• 한국양식학회지
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• 제10권4호
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• pp.387-394
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• 1997

A total of 353 farmed rockfish, Sebastes schlegli Hilgendorf, 1880 were sampled from 3 localities on Korean coastline over a 12 month period. Full parasitological examination revealed the polypisthocotylean monogenean Micorcotyle sebastis Goto, 1894 to be abundant with infections consistently reaching over 90~100% prevalence throughout the year. A seasonal pattern in parasite abundance on the gills is evident, with the population peaking twice, the largest in winter and again in summer. While the parasitic load on the left and right gills was not dissimilar, parasites within the gill sets were found to favour settlement of the II and III gill arches. A comparison of parasite abundance with host length, revealed that the smaller length fish classes (<17cm standard body length) had significantly heavier infections than those of larger fish (>17 cm standard body length). This report represents the fist record of Microcotyle sebastis on farmed rockfish in Korean coastal waters.

• 한국양식학회:학술대회논문집
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• 한국양식학회 2006년도 수산관련학회 공동학술대회 발표요지집
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• pp.580-581
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• 2006

• 한국가축번식학회지
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• 제25권4호
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• pp.359-369
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• 2001

황해와 남해산이 각각 50마리씩 총100마리의 조피볼락 (Sebastes schlegeli)의 DNA를 혈액으로부터 추출하여 30개의 무작위 primer를 사용한 RAPD(random amplified polymorphic DNAs)-PCR (polymerase chain reaction) 방법으로 분석하였다 genomic DNA의 독특한 특징들이 그 어종군의 특징을 알아내기 위해서 사용되었다. 30개의 primer 중에서 7개의 primer로 부터 증폭된 전체 산물 (307) 중에서 약 67.4%인 207개의 다형성의 산물 (polymorphic products)이 나타났고, 1개의 primer당 약 2.7개의 다양성의 산물 (polymorphic bands)이 확인되었다. 황해산의 경우 bandsharing analysis를 통해서 볼 때 0.22로부터 0.63까지의 bandsharing value가 확인되었고, 이러한 수치는 0.39$\pm$0.02의 평균값을 나타내었다. 황해산과 남해산 2개체군의 RAPD-PCR산물의 전기영동적 분석을 통해서 볼 때 황해산 조피볼락의 개체들 사이에서 변이가 약간 높게 나타났지만 매우 유사한 특징을 나타내었다. 그러나 일부 개체에서 적은 수이지만 polymorphic bands가 확인되었다. 더 많은 개체군과 다른 연구방법을 통한 연구가 있어야 되겠지만, 이러한 결과는 RAPD 방법을 통하여 2 지역산 조피볼락의 유전적 차이를 어느 정도 확인할 수 있는 가능성을 제시해 주고 있다.

• Parasites, Hosts and Diseases
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• 제55권2호
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• pp.219-224
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• 2017

In July 2012, philometrid nematodes were discovered in cultured rockfish (Sebastes schlegeli) in Cheonsuman (Bay), the Republic of Korea. The nematodes were detected in the epithelial tissues of the rockfish and were identified as Clavinema mariae based on morphological studies using light and scanning electron microscopy. They revealed the characteristics same as previously identified C. mariae, notably having a long body with narrow posterior half, no caudal projection, a cylindrical-shaped esophagus, a well-developed anterior bulbous part of the esophagus, cephalic papillae, and a dorsal esophageal gland. This is the first confirmation of C. mariae infection in rockfish in Korea.

• Fisheries and Aquatic Sciences
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• 제7권3호
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• pp.99-108
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• 2004

Vitellogenin (VTG) was purified from serum of $estradiol-l7{\beta}-treated rockfish$(Sebastes schlegeli) by precipitation with $EDTA-Mg^{2+}$ and ammonium sulfate and two step chromatography (anion exchange chromatography and gel permeation chromatography) was performed on FPLC system. Rockfish VTG (rfVTG) was characterized and its properties were determined. The monomers have apparent, molecular mass of about 188 kDa as indicated by SDS-PAGE. Amino acid composition analysis of rfVTG was similar to VTG from other oviparous teleosts. Cysteine and lysine were present at relatively high level. Leucine was present at relatively lower level than in other species. The N-terminal amino acid sequence was evaluated to identify rfVTG. Western blot analysis using an antibody against the purified VTG showed that the antibody reacted with both plasma of $estradiol-l7{\beta}-treated rockfish$ treated male and purified VTG, whereas there was no reaction with male serum of the control. An ELISA was developed using monoclonal and polyclonal antibodies against rfVTG. The assay range was 3.2 ng/mL and 1,000 ng/mL and the value of the intra and inter assay variations were within $9.7{\%}$ and $11.2{\%}$, respectively. Recovery rate was $96.8{\%}$. The sandwich ELISA could be useful for the detection of VTG and could be good for screening of estrogenic compounds.

• Fisheries and Aquatic Sciences
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• 제6권4호
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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.

• 한국양식학회지
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• 제12권3호
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• pp.237-245
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• 1999

In this study, we evaluated the efficiency of chemical marking of black rockfish scales by immersion in oxytetracycline hydrochloride (OTC, 500 ppm), alizarin red S (AR, 250 ppm) and calcein (CARL, 250 ppm) diluted rearing water. Immersion treatment of chemicals had no effects on both mortality and growth of black rockfish. Marking sucess was 100% in all treatment durations (24, 48 and 72 hours) with three chemicals and marking quality was higher in 48 and 72 hours than 24 hours treatment. Marking retention rates at 24 weeks after treatment were 100% in OTC and CAL treated group, but marking quality was higher in CAL treated group (brilliant 92%, bright 8% and dim 0%) than in OTC treated group (brilliant 4%, bright 70% and dim 26%). AR treated group had lower marking retention rates and marking quality than OTC and CAL treated group. As a results, immersion treatment with OTC and CAL was effective in marking scales of black rockfish and practical in releasing program and other studies requires same rearing environment.

• Fisheries and Aquatic Sciences
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• 제4권4호
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• pp.197-200
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• 2001

To investigate the re-treatment time of Microcotyle sebastis by oral administration of praziquantel, the residue levels of praziquantel in plasma of rockfish Sebastes schlegeli administered orally at a dose of 200 mg/kg B.W. were analyzed by reversed-phase HPLC, and the concentrations of praziquantel in the plasma were correlated with the extermination of M. sebastis. The absorption and depletion of praziquantel in the blood of rockfish were fast and the residual concentrations of praziquantel declined below $4\mu g/mL$ within 24 hr post treatment. Most of worms were exterminated within 3 hr after oral administration of praziquantel, however, a small number of M. sebastis were not killed by the treatment until end of the experiment. Considering fast drop of praziquantel in blood and extermination pattern of M. sebastis in the present results, retreatment at an interval of 9-12 hr would be effective for eradication of M. sebastis.

• Fisheries and Aquatic Sciences
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• 제1권1호
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• pp.79-81
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• 1998

To investigate the influence of originated host and water temperature on the infectivity and growth of Microcotyle sebastis, juveniles of Schlegel's black rockfish (Sebastes schlegeli) were exposed to the eggs of M. sebastis originated from. Schlegel's black rockfish and black rockfish (Sebastes inermis) at $10^{\circ}C$ and $10^{\circ}C$. There were significant differences between the two isolates in the infectivity of eggs, and the growth of worms. The growth of M. sebastis was significantly affected by water temperature, and worms grew faster in $20^{\circ}C$ than in $10^{\circ}C$.

• 한국어병학회지
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• 제31권1호
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• pp.35-39
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• 2018

Atypical furnculosis caused by atypical Aeromonas salmonicida, is an emerging problem of farming of rockfish (Sebastes schlegeli) in Korea. In this study, protection against atypical furunculosis was compared in rockfish vaccinated with A. salmonicida formalin killed cell (FKC) and adjuvant containing FKC. The formalin inactivated A. salmonicida vaccine provided a low protection of 20% and 10% relative percent survival (RPS) at 44 and 58 days post vaccination. However, addition of adjuvant (squalene and aluminum hydroxide) into inactivated A. salmonicida vaccine clearly enhanced the level of protection showing 70% and 50% RPS at 44 and 58 days post vaccination.