• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.482-489
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• 2012

Visual monitoring is hard to apply on fish because they are living in a water system. To overcome this problem, acoustic telemetry, which is effective for underwater monitoring, is often used for studying fish behaviors, such as movement distance, route and patterns. In this study, in order to monitor the movement pattern of Squaliobarbus curriculus (family Cyprinidae), we used acoustic telemetry and identified the home range and movement distances. A total of nine individuals were released at two different locations: one is at the estuary barrage (Sc1~3) and the other is at the lower part of Baekjae Weir (Sc4~9), located in Geum River. Approximately, a 70 km section from the estuary barrage was investigated. Fish, which were released at the estuary barrage, utilized up to 12.7 km upstream as home range from the release site. At the lower part of Baekjae Weir, most of the fish moved and stayed within a 7.2 km downstream area, except for Sc6, which moved 53.4 km (linear maximum distance from release site) downstream from the release site. Relatively small sized fish (Sc7~9) did not show any movement. Accumulated movement distance significantly correlated with the standard length of S. curriculus ($r_s$=0.715, p=0.03). Moreover, the standard length of moving fish was significantly larger than that of not moving fish (Mann-Whitney U test, p=0.024). Therefore, the movement distance of S. curriculus has been correlated with fish size; movement distance was increased with the standard fish length. Although the sample size of monitored fish was small, various meaningful data were collected by acoustic telemetry. Consequently, this technique could be a method available for effectively monitoring the behavior and ecology of native Korean and endemic species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.131-136
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• 1995

An attempt was made to elucidate the stability of serum metabolites and enzyme activities in blood samples taken from rockfish(Sebastes schlegeli), Israeli carp(Cyprinus carpio) and rainbow trout Oncorhynchus mykiss) under different storing conditions. The concentrations of total protein(TP), albumin(ALB), triglyceride(TG), cholesterol(CHOL) glucose(GLC), phosphorus(P) and sodium(Na), and the activities of alanine aminotransferase(ALT) and aspartate aminotransferase(AST) in serum were investigated for 16 days at $15^{\circ}C$(room temp.) and $4^{\circ}C$ (refrigerative) condition, or frozen at $-20^{\circ}C$ for period of 30 days. Though there was a little difference between fish species, the concentrations of TP, ALB, GLC, P, Na in serum were stable at all storing temperatures, while those of TG, CHOL, ALT and AST were not stable, particularly even at the normal temperature. In general, serum components were more stable at refrigerative and frozen conditions than at room temp. storing. However, it was noticeable that the stability of CHOL in rockfish serum was found to be more unstable at $-20^{\circ}C$ than kept at $15^{\circ}C$ or$4^{\circ}C$.

• Journal of Environmental Impact Assessment
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• v.27 no.3
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• pp.307-321
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• 2018

Fish fauna and lentic ecosystem health assessment in freshwater were analyzed in the two reservoirs (Uirim Reservoir(Ur) and Solbangjuk Reservoir(Sr)) of the Jecheon City during May-September 2017. Total numbers of the species and genus (7 family) sampled were 21 and 16, respectively. Cyprinidae was most dominant taxa, which accounted for 11 species (52.4%) of the total species, and the relative abundance, based on the number of individuals, was 318 individuals (46.2%). Subdominant families were taxa of Centrachidae (2 species; 264 ind. (38.4%). The dominant species, based on the relative abundance, were Squalidus chankaensistsuchigae(22.7%). Subdominant species were Lepomis macrochirus(19.5%, 134 ind.) and Micropterus salmoides(18.9%, 134 ind.). Trophic state index of Korea ($TSI_{KO}$), based on chemical oxygen demand (COD), total phosphorus (TP) and chlorophyll-a (CHL),ranged mesotrophic state. The purpose of this study was to apply a multi-metric model of Lentic Ecosystem Health Assessments (LEHA) for environmental impact assessments of two reservoirs and assessed the ecological health model values. Trophic composition's metrics showed that tolerant species (56.8%, 98.3%) and omnivore species (43.9%, 65.6%) dominated the fish fauna in the two reservoirs (Ur and Sr) of Jecheon City, indicating a biological degradation in the aquatic ecosystem. The relative proportions of Micropterus salmoides, also showed greater than 16.3% (Ur), 31.1% (Sr) of the total, indicating a ecological disturbance. The average value of LEHA model was 22 (Ur) and 12 (Sr) in the reservoirs, indicating a "poor condition (Ur)" and "very poor condition (Sr)" by the criteria of MOE (2014).

• Applied Microscopy
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• v.40 no.1
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• pp.1-8
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• 2010

The ultrastructure of spermatogenesis and sperm in Chinese minnow, Rhynchocypris oxycephalus belonging to Leuciscinae was investigated by light and electron microscopes. The whitish testis was located between intestine and air bladder. The size of testis was major axis 2.3 cm, minor axis 6 mm. The testis contained numerous testicular cysts, and spermatogenesis was non-synchronized in these testicular cysts. In the case of spermatogonium, the nucleus was comparatively large ellipsoidal, and mitochondria showed a marked development. The size of primary spermatocyte was smaller than that of spermatogonia, and secondary spermatocyte was smaller than primary spermatocyte. The chromatin of spermatocyte was highly condensed according to their development. The nucleus with electron-dense was round shape. In spermiogenesis, flagella started to be formed and chromatin was more condensed. The mitochondria were rearranged in a middle piece. The sperm was formed by loss of cytoplasm. The head of mature sperm was a spherical shape and have not acrosome. The microtubules of flagella were arranged 9+2 structure. Also, the tail of sperm have not lateral fins.

• Korean Journal of Ichthyology
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• v.18 no.1
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• pp.27-35
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• 2006

During spawning season of female in a Korean oily bitterling, Acheilognathus koreensis, the ventral region near the base of the pectoral fin becomes to be protruded outward of body and enlarged. This ventral process consists of both organs as rectum (vent) and inner ovipositor. The rectum consists of mucosa, lamina propria-submucosa, muscularis, and squamous epithelial layer (peritoneum=serosa) surrounding them. The mucosa contains numerous mucous cells meaning acid mucopolysaccharides in nature. The inner ovipositor is similar to that of the rectum, but the mucosa have no mucous cell, unlike that of the rectum. Whereas, the outer ovipositor has a straight and long tube which are not connected with the ventral process any more. The outer ovipositor was similar to the structure of the inner ovipositor in the ventral process. However, the outer ovipositor has no muscularis, and consists of three layers: mucosa, lamina propria-submucoa, and squamous epithelia. The outer ovipositor without the muscularis seems serves as a tube that eggs discharged from the outer ovipositor allow to send inside mussel, unlike that of the inner ovipositor performing rhythmic contractions of the layers of the muscularies for propelling to the matured oocytes to the outer ovipositor.

• Korean Journal of Ichthyology
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• v.25 no.2
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• pp.135-140
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• 2013

Microphysogobio koreensis, an endemic Korean freshwater fishes belonging to Cyprinidae, is protected as a 2nd grade of endangered fishes by the ministry of the Environment. For this species, the study on the spawning microhabitat including structure of streambed and spawning grounds was carried out. The streambed that this species mainly lives consists of boulders, cobbles, and pebbles, the so-called Bb type, with a depth of 0.3 to 1.0 m and a rapid velocity of $0.5{\pm}0.2$ m/sec. But the main spawning grounds where the spawning is actually occurring, is relatively shallower, $0.4{\pm}0.1$ (0.4~0.6) m depth, and faster, $0.8{\pm}0.1$ (0.6~0.9) m/sec velocity, whereas the region that the fertilized eggs are attached are rather slowest to 0.4m/sec. The spawning starts at a water temperature of $20^{\circ}C$ in earlier May, laying their eggs on the cobbles' or boulders' surface or in between them. In particular, with a wide range of streambed structures, natural spawning grounds' environments may let the fertilized eggs not be swept from rapid current and secure efficient dissolved oxygen. The individuals, however, do not appear at the grounds any more after the spawning season, and it is expected that they may move into deeper water such as Lakes or lower streams.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.1
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• pp.15-27
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• 1974

Since the summer of the year 1972 ulcer disease of common carp, colour carp ana goldfish had suddenly spread widely and caused a serious mortality at fish farms especially around Gim-hae and Yang-san, near Busan. The present study aimed to find out the causative organisms, histopathological changes and the way of treatment, and the results are summarized as follows : Two kinds of pathogenic bacteria, i. e, Chondrococcus columnaris and Aeromonas sp. were isolated from the mucus of the lesion. According to the macroscopic findings, these symptoms began with the hemorrhagic spots under scales which fell out, after the collapse of the dermis, which was followed by lesion to form ulcer, and then the muscle was exposed. The fin was eroded mostly from the distal part, but sometimes from the basal part. Gills showed grey colour, and this part of the tissue collapsed. According to the histopathological findings, the dermis was exposed after the collapsed of the epithelium of the skin, and the necrosis of the musculature occurred, the muscular fibre being destroyed. The epithelial cells of gill tissue proliferated, thus gill filaments were conglutinated and collapsed. Fatty degeneration happened at the liver but the other organs seem to be normal. Treatment with the following mixtures were effective the water temperature of $22\~25^{\circ}C$, but not effective when the temperature was under as low as $13\~15^{\circ}C$. Mixture 1. Aivet (HB-115.HCI) 0.3ppm Malachite green 0.2ppm. Dipterex 0.4ppm Mixture 2. Furanace (P-7138) 0.05ppm Malachite green 0.2ppm Dipterex 0.4ppm When lesion healed, the epithelium, dermis, and the muscular fibre were regenerated.

• Journal of fish pathology
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• v.9 no.1
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• pp.11-13
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• 1996

Ergasilus sieboldi, a parasitic Copepoda, was detected from the gill of Silurus asotus fingerling(7~10 cm long) cultured at a fish farm in Chungnam Province (Fig. 1 and 2). The infected fish did not show any particular external symptoms except a feeble swimming around the boarder of the pond. The isolated parasite was of 1.07 mm in body length with two egg sacks of 1.05 mm and one pair of hook-shaped secondary tentacle. Bychowsky(1963) described that this parasite infected the gill of Salmonidae, Serranidae, Cyprinidae and Siluridae and that the fish in the Baltic Sea, Black Sea. Caspian Sea. Japanese sea zones, Siberian rivers and Lake Bikal were infectd. Bychowsky further pointed out that heavily infected fish with this parasite become emaciated and slow in growth. and often die. As this parasite infected on the peri-branchial area. the infected fish showed a severe disturbance of respiration. Urawa et ai.(1980) studied on the development of Neoergasilus japonicus. an Ergasilidae, which infects Japanese freshwater fish. In Korea, Chun(1985) reported the identification of Ergasilus sieboldi from imported carp. and Neoergasilus and Pseudogasilus japonicus from bluegills. respectively. Chun also identified Pseudoergasilus zacconis in cultured ayu(Plecoglossus altivelis). However. this report deals with the detection of Ergasilus sieboldi from cultured catfish(Silurus asotus) for the first time in Korea.

• Korean Journal of Ecology and Environment
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• v.45 no.4
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• pp.403-411
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• 2012

Acoustic telemetry is used to obtain a relatively continuous record of fish movement. This method has several advantages for studying migrating fish populations that are moving from large rivers. The Nakdong River is the longest river in South Korea and the main stream has faced a change, which consists of the installation of the large weirs. In this study, we applied acoustic telemetry to monitor the movement pattern of Erythroculter erythropterus (family Cyprinidae) and identified home range and movement distance in the Nakdong River. A total of fourteen individuals were released at three different locations and around 80 km section from the estuary barrage was investigated. Eight individuals were tagged and released at estuary barrage (N02) utilized up to 15.9 km (home range) upstream from the release site as home range. Four individuals were tagged and released at Samrangjin (N07), most fish moved and stayed within 9.7 km (home range) downstream area, except E12, which did not show any movement. Two individuals were tagged and released at Changnyeong-Haman weir (N10), and all individuals migrated downstream from the release site. Especially, E14 recorded the longest accumulated detected distance, 36.7 km downstream during 32 days after release. There was no correlation identified between movement (accumulated detected distance and home range) and standard length (Spearman rank correlation, p>0.05). Although, this technique could be an available method to monitor behavior and ecology of freshwater fish effectively, increment of number of receivers and tags are required for more detailed results of fish migration.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.296-304
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• 2011

This study was carried out to investigate the relation between water quality and structure of the aquatic ecosystem in the Lake Gachang from February to December in 2010. The annual mean COD (Chemical Oxygen Demand) in Lake Gachang was 3.5 mg $L^{-1}$, indicating, level II of environmental standards and the trophic state was mesotrophic. The seasonal succession of phytoplankton showed that Bacillariophyceae was mostly dominant species throughout the year except August. In case of zooplankton, rotifers dominate in the most seasons, but copepod (Nauplii) in August. The macrophyte plants showed diverse species composition consisted of 9 varieties, 77 species, 64 genera, 34 families and 24 orders. Surveyed species of macroinvertebrates were classified into 1 phyla, 2 classes, 4 orders, 7 families, 9 species. The macroinvertebrates showed FFG (Functional Feeding Groups) such as GC (Gathering-Collector) and SH (Shedder). A total of 42 species of fish was collected including $Zacco$ $koreanus$ and $Coreoperca$ $herzi$. In this study, we investigated environmental factors including pollutant source, load, water quality and distribution characteristics of biota such as phytoplankton, zooplankton, macrophyte plants, macroinvertebrates, fish.