• Korean Journal of Environment and Ecology
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• v.37 no.3
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• pp.198-208
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• 2023

This study collected samples of Korean dark sleepers (Odontobutis interrupta) in the Keumdang Stream from March to November 2021 to investigate their feeding habits. The sizes were classified by age (1 year and 2 years old, and 3 years or older). The food organisms of O. interrupta included Isopoda, Amphipoda, and Decapoda of the Malacostraca, Ephemeroptera, Odonata, Hemiptera, Plecoptera, Coleoptera, Diptera, and Trichoptera belonging to the aquatic insect of Arthropoda (accounting for 86.6% of the population), Tubificida, Haplotaxida, and Rhynchobdellida belonging to the Clitellata of Annelida (accounting for 7.3%), Systellommatophora and Mesogastropoda belonging to the Gastropodo of Mollusca (accounting for 2.8%), fish (accounting for 3.3%), and fish eggs. Korean dark sleepers fed mostly on aquatic insects, fish, crustaceans, and annelids. Aquatic insects were the most important food source, with 70.1% of the population, 31.7% in biomass, and 72.6% in the index of relative importance. Korean dark sleepers were carnivorous in diet and belonged to the stalker in food intake characteristics and forms. A food migration was observed since less Diptera was found, and more fish, Decapoda, Trichoptera, and Odonata were found in the biomass of the feed consumed by larger species. Diptera (65.3%), Haplotaxida (14.5%), Ephemeroptera (7.0%), Diptera (58.6%), Ephemeroptera (24.5%), fish (4.8%) Diptera (30.1%), Ephemeroptera (20.4%), Isopoda (13.3%) were mainly fed in the autumn.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.195-206
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• 2021

In 2020, South Korea initiated research and development of a longitudinal connectivity evaluation between upstream and downstream based on stream ecosystem health. This study analyzed the migration of upstream and downstream migratory fish species, fish distribution characteristics, trophic guilds, tolerance guilds, and species composition changes from 2015 to 2020 at Songrim weir in Yeongok stream, where the cross-structure of an ice harbor-type fishway for fish movement was recently improved. A total of 5,136 fish, including 36 species, were collected and three major migratory fishes were identified, namely, Tribolodon hakonensis, Plecoglossus altivelis altivelis, and Oncorhynchus keta. According to the comparative analysis before (Pre-I) and after (Post-I) improvement of the fishway, the relative abundance of primary freshwater fish increased in the upstream section, while the number of migratory fishes decreased. The fish species that used the fishway in the Songrim weir were Tribolodon hakonensis (58.4%) and Plecoglossus altivelis altivelis(11.8%). According to the Wilcoxon Signed-Rank Test migratory fish showed a statistically significant difference (p<0.05) in the upstream and downstream, showing a biological improvement effect of the crossstructure. On the other hand, the annual change of migratory fish based on the MannKendall trend test did not significantly increase or decrease (p>0.05). Therefore, in the fish passage improvement project, it is necessary not only for physical, hydrological, and structural tests, but also for pre- and post-biological tests on the use and improvement effect of fishway.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.4
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• pp.381-386
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• 2010

We have cultured the bluefin tuna in Yokjido, Tongyeong with floating cage which was vulnerable to harmful dinoflagellate, Cochiodinium polykrikoides. This study inspected a vertical migration of phytoplankton and Chl-a for reasonable sinking depth in floating cage. Furthermore, we analyzed the fluctuation of the phytoplankton including harmful dinoflagellates occurring in Yokgido for 6 years. Total cell density showed a significant monthly variation and the flora was predominated with diatoms. Gymnodinium sp. occurred 19 times, the greatest number of occurrence in all kinds of dinoflagellates during summer. In particular, the total number of occurrence at C. polykrikoides was 8, and harmful dinoflagellates such as Karenia brevis/Fibrcapsa japonica occurred. The relationship between Chl-a concentration/total cell number and sunset/sunrise was significant and reasonable sinking depth in floating cage was found to be at least 3m from the water surface, which was associated with massive fish kills caused by C. polykrikoides.

• Fisheries and Aquatic Sciences
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• v.15 no.2
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• pp.117-123
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• 2012

The starry flounder Platichthys stellatus, like all flatfish, exhibits conspicuous lateral asymmetry in numerous traits, most obvious of which is the migration of one eye to the other side of the head during metamorphosis. Additional changes related to eye migration include asymmetrical pigmentation, and a behavioral shift from larvae that exhibit upright, open-water swimming to juveniles and adults that lie on the ocean floor, eye side up. However, the morphology of these juveniles has been quite plastic in recent years, a phenomenon which is thought to be related to a diverse suite of semi-intensive and intensive larviculture methods. The cause of morphological abnormalities in the farmed flatfish is poorly understood. In the present study, we observe the features of morphological specificity and abnormality of immature fish (mean total length 23 cm) and survey the occurrence frequency of the specificity and abnormality of juvenile (mean total length 6.70 cm) in artificial culture facility. We find 2 types of abnormality (e.g., albino in ocular side and hypermelanosis in blind side) and 1 type of specificity (e.g., lateral polymorphism). These considerably differ from normal individuals (has sinistral eye and pigmented on only one side) by several characteristics (dextral eye, ocular side albinism, blind side hypermelanosis). The incidences of albinism, hypermelanosis, and body reversal are $10.1{\pm}2.56%$, $91.7{\pm}1.7%$, and $13.1{\pm}1.1%$, respectively. These suggest that these morphometric and morphological differences occur more in artificial environment during and just after metamorphosis.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1344-1354
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• 2022

Laryngeal cancer is one of the highest incidence, most prevalently diagnosed head and neck cancers, making it critically necessary to probe effective targets for laryngeal cancer treatment. Here, real-time quantitative reverse transcription PCR (qRT-PCR) and western blot analysis were used to detect gene expression levels in laryngeal cancer cell lines. Fluorescence in situ hybridization (FISH) and subcellular fractionation assays were used to detect the subcellular location. Functional assays encompassing Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), transwell and wound healing assays were performed to examine the effects of target genes on cell proliferation and migration in laryngeal cancer. The in vivo effects were proved by animal experiments. RNA-binding protein immunoprecipitation (RIP), RNA pulldown and luciferase reporter assays were used to investigate the underlying regulatory mechanisms. The results showed that KIF26B antisense RNA 1 (KIF26B-AS1) propels cell proliferation and migration in laryngeal cancer and regulates the toll-like receptor 4 (TLR4) signaling pathway. KIF26B-AS1 also recruits FUS to stabilize TLR4 mRNA, consequently activating the TLR4 signaling pathway. Furthermore, KIF26B-AS1 plays an oncogenic role in laryngeal cancer via upregulating TLR4 expression as well as the FUS/TLR4 pathway axis, findings which offer novel insight for targeted therapies in the treatment of laryngeal cancer patients.

• Korean Journal of Ichthyology
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• v.34 no.3
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• pp.160-171
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• 2022

This study investigated the characteristics of fish communities, habitat characteristics and the age of Lefua costata in the Jusucheon of Gangneung-si, Korea from January to December 2013. The survey collected 23 species belonging to ten families from 6 survey stations. The dominant and subdominant species were Zacco koreanus (relative abundance, 22.1%) and Rhynchocypris steindachneri (20.1%), respectively. The next most abundant species were Tridentiger brevispinis (10.7%), Orthrias nudus (9.7%), Zacco platypus (8.6%), Lefua costata (7.9%), Iksookimia koreensis (6.0%) and Pungitius sinensis (3.0%). Among the fish species collected, one species, P. sinensis, was class II endangered wildlife by the Ministry of Environment, and four species (Z. koreanus, I. koreensis, Silurus microdorsalis and Cottus koreanus), were endemic to Korea. Additionally, five migration fish species (Tribolodon hakonensis, Hypomesus nipponensis, Gasterosteus aculeatus, Oncorhynchus keta and Plecoglossus altivelis) were collected. The similarity index based on species composition and numbers separated fish communites in the Jusucheon according to main section, i.e., uppermost(St. 1), upper (St. 2~4), middle (St. 5), lower (St. 6). Ecosystem health of Jusucheon Stream (fish assessement index) evaluated using fish was assessed as very good (5 stations) and good (1 station). The main inhabit of L. costata was the middle-lower stream of aquatic plants habitats with mud bottoms, very slow water velocity and water depth 40~80 cm. The age groups for L. costata (female) estimated by the frequency distribution of total length in the spawning season (May) indicated that the 24~37 mm is 1-year old, the 38~51 mm group is 2-year old, the 52~63 mm is 3-year old, 64~77 mm is 4-year old and the 80~91 mm is more than 5-year old. Finally, characteristics of fish communities, habitat characteristics and the age of Lefua costata in the Jusucheon was discussed.

• Korean Journal of Ichthyology
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• v.30 no.3
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• pp.144-154
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• 2018

This study investigated the characteristics of fish communities at the Hangang River in Seoul from Jun 2016 to March 2017. During the survey period, there were 56 species of 17 families collected from 5 survey stations. The species that appeared mainly in the brackish water was Coilia nasus, Leiocassis nitidus, Lateolabrax maculata, Repomucenus olidus, Trachidermus fasciatus, Mugil cephalus, Chelon haematocheilus, Synechogobius hastus, Tridentiger bifasciatus and Takifugu obscurus. The migration fish of Anguilla japonica, C. nasus, Plecoglossus altivelis, Hypomesus nipponensis and T. obscurus appeared in this surveyed area. Korean endemic species were 11 species (17.9%) and accounted for a low rate. There were 6 species (10.7%) exotic species including Cyprinus carpio, Carassius cuvieri, Hypophthalmichthys molitrix, Megalobrama amblycephala, Lepomis macrochirus and Micropterus salmoides. The dominant species by stations were Acheilognathus gracilis (St. 1) and Hemibarbus labeo (St. 2, 3, 4, 5). Regarding the tolerance guild according to water quality, there were 3 (7.1%) sensitive species, 24 (42.9%) intermediate species, and 28 (50.0%) tolerance species. Twenty (35.7%) were insectivore species, 18 (32.1%) were omnivore species, 14 (25.0%) were carnivore species, and 4 (7.1%) were herbivore species, indicating the dominating presence of insectivore and omnivore fish species.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.85-94
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• 2001

The vertical distribution and activity patterns of fishes during the evening and morning transitions were investigated acoustically and by pelagic trawling on October 2-10, 1997 in the Korean Eastern Sea. The acoustic data were collected from four stations with a scientific echo sounder operating at a frequency of 38 kHz, and the echogram was used to analyze the diel vertical migration of fish. Biological sampling was accomplished by pelagic trawling to identify fish species recorded on the echograms, and the species and length compositions were investigated. Vertical profiles of water temperature, salinity at the trawl station were taken with a CTD system and were related to the diel movement and the depth distribution of fish. During the day, one group of fish mainly distributed above the depth layer of 50 m, the other group was at deeper water, approximately 250 m, but began to migrate toward the surface before sunset with a time difference. During the night, they were dispersed between the surface and the depth of 125 m. Just prior to sunrise, the scattering layer was divided with 2 groups and began to migrate downwards, respectively. Several trials of pelagic trawling for scattering layers suggest that the most dominant scatterer in the survey area of this study was Japanese flying squid, Todarodes pacificus..

• Journal of fish pathology
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• v.18 no.3
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• pp.277-285
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• 2005

Israeli carps were intraperitoneally injected with an aqueous extract of red ginseng (RG) at five different concentrations (0, 1, 10, 25 and 50 mg/kg of body weight). The fish were sacrificed after 3 days and measured the neutrophil activity and plasma components. The activity of lysozyme, Ht, TIC and NBT reduction were significantly enhanced in the concentrations of more than 10 mg/kg. Further attempts were made to measure the effects of RG on leucocyte function at five different concentrations (1-100 ${\mu}g/m{\ell}$), in vitro. The proliferation of lymphocytes co-incubated with phytohaemagglutin (PHA) and concanavalin A (Con A) was significantly increased at 10 ${\mu}g/m{\ell}$ concentration, but suppressed at the highest concentration (100 ${\mu}g/m{\ell}$). RG alone or with lipopolysaccharide (LPS) had no effect on proliferation at any concentrations tested. Migration and reactive oxygen intermediates (ROI) production of leucocytes were enhanced in all concentration higher than 10 ${\mu}g/m{\ell}$. These results suggest that the RG activates the leucocyte function and may be able to be used as a stimulant of fish innate defences.

• Journal of Marine Life Science
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• v.6 no.2
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• pp.106-116
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• 2021

To secure basic data by monitoring the growth of salmon (Oncorhynchus keta) released to the Taehwa River. After discharge, the characteristics of the young salmon distribution and migration rate habitat were investigated for two years. A total of 4 points [Sunbawi bridge (St.1), Guyeong bridge (St.2), Samho bridge (St.3), and Myeongchon bridge (St.4)] were investigated. The survey of 2017 indicating an increase of 10 mm in average length and 0.8 g in average weight, and the survey of 2018 indicating an increase of 10 mm in average length and 0.5 g in average weight. Among 39 species, 10 insectivorous and 12 omnivorous, are believed to compete with young salmon for food. 6, 5, 6 and 8 predatory fish species has emerged at each site, respectively. According to this study, it is believed that St.1 and St.2 points are more proper as discharge location of young salmon because these two points have less varied in depth, flow rate, salt concentration etc. In addition, it is thought that the night or dawn time in early January is the best discharge time of young salmon fish because predatory fish such as Korean piscivorous chub and bass etc. does not eat food actively at that time.