• Journal of Environmental Science International
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• v.22 no.8
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• pp.925-935
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• 2013

In this study, a comprehensive field monitoring was conducted to understand habitat conditions of fish species in up and downstream of Hoengseong Dam. Based on the monitoring data, riverine health conditions such as composition ratio of fish species, bio-diversity (dominance index, diversity, evenness and richness), index of biological integrity (IBI) and qualitative habitat evaluation index (QHEI) were assessed, and optimal ecological flowrates (OEF) were estimated using the habitat suitability indexes (HSI) established for three fish species Coreoleuciscus splendidus, Pungtungia herzi and Microphysogobio longidorsalis selected as icon species using the physical habitat simulation system (PHABSIM). The total number of species sampled was 20 species, and two species of Zacco platypus (30.4%) and C. splendidus (20.9%) dominated the fish community. As a result, it was revealed that IBI and QHEI values decreased from upstream to downstream along the river. The estimated IBI value ranged from 24 to 36 with average being 30.9 out of 50, rendering the site ecologically fair to good health conditions. HSI for C. splendidus were determined according to three different month in terms of season: Spring (April), Summer (August) and Autumn (October). HSI for flow velocity were estimated at 0.7 to 0.8 m/s for the Spring, 0.5 to 1.0 m/s for the Summer and 0.8 to 0.9 m/s for the Autumn. HSI for water depth were estimated at 0.3 to 0.5 m for the Spring; 0.3 to 0.5 m for the Summer; and 0.3 to 0.4 m for the Autumn. OEF was estimated at 4.2 and $6.5m^3/s$ for the Spring and Autumn, and $12.0m^3/s$ for the Summer. Overall, it was concluded that the Hoengseong Dam has been relatively well protected from the anthropogenic disturbance for the legally protected species including the endemic species studied in this study.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.72-80
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• 2017

Fish fauna and community structures in freshwater were analyzed in the streams (12 stations) of the Bogil Island from May to September 2015. Total numbers of the sampled species and genus (9 families) were 21 and 17, respectively. Gobiidae was the most dominant taxa, which accounted for 47.6% (10 species) of the total species, and the relative abundance, based on the number of individuals, was 60.4% (1,157 individuals). Subdominant families were three taxa of Cyprinidae (3 species; 500 ind.), Mugilidae (2 species; 168 ind.) and Mugilidae (2 species; 128 ind.). The dominant species, based on the relative abundance, was Rhynchocypris oxycephalus (20.7%) and the subdominant species were Gymnogobius urotaenia (19.5%), Leucopsarion petersii (17.2%) and Chelon haematocheilus (8.5%). These species were composed of upstream-resident fish as well as migratory fishes, so the streams of the Bogil Island had unique characteristics in the fish compositions. Based on all the species sampled, 9 species (42.9%) were primary freshwater fishes, 11 species (52.4%) were peripheral fishes and 1 species (4.8%) was amphidromous fish. Korean endemic species and exotic species were not found in the streams of Bogil Island. According to the analysis of fish community structure, species richness index and species diversity index were highest (1.831, 1.957) in the Site 8 and lowest in the Site 4. In the meantime, the dominance index was highestin the Site 4 (1.00) and lowest in theSite 8 (0.17).

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.297-303
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• 2021

In this study, nine major sites of Yulcheon stream, a principal tributary of the Seomjingang River, were surveyed from April 2020 to October 2020, and their fish fauna and community structure were analyzed. A total of five families and 19 species of fish were identified. Among the 19 species, seven species were found to be endemic to Korea: Rhodeus uyekii, Squalidus gracilis majimae, Microphysogobio yaluensis, Odontobutis interrupta, Cobitis tetralineata, Zacco koreanus, and Squalidus chankaensis tsuchigae. Among five families, the family Cyprinidae had the largest number of species (15), whereas the rest of the four families: Gobiidae, Odontobutidae, Cobitidae, and Osphronemidae, had one species each. The two dominant species in the family Cyprinidae were identified as Z. platypus and Z. temminckii. The community index of nine major sites of Yulcheon stream was 0.499 dominance, 2.279 diversity, 0.774 evenness, and 2.594 species richness. The number 3 site had 14 species, the largest number of species among all sites, and the dominance rate (0.480) was low, whereas diversity (2.173), and species richness (2.701) were the highest. As a result of cluster analysis, clusters matched according to the structure of the river types, but St. 9, which confirmed a relatively small number of populations, showed a structure similar to that of the upstream section. In the case of St. 5, a separate cluster was formed by a large number of species and populations.

• Ecology and Resilient Infrastructure
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• v.9 no.2
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• pp.100-106
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• 2022

The relationships between river length and weir density versus fish species observed were analyzed for 210 local rivers in the Seomjin River system (SJR). A nonlinear exponential relationship between river length and number of fish species were observed. Model coefficient was 0.03 and coefficient of determinant (R²) was 0.59, meaning that about 59.0% of total variance was explained by river length variable. Predicted value by model and observed number of species showed a difference. About 110 local rivers (about 52.4%) showed lower value than predictive value. The average index of weir's density (IWD) in the SJR was about 2.7/km, which was significantly higher than that of other river basins. As a result of nonparametric 2-Kimensional Kolmogorov-Smirnov (2-DKS) analysis based on the IWD, the threshold value affecting fish diversity was about 2.5/km (D_max=0.048, p<0.05). Above the threshold value, it means that the number of fish species would be decreased. In fact, the ratio of the expected species to the observed species was lowered to less than 70%, when the IWD is higher than the threshold value. To maintain aquatic ecological connectivity in future, it is necessary to manage IWD below the threshold value.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.1
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• pp.18-25
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• 2020

Monthly fluctuation in abundance and species composition of fish in coastal waters off Oenaro island, Goheung were investigated using seasonal samples collected by a shrimp beam trawl in 2018. A total of 5,981 fishes were sampled and classified into 48 species, 32 families, and 9 orders. The dominant species was Engraulis japonicus (993 individuals, 16.60%), Amblychaeturichthys hexanema (844 individuals, 14.11%), and Thryssa kammalensis (674 individuals, 11.27%). The highest number of individuals was found in August (958 individuals), while the lowest number of individuals was found in January (136 individuals). The diversity index was the highest in November (H' = 2.37) and the lowest in January (H' = 1.77).

• Animal Systematics, Evolution and Diversity
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• v.21 no.2
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• pp.207-217
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• 2005

The fish described in this paper were sampled from four watersheds in the Eastern, Chao Phraya, Peninsular, and Maeklons regions of central Thailand, between the years 2000-2004. A total of 124 species were captured from 160 stream and river sites, using an electrofishing method. 33 of these species were captured in the Eastern region and 42 in the Peninsular region. In the Chao Phraya and Maeklong areas, the fish species were both more abundant and more varied, and 52 and 91 species, respectively, were collected in these regions. Seven species (Brachydanio albolineatus, Rasbora paviei, System us binotatus, Homaloptera smithi, Monopterus albus, Macrognathus circumcintus, Channa gaucha) were commonly found in all of the watersheds.

• Korean Journal of Ichthyology
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• v.10 no.1
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• pp.61-66
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• 1998

The fish fauna and community structure were surveyed at the Naerin Stream of Puk'an River from June 1996 to September 1997. The fishes collected were 36 species, 28 genera belonging to 10 families, in which 16 species were endemic species of Korea. Oncorhynchus mykiss was an exotic fish. The dominant species was Zacco temmincki(relative abundance 42.94%), and subdominant species was Moroco kumgangensis(12.91%). The rare species less than 0.03% of all were Opsariichthys bidens, Squalidus japonicus coreanus, Misgurnus mizolepis, Leiocassis ussuriensis and Siniperca scherzeri. The species diversity, evenness, and dominance index on the fish community were 0.947, 0.609, and 0.218.

• Ocean Science Journal
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• v.42 no.3
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• pp.179-192
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• 2007

Understanding in climate effects on marine ecosystem is essential to utilize, predict, and conserve marine living resources in the 21st century. In this review paper, we summarized the past history and current status of Korean fisheries as well as the changes in climate and oceanographic phenomena since the 1960s. Ocean ecosystems in Korean waters can be divided into three, based on the marine commercial fish catches; the demersal ecosystem in the Yellow Sea and the East China Sea, the pelagic ecosystem in the Tsushima Warm Current from the East China Sea to the East/Japan Sea, and the demersal ecosystem in the northern part of the East/Japan Sea. Through the interdisciplinary retrospective analysis using available fisheries, oceanographic, and meteorological information in three important fish communities, the trend patterns in major commercial catches and the relationship between climate/environmental variability and responses of fish populations were identified. Much evidence revealed that marine ecosystems, including the fish community in Korean waters, has been seriously affected by oceanographic changes, and each species has responded differently. In general, species diversity is lessening, and mean trophic level of each ecosystem has decreased during the last $3\sim4$ decades. Future changes in fisheries due to global warming are also considered for major fisheries and aquaculture in Korean waters.

• Korean Journal of Ichthyology
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• v.26 no.2
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• pp.133-138
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• 2014

We investigated the spacial distribution and species composition of fish larvae during winter season (January 2013~March 2013) in Jinhae Bay, Korea. During the study period, a total of 12 larvae species belonging to 8 families were collected, and the dominant species were Pholis crassispina, Clupea pallasii, Liparis tanakae, Hexagrammos otakii. These four species accounted for 93% of the total number of individual collected. High density and species diversity occurred around Jam-do and eastern area of Chilcheon-do, suggesting that these areas are the main spawning ground of fish larvae in Jinhae Bay.