• Korean Journal of Ichthyology
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• v.13 no.4
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• pp.230-236
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• 2001

Feeding habits of Gobiobotia brevibarba were investigated at Hongcheon River of Bangokri, Seomyon, Hongcheongun, Kangwondo from January to December, 2000. G. brevibarba was a carnivore and consumed mainly Ephemeroptera, Tricoptera and Diptera. Small quantities of Plecoptera and Coleoptera were included as a minor food items. The species showed ontogenetic changes in feeding habits. Individuals of small size (21~50 mm SL) fed mainly on small prey organisms such as Diptera and Ephemeroptera. However, larger Tricoptera were heavily selected with increasing fish size. The relative proportion of these food items changed with season. The prey selection indices for Ephemeroptera were positively selected in spring, summer and autumn, and negatively selected in winter, Diptera were positively selected in March, October and November.

• Korean Journal of Ichthyology
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• v.24 no.4
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• pp.253-262
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• 2012

A skeletal system of Coreoleuciscus splendidus from Seomjin and Mankyeong Rivers is described and figured in detail. The osteological characteristics are as follow: preorbital area elongated; eight proximal radials on the anal fin; 1st basibranchial bone with a bottle gourd shape; two types of pharynegeal teeth; intercalarium's ascending process absent and rib 4 broad greatly. Meanwhile, the number of actinost and the length of external process and internal process on the pelvic girdle are variable with individuals. These characteristics are shown in the two population. The epural on the caudal skeleton, however, has two types only in C. splendidus of Mankyeong River.

• Animal cells and systems
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• v.4 no.2
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• pp.109-115
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• 2000

To clarify taxonomic status of the two sibling species, Moroco oxycephalus and M. lagowskii reproductive isolation mechanisms were investigated at sympatric area located in Kansung-up, Kosung-gun, Kangwon-do, Korea. Genetic analysis was performed to reveal mating system and intensity of Hybridization between the two species. The frequencies of hybrids were increased since 1989, and then the observed hybrid frequencies ($H_O$) did not significantly differ from the expected hybrid ($H_E$) in 1998 and 1999. However, based on histological analysis of two parents and their hybrid s gonads, the hybridizations between M. oxycephalus and M. lagowskii produced mostly fertile females but sterile males in accordance with Haldane s rule. Although it was suspected that pre- and postmating isolation mechanisms were affected between the two species, M. oxycephalus and M. lagowskii seemed to be strongly isolated with microhabitat at sympatry until 1997. Since 1998, hybrid frequencies were increased by habitat disturbance. However, their hybrid frequencies would be reduced by postmating isolation mechanisms. Therefore, the two species are considered to be distinct species recently diverged.

• Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.1-6
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• 2006

Mature spermatozoa of dark chub Zacco temmincki (Temminck and Schlegel), were examined under a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The spermatozoa have a spherical, homogeneously electron-dense nucleus with an axial nuclear fossa containing two laterally oriented centrioles. The centrioles, which are arranged at about a $120^{\circ}$ angle to each other, have the 9+2 microtubule structure typical of flagella. The mature spermatozoon is of the primitive anacrosomal aquasperm type. The nuclear envelope is strongly undulated and contains nuclear vacuoles of different sizes and positions. The midpiece contains six or more mitochondria and encircles the basal body of the flagellum with an axoneme covered by the plasma membrane. Cytoplasmic vesicles lie between the axonemal doublets and the plasma membrane, and encircle the anterior part of the tail. The plasma membrane of the flagellum extends laterally and forms a pair of side fins. The species showed minor differences in number and structure of mitochondria, the angle between centrioles, and total length and occurrence of the fins. These characters, especially the side fins, appear to be apomorphic and useful for determining phylogenetic relationships at the genus or family level.

• Korean Journal of Ichthyology
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• v.17 no.1
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• pp.57-63
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• 2005

The digestive apparatus and food of the Korean bitterling, Acheilognathus signifer, from the upper reaches of the Hongcheon River were investigated by examining their gill rakers, pharyngeal teeth, and digestive-tube contents. Gill rakers of the first arch were relatively few (17 to 21, mean = 19) and short (mean = 0.36 mm, SD = 0.035). The 2nd to 5th pharyngeal teeth were well developed, while the first tooth was poorly developed. Gill rakers and pharyngeal teeth were completely formed early in life. The digestive tube was long and arranged in many coils. The digestive-tube contents of Korean bitterling mainly consisted of phytoplankton and detrital microorganisms.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.5
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• pp.363-370
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• 2008

The ichthyofauna of certain reservoirs in Pohang-si, Gyeongsangbuk-do, were studied during the period from October 7-19, 2005. During the study period, 9,480 individuals (ind.) belonging to 22 species, 17 genera, 8 families and 4 orders were collected. Of these, 11 species were cyprinidae fishes, and the dominant species was Pseudorasbora parva (relative abundance 47.14%). There were six Korean endemic species (289 ind., relative abundance 3.04%), including Squalidus chankaensis tsuchigae, Squalidus mulimaculatus, Hemiculter eigenmanni, Iksookimia yongdokensis and Coreoperca herzi, and the dominant Korean endemic species was Pseudobagrus brevicorpus (relative abundance 3.04%) collected in Hoehakji, Cheonggyeji, Ahnsimji and Mabukji. There were five introduced species. Three species, including Hemiculter eigenmanni, Pseudobagrus fulvidraco and Hypomesus nipponensis, were introduced from other native stream systems, and two species, including Carassius cuvieri and Lepomis macrochirus, originated in foreign countries. Of these, Lepomis macrochirus (l,521 ind., relative abundance 16.05%) was collected at the all reservoirs except at Gidongji. These results suggest that the exotic fishes in question have been widely dispersed within the reservoirs in Pohang-si.

• Korean Journal of Ichthyology
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• v.12 no.4
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• pp.223-229
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• 2000

Phylogenetic relationships between 8 species Korean loaches (Cobitidae) were investigated by comparing mitochondrial cytochrome b gene sequences. However our results are in accordance with finding observed using other morphological studies, new interesting interspecific variation in Korean loaches were found. Orthrias and Lefua appeared to be paraphyletic in Cobitidae observed. Their sequence divergence value was agreed with interfamilic sequence divergences between Cobitidae and Cyprinidae ranged from 0.184 to 0.272. Otherwise, the present results support that two species of Iksookimia and Cobitis melanoleuca were early diverged respectively. And another remarkable result was sequence divergence between Misgurnus anguillicaudatus from China and M. anguillicaudatus from Yongdok, Korea. That was 0.099, which was interspecific value. Also the phylogenetic location of some Iksookimia species was suggested as the cobitid intergeneric hybrid origin.

• The Korean Journal of Zoology
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• v.16 no.2
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• pp.97-108
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• 1973

Karyological characteristics and relative DNA values were investigated in four species of the family Cyprinidae of Korean fresh-water. The results obtained were as follows; 1) The two Hemibarus species, H. longirostris and H. labeo, had the aiploid chromosome number of 50. The compliment of former consisted of 7 metacentric, 14 submets- and subtelocentric and 4 telo- or acrocentric pairs, whereas latter had 9, 11 and 5 pairs respectively, Total arm numbers (AN) were 92 and 90. 2) In the case of two species of genus Moroce, M. oxycephalus and M. lagowskii, their diploid number and karyotype showed in identical pattern for each other (2n=50); 6 pairs of metacentrics, 14 pairs of submeta- and subtelocentrics and 5 pairs of telo- or acrocentrics. The AN of both species were 90. 3) Relative DNA values of all species were measured as about 60% that of gold fish. From the above observation, the cytogenetical character was discussed with special concern to the phylogenetic significance.

• Animal cells and systems
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• v.12 no.4
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• pp.297-304
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• 2008

Morphology and distribution of the minute tubercles projected on the skin surface of larvae with its development were observed in the Korean bitterling, Acheilognathus somjinensis. The minute tubercles appeared to be two distinct morphologies, hemispheric or scaly and vestigial structures. Just after hatching, the epidermis of the larvae consists of a thin single cell layer having smaller basophilic flat or round-flattened basal cells. As the larvae grow, the epidermis contains more small flat cells and large epidermal cells which are round and hemispheric, or scaleshaped, called minute tubercles. They are distributed over the anterior part and most part of yolk sac, posterior region of yolk sac and the body region. Vestigial epidermal cells, another minute tubercle, occur only in the caudal fin-fold region, which they are shrunken and flattened, causing the cell boundary to be unclear. They increase in number and height from just to 5 days after hatching, but they become reduced as the larvae develop gradually. The required time for those disappearance was different each by regional body: at day 20 after hatching in the anteriormost part of yolk sac, and day 11 after hatching in the posterior part of yolk sac and the body, and day 21 after hatching in two regions such most part of the yolk sac and the caudal finfold regions.

• Korean Journal of Ecology and Environment
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• v.41 no.4
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• pp.490-498
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• 2008

This study was to analyze fish composition and ecological indicator characteristics from eight sampling sites of Geum River, October 2007. Total number of family and species sampled were 9 and 40. The most dominant family was Cyprinidae (27 species, 85%), and then followed by Cobitidae, Odomtobutidae, and Gobiidae. Constancy values of Zacco platypus and Zacco temminckii were 1.00 and 0.30, respectively, and the relative abundance of Acheilognathus koreensis and Pseudogobio esocinus were greater than 5% of the total. The number of Korean endemic species sampled in this Geum River study was 7 family 19 species, which is 47.5% of total 40 species, and endangered species of Pseudopungtungia nigra and Gobiobotia brevibarba were only 0.5% of the total and these species were only distributed within the upstream regions. Exotic species, Micropterus salmoides, which is known as large-mouth bass, were observed in two sites of G3 and G7. Analytical results of fish community showed that community dominance index was 0.19, which is low, and the species evenness index (0.74), diversity index (2.03), and richness index (3.00) appeared high. These results indicate that structure of fish community is stable in the Geum River. According to various guilds analysis, the relative abundance of tolerant and omnivores at all sites were 40% and 47% of the total, respectively. This monitoring data may contribute changes of fish fauna and compositions in relation to habitat modifications and chemical water quality degradations in the future.