• Ocean and Polar Research
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• v.30 no.1
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• pp.79-87
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• 2008

Hydroacoustic technique was used to analyze spatiotemporal stability and distribution of demersal fish aggregations in the coastal region to overcome some limitations of the existing methods such as net and diving. The survey was carried out in the Baekeum Bay on the south coast of Korea in January 2007. The bottom depth in the study site ranges from 7 to 25 m. In order to outline aggregations of demersal fish initial scanning using 200 kHz split-beam transducer was randomly conducted over the large area. Having detected fish aggregation in the specific region, intensive acoustic survey of irregular star pattern was carried out along 14 transects across the area in question. The results of the acoustic survey show that all demersal fish aggregations are concentrated about 5 m from sea bottom having a slight slope and remain steady with no spatial or temporal variations during acoustic survey. The hydroacoustic method used in this study offers a new approach to understand vertical and horizontal distribution, spatiotemporal stability, and biomass estimate of demersal fish aggregations in coastal regions. Additionally, the number of individual fish estimated from in situ acoustic target strength data can be used to understand the standing stock of demersal fish aggregation.

• Parasites, Hosts and Diseases
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• v.46 no.4
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• pp.247-251
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• 2008

This study investigated freshwater fish for their current infection status with metacercariae of Clonorchis sinensis in Korea. Twenty-one species of freshwater fish (n = 677) were collected from 34 regions nationwidely from February 2007 to June 2008. They were individually examined by digestion technique. Eight species of freshwater fish from 17 different regions were recognized positive for the metacercariae of C. sinensis. The positive rates (range of metacercariae number per fish) of fish by the species were as follows: 48% (1-1,142) in Pseudorasbora parva, 60% (1-412) in Pungtungia herzi, 15.7% (1-23) in Pseudogobio esocinus, 29% (1-7) in Acheilognathus intermedia, 21% (1-4) in Odontobutis interrupta, 33% (1-6) in Zacco temmincki, 3.6% (1-4) in Zacco platypus, and 26.3% (1) in Hemibarbus labeo. The two species, P. parva and P. herzi, are able to be the index fish for estimation of C. sinensis transmission in a certain locality. Still several species of freshwater fish are briskly transmitting C. sinensis infection in many riverside areas of southern Korea.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.1
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• pp.39-46
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• 2019

In this study, before system development for the elimination of foreign fish species, we propose an algorithm to classify fish species by training fish images with CNN. The raw data for CNN learning were directly captured images for each species, Dataset 1 increases the number of images to improve the classification of fish species and Dataset 2 realizes images close to natural environment are constructed and used as training and test data. The classification performance of four CNNs are over 99.97% for dataset 1 and 99.5% for dataset 2, in particular, we confirm that the learned CNN using Data Set 2 has satisfactory performance for fish images similar to the natural environment. And among four CNNs, AlexNet achieves satisfactory performance, and this has also the shortest execution time and training time, we confirm that it is the most suitable structure to develop the system for the elimination of foreign fish species.

• Fisheries and Aquatic Sciences
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• v.27 no.8
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• pp.501-514
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• 2024

Fishes are found in different lentic and lotic aquatic ecosystems. Determining the composition of fish communities is a crucial component of water quality evaluations and conservation strategies in flowing rivers. The present study is carried out to investigate fish species diversity, richness, and abundance in two second-order streams: Gereb Tsedo (GTS) and Elala in the Tekeze sub-basin. We collected fish with backpack electrofishing during August and December 2013 and March 2014. Fish species richness and the total number of species per stream and per microhabitat were calculated for each stream. Species diversity for each site was calculated using the Shannon index of diversity using the standard formula H' = -Σpi ln (pi). Diversity data among habitats and streams were compared using one-way analysis of variance (ANOVA) and Tukey post hoc comparisons, using the statistical software package STATISTICA 11. A total of 6,554 specimens representing four species: Garra blanfordii, Grra ignestii, Garra dembecha and Garra aethiopica, were caught. They are all indigenous riverine fish species of the family Cyprinidae. Fish abundance was significantly higher in GTS than Elala stream (t-test, t = 1.444, df = 3, p < 0.05). Across the two streams, the overall relative fish abundance was higher in pools, with 53%, followed by runs and riffles with 35% and 12%, respectively. Garra blanfordii was dominant in pools while G. aethiopica was the least dominant. Stream and habitat types were likely the more important driving factors behind the observed patterns of diversity, although the impact of other, not evaluated variables cannot be excluded. Most likely, the observed patterns do not represent a signature of fish dispersal limitation given that almost all species were widely distributed across the study area.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.6
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• pp.745-751
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• 2019

Seasonal variation in species composition of fishes in the Sannam reservoir in Changwon, Korea was determined using samples collected by a three-sided fyke net in 2018. During the study period, we collected 2,181 individuals of 9 species, with a total weight of 111,552.2 g. The dominant species were Lepomis macrochirus, Carassius carassius, Erythroculter erythropterus, and Cyprinus carpio. These species accounted for 96.1% of the total number of individuals. The number of fish species, number of individuals, biomass and species diversity indices fluctuated with the seasons. The peak number of fish species occurred in May and August, the biomass of fishes was highest in May. Whereas the number of individuals was highest in February.

• Korean Journal of Ecology and Environment
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• v.53 no.3
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• pp.229-240
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• 2020

In this study, the results of fish assemblage survey for 16 reservoirs in the Yeongsan·Seomjin-River watershed were presented with fish assemblage characteristics analysis in relation to reservoir size. The survey method including number of sampling sites was followed the "Biomonitoring survey and assessment manual" of the Ministry of Environment/National Institute of Environmental Research (MOE/NIER), and the reservoirs were categorized as three size groups, small, medium or large reservoirs, based on the MOE/NIER as well. Total 13 family classified into 44 species were collected from 2018 (7 reservoirs) to 2019 (9 reservoirs), and the dominant and subdominant species were Hemiculter eigenmanni (Relative abundance, RA, 32.9%) and Lepomis macrochirus (RA, 31.4%), respectively. As a result of the analysis in relation to the reservoir size, the average (±standard deviation) number of species of the small, medium and large reservoirs were 11±2.9, 14.3±2.1, 22.7±0.6, respectively, which showed positive correlation with the reservoir size. Total 6 fish assemblage characteristics(number of species, number of individuals, richness index, herbivorous fish ratio, carnivorous fish ratio, exotic fish ratio) showed significant differences between the each reservoir size groups (P<0.05). As a result of cluster analysis, 16 reservoirs were clustered into 5 groups with 60% similarity, and the each reservoirs seems to be clustered depends on the distance from each other, watershed and their historical geology rather than size. These results are baseline information for the understanding of fish assemblage in Korean reservoirs, important for establishing management policy of reservoirs in the Yeongsan·Seomjin-River watershed.

• Journal of fish pathology
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• v.6 no.1
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• pp.11-20
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• 1993

To study the immune responses of the japanese eel. Anguilla japonica, fish were injected intraperitoneally with several types of Edwardsiella tarda antigen, i. e., FKC(formalin killed cells), HKC(heat killed cells) or LPS(lipopolysaccharide), and the changes of immunocytes numbers, phagocytosis and agglutination titre in the peripheral blood of the fish were investigated. The number of lymphocytes in the peripheral blood of eels were decreased until 6 hours after injection, and then were turn to normal levels after 24 hours of injection. However, the level were slightly increased and were remained after 24 hours. The number of neutrophils of FKC, HKC or LPS injected fish were the highest at 12 hours after injection and were decreased slowly after that. Three weeks after the injections, the agglutination of antibody titre of all immunized groups were reached at 128 and were remained this level thereafter. However 6 weeks after the injections, that in HKC injected fish were dropped the level up to 4. Fish were injected with LPS and the blood from the fish were bled after 12 hours. Then the blood were incubated with E. tarda. Six hours after incubation, the phagocytic index was reached the highest level, 28.3. One week after the LPS injection, the blood were again bled and incubated with E. tarda. The phagocytic index at this time was 3.9. The phagocytic indexes of the fish injected with FKC and HKC, treted as same LPS injected fish as above, were 18.8 and 10.7, respectively. The phagocytic index of the control fish was 1.2. The antibacterial activities of normal antiserum against E. tarda were shown for both FKC and LPS injected fish, but not for HKC injected fish. The RPS(relative percentage of survival) of HKC, FKC and LPS injected fish in the challenge test were 10%, 20% and 30%, respectively. These results suggest that the effect of protection of the eel which were injected with antigen were varied with the method of preparation of the antigen.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.2
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• pp.319-344
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• 2015

A seasonal characteristic of marine environment and fish assemblages in the coastal waters of Jeju Island were determined using samples collected by a trammel net in from 2012 to 2013. Annual mean temperature and salinity were $18.8^{\circ}C$, 33.7psu (2012) and $18.8^{\circ}C$, 33.8psu (2013) which shows stable water mass. nutrient concentrations represent that dissolved inorganic nitrogen (DIN) ranged from 0.030 to 0.217mg/L, dissolved inorganic phosphorus (DIP) from 0.002 to 0.010mg/L, and silicate ($SiO_2$) from 0.096 to 0.292mg/L. Chlorophyll a concentrations of phytoplankton ranged from 0.905 to $1.125{\mu}g/L$ were appeared the highest in summer and the lowest in winter. Suspended Solid(SS) concentrations ranged from 1.200 to 2.100mg/L (mean, 1.634mg/L) were appeared the highest in autumn and the lowest in spring. During the survey period, a total of 83 species (48 families and 12 orders) of fishes were identified, Perciformes and Scorpaeniformes accounted for 63.9% of the total number. The number of species was higher in summer than in winter, showing a peak in summer at 57 species and a low in winter at 47 species. The number of individuals and the biomass peaked in summer at 694 individuals and 151.9kg, and were the lowest in autumn at 466 individuals and 106.5kg. The diversity index, evenness index and richness index were appeared 2.92~3.14, 0.75~0.83 and 7.06~8.56 at each stations. the dominance index were appeared highest in spring and summer, were appeared the lowest in winter and autumn. The Filefish (Stephanolepis cirrhifer), Bluestriped angelfish (Chaetodontoplus septentrionalis), Marbled rockfish (Sebastiscus marmoratus), Rabbit fish (Siganus fuscescens), Blackfin sweeper (Pempheris japonica) were dominant species, which occurred abundantly during the entire survey period. The subtropical fishes were identified total of 41 species (49.4%) and the number of species was higher in summer at 29 (50.9%) species and a low in winter at 20 (42.6%) species. The dominant species of subtropical fishes were appeared Bluestriped angelfish, Blackfin sweeper, Rabbit fish, Scarbreast tuskfish (Choerodon azurio), Ballonfish (Diodon holocanthus), Flagfish (Goniistius zonatus), Blue-spotted boxfish (Ostracion immaculatus) in study sites. The subtropical fishes of species, individual and biomass showed significant correlation with environmental factors (Chlorophyll a, DIN, DIP, $SiO_2$) in almost all sampling sites.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.3
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• pp.400-409
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• 2008

The purpose of this study is to examine annual changes of coastal fisheries production in the shore of Jeonbuk Province in Korea. The catch data of an experimental vessel that used dredge nets were used to study fish species and catch per unit of fishing effort carried out from April 2002 to November 2004. The total number of fish species caught in 2002 was 23, and 15 in 2004. Total number of individuals were 6,008 and their total weight was 376.38 kg in 2002. In 2004, total number of fishes was 2,469, and their weight was 211.99 kg. The annual changes in fisheries production in the western coast of Korea were also analyzed from 1990 to 2007. The total near shore fisheries products in Korea has been relatively stable around 1,4000,000 metric tons to 1,8000,000 tons during this period. Similarly the Chungnam Province's annual fish catch had steadily risen from about 51,187 tons in 1990 to 85,637 tons in 2007. However, Jeonbuk Province's annual fish catch declined dramatically at around 133, 000 tons in 1990 to 45,000 tons in 2007. In summery, while the overall Korea's fisheries production has been stable over the past decade, that of Jeonbuk Province suffered drastic decline in the period. This decline was reflected in the decreased number of fish species, total individuals, and total catch in surverys performed with an experimental vessel.

• Korean Journal of Ichthyology
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• v.21 no.3
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• pp.167-176
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• 2009

Species composition and seasonal variation of fish assemblages in the western coastal waters of Jeju Island were determined using samples collected by a trammel net, gill net and fish pot in 2008. During the survey period, a total of 81 species (45 families and 13 orders) of fishes were identified, and Perciformes and Scorpaeniformes accounted for 69.1% of the total number. The number of species was higher in warm months than in cold months, showing a peak in July at 54 species and a low in April at 42 species. The number of individuals and the biomass peaked in September at 895 inds. and 135 kg, and were lowest in December at 450 inds. and 52 kg. The diversity indices of fish catches in trammel net and fish pot were 2.88~3.22 and 1.31~1.87, respectively, and were highest in September. Sebastiscus marmoratus, Stephanolepis cirrhifer, Choerodon azurio and Pseudolabrus sieboldi were dominant species, which occurred abundantly during the entire survey period.