• Journal of fish pathology
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• v.9 no.1
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• pp.11-13
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• 1996

Ergasilus sieboldi, a parasitic Copepoda, was detected from the gill of Silurus asotus fingerling(7~10 cm long) cultured at a fish farm in Chungnam Province (Fig. 1 and 2). The infected fish did not show any particular external symptoms except a feeble swimming around the boarder of the pond. The isolated parasite was of 1.07 mm in body length with two egg sacks of 1.05 mm and one pair of hook-shaped secondary tentacle. Bychowsky(1963) described that this parasite infected the gill of Salmonidae, Serranidae, Cyprinidae and Siluridae and that the fish in the Baltic Sea, Black Sea. Caspian Sea. Japanese sea zones, Siberian rivers and Lake Bikal were infectd. Bychowsky further pointed out that heavily infected fish with this parasite become emaciated and slow in growth. and often die. As this parasite infected on the peri-branchial area. the infected fish showed a severe disturbance of respiration. Urawa et ai.(1980) studied on the development of Neoergasilus japonicus. an Ergasilidae, which infects Japanese freshwater fish. In Korea, Chun(1985) reported the identification of Ergasilus sieboldi from imported carp. and Neoergasilus and Pseudogasilus japonicus from bluegills. respectively. Chun also identified Pseudoergasilus zacconis in cultured ayu(Plecoglossus altivelis). However. this report deals with the detection of Ergasilus sieboldi from cultured catfish(Silurus asotus) for the first time in Korea.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.50 no.4
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• pp.633-642
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• 2014

Monthly variation in abundance and species composition of the fishes were investigated based on specimens collected by gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010. The collected fishes were 1,529 individuals (183,840g) of the total, identified into 6 orders, 16 families and 24 species. The most dominant order fish was Perciformes comprised 9 species, 7 families, and followed Pleuronectiformes comprised 5 species, 3 families, Scorpaeniformes comprised 5 species, 2 families. These 3 orders constituted 81.1% of the total collected fish. During the study, most dominant species was Hexagrammos otakii accounted for 189 individuals (12.4%) of the total, followed by Lateolabrax japonicus 165 individuals (10.8%), Hexagrammos agrammus 154 individuals (10.0%). The fish was collected by a gill net in coastal water of Yeosu from October, 2009 and February, May, August, 2010, the diversity index of the fishes was 2.09~2.66, which was the highest in August, 2010 and the lowest in February, 2010. The evenness index of them was 0.84~0.89, which was the highest in August, 2010 and the lowest in February, 2010 and the richness index of them was 2.02~3.14, which was the highest in October, 2009 and the lowest in February, 2010. The analyzed species diversity index by the each stations was 2.47~2.66 and the evenness index was 0.84~0.90 and the richness index 2.99~3.37. The similarity of community structure per season was very high which was the least in spring and fall. In addition, the community structure was very similar in state 3 and 2 out of each stations.

• Journal of fish pathology
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• v.5 no.2
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• pp.93-118
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• 1992

The research was carried out to examine the chronic toxic effects of nitrite on the Japanese eel, Anguilla japonica by neans of histological observations. Young eel, 10.8g mean body weight. were exposed to 6 different concentrations of nitrite(1, 5, 10, 20, 30 and 40ppm) for 10 weeks. Each concentration was treated under 5 different levels of pH(5.5, 6.0, 6.5, 7.0 and 7.5) and each of these treatment was tested at 2 different temperature regimes($25^{\circ}C$ and $30^{\circ}C$). Proper concentration of nitrite was made by $NaNO_2$ and proper pH levels were made by the combinations of 0.1M $KH_2PO_4$ and 0.1M $NaHCO_3$. Histopathological test of gill tissues were made along with the test of the formation of thrombocystes and chloride cells on the gill filaments. At the lower pH levels, mucus secretion from the gill was incrased as the nitrite concentration increased. As the level of nitrite increased the number of chloride cells on the gill filament were decreased. Most of the remained chloride cells were observed only at the terminar part of the gill filament at 40ppm of nitrite. Degeneration of gill tissues were observed when nitrite levels were over 10ppm along with detachement and sweption of the epithelial cells of the gill lamellae. Shrunken gill lamellae and formation of thrombosis in the capillaries of gill lamellae were also observed. When temperature goes higher at the higher level of nitrite, necroses in the gill lamellae was increased. At the lower than 10ppm of nitrite, degeneration of gill lamellae was occured at the beginning of the test period but regenerated later. Negative effects of nitrite on the growth of young eel was started between 5~10ppm at the pH level of 7.0 and 7.5. Thrombosis formation were also started at this level. The safety concentration of nitrite at the pH levels of 7.0 and 7.5 on the small eel seems to be 1ppm. Thrombosis and gill lamella detachment and necrosis in the gill capillaries were not observed at this level. Chloride cells were appeared the whole part of the gill filament.

• Journal of fish pathology
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• v.9 no.2
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• pp.137-145
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• 1996

A specific disease syndrome, which led to massive mortality on larve of rockfish(Sebastes schlegeli) in marine hatcheries at Chungnam area during the period 1995~1996 was studied. The causative agent isolated from the diseased or dead larvae was identified as Vibrio ordalii on the basis of biochemical and biological characteristics. In the experimental challenges aganist 0 and 1 summer fish conducted at two different temperatures as $18^{\circ}C$ and $25^{\circ}C$, Vibrio ordalii showed higher virulence to no summer fish at $18^{\circ}C$ than 1-summer fish at $25^{\circ}C$. These results were consistent to field data obtained during epizootic outbreaks in the farms. Moribund and died larvae presented telangiectasis of secondary gill lamella and brain, dissecting of respiratory epithelium, atrophy of hepatic cells and necrosis of kidney associated with the presence of the bacteria. But the digestive tissue of these fish showed no significant change.

• Korean Journal of Ichthyology
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• v.17 no.4
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• pp.279-286
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• 2005

The fish species composition and its seasonal variation of the middle East Sea of Korea were investigated from May 2004 to January 2005 using gill and set nets. A total of 59 species of fishes belonging to 31 families in 11 orders were identified in the gill and set nets; 33 species in 15 families and 6 orders were collected by the gill net, and 36 species in 26 families and 10 orders were collected by the set net. Among the fishes collected by gill net, the order Scorpaeniformes was dominant; the number of species as well as individuals was highest in summer; the biomass was highest in winter. However, in fishes collected by set net, the order Perciformes was dominant, the number of species was highest in autumn, the number of individuals was highest in spring, and the biomass was highest in winter. The fish composition of the middle East Sea differed considerably from that of the south East Sea, especially in the species composition of the order Scorpaeniformes and Pleuronectiformes. Principal component analyses for each net showed that the fish species composition depends on the kind of net used, even though the investigation was carried out in the same area and at the same time.

• Applied Microscopy
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• v.30 no.3
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• pp.311-319
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• 2000

The gill morphology and ultrastructure of the fleshy shrimp, Penaeus chinensis were investigated by light and electron microscopy. Fleshy shrimp has dendrobranchiate gills. Gill has a longitudinal septum dividing them into afferent and efferent channel. Each gill lamella is covered by multi-layered thin cuticle of different electron density. The lamella basal cell is squamous and contains cytoplasm of electron dense. Simple epithelial layer consists of squamous epithelium contained large nucleus. The lamella pillar structures are characterized by the axial microtubules and lateral membrane interdigitations Secretory cells of AB-PAS negative are multicellular gland. In active gland each cell boundary is not apparent and the cytoplasm contains smooth endoplasmic reticula, mitochondria, membrane-bounded secretory vesicles of low electron density and granular resettes. In inactive gland each cell boundary is apparent and the cytoplasm is occupied with numerous small granules of electron dense. The well-developed rough endoplasmic reticula and Golgi apparatus are observed in the unicellular gland of alcian blue positive.

• Journal of fish pathology
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• v.21 no.1
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• pp.67-79
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• 2008

This study was conducted to find out biological response of bivalves exposed to tributyltin chloride(TBTCl). The results of the study confirmed that TBTCl induce the reduction of oxygen consumption rateand histopathological feature in the gill structure of equilateral venus, Gomphina veneriformis. The experi-mental groups consisted of a control and 3 TBTCl exposure groups (0.4, 0.6 and 0.8 yg TBTCl L') and theexperimental period was 36 weeks. For histological analysis, gill tissues were fixed in Bouin's fluid andthen stained H-E stain, AB-PAS (PH 2.5) reaction and Masson's trichrome stain after having serially sec-tioned the tissue by paraffin method at thickness of 4-6 (an. The oxygen consumption rate was not signifi-cantly different between the control and exposure groups at 4 weeks, but in all exposure groups at 28 weeks,it was significantly different to the control. Gill of G. veneriformis had demibranch that attached two sheetsof lamellae and a lamella was composed of numerous filaments, numbering 25 on average. The frontal fila-ment zone had three types of cilia; frontal, latero-frontal and lateral depending on locations while the lateralcilia were the longest and largest in number. The mucous cells observed in filaments were more abundant in(542c) in AB-PAS (PH 2.5) reaction. Gill exposed to TBTCl was extended hemolymph sinus and increased hemocytes at 4 weeks, and then it showed increases of mucous cells and partially disappearance of frontalcilia. In the group of 0.8 yg TBTCl L' at 12 weeks, hypertrophy of frontal and latero-frontal epithelia wasobserved. Also it observed m decrease of mucous cell containing weekly acid mucosubstance and appearedpartially destruction muscle fiber bundle, In the groups of 0.4 and 0.6 ug TBTCl L' at 36 weeks, it appearedpartially modification of epithelia and in 0.8 us TBTCl L' group, observed filaments that come out chiti-nous rod from disappearance of frontal and latero-frontal epithelia.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.6
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• pp.699-705
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• 1999

The effects of iron on gill tissue and metabolic rate represented by oxygen consumption of olive flounder, Paralichthys olivaceus were determined. The effects were further studied by means of survival rate of the fish exposed to a serial concentrations of iron. The olive flounder exposed to iron concentrations over 0.93 mg/$\ell$ showed curvature and terminal clubbing of gill lamellae at 2 weeks post-exposure. In iron concentration 4.89 mg/$\ell$, gill of the fish were seriously damaged just after 2 weeks, showing hyperplasia of filament epithelia, deformation of lamella epithelia, chloride cell damage, and separation of lamella epithelial layer, Gills exposed to 9.78 mg/$\ell$ iron concentration resulted in fusion and necrosis of the lamellae after 2 weeks. Significant decreases of metabolic rate of the fish were observed after 4 weeks at iron concentration 0,93 mg/$\ell$ and after 2 weeks at iron concentrations over 4.89 mg/$\ell$. Survival rate of the olive flounder decreased significantly after 4 weeks at the iron concentration over 4.89 mg/$\ell$. These results lead us to conclude that, as far as the iron effects are concerned, its concentrations should not exceed at least more than 0.93 mg/$\ell$ in the fish farm and coastal waters for normal growth of the olive flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.1
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• pp.7-16
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• 1971

This paper deals with the numbers of vertebrae, gill rakers and relative growth of the Pacific saury, Cololabis saira along the eastern coast of Korea in May, July and December 1970. About 90 percent of the total fish population possessed 64-66 vertebrae with the mean of 64.80 and the mode of 65. The number of gill rakers varied from 33 to 44 in December with the mean of 37.08. With regard to the number of vertebrae and gill rakers of the medium (26.0-28.0 cm in fork length) and large (30.0-31.0 cm in fork length) sized groups, there are similarities between the northbound modium sized group and the southbound large sized one, and also between the southbound medium and southbound large sized groups. Although no correlation was found between the numbers of vertebrae and gill rakers, in December the number of vertebrae of the large sized group exceeded that of the medium sized group, and on the other hand the number of gill rakers of the large sized group was fewer than that of the meduim sized one. There was a tendency of decreasing in ratio of the head length to the fork length as the latter increased, The relationships between the fork length and the head length varied depending on the northbound and southbound migration of the fish. The same tendency was also seen in the relationship between the fork length and the body weight. The body weight increased from July to December (from medium to largo sized group) showed more than twice than that from December to the following July (from medium to large sized group). The coefficient of fatness remained constant in December, but a distinct variation was found between the medium and large sized groups in July, corresponding to the spawning sea-son of the fish. Relatively higher coefficient was found in December as compared to that found in July.

• Journal of fish pathology
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• v.8 no.2
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• pp.111-118
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• 1995

This experiment was carried out in order to elucidate the effect of NaCl(0.85%) acclimation on congestion symptoms in central venous sinuses(CVS) of gill filaments and on the alteration of blood constituents in cultured eels for 1, 2, 3, 4, 5, 6 and 7days after handling stress. After giving a handling stress on eels, the frequency of gill congestion was about 90%. It gradually decreased to 40% on the 3rd day, then increased to 60% on the 7th day in NaCl(0.85%) acclimation. The values of haematocrit(Ht), methemoglobin(Met-Hb), glucose (GLU), calcium($Ca^{++}$), lactic dehydrogenase(LDH), glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase(GOT) were lower than those of the control, whereas magnesium($Mg^{++}$) and haemoglobin(Hb) were higher than the control. However total protein(Tp) and albumin (ALB) levels similar to the control. When the fish after giving a handling stress were cultured in NaCl-free water as a control, the frequency of gill congestion and the value of blood components showed a similar pattern to that obtained from the NaCl acclimated experiments. However, in the early period(1-3day) after handling stress, NaCl acclimating slightly helped the natural tendancy of recovery. These results suggest that the frequency of gill congestion is not always reduced over the whole period of NaCl acclimation. However, the acclimation to NaCl solution may be a somewhat useful therapy for the gill congestion in stressed eels.