• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.26-31
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• 2009

Ecological characteristics of Cobitis pacifica inhabited in the Yeongok Stream, Gangwon-do, Korea was investigated from May 2006 to August 2007. The major habitat was composed of sand bottom with current velocities of $0.23{\sim}0.56m\;sec^{-1}$ and depths of $20{\sim}50cm$. The sex ratio of female to male was 1 : 0.93. It was presumed that the spawning season was the period of water temperatures of $25{\sim}27^{\circ}C$. Sexually matured individuals appeared over the two years of age. Frequency analysis of body length indicated that the group with $40{\sim}59mm$ in body length was one-year-old, the group of $60{\sim}89mm$ was two-years-old, the group of $90{\sim}109mm$ was three-years-old, and the group of over 110 mm was four-years-old. The average number of eggs in the ovaries was estimated as 809 per matured female. Main prey items were Ephemeroptera and Diptera.

• Animal cells and systems
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• v.6 no.1
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• pp.45-51
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• 2002

We compared the complete mitochondrial cytochrome b gene sequences of Korean and European cobitids to provide independent evidence for assessment of systematic and biogeographic relationships of species in the genus Cobitis. The data suggested monophyly of the genus Cobitis and the inclusion of Korean Cobitis species within the group having one lamina circularis, a primitive condition. Also, all the phylogenetic analyses using maximum parsimony, maximum likelihood, and neighbor joining methods showed a monophyletic relationship among Cobitis. The basal position of the Caspian C. cf. sibirica reported here reflects the eastern Asiatic origin cf. the European Cobitis and establishes C. cf. sibirica as an independent lineage. The Korean C. pacifica diverged next to C. cf. sibirica in basal group from the genus Cobitis. This result is in agreement with the hypothesized Asiatic origin of some European freshwater fish lineages. The phylogenetic relationships in this study showed a close affinity between C. zanadreai and C. sinensis. Two new species, C. tetralineata and C. pacifica in Korea also are closely related to monophyletic group clustering the type species of the Acanestrinia subgenus (C. elongata) with all the endemic Italian species (C. bilineata and C. zanandreai). This may suggest that the affinity between the Korean and Danubian-Italian imply genetic convergence or genetic plesiomorphic state between allopatric species that are separated for the Miocene. The mtDNA-based phylogeny for the species of the genus Cobitis from Kores and Europe permits phylogenetic assessment of the morphological transitions of Iamina circularis.

• 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 Ecology and Environment
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• v.44 no.1
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• pp.1-8
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• 2011

We investigated developmental stages of embryo and early life history of the Korean indigenous fish, the northern loach, Cobitis pacifica in 2009 in order to understand fundamental knowledges for conservation of this species. Eggs were obtained after hormones injections (LHRH-a, HCG) and were artificially fertilized by the dry method. The embryo was spherical, separative demersal, faint white, and averaged $1.09{\pm}0.04\;mm$ (n=20) in diameter. The hatching of the embryo took place in about 48 hours after fertilization under water temperature of $21.0{\sim}24.0^{\circ}C$ and the newly hatched larvae averaged $2.87{\pm}0.05\;mm$ (n=20) in total length (TL). Four days after hatching, the larvae grew up to $6.86{\pm}0.10\;mm$ (n=10) in TL and york sac absorption, mouth and anus opening were shown. Fourteen days after hatching, most of fin-rays appeared at $10.71{\pm}0.34\;mm$ (n=10) in TL and color spots on the body surface were attained. Twenty six days after hatching, the larvae grew up to $14.88{\pm}0.45\;mm$ (n=10) in TL, and all their fin-rays were formed. Therefore, according to current study regarding the morphological development of Cobitis pacidica, the conversion from larval to juvenile stages occurred at 26 days after hatching. Eighty days after hatching, the larvae were $33.3{\pm}1.25\;mm$ (n=10), and their body shape and color pattern were similar to adult fish. In this study, embryonic development and early life history of the northern loach, Cobitis pacifica show morphological characteristics of Cobitidae family. We expected that our results can be used as an fundamental knowledges for restoration study of indigenous fish species.

• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.238-248
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• 2010

We performed field investigations at six stations in Buk Stream of Goseong-gun, Gangwon-do, Korea, from May to September 2009 to understand the stream's fish fauna and community structure. In the survey, 31 species belonging to 20 families were collected. Dominant species by number was Zacoo koreanus (30.0%), and subdominant species were Pungitius kaibarae (9.4%) and Rhynchocypris steindachneri (9.3%). In biomass, the dominant species was Tribolodon hakonensis (35.5%), and subdominant species were Z. koreanus (22.5%) and Cobitis pacifica (7.5%). Eight Korean endemic fish species and two endangered species (P. kaibarae and Pungitius sinensis) were collected. In addition, four anadromous fish species (T. hakonensis, Oncorhynchus masou masou, O. keta, Gasterosteus aculeatus) and two amphidromus fish species (Plecoglossus altivelis altivelis and Gymnogobius urotaenia) were observed. Interestingly, we verified the existence of several fish species in Buk Stream where they have not lived before. Those species were previously reported to live only in rivers that run into the western and southern sea of Korea. Five of those species (Zacoo koreanus, Z. platypus, Silurus microdorsalis, Liobagrus andersoni and Coreoperca herzi) were reported in Buk Stream in the 1980s. The other species (Pungtungia herzi, Pseudorasbora parva, Squalidus multimaculatus, Misgurnus mizolepis, Koreocobitis rotundicaudata, Silurus asotus and Odontobutis interrupta) have been introduced since the 1990s.