics help us to assess the aquatic ecosystem health. The fish fauna and the length-weight relationship of Zacco platypus in the Seomjin River system were investigated from July 2018 to May 2019. The collected species during the survey period were 49 species belong to 14 families including 19 Korean endemic and two endangered species. According to Bray-Curtis similarities, 14 sites were divided into four groups based on the fish community composition; two groups(group A, B) and two uncategorized sites(group C, D). There were significant differences between groups A and B(analysis of similarities, R=0.722, p=0.002). A similarity percentage analysis revealed that Z. koreanus(8.55%), Micropterus salmoides(6.90%), and Lepomis macrochirus (4.90%) contributed to these differences of fish assemblages between group A and B. Group A showed higher relative abundances of exotic species such as M. salmoides and L. macrochirus, while Z. platypus and Z. koreanus which are the common species in Korea, were the most dominant species in group B. Based on the length-weight relationship of Z. platypus, b values were varied from 2.82 to 3.80, indicating that growth patterns of the species were spatially different. This study could be served as baseline data for understanding fish fauna, assessing habitat characteristics based on the fauna, and identifying health conditions of Z. platypus in the Seomjin River system.

• 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 Ichthyology
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• v.17 no.4
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• pp.271-278
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• 2005

The ichthyofauna and fish community were studied in Miho Stream from May 2004 to August 2005. During the surveyed period 41 species belonging to 10 families were collected. Twelve of the species (29.3%) are endemic to Korea. Exotic fishes were Carassius cuvieri, Lepomis macrochirus, and Micropterus salmoides. Dominant species was Zacco platypus (54.7%). Comparing the present result with that of Son (1982), the indices of diversity,evenness and richness were lower and the dominance index was higher; Lampetra reissneri, Anguilla japonica, Acheilognathus macropterus, Coreoleuciscus splendidus, Pseudopungtungia nigra, Gobiobotia naktongensis, Lefua costata, Pseudobagrus koreanus, Monopterus albus and Iksookimia choii did not appear; Carassius auratus, Rhodeus uyekii, Rhodeus notatus, Acheilognathus lanceolatus, Pseudogobio esocinus, Hemibarbus longirostris, Microphysogobio yaluensis, Cobitis lutheri, Iksookimia koreensis, Pseudobagrus fulvidraco, and Rhinogobius brunneus, remarkably decreased, and Z. platypus, Pseudorasbora parva, and Squalidus gracilis majimae increased.