• Development and Reproduction
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• v.17 no.4
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• pp.427-434
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• 2013

The histological changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. The retinas size of both species increased in the 9 days post-hatching (DPH) (p<0.05). In the just-hatched Ussurian bullhead, the retina already consisted of six layers: the epithelial layer, ganglion cell layer, inner nuclear layer, inner plexiform layer, outer limiting membrane layer, and rod and cone layer. The Korean bullhead had the same components. At 50 DPH, the thickness of the retina was $538.0{\pm}7.19{\mu}m$ in the Ussurian bullhead and $558.9{\pm}9.44{\mu}m$ in the Korean bullhead. The relative thickness of each layer of the retina did not differ significantly in the two species. Although the growth of the Korean bullhead's retina was faster, the relative thickness of each layer in the retina did not change during early development. After hatching, some parts of the tissue gradually became denser. Immediately after hatching, the kidney and midgut epithelium of the Ussurian bullhead and Korean bullhead were already formed and grew gradually thereafter. From 0 DPH to 30 DPH, the nuclear height in the midgut epithelium did not differ significantly between the two species, but at 50 DPH, it was $11.4{\pm}2.45{\mu}m$ in the Korean bullhead and $9.9{\pm}2.13{\mu}m$ in the Ussurian bullhead. During the experimental period, the major axes, minor axes, surface areas, and volumes of the proximal tubule cells in the kidney did not differ significantly between the two species. Thus, the early histological development of the Ussurian bullhead is similar to that of the Korean bullhead.

• Development and Reproduction
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• v.17 no.3
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• pp.257-268
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• 2013

Morphometric changes in the Ussurian bullhead, Leiocassis ussuriensis, and the Korean bullhead, Pseudobagrus fulvidraco, were observed during the early period of growth. Yolk length, yolk height, and yolk volume in the two species decreased within 9 days post-hatching (DPH) (p<0.05). The body lengths and body heights of both species increased gradually to 150 and 130 DPH, respectively (p<0.05). The horizontal distance between the anteriormost extension of the head and the anterior insertion of the pectoral fin, the anteriormost extension of the head ${\times}$ the verticality position of the anterior insertion of the primary dorsal fin rays, and the anterior insertion of the primary dorsal fin ${\times}$ the anterior insertion of the pectoral fin were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). However, the relative sizes of the head region, pectoral fin, ventral fin, and anal fin were greater in the Ussurian bullhead than in the Korean bullhead (p<0.05), and relative body depth and the size of the outer-mandible barbel were greater in the Korean bullhead than in the Ussurian bullhead (p<0.05). The growth curves of the morphometric characteristics of both species were divided into three types.

• Korean Journal of Ichthyology
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• v.18 no.1
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• pp.20-26
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• 2006

Bagrid catfish hybrid between Korean bullhead (Pseudobagrus fulvidraco) and Ussurian bullhead (Leiocassis ussuriensis) was produced by artificial fertilization. Modal chromosome numbers of Korean bullhead, Ussurian bullhead and their hybrid were the same as 2n=52. The karyotypes were 22 metacentric (M), 22 submetacentacentric (SM), and 8 acrocentric (A) chromosomes for Korean bullhead, 22M+14SM+16A for Ussurian bullhead and 22M+18SM+12A for their hybrid. The hybrid bullhead karyotype consisted of each haploid set of parental species chromosomes. Erythrocytic sizes and DNA contents of hybrids were intermediate between two parental species.

• Development and Reproduction
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• v.16 no.4
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• pp.271-277
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• 2012

The effects of ovulation induction in ussurian bullhead, Leiocassis ussuriensis, were investigated by treating ussurian bullhead with hCG, LHRHa, GnRHa, ovaprim, and pimozide. hCG was injected to ussurian bullhead at 0.75% NaCl, 5,000, 10,000, 20,000, and 30,000 IU, respectively. The ovulation inducement rates were 100% in 20,000 and 30,000 IU. Fertilization rates were 82.7% and 79.8%. Hatching rates were 59.4% and 57.2%. Ovulation time was between 16-19 hr The concentrations of LHRHa injected were 0.75 NaCl, 50, 100, 200, 300, and $300{\mu}g/kg$. The ovulation inducement rates were 100% in 300 and $400{\mu}g/kg$. Fertilization and hatching rates were 84.9% and 68.4% at $200{\mu}g/kg$. The times to ovulation were between 23 hr and 34 hr. Ovaprim of 0.75% NaCl, 1.0, 1.5, 2.0, 2.5 and 3.0 ml/kg were injected to the abdominal cavity. The ovulation inducement rate was highest at 2.0 and 3.0 ml/kg to 92% and ovulation time was between 27-38 hr. LHRHa concentrations of 0.75% NaCl, 50, 100, 200, 300 and $400{\mu}g$ were injected with pimozide ($1,000{\mu}g$). Ovulation inducement rate was 100% from 200 to 400 IU with pimozide. Ovulation time was 22-36 h. Fertilization and hatching rates were 88.9% and 70.4% in $200{\mu}g/kg$ with pimozide.

• Journal of Aquaculture
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• v.22 no.1
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• pp.74-78
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• 2009

Backcross hybridization between Korean bullhead Pseudobagrus fulvidraco female and Korean bullhead P. fulvidraco $\times$ Ussurian bullhead Leiocassis ussuriensis hybrid male was performed, and early viability and karyotype of the backcross hybrids were examined along with their parental species. Mean fertilization rate (86.8%), hatching success (70.7%) and early survival rate (76.4%) of backcross hybrids were similar with those found in the maternal species, the Korean bullhead. From the chromosome analysis, modal chromosome numbers of Korean bullhead, Ussurian bullhead, their hybrid and backcross hybrid were the same as 2n = 52. However, their karyotypes were different among genotypes. The karyotype of backcross hybrid was 22 metacentric + 18 submetacentacentric + 12 acrocentric chromosomes.

• Proceedings of the Zoological Society Korea Conference
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• 2000.10a
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• pp.183.3-184
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• 2000

No Abstract, See Full Text

• Development and Reproduction
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• v.19 no.4
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• pp.189-196
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• 2015

This study was examined the ovogenesis of Ussurian bullhead, Leiocassis ussuriensis and the morphological development of its larvae and juveniles and to use the results as basic information for the preservation of species and resource enhancement. For artificial egg collection, human chorionic gonadotropin (HCG) was injected at a rate of 10 IU per gram of fish weight. During breeding period, water temperature maintained at $24.5{\sim}26.5^{\circ}C$ (mean $25.0{\pm}0.05^{\circ}C$). The process of ovogenesis reached the two-cell stage in 50 minutes after fertilization. In 73 hours of fertilization the movement of the embryoid body became active state and the larvae began to hatch from the tail through the oolemma. Length of prelarvae were 6.33~6.50 mm long (mean $6.40{\pm}0.06mm$) just after hatching having yolk with their mouth not opened. After thirty eight days of hatching, juveniles were 30.6~32.5 mm long (mean $31.5{\pm}0.65mm$). The color was dark yellowish brown throughout the entire body, and the number of caudal fin rays developed to thirty six perfectly.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.405-412
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• 2000

The fine structure of spermatozoa of Leiocassis ussuriensis was examined with scanning and transmission electron microscopies. The spermatozoon of L. ussuriensis is approximately $68.8\;{\mu}m$ in length and a relatively simple cell with a spherical nucleus, a short midpiece and a tail. The ultrastructure of spermatozoa of L. ussuriensis is characterized by the following features. The nuclear fossa, the length of which is about two-thirds of the nuclear diameter, contains two centrioles. The centrioles are orientated approximately $180^{\circ}$ to each other. The mitochondria are arranged in two layers and their number is 12 or more. The axoneme is the 9+2microtubular pattern and has inner but no outer dynein arms as in other bagrids. The two axonemal fins are in the same plane with the two central microtubules, the doublets 3 and 8. The axonemal fins and the inner dynein arm are shared in Bagridae and the deep nuclear fossa is shared in Siluriformes. The axonemal finsobse observed in Bagridae and Amblycipitidae of Siluriformes might be the apomorphic character in Ostariophysi. They are not reported in Cyprinidae and Characiformes.