• 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.

• Development and Reproduction
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• v.12 no.3
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• pp.215-220
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• 2008

Sex differentiation process of the spotted Black Bullhead, Pseudobagrus koreanus, was investigated using fish samples of different age after hatching. The primordial germ cells appeared separately under air bladder in 1-day larva (total length: $6.63{\sim}6.95\;mm$). The primordial gonad with a genital ridge developed in 5-day prelarva ($7.50{\sim}9.36\;mm$). The ovarian differentiation started in about 25-day juvenile ($11.58{\sim}13.21\;mm$). The somatic tissues enlongated in the tip of one end of undifferentiated gonad and fused each other. Thus a small ovarian cavity appeared. The testicular differentiation was initiated in 30-day juvenile ($12.19{\sim}13.72\;mm$). The rudiment of sperm duct was appeared in the lower part of the undifferentiated gonad. In 50-day juvenile ($16.28{\sim}17.06\;mm$), the ovary started to fill with peri-nucleolus oocytes, and the spermatogonia started to develop. In 250-day juvenile ($35.49{\sim}51.12\;mm$), the ovary became bigger and filled with oocytes, and the number of spermatogonia started to increase. Considering these results, the spotted Black Bullhead could be a differentiated type in sex differentiation and gonochorism in sexuality.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.369-374
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• 2009

The stumpy bullhead (Pseudobagrus brevicorpus) endemic to Korea is one of critically endangered freshwater fish species. To provide baseline data for its captive breeding and reintroduction we investigated basal characteristics on its growth and sexual maturation in an artificial rearing environment. After 698-day rearing the stumpy bullhead grew up to $89.22{\pm}10.29\;mm$ in total length (TL) and $70.93{\pm}7.68\;g$ in total body weight (BW)($BW=5\times10^{-5}\;TL^{2.678}$; $R^2=0.995$), and showed survival rate of 74.2%. The sex ratio was 1 (471 females) : 1 (473 males), and males ($TL=87.44{\pm}1.07mm$; $BW=8.43{\pm}0.31\;g$) showed significantly faster growth than females ($TL=78.38{\pm}0.92mm$; $BW=6.38{\pm}0.20\;g$) after 663-day rearing. However, condition factor of females was significantly higher than that of males (P<0.05). The number of eggs per female ranged from 508 to 867 (average 734), and their diameters ranged from 0.04 to 1.65 mm. The females which reared about two years in the laboratory condition was able to spawn in the early June after 1~2 days of human chorionic gonadotropin (HCG) injection. The number of hatched fries ranged from 113 to 338 (average 216).

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.278-279
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• 2004

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.280-281
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• 2004

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.338-343
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• 2006

Histological observations of the barbels of torrent catfish (Amblycipitidae) in Korea are reported. The bullhead torrent catfish (Liobagrus andersoni) and Korean torrent catfish (L. obesus) have eight obvious barbels in two pairs each on the maxilla and mandible. Each barbel is composed of an epidermis, dermis, and central cartilagerod. The epidermis of the maxillary and mandibular barbels of the bullhead torrent catfish is thicker than that of the Korean torrent catfish (P<0.05) and is formed of stratified epithelium that contains many cutaneous taste buds and a few small club cells. There are many taste buds on the upper part of each barbel. The dermis consists of loose connective tissue fibers that enclose blood vessels and bundles of nerve fibers. The barbels of these fish can be categorized into stiff and flexible types and are accessory, feeding, and sensory structures. Our results validate the barbels as gustatory receptor organs for these fishes.

• Korean Journal of Ichthyology
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• v.18 no.3
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• pp.209-215
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• 2006

A closely associated set of characteristics was analyzed using both classical and truss dimensions to discriminate the morphometric traits of three species of torrent catfish (Amblycipitidae) in Korea. After arcsine square root transformation, 18 measurements relative to the standard length and three measurements relative to the head length of each species of torrent catfish were compared statistically. Classical and truss dimensions of each of four morphometric traits showed higher values in the bullhead torrent catfish, Liobagrus obesus, than the Korean and south torrent catfish (L. andersoni and L. mediadiposalisa, respectively; P<0.05). Truss dimensions of three morphometric traits were higher in the bullhead and Korean torrent catfish than in the south torrent catfish (P<0.05). There were no significant differences in six morphometric traits among these Amblycipitidae. The dimensions used in this study may be useful as taxonomic indicators to discriminate species of Liobagrus in Korea.

• Development and Reproduction
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• v.16 no.2
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• pp.137-143
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• 2012

The main objective of this study is to investigate the effects of ovulation induction by treating HCG, LHRHa, GnRHa, ovaprim and pimozidein in long snout bullhead, L. longriostris. All hormons were injected into the muscles of back. Concentration of LHRHa to injection were 20, 50, 100, 150 and 200 ${\mu}g/kg$ and same concentration of LHRHa was injected after 24 hour. The ovulation induction rate was 100% and fertilization and hatching rates were 68.4, 45.2, 58.4 and 33.6% in 50 and 100 ${\mu}g/kg$. The times to ovulation were between 28 and 44 h. HCG was injected in long snout bullhead at 5,000, 10,000, 15,000, 20,000 and 25,000 IU/kg. The ovulation induction rate was 50% in 15,000 and 20,000 IU/kg. Fertlilzation and hatching rates were 55.2, 45.6, 52.8 and 44.8%. Ovulation time was between 72~80 h. HCG concentration of 500, 1,000, 2,000 and 4,000 IU/kg were injected with $50{\mu}g$ of LHRHa. Ovulation and hatching rates in 2,000 IU/kg were 75 and 35%. Ovulation time was 28~48 h. Ovaprim of 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mL/kg were injected to the abdominal cavity. The ovulation induction rate was highest at 2.5 mL/kg to 50% and ovulation time was between 66~86 h. LHRHa concentration of 50, 100, 200, 300 and 400 ${\mu}g/kg$ was injected with pimozide (1,000 ${\mu}g/kg$). Ovulation induction rate was 87% at 100 and 200 IU/kg with pimozide. Ovulation time was between 66~86 h.

• Journal of fish pathology
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• v.8 no.2
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• pp.81-90
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• 1995

One new and one the first recording digenetic trematodes are described from Korean freshwater fishes : Orientocreadium koreanum sp. nov. from Liobagrus andersoni Regan (Korean torrent catfish) and O. psedobagri Yamaguti, 1934 from Pseudobagrus fulvidraco (Richardson) (Korean bullhead). The problems of the family Orientocreadiidae and the major identifying characters of O. koreanum are discussed.

• Fisheries and Aquatic Sciences
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• v.10 no.4
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• pp.196-199
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• 2007

The spermatozoa of Leiocassis nitidus are relatively simple cells composed of a spherical head, a short midpiece, and a tail, as in most Siluriformes. The ultrastructure is characterized by the following features: Acrosome absent, as in most teleosts; around nucleus about $1.8\;{\mu}m$ long, with a deep nuclear fossa containing the proximal and distal centrioles and mitochondria. Two centrioles approximately $180^{\circ}$ from each other; 10 or more mitochondria surrounding the axoneme (with a 9+2 microtubular pattern), arranged in two layers in the postnuclear cytoplasm and separated from the axoneme by the cytoplasmic canal. Two lateral fins on the same plane as the two central microtubules; doublets 3 and 8, which are ultrastructural characteristics of the sperma tail unlike other siluroids laking the lateral fins.