• Korean Journal of Ichthyology
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• v.30 no.2
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• pp.71-74
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• 2018

The karyotype analysis of an endangered freshwater fish, Microphysogobio koreensis, was performed to obtain basic data for phylogenetic information. To carry out our study, 4 specimens were collected in Seomjingang River and Nakdongang River and its kidney was treated by flame-drying method. The chromosome number of this species demonstrated 50 diploid chromosomes, with two populations of M. koreensis not significantly different. The karyotype revealed 2n=26m+24sm, consisting of 26 metacentric (m) and 24 submetacentric (sm) chromosomes with the total fundamental arm number determined as FN=100. Total arm length and arm ratio of the chromosomes were $1.44{\sim}2.68{\mu}m$ and 1.27~2.27, respectively. The karyotype of M. koreensis was first reported in this study.

• Korean Journal of Environment and Ecology
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• v.19 no.1
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• pp.46-54
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• 2005

The change of fish community in the Wonju-stream was investigated from May to November, 2004. During the period,24 species belonging to 6 families were collected. There were 10 Korean endemic species$(41.7\%)$, including Pseudopungtungia tenuicorpa, Coreoleuciscus spiendidus, Squalidus gracitis majimae, Squalidus japonicus coreanus, Microphysogobio yaluensis, Microphysogobio longidorsalis, Iksookimia koreensis, Koreocobitis rotundicaudata, Liobagus andersoni and Odontobutis interrupts. The dominant species was Zacco Platypus$(54.7\%)$, and the subdominant species was Rhynchocypris oxycephalus$(16.7\%)$. Also, Carassius auratus$(5.4\%)$, I. koreensis$(3.4\%)$, Orthrias toni$(3.3\%)$, and Pungtungia herzi$(3.0\%)$ appeared. According to the fish species compositions, the fish community was divided into 2 groups by an unweighted pair group method using arithmetic averages(UPGMA). The comparison of the fish community showed that benthic fish species were decreased, while, the number of water-column species, resistant 1,o substrate changes and water pollution were increased.

• Korean Journal of Ichthyology
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• v.29 no.4
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• pp.261-266
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• 2017

Microphysogobio koreensis is an endemic Korean freshwater fish that is protected as an endangered fish by the Ministry of Environment in Korea. In this study, we attempted to investigate the spawning period and spawning characteristics of M. koreensis to obtain basic information for its conservation. Though natural and histological observation, the spawning season occurred between April and May, with peak spawning occurred in early May when the water temperature was $20{\sim}23^{\circ}C$. During the spawning season, males had a bright-orange body and a thick red horizontal line from the rear of the operculum to the caudal peduncle, along with a lateral line, while females had a dark brown body. Nuptial organ had not appeared. The number of eggs in the ovaries was 10,705~22,165 ($15,573{\pm}4,274$). The number and appearance ratio of mature eggs were 1,100~5,920 ($3,383{\pm}2,126$) and 10.3~44.8% ($22.4{\pm}15.6$), respectively. And the size of mature eggs was 0.60~1.00 mm ($0.74{\pm}0.06$).

• Korean Journal of Ichthyology
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• v.24 no.3
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• pp.160-166
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• 2012

Egg development and early life history of the endangered Korean freshwater fish, Microphysogobio koreensis, was investigated to get a basic information for establishing its conservation strategy. The matured adult fishes were sampled at Imsil-gun, Jeollabuk-do, Korea in May 1 2012 and artificially fertilized. The fertilized eggs were spherical, separated demersal and $1.8{\pm}0.14mm$ in diameter. The hatching of the embryo began at about 29 hours after fertilization under water temperature of $23^{\circ}C$. The newly hatched pre-larvae were average $2.2{\pm}0.48mm$ in total length. At 4 days after hatching, the post-larvae were $3.6{\pm}0.55mm$ in total length and york sac was completely absorbed. At 20 days after hatching, their fin rays were formed and finally the larvae entered juvenile stage and grew up to $6.5{\pm}0.77mm$ in total length. At 60 days after hatching, the total length reached $24.4{\pm}1.71mm$, and the band patterns of he head and lateral side were similar to adult fish. Based on this study, the fertilized eggs of M. koreensis hatched more quickly and the pre-larvae length was also smaller, compared with related species.

• Korean Journal of Ichthyology
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• v.11 no.1
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• pp.1-11
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• 1999

The five species of the genus Microphysogobio in Korea are reviewed with the keys to species and their illustrations: M. longidorsalis, M. jeoni sp. nov., M. koreeneis, M. yaluensis, and M. rapidus. Microphysogobio tungtingensis uchidai was treated as a junior synonym of M. yaluensis based on having the distinct papillae of upper lip and the color pattern on body sides by the examination of the type specimens. Microphysogobio jeoni is described as a new species from the specimens collected in the Naktong River, Han River and Keum River, Korea. it is well distinguished from the related species by the slender body, undeveloped papillae of upper lip and unspotted fins. Microphysogobio yaluensis was showed the clinal variations in the number of lateral line scales and vertebrae among the populations in the western drainages of Korea. It is remarked biogeographically that the five species of Microphysogobio are all endemics to Korea with the restricted ranges.

• 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 Ichthyology
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• v.33 no.1
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• pp.8-14
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• 2021

Spawning behavior of the endangered Korean fish, Microphysogobio koreensis, was investigated in the Seomjingang (river), Imsil-gun, South Korea, during the spawning season, April to May 2012. The mating system of M. koreensis, a broadcast spawner, was a primitive spawning mode, and involved one male and one female, unlike group spawning fishes. Spawning behavior of M. koreensis in the wild were observed in eight patterns as resting, male chase, body beating, parallel swim, female withdrawal, male competition, spawning and not guard while spawning behavior in the glass tank were verified in six patterns as resting, male chase, body beating, parallel swim, spawning and not guard. In particular, a behavioral attempt of the pre-spawning stage showed more frequently in the wild than in the glass tank. We assume that difference of spawning behavior might be implication on behavioral restrictions in small and narrow indoor glass tank.

• Korean Journal of Environment and Ecology
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• v.16 no.4
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• pp.403-408
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• 2003

Fishfauna were investigated in the Baekdudaegan Mountain area (Manbokdae-siribong) streams. At the uppertributary of Seomjin River, 17 species of 5 families were collected and the dominant species was Zacco temminki. Korean endemic species were six (35.3%) species, Acheiognathus koreensis, Coreoleuciscus splendidus, Squalidus gruacilis majimae, Microphysogobio yaluensis, Iksookimia longicorpus, and Odontobutis platycephala. Only Lampetra reissneri designated as a vulnerable species, was confirmed at the stream. At the upper streams of the Nakdong River, collected fishes were identified as 11 species of 3 families. The dominant species was Zacco temmincki, and two species (18.2%), Squalidus gracilis. majiimae and Ikosokimia longicorpus were Korean endemic.

• Korean Journal of Environmental Biology
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• v.33 no.3
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• pp.314-329
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• 2015

The fish fauna was investigated from 2010 and 2013 at main stream and tributaries in the Seomjin River which has no estuary dike. The collected fishes were identified into 37,751 individuals of 107 species of 81 genera belonging to 41 families. Among the collected fishes the primary freshwater fishes were 57 species (Relative Abundance: 53.3%), the secondary fishes were 10 species (RA: 9.3%) and the marine fishes were 40 species (RA: 37.4%). The dominant species was Zacco platypus (RA: 28.7%), and the subdominant species was Zacco koreanus (RA: 15.0%). The endemic species were 21 species (RA: 31.3%). The endangered fishes were Acheilognathus somjinensis (Level I), Lampetra reissneri (Level II) and Microphysogobio koreensis (Level II). The exotic species were Carassius cuvieri, Lepomis macrochirus and Micropterus salmoides. We supposed that Odontobutis interrupta in the Seomjin River is translocated species.

• Korean Journal of Ichthyology
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• v.17 no.4
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• pp.271-278
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• 2005

The ichthyofauna and fish community were studied in Miho Stream from May 2004 to August 2005. During the surveyed period 41 species belonging to 10 families were collected. Twelve of the species (29.3%) are endemic to Korea. Exotic fishes were Carassius cuvieri, Lepomis macrochirus, and Micropterus salmoides. Dominant species was Zacco platypus (54.7%). Comparing the present result with that of Son (1982), the indices of diversity,evenness and richness were lower and the dominance index was higher; Lampetra reissneri, Anguilla japonica, Acheilognathus macropterus, Coreoleuciscus splendidus, Pseudopungtungia nigra, Gobiobotia naktongensis, Lefua costata, Pseudobagrus koreanus, Monopterus albus and Iksookimia choii did not appear; Carassius auratus, Rhodeus uyekii, Rhodeus notatus, Acheilognathus lanceolatus, Pseudogobio esocinus, Hemibarbus longirostris, Microphysogobio yaluensis, Cobitis lutheri, Iksookimia koreensis, Pseudobagrus fulvidraco, and Rhinogobius brunneus, remarkably decreased, and Z. platypus, Pseudorasbora parva, and Squalidus gracilis majimae increased.