• Fisheries and Aquatic Sciences
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• 제9권2호
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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.

• 한국발생생물학회지:발생과생식
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• 제10권3호
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• pp.177-184
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• 2006

레티놀 결합 단백질(retinol-binding protein, RBP)은 고등 척추동물에서 혈류를 통해 특이적으로 레티놀을 표적세포에 운반해 주는 중요한 역할을 한다. 우리나라의 연안에 서식하고 있으며 산업적으로 중요한 조피볼락(Sebastes schlegeli)을 대상으로 4-nonylphenol(NP)가 RBP mRNA 발현에 미치는 영향을 구명하기 위해 간으로부터 cDNA library를 제작하고 RBP 단편의 염기서열을 분석하였다. 분석된 RBP mRNA 서열로부터 아미노산 서열을 추정하여 다른 종의 RBP 아미노산 서열과 비교한 결과 Sparus aurata와는 80%, 무지개 송어(Oncorhynchus mykiss)와는 72%, 유럽 뱀장어(Anguilla anguilla)와는 78%의 높은 상동성을 보였다. 조피볼락에서 4-NP에 대한 RBP와 VTG mRNAs 발현에 미치는 영향을 northern blot 분석 방법에 의해 조사하였다. 4-NP를 10 mg/kg BW로 주사한 실험구에서는 암수 모두 VTG mRNA 발현에 영향을 주지 않았으나, RBP mRNA 발현은 수컷에서 48시간 후에 감소하였다. 4-NP를 25 mg/kg BW으로 주사한 실험구에서는 24시간 후에 암수 모두 VTG mRNA 발현이 증가하였으며, RBP mRNA 발현은 48시간 후에 암수 모두 감소하였다. 이들 결과로부터 조피볼락에서는 4-NP 등의 에스트로겐 유사물질이 RBP와 VTG 유전자 발현에 상반되는 효과를 유도함을 알 수 있었다.

• 한국수산과학회지
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• 제49권2호
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• pp.154-160
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• 2016

Several our studies have focused recently on the mass production of the freshwater Cladoceran Moina macrocopa which can substitute Artemia nauplii for the culture of larval marin fish. A 6 weeks experiment was conducted to investigate the effects of enrichment on the fatty acid composition of Moina macrocopa through feeding Schizochytrium sp. containing highly unsaturated fatty acids and to study the impacts of n-3-HUFA enriched Moina on improving survival rate and fatty acid compostion of larval rockfish Sebastes schlegeli. After feeding for 6 weeks, the Moina-fed fry resulted in a higher survival rate of 99.2% compared to the Artemia-fed fry 12.8%. In addition, the Moina-fed fry had the fast growth rate 45.6mm compare to the Artemia-fed fry 25.7 mm at the end of the experiment. The Moina-fed fry showed significantly higher level of 16.47% DHA than their Artemia-fed fry counterparts of the level of 3.97% with respect to DHA. PL, the cell membrane components in living food organisms, constituted 63.8% of the Moina, which was significantly higher than in the 40.1% of the Artemia. The present study indicate that Moina macrocopa can be used as Artemia substitute and improving the survival rate rockfish larvae through enchriment Schizochytrium sp.

• 한국수산과학회지
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• 제49권6호
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• pp.823-829
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• 2016

Yacon (YC), ginger (GG) and blueberry (BB) were added to the diet of juvenile rockfish Sebastes schlegeli to investigate the effects of these substances on growth, feed utilization and resistance to Streptococcus iniae compared to feed additive ethoxyquin. A total of 480 fish were distributed in 12 tanks and four experimental diets [control (Con), with 0.01% ethoxyquin, and 1% YC, GG and BB diets] were provided in triplicate. After an 8-week feeding trial, 20 fish from each tank were infected with Streptococcus iniae. Fish fed the BB diet had higher weight gain than fish fed the GG and Con diets. Feed efficiency of fish fed the GG and YC diets was higher than that of fish fed the BB and Con diets. The protein efficiency ratio of fish fed the GG diet was higher than that of fish fed any other diet. The cumulative mortality 54 h after infection of fish fed the Con diet was higher than that of fish fed any other diet. These results indicate that YC, GG, and BB are effective dietary additive, not only improving growth performance and feed utilization but also lowering the mortality of juvenile rockfish exposed to S. iniae.

• 한국수산과학회지
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• 제48권5호
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• pp.731-738
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• 2015

Nematode infection in the epithelial tissue of cultured rockfish Sebastes schlegeli was first reported in 2012. Since then, nematode infections have caused serious economic losses in rockfish aquaculture on the west coast of Korea. Taxonomic and life cycle information for this parasite are currently unknown. In this study, 18S rRNA and cytochrome c oxidase subunit I (COI) genes were used for molecular identification and polymerase chain reaction (PCR) to detect the invisible stages of this parasite. Nucleotide sequences of the 18S rRNA of the rockfish nematode showed 98% identity with that of Philometra morii. Therefore, this rockfish nematode was classified to the Philometridae family. However, we could not identify it to genus level using 18S rRNA. Its COI nucleotide sequences shared 85% and 82% identities with those of Bursaphelenchus sinensis and Philometra overstreeti, respectively. In addition, two gene-specific primer sets were designed based on the 18S rRNA gene to detect the intermediate host and nematode larvae. These primers were specific to this rockfish nematode without cross-reacting to other pathogens. The detection limit of the PCR assay using these primers was 1,000 copies of nematoda plasmid DNA. Therefore, the PCR assay described here is suitable for the detection of nematode DNA within rockfish. In addition, this PCR assay could be used to detect nematode larvae and the intermediate host.

• 한국해양바이오학회지
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• 제1권2호
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• pp.119-125
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• 2006

어류의 insulin-like growth factor-I (IGF-I)의 생화학적 작용기작을 연구하기 위하여 한국산 조피볼락의 IGF-I cDNA 유전자 cloning을 행하였다. 완전한 cDNA 유전자 염기서열은 PCR과 RACE 방법을 통하여 얻어진 DNA로부터 결과를 얻을수 있었다. 결정된 IGF-I의 염기서열은 flounder, chinook salmon, human IGF-I의 염기서열과 비교한 결과 각각 93.6%, 90.7%, 85.4%의 높은 상동성을 보였다. 생화학적으로 활성이 있는 재조합 IGF-I을 얻기 위하여 IGF-I의 B-C-A-D domain 부분을 PCR로 얻은 뒤 E. coli BL21(DE3)에 넣어 overexpression 시켰다. Ni-NTA colummn을 사용하여 순수한 재조합 단백질을 정제할수 있었다. 정제된 단백질은 SDS-PAGE 상에서 7 kDa의 단일 band를 보여 주었으며 [$^3H$]-thymidine 결합정도를 측정하는 방법으로 활성을 가지고 있음을 확인할수 있었다.

• 한국수산과학회지
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• 제41권3호
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• pp.221-227
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• 2008

The black rockfish (Sebastes schlegeli) is an important commercial species in Korean fisheries. We used acoustic telemetry using coded ultrasonic transmitters to track the home ranges and homing routes of the black rockfish that inhabit in the Tongyeong marine ranching area. Twenty-four fish were released at five points. The distance from the capture point (C1) to the released point was 0 (R7), 0.2 (R1), 0.9 (R2), 1.3 (R3) and 1.9 (R4) km. Two of the three fish released at R1 (0.2 km) returned home in under 48hrs. Another was found 0.8km from C1. Two of the five fish released at R2 returned home, but it took over 250 days. None of the ten fish released at R3 and R4 returned home. Three of the ten fish moved 1.1-2.6 km from C1 and were found near a cage or a natural reef. Six fish were released at R7. The younger the fish, the wider was its movement range around the artificial reefs. Fish over 3 years old were likely to move less far.

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

• 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.

• 수산해양교육연구
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• 제28권4호
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• pp.1068-1075
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• 2016

The suitable temperature and salinity for the long-distance transportation for the rockfish were investigated by assessing survival rate, metabolism, histological change. All experimental groups showed survival rates of 100%. Daily Oxygen consumption rhythm was decreased during nights and increased during days. Average oxygen consumption was significantly decreased as temperature and salinity were decreased. Ammonia excretion was significantly increased as temperature and salinity were decreased. Histological changes were observed in the skin and gill of the rockfish exposed to 10 psu under all the temperature conditions, with larger changes at $4^{\circ}C$. Further, nucleus deformation and uniformity in the cytoplasm were also observed.