• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2000.06a
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• pp.103-103
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• 2000

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.36 no.2
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• pp.89-95
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• 2000

Test fishing was carried out to examine the selectivity of the mesh size in trammel net for tonguefish (Cynoglossidae spp.) from May to August, 1999 and a total of 30 times of test fishing have been done in the coastal waters around Dolsando, Yosu, South Chunra province, Korea. A gill net and a trammel net which were composed of three different mesh sizes (70.5mm, 86.6mm and 101mm) were used for the experiment. The selectivity curve of mesh size was estimated by Kitahara's method for Robust tonguefish (Cynoglossus robustus). The results obtained are summarized as follows ; 1. Catching efficiency of the trammel net (70.5mm-sized-lint main net) was 39.0% and it was 2.5 times higher than 15.8% for the gill net. 2. The optimum l/m value of the trammel net was 3.51 and it was 0.13 higher than 3.38 for the gill net. 3. The selectivity of trammel net was similar to that of the gill net for low length-class. However, the selectivity of trammel net was not good compared with that of the gill net for high length-class. The 50% selectivity was 1.33 for the trammel net and 0.83 for the gill net. According to the experimental results, fishing efficiency of the trammel net was better than that of the gill net for tonguefish (Cynoglossidae spp.) and it was known that catch length for targeted species could be selected by controlling the mesh size.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.2
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• pp.116-125
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• 2007

An experiment to acoustically analyze the shape of gill-net in the current was conducted in Jaran Bay, Gosung, Korea on the 9th to 10th September(spring tide) and 28th to 29th September(neap tide) 2006. It was measured by a 3D underwater positioning system with a radio-acoustic linked positioning buoys. Six of 7 acoustic transmitters used in the experiment were attached on the float line of the gill-net and the other was fixed on the sea bed. During spring tide, the maximum movement of the gill-net was 27.0m(22:00) in the west(4.4cm/s, $311.9^{\circ}$) and 20.6m(04:00) in the east(3.9cm/s, $66.5^{\circ}$). The maximum extension of the gill-net(the distance between P1 and P6) was 119.8m(21:00, 11.6cm/s, $321.9^{\circ}$) and the minimum was 109.9m(23:00, 16.1cm/s, $88.5^{\circ}$). During neap tide, the maximum movement was 38.0m(20:00) in the east(9.6cm/s, $278.2^{\circ}$) and 11.0m(12:00) in the west(1.9cm/s, $232.1^{\circ}$). The maximum extension was 99.6m(14:00, 12.5cm/s, $94.7^{\circ}$) and the minimum was 85.0m(06:00, 9.0cm/s, $265.8^{\circ}$). During spring tide, the maximum height of the gill-net from the sea bed was 3.7m(02:00, 7.4cm/s, $151.6^{\circ}$) and the minimum was produced the three times as 1.5m. At that time, the current speed and direction was 17.9cm/s and $85.3^{\circ}$(23:30), 16.1cm/s and $249.4^{\circ}$(05:00), and 13.7cm/s and $291.4^{\circ}$(06:30), respectively. During neap tide, the maximum height was 3.6m(12:30, 2.1cm/s, $242.3^{\circ}$) and the minimum was 1.5m(14:00, 12.5cm/s, $94.7^{\circ}$).

• Journal of fish pathology
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• v.20 no.3
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• pp.315-325
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• 2007

Histological changes in gill and liver of eel, Anguilla japonica (average weight 96±3.6 g) were examined with formalin bath at 0~500 ppm for 1, 6 and 24 h. Hyperplasia, hypertrophy, cell fusion, desquamation and necrosis of epithelial cells at gill lamella and gill filament were observed from 6 h at 200 ppm, 1 h at 300 ppm, 1 h at 400 ppm and 1 h at 500 ppm. In the exposure of formalin 100 ppm for 24 h, epithelial cells arrangement of gill filament and gill lamella showed thinner and more regular order than the control. trophy and pyknosis of hepatocytes, congestion at sinus or central vein, degeneration of cytoplasm were observed in the liver from 24 h at 100 ppm and 200 ppm, 6 h at 300 ppm, 1 h at 400 ppm and 500 ppm. However, there were not any histological changes at liver of 100 ppm-1, 6 h, 200 ppm-1, 6 h and 300 ppm-1 h compared with the tissue of control.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.85-94
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• 2011

Present study aimed to investigate the effect of zinc accumulation on the tissues of Carassius auratus with various rearing condition. Heavy metal, Zn, was accumulated in the gill, bone and muscle increased for exposure period of 40 days. Moreover, the accumulated concentration of Zn in the gill showed relatively higher than that in other tissues. Also, activities of antioxidant enzymes in the gill, kidney, liver and muscle tissues after exposure to Zn were increased in the manner of exposure period. Antioxidant enzyme activities were shown higher in the gill and muscle than those in the kidney and liver tissues. The gill of C. auratus showed abnormal shapes in its secondary lamellae by long time exposure condition and determined the increased numbers of mucous cells in gill exposed to Zn. In addition, the edema, the exfoliation of epithelial cell was shown in the gill and membrane damages were observed in mitochondria and nucleus. In the kidney, we observed not only the atrophied glomerulus, but the expansion of empty space in Bowman's capsule. Based on the above results, it is considered that the exposure to the high level of Zn for long period possibly involves in the decrease of respiratory and excretory rates, giving rise to secondary lesion of tissues.

• Journal of fish pathology
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• v.9 no.2
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• pp.147-155
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• 1996

This study was carried out to examine the acute toxic effects of ammonia to the eel, Anguilla japonica in high temperature and pH levels by histopathological observations. The eels of 40 g average body weight were exposed to 4 different concentrations of total ammonia (0, 10, 20, 30 mg/$\ell$) for 24~120 hours. Each concentration was treated under 4 different levels of pH (7.5, 8.0, 8.5, 9.0) and each of these treatments was tested at 2 different temperatures ($27^{\circ}C$, $32^{\circ}C$). Histopathological changes in gill tissues were observed by hematoxylin-eosin stain. As increasing of pH (from 7.5 to 9.0), water temperature (from $27^{\circ}C$ to $32^{\circ}C$), total ammonia concentration (from 0 mg/$\ell$ to 30 mg/$\ell$) and exposure time (from 24 hours to 120 hours), gill discolorated to dark brown with the naked eye and gill tissues showed hypertrophy of gill lamellae, winding of the secondary gill lamellae, epitherial separation and necrosis histopathologically. When gill lamellae epithelium was separated from the blood vessels, gill discolorated to dark brown with the naked eye.

• Korean Journal of Ichthyology
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• v.25 no.1
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• pp.1-8
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• 2013

Rockfish, Sebastes schlegeli (total length; $10.36{\pm}0.49cm$, total weight; $16.28{\pm}1.86g$, N; 290) were exposed to various concentrations of naphthalene for 28 days. Exposure concentrations of naphthalene established control, ethanol (solvent) control, 0.5, 1.0, 1.5 and 2.0 mg Nap $L^{-1}$. After exposure, We observed survival rate, and degree of tissue change (DTC) in gill under optical microscopy. Survival rate of the rockfish was more than 90% in control, ethanol control, 0.5 and 1.0 mg Nap $L^{-1}$, whereas it decreased in 1.5 and 2.0 mg Nap $L^{-1}$ (respectively 80%, 62.2%). In histological observation of gill, hyperplasia of epithelial cells observed in all exposure groups. But no showed increase of DTC which was related to concentration. Whereas, DTC at fusion of gill lamellar, lamellar telangiectasia, stasis, aneurysm and necrosis showed dose dependent increase. Especially, fusion of gill lamellar, lamellar telangiectasia and stasis observed at more 1.0 mg Nap $L^{-1}$, and aneurysm and necrosis at more 1.5 mg Nap $L^{-1}$. These results showed naphthalene caused survival and severe change to the gill of the rockfish which was related to exposure concentration.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.49 no.4
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• pp.341-351
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• 2013

Physical characteristics of PA (Polyamide) gill net and biodegradable gill net made by PBS (Polybutylene succinate) (mesh size 63mm, mesh thickness number 2, 2.5, 3) were analyzed to investigate catching efficiency of the biodegradable gill net for Pacific herring. Total 11 numbers of catching efficiency tests were carried out using commercial fishing vessel at Imwon port in Kangwon province from May to June 2013. The amount of catches were 1,535.7kg (18 species) through the catching efficiency tests and it is expected that the practicalization of biodegradable gillnet is possible because there is no difference for catches between PA gillnet and PBS gillnet. Catches of herring according to the thickness of net twine was the highest at No.2 and the thicker net twine tends to decrease the catches.

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.213-219
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• 2003

Experiments were carried out to investigate the accumulation and elimination changes in the tissue of juvenile rockfish (Sebastes schlegeli) after sub-chronic dietary Cu (0, 50, 125, 250 and 500 mg/kg) exposure for 60 days and depuration for 30 days. The profile of Cu accumulation in the tissue of rockfish was dependent on the exposure periods and Cu concentration. Liver of rockfish is a more important storage tissue than other tissues, and the order of Cu accumulation in tissues was liver > intestine > kidney > gill > muscle. The accumulation factors were increased with the exposure period in gill, intestine, liver, kidney and muscle. An inverse relationship was observed between the accumulation factor and the exposure concentrations in the gill, kidney and muscle. Cu elimination in tissues of rockfish were decreased with periods for the 30 days of depuration except kidney and muscle. The order of Cu elimination in organs during depuration was intestine > liver > gill.

• Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.324-330
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• 2009

Cadmium (Cd) accumulation and elimination were assessed in the tissues of the clam R. philippinarum at four experimental concentrations (control, 10, 20, 100, and $200\;{\mu}g/L$) over an exposure period of 2 weeks and an elimination period of 1 week. Cd accumulated in the digestive gland, gill, and residual clam tissues, and accumulation increased with time of exposure and concentration (100 and $200\;{\mu}g/L$). After 2 weeks of Cd exposure, the order of Cd accumulation in tissues was gill > digestive gland > residual tissues. An inverse relationship was observed between concentration factor (CF) and exposure level, but the CF showed an increase with exposure time. During the depuration period, Cd concentrations in the digestive gland, gill, and residual tissues decreased immediately on the cessation of exposure, except in individuals at the $200\;{\mu}g/L$ concentration. The Cd elimination rate from tissues decreased in the order of digestive gland > gill > residual tissues during the depuration period.