• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.5
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• pp.404-409
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• 2006

This study investigated the reproductive cycle of the female hairychin goby, Sagamia geneionema, histologically. The fecundity of female hairychin goby ranged from 1,002 to 1,240 eggs when they reached a total length of 9.1-10.0 cm. Fecundity is related to total length. The gonadosomatic index (GSI) increased from December (1.87$\pm$0.46) and reached a maximum in April (11.57$\pm$1.92). The histological changes in the ovary were correlated with the GSI. Oocytes at the chromatin-nucleolus and peri-nucleolus stages were observed in the ovary year-round. In December, oocytes containing yolk appeared in the ovaries of a few fish. Most oocytes appearing in January were at the yolk globule stage. The frequency of oocytes appearing at the yolk globule stage from January to March was higher than in other months. Subsequently, empty follicles and atretic oocytes were observed in the ovaries in May. Based on the histological observations of gonad development and the monthly change in the GSI, the reproductive cycle was classified into the following successive stages: growing (October to November), mature (December to January), ripe and spawning (February to April), and degenerative and resting (May to September) stages. The histological observations of ovaries during the spawning period indicate that this species is a multiple spawner with abbreviated iteroparity based on the developmental pattern of oocytes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.8 no.4
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• pp.225-233
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• 1975

Morphological changes of early post-larval and young stages of Chasmichthys dolichognathus HILGEnDORF (Family Gobiidae) have been studied based on the samples of 953 individuals collected in June 1968, July 1969 and July 1971. Particular emphasis was paid on the development of fin rays, chromatophore patterns and ventral fins. The primordial fin rays of the first dorsal fin appear in the post-larvae of around 8.0 mm in total length, and dorsal fin fully develops in the larvae of around 9.2 mm. In the early young stages of 17.0 mm in total length fin rays have completely developed. According to chromatophore patterns the larvae are grouped into three successive groups. The larvae at the early stages of 6.3-14.2 mm have melanophores on the whole dorsal surface, the posterior ventro-lateral part of the tail and the basal part of the caudal fin. In the later larval stages of 17.0-24.4 mm a group of melanophores are added on medio-lateral part of the tail. These melanophores extend anteriorly and eventually cover the medio-lateral part of the whole body. In the early young stages of 97.2-34.8 mm the chromatophores cover the whole body surface in cloudy and H-shaped patterns. The chromatophore patterns of this stage are distinctive as generic characters of the fish. Fin membranes of the ventral fin appear in the post-larval stage (ca. 7.4 mm), and the primordial fin rays develop in the late post-larval stages (ca. 14.2 mm). The fin rays develop into a complete sucker in the young fish stage of around 30.0 mm in total length.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.72-80
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• 2017

Fish fauna and community structures in freshwater were analyzed in the streams (12 stations) of the Bogil Island from May to September 2015. Total numbers of the sampled species and genus (9 families) were 21 and 17, respectively. Gobiidae was the most dominant taxa, which accounted for 47.6% (10 species) of the total species, and the relative abundance, based on the number of individuals, was 60.4% (1,157 individuals). Subdominant families were three taxa of Cyprinidae (3 species; 500 ind.), Mugilidae (2 species; 168 ind.) and Mugilidae (2 species; 128 ind.). The dominant species, based on the relative abundance, was Rhynchocypris oxycephalus (20.7%) and the subdominant species were Gymnogobius urotaenia (19.5%), Leucopsarion petersii (17.2%) and Chelon haematocheilus (8.5%). These species were composed of upstream-resident fish as well as migratory fishes, so the streams of the Bogil Island had unique characteristics in the fish compositions. Based on all the species sampled, 9 species (42.9%) were primary freshwater fishes, 11 species (52.4%) were peripheral fishes and 1 species (4.8%) was amphidromous fish. Korean endemic species and exotic species were not found in the streams of Bogil Island. According to the analysis of fish community structure, species richness index and species diversity index were highest (1.831, 1.957) in the Site 8 and lowest in the Site 4. In the meantime, the dominance index was highestin the Site 4 (1.00) and lowest in theSite 8 (0.17).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.114-120
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• 1998

The spawning behavior, development of eggs and larvae of the Korea freshwater goby, Rhinogobius brunneus (Temminck et Schlegel) were studied. The eggs were spawned as a one-layer mass, hanging from the underside of a small pebble, and guarded by one male. The eggs were elliptic, about 1.48 mm in length and 0.65 mm in breadth, with a round top and a somewhat flat base with glutinous fibers. Hatching in the indoor tank with $17.0^{\circ}C$ in mean water temperature started from the 146 hours after fertilization. In the late developing stages, the embryo moved and freely changed its head to face the free tip of the chorion (normal egg) or to the basal end with a boundle of adhesive filaments (agrippa egg). Newly-hatched larvae were $3.10\~3.30$ mm in total length (mean: 3.22 mm), and mouth and anus were not yet open. Melanophores were present on the air- bladder, around the anus, and on the ventral part of the caudal region. The larva $3\~4$ days old transformed to postlarval stage, and they were $3.30\~3.85$ mm in total length (mean: 3.60 mm). As yolk sac and oil globules werw nearly absorbed, mouth and anus were open, and they fed rotifers actively. In $20\~22$ days after hatching the larvae grew to 5.85 mm in 71, and the caudal notochord flex at $45^{\circ}$.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.297-303
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• 2021

In this study, nine major sites of Yulcheon stream, a principal tributary of the Seomjingang River, were surveyed from April 2020 to October 2020, and their fish fauna and community structure were analyzed. A total of five families and 19 species of fish were identified. Among the 19 species, seven species were found to be endemic to Korea: Rhodeus uyekii, Squalidus gracilis majimae, Microphysogobio yaluensis, Odontobutis interrupta, Cobitis tetralineata, Zacco koreanus, and Squalidus chankaensis tsuchigae. Among five families, the family Cyprinidae had the largest number of species (15), whereas the rest of the four families: Gobiidae, Odontobutidae, Cobitidae, and Osphronemidae, had one species each. The two dominant species in the family Cyprinidae were identified as Z. platypus and Z. temminckii. The community index of nine major sites of Yulcheon stream was 0.499 dominance, 2.279 diversity, 0.774 evenness, and 2.594 species richness. The number 3 site had 14 species, the largest number of species among all sites, and the dominance rate (0.480) was low, whereas diversity (2.173), and species richness (2.701) were the highest. As a result of cluster analysis, clusters matched according to the structure of the river types, but St. 9, which confirmed a relatively small number of populations, showed a structure similar to that of the upstream section. In the case of St. 5, a separate cluster was formed by a large number of species and populations.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.1-7
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• 2021

Using stereo, light, and scanning electron microscopes, we researched the anatomical and histological structure of Chaenogobius gulosus's olfactory organ and compared it to those of sympatric gobies Luciogobius guttatus and Favonigobius gymnauchen. Results revealed the following common characteristics: i) tubular anterior nostril (AN) and flat posterior nostril (PN), ii) a single longitudinal lamella, iii) two accessory nasal sacs (ANS, ethmoidal and lacrimal), iv) abundant sensory epithelium lymphatic cells (LC), v) an eosinophil cell, and vi) a ciliary length a quarter of the knob diameter in the olfactory receptor neuron (ORN). Some characteristics are specific to C. gulosus and different from the other two gobies: i) 0.5~1.0 mm AN and 0.2~0.5 mm PN (vs. 0.2~0.3 mm and 0.2~0.3 mm in L. guttatus; 0.2~0.4 mm and 0.1~0.3 mm in F. gymnauchen), ii) two ANS (vs. absence in L. guttatus; two in F. gymnauchen), iii) abundant LC (vs. low in L. guttatus and F. gymnauchen), iv) low density non-sensory cilia on the lamellar surface (vs. high in L. guttatus; low in F. gymnauchen), and v) a quarter ciliary length to knob diameter ratio in the ORN (vs. mixture of a quarter to equal ratio in L. guttatus; two or three times in F. gymnauchen). From these results, we confirmed the C. gulosus olfactory organ has adapted anatomically and histologically to the sand-rock tidal zone.

• Korean Journal of Ichthyology
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• v.13 no.2
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• pp.117-122
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• 2001

Three species, Gymnogobius urotaenia, G. sp. 1 and G. sp. 2, collected at Hosan-river, Hosan-ri, Samcheock-si, Gangwon-do, Korea, were examined for the study of sexual dimorphism. The three species have peculiar nuptial pigmentation during the breeding season: all females of the three species showed an intense black coloration on the ventral part of the head, the pelvic fin, the anal fin and the margin of the first dorsal fin. There was a difference between G. sp. 1 and the other two species in 1/3 from margin of first dorsal fin. Namely, G. sp. 1 showed an intense black coloration, whereas the other two species had an intense yellow coloration. All females of the three species showed the same, intensely yellow coloration in the ventral part of the body. Males of G. urotaenia and G. sp. 2 had almost the same nuptial pigmentation, however the former showed diffuse black coloration in the anal fin, whereas the latter had an intensely black anal fin. Males of G. sp. 1 differed from those of the other two species in their yellow color on the ventral part of the head, the pelvic f ins, the anal fin, in contrast to the diffuse black coloration in those parts in the other species. The genital papilla of males was triangle-shaped, but that of females was heart-shaped. Significant differences between sexes include: G. urotaenia, 7 characters (body depth, head length, snout length, upper jaw length, head depth, pectoral fin ray length, eye diameter); G. sp. 1, 11 characters (body depth, head length, caudal peduncle length, caudal peduncle depth, snout length, upper jaw length, head width, head depth, anal fin ray length, pectoral fin ray length and caudal fin ray length); G. sp. 2, 10 characters (body depth, head length, caudal peduncle depth, snout length, upper jaw length, head width, anal fin ray length, pectoral f in ray length, caudal fin ray length and eye diameter). Of the 5 characters which showed differences in all three species (body depth, head length, snout length, upper jaw length and pectoral fin ray length), females had higher values than males only in body depth, whereas males values in all other characters. The upper jaw length was the most distinctive sexually dimorphic feature, the upper jaw extended beyond the posterior margin of the eyes (p<0.001) in males but not in females.

• Korean Journal of Ichthyology
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• v.13 no.2
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• pp.143-157
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• 2001

To determine seasonal fluctuations in abundance and species composition of the fishes, samples were collected by bottom trawl off Kohung Penisula from February to December 1999. A total of 7,197 fishes were sampled and identified into 123 species, 54 families, 13 orders and 2 classes. Of the 13 orders, Perciformes, Scorpaniformes, Pleuronectiformes and Tetraodontiformes accounted for approximately 82.9% of the total. Gobiid fishes were dominant, representing 13 species. Leiognathus nuchalis, Konosirus punctatus, Engraulis japonicus, Ilisha elongata, Trichiurus japonicus, Argyrosomus argentatus, Ditrema temmincki, Takifugu niphobles, Hexagrammos otakii and Lateolabrax japonicus accounted for 71.4% of the number of individuals. Mugil cephalus, Sebastes schlegeli, Lateolabrax japonicus, Konosirus punctatus, Hexagrammos otakii, Conger myriaster, Liparis tanakai, Seriola quinqueradiata, Trichiurus japonicus, Sebastiscus marmoratus and Limanda yokohamae accounted for 50.7% of the total biomass. The number of species showed a seasonal variation, higher in spring, summer and autumn than in winter. The Largest numbers of individuals and greater biomass were observed in August. The economic fishes of this area were Konosirus punctatus, Engraulis japonicus, Mugil cephalus, Sebastes inermis, Sebastes schlegeli, Sebastes oblongus, Sebastiscus marmoratus, Platycephalus indicus, Hexagrammos agrammus, Hexagrammos otakii, Lateolabrax japonicus, Epinephelus akaara, Epinephelus septemfasciatus, Seriola quinqueradiata, Pagrus major, Acanthopagrus schlegeli, Argyrosomus argentatus, Oplegnathus fasciatus, Trichiurus japonicus, Pampus echinogaster, Paralichthys olivaceus, Kareius bicoloratus, Limanda yokohamae and Takifugu porphyreus.

• Korean Journal of Ichthyology
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• v.13 no.1
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• pp.40-49
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• 2001

The ichthyofauna and fish community of the Dongjin River system were surveyed at 21 sites from October 1998 to September 1999. We confirmed the presence of 53 species in 14 families belonging to seven orders. Thirty-two species of cyprinid fishes accounted for 60.4% of the total, four species of cobitid and gobiid fishes 7.5% of the total, and two species of bagrid and centrarchid fishes for 3.8% of the total. The dominant species in the Dongjin River system was Zacco platypus (relative abundant 26.0%), the subdominant species was Carassius auratus (14.7%). The dominant and subdominant species in each stream of the Dongjin River system were determined. In the Dongjin River, the dominant species was Z. platypus (40.6%), the subdominant Acheilognathus lanceolatus (20.5%); in Wonpyeong stream, Pseudorasbora parva (22.6%) and Hypomesus olidus (13.2%); in Gobu stream C. auratus (67.5%) and Cyprinnus carpio (15.4%). Fourteen of the 53 species from the the Dongjin River system comprised 28.6% of the total Korean endemic species; seven rare species accounted for less than 0.1% of the total. Four exotic fish species were found: Cyprinus carpio (Islaeli carp), Carassius cuvieri, Micropterus salmoides and Lepomis macrochirus. The species dominance, diversity, and evenness index of the fish community from the Wonpyeong stream were 0.12, 1.08, and 0.91, respectively, indicating better conditions than those of the Dongjin River and the Gobu stream. The fish community of the Wonpyeong stream showed closer relationship to that of the Dongjin River than to that of the Gobu stream.