• Korean Journal of Ichthyology
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• v.12 no.2
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• pp.89-95
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• 2000

Two species of the genus Koreocobitis in Korea are reviewed with a key to species and their illustrations: Koreocobitis rotundicaudata and K. naktongensis sp. nov. A new species, Koreocobitis naktongensis is described based on 9 specimens collected from the Naktong River, Korea. The new species is distinguished from Koreocobitis rotundicaudata by the following combination of characters: yellow body colouration with many brownish speckles, truncate caudal fin, fewer vertebrae, and longer head. It is remarked biogeographically that Koreocobitis naktongensis is distributed only in the Naktong River, Korea.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.299-305
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• 2007

Ecological characteristics of Koreocobitis rotundicaudata was investigated in the mid-upper part of the Naerin stream in Hongcheon gun, Gangwon do, Korea from April 2006 to March 2007. It inhabited mostly on the cobble and pebble bottoms with water-current velocities of 0.3~0.8 m/sec and depths of 30~80 cm. The sex ratio of female to male was 1 : 0.78. It was presumed that the spawning season was from May to June with water temperatures $20.1{\sim}23.1^{\circ}C$. Sexually matured individuals appeared over the two years of age. Body length frequencies indicated that the 40~69 mm group is over one year old, the 70~109 mm over two years old, and 110~142 mm over three years old. The average number of eggs in the ovaries was 1,365. Main prey materials were Ephemeroptera and Chironomidae mostly.

• Korean Journal of Ichthyology
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• v.21 no.4
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• pp.247-252
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• 2009

The egg development and early life history of the Korean endangered fish Koreocobitis naktongensis (Cobitidae) were investigated. Eggs from the females were obtained by injecting 10 IU/g of human chorionic gonadotropin and inseminated with sperm by the dry method in the laboratory. The fertilized eggs were 1.0~1.2 mm in diameter and had no oil globules. The embryo began to hatch about 38 hrs after fertilization under water temperature of $20{\pm}1^{\circ}C$. The newly-hatched larvae were 2.6~2.8 mm in total length, and their mouth and anus were not yet opened. Seven days after hatching, the postlarvae were 4.5~5.2 mm in total length, and their yolk sacs were completely absorbed. They entered the juvenile stage when all fin-rays were formed at 50 days after hatching, and their total lengths were 21~27 mm.

• Korean Journal of Ichthyology
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• v.23 no.3
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• pp.234-241
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• 2011

Habitat, reproduction and feeding habit of endangered fish Koreocobitis naktongensis from Jaho stream, Gyeongsangbuk-do, Korea were investigated from March 2010 to June 2011. This species inhabits at the upper and middle parts of stream, which were composed of cobbles and pebbles bottom. The current velocities in these microhabitat were 5~10 cm/sec and depth were 50~110cm. The sex ratio of female to male was 1 : 0.92. It is presumed that the spawning season is from May to June when water temperatures were 17 ~ 20$^{\circ}C$. The average number of mature eggs in ovary were about 22,643 (15,909~30,323), mean egg diameter was 0.87${\pm}$0.05mm. K. naktongensis fed mainly on Chironomidae (IRI, 72.0%) and Ephydridae (26.9%) of Diptera.

• Korean Journal of Ichthyology
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• v.21 no.sup1
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• pp.7-28
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• 2009

The family Cobitidae of Korea was reviewed as 16 species in 5 genera with the key to species for the identification by the external features. The three genera of Iksookimia, Koreocobitis, and Kichulchoia erected from the genus Cobitis were reclassified based on the presence or absence of Gambetta’s zones on the body sides, their body pigmentation, the shape of lamina circularis in males, the number of unbranched anal fin rays, and some molecular phylogenetic data. By the results of these reexamination, the generic names of the three species were changed as Cobitis choii, Iksookimia pacifica, and Kichulchoia mutifasciata. It was remarked biogeographically that most species of genera Cobitis, Iksookimia, Koreocobitis, and Kichulchoia show the disjunct distributions with bottom-dwelling preferences as endemic to Korean peninsular. Three species of Cobitis choii, Kichulchoia brevifasciata, and Koreocobitis naktongensis are considered to be critically endangered according to the severe habitat destruction and the alteration of river topography.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.15-21
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• 2021

The Nakdong nose loach, Koreocobitis naktongensis is an endangered freshwater fish endemic to Korea. The spawning behaviour of the K. naktongensis was observed after treating Ovaprim in laboratory aquarium from 20~27 April 2010. The behavioral patterns were categorized into three stages of pre-spawning, spawning and post-spawning behaviors. Before spawning K. naktongensis usually repeated taking a rest and swimming. On average, initial spawning activity started 11 to 12 hours later after injection with Ovaprim. During the spawning period, the number of spawning acts ranged from 1 to 18. The spawning ratio of female to male was 1 : 1. The male embraced the back of the female's dorsal fin with his lamina circularis. It looked like a complete circle at that time. After spawning, parental care was not observed. Individuals not participating in spawning have been observed to feed on some of the fertilized eggs.

• Korean Journal of Environment and Ecology
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• v.30 no.1
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• pp.71-80
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• 2016

The fauna of freshwater fish and water chemistry characteristics were investigated from June, 2014 to October, 2014 at 10 sites in Taebaeksan Provincial Park. A total of 7 species under three families were collected from the survey sites and among them one endangered species - Koreocobitis naktongensis - was identified. The endemic species of Korea were 2 species: Koreocobitis naktongensis, Iksookimia koreensis. Dominant species was Rhynchocypris oxycephalus(89%) and subdominant species was Orthrias nudus(8.9%). Water quality including conductivity, turbidity, pH and total dissolved solids(TDS) varied largely depending on the sampling locations. Values of ambient conductivity and TDS were greater in the upstream than in the downstream, and seasonal variabilities were also higher in the upstream. The pH decreased towards the downstream, and especially showed a sharp decrease in S5. This phenomenon was evident due to a dilution by the influx in the acid mine drainage(AMD) of S4. Physical habit conditions, based on qualitative habitat evaluation index(QHEI) model, indicated a "Sub-optimal" condition(mean: 157.3; range: 78 ~ 194) in the Sodo stream watersheds.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.419-428
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• 2013

The objectives of this research were to determine ecological characteristics and chemical gradients in two different loach populations-Misgurnus anguillicaudatus ($M_a$) and Koreocobitis rotundicaudata ($K_r$). Eight chemical parameters were compared to test the chemical preferences between the two species. The population of Kr occurred more in better water quality, compared to the $M_a$-population. The $M_a$-population co-occurred more with tolerant species (TS) and omnivores, whereas the $K_r$-population co-occurred more with sensitive species (SS) and insectivores. The differences in the tolerance and trophic composition matched well with the result of stream health assessment, based on the multi-metric model of Index of Biological Integrity (IBI). The IBI value in habitat with the $M_a$-population was "19.6" (range: 8~40) indicating a fair condition, and the IBI values of $K_r$-population was 29.4 (range: 12~40) indicating good condition. Similar results were found in physical habitat health analysis (QHEI). Overall, data analysis showed that the $M_a$-population belong to the tolerant species and $K_r$-population belong to sensitive species in the tolerance classification.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.62.2-62
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• 1996

No Abstract, See Full Text

• Korean Journal of Ichthyology
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• v.18 no.3
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• pp.244-250
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• 2006

The ichthyofauna and fish community structure were investigated at five stations in Yeongok stream, Gangneung, during April and December 2005 monthly. During the surveyed period twenty nine species belonging to ten families were collected. Dominant species in number was Zacco platypus (relative abundance : 29.0%) and subdominant was Rhynchocypris steindachneri (12.1%). There were six Korean endemic species including Rhynchocypris kumgangensis. Koreocobitis rotundicaudata and Luciogobius guttatus that were not reported in near streams were collected in Yeongok stream only. Ladislabia taczanowskii was considered as a geographically important species. There were stabilized fish community structure with species diversity index of the community 2.521 in Yeongok stream ichthyofauna.