• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.3
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• pp.233-242
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• 2019

Species composition and yearly variation of fish eggs and larval fishes were investigated from 2014 to 2016. During the study period, the fish eggs were identified as belonging to 14 taxa. The dominant species of fish eggs were Leiognathus nuchalis, Engraulis japonicus, and Konosirus punctatus. These three species accounted for 97.4% of the total number of individuals collected. The collected larval fishes were identified into 37 taxa, 22 families, and seven orders. The dominant species of larval fish were Leiognathus nuchalis, and Gobiidae fishes. These three species accounted for 85.4% of the total number of individuals collected. The diversity index of the larval fishes was the highest in 2014 (H' = 1.60) and the lowest in 2015 (H' = 1.15). The evenness index was the highest in 2016 (J = 0.51) and the lowest in 2015 (J = 0.39). The dominance index was the highest in 2015 (D = 83.5%) and the lowest in 2016 (D = 70.9%). In addition, the economically important species in this area were Engraulis japonicus, Konosirus punctatus, Hippocampus coronatus, Sebastes schlegelii, Acanthopagrus schlegeli, and Cynoglossus joyneri.

• Proceedings of the National Institute of Ecology of the Republic of Korea
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• v.2 no.1
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• pp.53-61
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• 2021

Distribution of fish community depends largely on environmental disturbance such as habitat change. In this study, we evaluated the impact of environmental variables and microhabitat patch types on fish distribution in Yudeung Stream at 15 sites between early May and late June 2019. We used non-metric multidimensional scaling to examine the distribution patterns of fish in each site. Gnathopogon strigatus, Squalidus gracilis majimae, Zacco koreanus, and Zacco platypus were associated with riffle and boulder areas, whereas Iksookimia koreensis, Acheilognathus koreensis, Coreoleuciscus splendidus, Sarcocheilichthys nigripinnis morii, and Odontobutis interrupta were associated with large shallow areas. In contrast, Cyprinus carpio, Carassius auratus, Lepomis macrochirus, and Micropterus salmoides were found at downstream sites associated with large pool areas, sandy/clay-bottomed areas, and vegetated areas. On the basis of these results, we suggest that microhabitat patch types are important in determining the diversity and abundance of fish communities, since a mosaic of different microhabitats supports diverse fish species. As such, microhabitat patches are key components of freshwater stream ecosystem heterogeneity, and a suitable patch composition in stream construction or restoration schemes will support ecologically healthy food webs.

• Korean Journal of Ecology and Environment
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• v.41 no.1
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• pp.98-103
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• 2008

Genetic diversity and population genetic structure within or among three stream populations (Gab, Baekgok and Ji streams) of Korean endangered natural monument fish, Iksookimia choii, were assessed by amplified fragment length polymorphism (AFLP). AFLP analysis using three primer combinations generated 104 to 106 AFLP bands, and percent polymorphic bands were similar in those three populations ranging 21.5 to 24.5%. Heterozygosity and genetic diversity within or among populations were quite low for all of these populations with average values ranging from 0.067 to 0.084 and from 0.076 to 0.087, respectively. Analyses of pairwise distance and genetic similarity among three populations of I. choii also revealed the similar results with very low genetic differentiation one another. Although pairwise Fst values were very low, our data clearly indicated distinct genetic differentiation among the three populations. This is the first report concerning the genetic diversity and differentiation of this species, and provides basic genetic information that should facilitate attempts to conserve this species.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.431-440
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• 2008

Turbid water or suspended sediment is associated with negative effects on aquatic organisms; fish, aquatic invertebrate, and periphyton. Effects of turbid water on fish differ depending on their developmental stage and a level of turbidity. Low turbid water may cause feeding and predation rates, reaction distance, and avoidance in fish, and it could make fish to die under high turbidity and long period. Therefore, it is very important to find out how turbid water or suspended sediment can affect fish in domestic watersheds. The objectives of this study were 1) to introduce international case studies and their standards to deal with suspended sediment, 2) to determine acute toxicity in 4 major freshwater fishes, and 3) to determine in relation to adverse effect of macroinvertebrates and fish. Impacts of turbid water on fish can be categorized into direct and indirect effects, and some factors such as duration and frequency of exposure, toxicity, temperature, life stage of fish, size of particle, time of occurrence, availability of and access to refugia, etc, play important role to decide magnitude of effect. A review of turbidity standard in USA, Canada, and Europe indicated that each standard varied with natural condition, and Alaska allowed liberal increase of turbidity over natural conditions in streams. Even though acute toxicity with four different species did not show any fatal effect, it should be considered to conduct a chronic test (long-term) for more detailed assessment. Compared to the control, dominance index of macroinvertebrates was greater in the turbid site, whereas biotic index, species diversity index, species richness index, and ecological score were smaller in the turbid site. According to histopathological analysis with gills of macroinvertebrate and fishes, morphological and physiological modification of gills due to suspended sediments can cause disturbance of respiration, excretion and secretion. In conclusion, in order to maintain good and healthy aquatic ecosystem, it is the best to minimize or prevent impact by occurrence of turbid water in stream and reservoir. We must make every effort to maintain and manage healthy aquatic ecosystem with additional investigation using various assessment tools and periodic biomonitoring of fish.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.633-642
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• 2014

Monthly variation in abundance and species composition of the fishes were investigated based on specimens collected by gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010. The collected fishes were 1,529 individuals (183,840g) of the total, identified into 6 orders, 16 families and 24 species. The most dominant order fish was Perciformes comprised 9 species, 7 families, and followed Pleuronectiformes comprised 5 species, 3 families, Scorpaeniformes comprised 5 species, 2 families. These 3 orders constituted 81.1% of the total collected fish. During the study, most dominant species was Hexagrammos otakii accounted for 189 individuals (12.4%) of the total, followed by Lateolabrax japonicus 165 individuals (10.8%), Hexagrammos agrammus 154 individuals (10.0%). The fish was collected by a gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010, the diversity index of the fishes was 2.09~2.66, which was the highest in August, 2010 and the lowest in February, 2010. The evenness index of them was 0.84~0.89, which was the highest in August, 2010 and the lowest in February, 2010 and the richness index of them was 2.02~3.14, which was the highest in October, 2009 and the lowest in February, 2010. The analyzed species diversity index by the each stations was 2.47~2.66 and the evenness index was 0.84~0.90 and the richness index 2.99~3.37. The similarity of community structure per season was very high which was the least in spring and fall. In addition, the community structure was very similar in state 3 and 2 out of each stations.

• 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.

• Korean Journal of Ecology and Environment
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• v.54 no.2
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• pp.130-141
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• 2021

By reviewing previous literature, we analyzed the food sources of 20 out of 29 endangered fish species from freshwater ecosystems in South Korea. A total of 19 studies reported that food sources of 20 endangered fish species included 20 phyla, 31 classes, 58 orders, 116 families, and 154 genera. Arthropod, insecta, diptera, and chironomidae were the most fed animal food sources according to different resolution of taxa index on phylum, class, order and family. Similarity, bacillariophyta, bacillariophyceae, naviculales, and cymbellaceae were the most fed abundant plant sources. A larger number of fish species were reliant on animal food sources than plant food sources. 18 of the endangered fish preyed on arthropods, whereas only 6 species consumed bacillariophyta. To characterize the feeding groups of the 20 fish species, a hierarchical clustering analysis and non-metric multidimensional scaling analysis were conducted. The fish species were divided into two groups: 1) insectivores and 2) planktivores. A network analysis, which associated the link between endangered fishes and food sources, also revealed the same two groups. The highest hub score of food sources was for macroinvertebrates, including diptera (0.47), ephemeroptera (0.42), and trichoptera (0.38), based on the network analysis. Niche breadth was used to calculate the diversity of the food sources. Phoxinus phoxinus (0.57) showed thehighest food source diversity among the fish species, whereas Iksookimia pacifica (0.01) showed the lowest. This study will be utilized for the conservation and restoration of the endangered fish species.

• Fisheries and Aquatic Sciences
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• v.25 no.12
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• pp.637-647
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• 2022

A spotted scat, Scatophagus argus, has a high nutritional value and is among Asia's most widely consumed fish species. Thua Thien Hue's consumption market considers this species to be of high economic value and requires protection and conservation of the population. However, the studies on the identification and genetic diversity of S. argus distributed in Vietnam are still lacking. Therefore, mitochondrial cytochrome c oxidase subunit I (COI) gene was utilized to distinguish different populations and investigate the genetic diversity of two populations of S. argus from Tam Giang lagoon, Thua Thien Hue province (n = 31) and Ca Mau province (n = 14). The sequencing results indicated 13 distinct haplotypes among 45 sequences. Five single nucleotide polymorphisms were observed to distinguish Hue spotted scat population. The S. argus population in Ca Mau province was higher haplotype diversity (Hd) and nucleotide diversity (π) than those of Thua Thien Hue province, which demonstrates that there are minor differences between haplotypes. There were genetic distances ranging from 0%-4% within the populations and 6.67% between the two populations. In addition to the sequencing, the comparison of morphology, biology, culture, and the growth rate was sufficient to distinguish the spotted scat S. argus in Thua Thien Hue from Ca Mau.

• Journal of Aquaculture
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• v.21 no.3
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• pp.196-200
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• 2008

Korean spotted barbel Hemibarbus mylodon, is an endangered and endemic freshwater species in the Korean peninsula. Amplified fragment length polymorphism (AFLP) was used to analyze the genetic diversity and population genetic structure of three populations (Bukhan, Namhan and Imjin-river). Fifteen AFLP primer pairs produced 795 products of which 135 were polymorphic(17%). Percentages of polymorphic bands were similar among the three populations, with accounting 11.9%, 11.1%, and 13.4% for Bukhan, Namhan and Imjin-river populations, respectively. An average genetic similarity among the three populations was 0.969. The average heterozygosity (0.033-0.040) and genetic diversity (0.036-0.043) were significantly low. Pairwise distance and fixation index analyses of three populations also suggested quite a low genetic differentiation one another. These results would provide a fundamental baseline data to develop the effective strategy for the management and restoration of this endangered fish species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.1
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• pp.1-8
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• 2000

Benthic environments and composition of macrobenthic fauna around the marine fish culture cages were studied to clarify the effect of fish farming near Tongyong from August, 1995 to february, 1996. Sediment grain size and bottom dissolved oxygen under the fish cages were similar to that of a control site, but organic content was higher under the cages. Fewer species were found under the fish cages than under the control site, but conspicuously higher density was obtained under cages. Capitella capitals, Nebalia bipes were dominant infauna, and Asterina pertinifera and Astelias amurensis were dominant epifauna under the fish cage whereas Lumbrineris longifolia and Anphioplus sp. dominated in the control site. Diversity index showed seasonal variation under the fish cages, but showed little variation at the control site. The benthic fauna under the fish cages showed different community structures from the control site. As results, the fish culture cages affected the benthic environment and the community structure of benthic fauna by input of the organic content and biological effects such as dead shells.