• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.387-393
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• 2004

Experiments were carried out to investigate the lipid peroxidation (LPO), superoxide dismutase (SOD) activity and histopathological change of hepatic tissue for rockfish, Sebastes schlegeli after feeding sub-chronic dietary Benzo(a)pyrene (BaP) in the concentration of 0 (control), 0.5, 1.0, 1.5, 2.0 mg $kg^{-1}$ dry food of diet for 30 days. In 2.0 mg $kg^{-1}$ dry food group, the significant increase of LPO was observed in all period, and SOD activity was incresed at 30 days significantly in the same concentration. In the histological investigation of liver, there was the swelling of hepatic cells at 10 days over the 1.0 mg $kg^{-1}$ dry food concentration. At 30 days Periodic acid-Schiff (PAS) positive granule was observed in the same group and at 20 days was observed in 2.0 mg $kg^{-1}$ dry food group. And there was necrosis of hepatic cell in some fish of 2.0 mg $kg^{-1}$ dry food group at 30 days.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.5
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• pp.637-641
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• 1999

This study was carried out to understand feeding ecology of black rockfish, Sebastes inermis in the coastal waters off Shinsudo, Sachon. The specimens were collected by angling, gill net, small danish seine, and long-bag net from February 1984 to May 1985. The fish consisted of 5 age groups from 0 to 4. Feeding activity was more intensive in the early morning and late afternoon in spring and summer, but the fish showed intermittent feeding activities in autumn and winter. Although the food items of the fish changed slightly by seasons and with growth of the fish, main food items were cope pods, gammarids, caprellids, carideans, polychaetes, and brachyurans. Of these food items, cope pods were major preys for the fish of age group 0, and gammarids over age group 1. Evenness and diversity of the food items increased as the fish grew. In consideration of feeding organs, digestive organs and stomach contents of the fish, S. inermis seemed to be not only carnivore but also visual feeder consuming mainly small crustaceans.

• Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.91-96
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• 2006

The movement range and diurnal behavior of 17 wild black rockfish (Sebastes schlegeli) were monitored within the marine ranching area of Tongyeong from 27 July to 7 November, 2005 using acoustic telemetry. Coded transmitters were surgically implanted into the abdomen of fish. Two of ten fish released in summer moved about 2 km away from the capture point for 1 day. The others stayed within a 500-m radius of the release point for 1 week after release. The seven fish released in autumn stayed within 500 m of the release point. Most fish were more active and had a greater range of horizontal diurnal movement at night than during the day. Additionally, the range of horizontal diurnal variation was greater in summer than in autumn. While fish released in summer were more vertically active at night than during the day, those released in autumn preferred to move vertically during the day.

• Ocean Science Journal
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• v.43 no.2
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• pp.107-113
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• 2008

Laboratory bioassays were conducted to test the acute toxicity effects of sudden exposure to sodium cyanide (NaCN) on the endogenous rhythm of the oxygen consumption rate (OCR) in the black rockfish Sebastes schlegeli. The OCR of the black rockfish(n = 14, total length = $20.4{\pm}1.16\;cm$, wet weight = $158{\pm}25\;g$) was measured with an automatic intermittent-flow-respirometer. OCR decreased significantly when experimental fish were exposed to NaCN. When exposed to 10 ppb NaCN, fish were able to recover their OCR rhythmic activities. When fish were exposed to 20 ppb, however, the metabolic activity rhythms were not recovered. These results suggest that exposure to NaCN concentrations over 20 ppb cause severe physiological damage to the endogenous rhythms of black rockfish.

• Journal of Environmental Health Sciences
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• v.29 no.4
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• pp.55-57
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• 2003

Nine (34.6%) of the 26 rockfishes taken from Newport fish market, Oregon in July 2003 had a total of 135 monogenetic trematodes attached the gills. Microcotyle sebastis, Megalocotyle trituba and Trochopus australis were encountered, occurring in rockfishes examined. In the monogenetic trematodes in Sebastes spp, the prevalence were found to be between 30.8 and 40.0%. Prevalence of M. sebastis was 37.5%, 40.0% on M. trituba and 30.8% on T. australis. Nine of Sebastes spp. were infected with one or two species of monogenetic trematodes. Intensities of infection for M. sebastis, M. trituba and T. australis were recorded as 2.0 (2-12), 22.0 (48-62) and 1.0 (1-3), respectively. It may be that the intensities of infection for M. trituba should be high, and M. sebastis and T. australis little low.

• Journal of Aquaculture
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• v.17 no.3
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• pp.161-166
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• 2004

The influence of TBTO (Tributyltin-Oxide) at a series of concentrations (0.52, 1.41 and 3.05 $\mu$g/L) for a period of 3 weeks on estradiol-17$\beta$, testosterone and cortisol levels in male Korean rockfish, Sebastes schlegeli was investigated. Compared to the stable concentration of estradiol-17$\beta$, plasma testosterone level was decreased significantly at the 3rd week after TBTO exposure in plasma of fish (＞1.41 $\mu$g/L). The most profound physiological variation in TBTO exposed fish was a dramatic increase in plasma cortisol level at 3rd week. Conclusively, TBTO exposure caused increase level of cortisol as well as alteration of testosterone in the Korean rockfish. These results suggest that TBTO at environmentally relevant (nanomolar) concentrations disrupt endocrine secretions.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.221-232
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• 2015

Broadband echoes measured in live chub mackerel Scomber japonicus, goldeye rockfish Sebastes thompsoni, and fat greenling Hexagrammos otakii with different morphologies and internal characteristics were analyzed in time and frequency domains to understand the species-specific echo feature characteristics for classifying fish species. The mean echo image for each time-frequency representation dataset obtained as a function of orientation angle was extracted to mitigate the effect of fish orientation on acoustic scattering. The joint time-frequency content of the broadband echo signals was obtained using the smoothed pseudo-Wigner-Ville distribution (SPWVD). The SPWVDs were analyzed for each echo signature of the three fish species. The results show that the time-frequency analysis provided species-specific echo structure patterns and metrics of the broadband acoustic signals to facilitate fish species classification.

• Korean Journal of Environmental Biology
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• v.21 no.2
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• pp.177-180
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• 2003

Four genera of metazoan parasites were recovered from 3 of 6 Sebastes pinniger examined during January 2003. Two hundred forty-five metazoan parasites were recovered. Trochopus trituba Sekerak and Arai, 1977 and Anisakis larvae were found to he infected S. finniger Gill and te be abundant in this rockfish. One hundred eleven worms of monogenean trematodes and 134 larval anisakine nematodes were also found in this fishes. Precise positions with regard to gills, fins, and gastrointestinal tracts were recorded on S. pinniger to determine distribution of metazoan parasites of Trochopus trituba, Anisakis simplex larva, Contracaecum sp. larva, and Pseudo terranova decipiens larva. The monogenean trematodes, T. trituba were attacked to the gill arches and fin, and the larval anisakine nematodes, A. simplex, Contracaecum sp.,and P. decipiens were found on the visceral organs such as intestine, omentum and stomach wall. The second gill arches were the most heavily infested and posterodorsal region of the gill arches contained most monegenenn trematodes. The nam site of infestation of larval anisakine nematodes were the intestine.

• Environmental Analysis Health and Toxicology
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• v.20 no.3 s.50
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• pp.223-228
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• 2005

Rockfish Sebastes schlegeli was exposed to fluoranthene, a ubiquitous polycyclic aromatic hydrocarbon, at 1 and 10 $\mu$g/L for 4 weeks followed by depuration period of 8 weeks. Although the fluoranthene in the p]asma reached only 1.8$\~$1.9 times seawater concentration, it was 6.5 $\~$ 15.7 times higher in the liver, spleen and bile indicating efficient accumulation in the lipid -containing body tissues. When the exposed fish were then maintained in clean water, rapid fluoranthene decline occurred in the initial 2 weeks followed by a rather slow phase. This result suggests that fluoranthene accumulates efficiently provided the existence in the culture medium, but the contaminant disappears rapidly once the chemical source is removed. The fluoranthne residue in fish tissues my be a good indifator for relent PAHs exposure.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.300-302
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• 2002

The occurrence and infection level of parasitic Copepod, Clavella adunca on the black rockfish, Sebastes melanops at the Hatfield Marine Science Center Aquarium were studied. C. adunca was usually found on the base of fins, preferably on the pectoral fins. Seven specimens of black rockfish, Sebastes melanops were collected from Oregon Coast Aquarium. Copepods of ten Clavella adunca were present as ectoparasites attached to the fins in the black rockfish. The prevalence and relative density of Clavella adunca were 28.6% and 1.4 respectively. It is considered that the tissue of the fin membrane offers the most favorable conditions toy the attachment of C. adunca.