• Fisheries and Aquatic Sciences
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• 제6권2호
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• pp.59-65
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• 2003

The critical thermal maximum (CTM) of black rockfish, Sebastes schlegeli, was evaluated. Black rockfish were acclimated at $24^{\circ}C$, and then exposed to temperatures from 24 to $33^{\circ}C$. Black rockfish were kept in constant darkness and subjected to a gradual temperature increase $(1 ^{\circ}C\;12^{-1})$. The oxygen consumption rate (OCR) was measured using an automatic intermittent­flow-respirometer (AIFR) during the exposure period (from 119.3 to 143.5 h). The OCR increased from 94.5 to 214.2mL $O_2 kg^{-1}\;ww\;h^{-1}$ as the temperature rose from 24 to $29.4-30.9^{\circ}C$. Subsequently, the OCR increased abruptly, reaching 245.8-412.7mL $O_2 kg^{-1}\;ww\;h^{-1}$ at $32^{\circ}C$. This study suggests that the CTM for black rockfish is $29.4-30.9^{\circ}C$ when temperature is increased at $1^{\circ}C\;12h^{-1}$ following acclimation at $24^{\circ}C$.

• Fisheries and Aquatic Sciences
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• 제19권4호
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• pp.20.1-20.12
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• 2016

The osteological development in Sebastes koreanus is described and illustrated on the basis of 32 larvae [6.11-11.10 mm body length (BL)] and a single juvenile (18.60 mm BL) collected from the Yellow Sea. The first-ossified skeletal elements, which are related to feeding, swimming, and respiration, appear in larvae of 6.27 mm BL; these include the jaw bones, palatine, opercular, hyoid arch, and pectoral girdle. All skeletal elements are fully ossified in the juvenile observed in the study. Ossification of the neurocranium started in the frontal, pterotic, and parietal regions at 6.27 mm BL, and then in the parasphenoid and basioccipital regions at 8.17 mm BL. The vertebrae had started to ossify at ~7.17 mm BL, and their ossification was nearly complete at 11.10 mm BL. In the juvenile, although ossification of the pectoral girdle was fully complete, the fusion of the scapula and uppermost radial had not yet occurred. Thus, the scapula and uppermost radial fuse during or after the juvenile stage. The five hypurals in the caudal skeleton were also fused to form three hypural elements. The osteological results are discussed from a functional viewpoint and in terms of the comparative osteological development in related species.

• 한국수산과학회지
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• 제53권2호
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• pp.218-230
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• 2020

The single anatomical attribute that has the greatest influence on acoustic scattering from fish is the presence or absence of a swimbladder. This study examined the effect of removing the gas from the swimbladder on the broadband backscattering characteristics of six species of swimbladdered fish: striped beakperch Oplegnathus fasciatus, black scraper Thamnaconus modestus, dark-banded rockfish Sebastes inermis, goldeye rockfish Sebastes thompsoni, black rockfish Sebastes schlegeli and panther puffer Takifugu pardalis. Before and after removing the gas from the swimbladder, the species-specific, frequency-dependent backscattered echo signals from anaesthetized individuals of each fish species were measured at approximately 1° intervals spanning a 90° aspect angle range from -45° (head down) to +45° (head up) using a broadband echo sounder operating at 100-200 kHz. The relationship between the wavelength-normalized backscattering cross section (σ/λ²) and fish length (L/λ) was calculated for each species. The average σ/λ² value for the six fish species at a L/λ range of 19.79-25.85, with a mean of 22.89, was reduced by approximately 52.3% when the gas was removed.

• 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.

• 한국수산과학회지
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• 제14권3호
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• pp.171-178
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• 1981

1978년 5월에서 1980년 8월까지 알라스카만에사 한국 트룰어선의 어획물중에서 무작위 추출된 651마리의 적어를 사용하여 비늘 판독에 의해 성장을 연구하였다. 비늘에 형성되는 윤문은 눅역지수의 월변화에 의해 $2\sim5$월에 년 1회 형성되는 것으로 추정되었으므로 이윤문을 년윤으로 간주하였다. 표본어소의 윤경을 측정한 결과, 제1윤경을 제외한 전륜경에서 리현상이 확인되었고, 이 원인을 비늘의 수축에 의한 것으로 볼 수 없었으므로 산술평균법으로 리보정을 하여 윤문 형성시의 평균 수경을 추정하였다. 이 윤경으로 인경일체장 관계식을 사용하여 계산체장을 구해 버탈란피의 체장 성장식, $1_t=357.8(1-e^{-0.6124(t+1.8566)})$을 산출하였다. 이 식에 체장체중관계식을 침입하여 극한 체중($W_{\infty}=784.4g$)을 구하였다. 초기성장률 변화설을 검토한 결과, 그 원인이 초기 생활단계에서의 서식처 이동으로 인한 생태적 변화에 있기보다는 직선회귀법에 의한 리현상의 포정에 있을 가능성을 확인하였다.

• 한국수산과학회지
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• 제45권2호
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• pp.97-103
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• 2012

This study compared the composition and texture of muscle and levels of detoxification and antioxidant enzymes in the livers of stocked and cultivated rockfish Sebastes schlegeli released after the primary culture stage in Tongyoung, South Korea. The crude lipid content of muscle was significantly higher ($P$<0.05) in cultivated rockfish than stocked rockfish, while the texture did not differ significantly ($P$>0.05). The condition factor (CF) and hepatosomatic index (HSI) did not differ significantly and the growth of stocked and cultivated rockfish was similar. The levels of the detoxification enzymes cytochrome P450 (CYP) and Ethoxyresorufin-O-deethylase (EROD) were significantly lower in the livers of stocked rockfish, perhaps because of their reduced exposure to xenobiotic compounds. In addition, stocked rockfish had a significantly ($P$<0.05) lower CAT and higher GR than cultivated rockfish, but similar levels of tGPx, SOD, GSH, and GSSG. The present study shows that the growth rates of stocked and cultivated rockfish are similar and that stocked rockfish are exposed to fewer xenobiotic compounds and less oxidative stress.

• 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.

• 수산해양교육연구
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• 제25권6호
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• pp.1315-1323
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• 2013

The purpose of this research is to evaluate the effects of a commercial mixed extruded pellet(EP) and raw fish moist pellet(MP) diet on diseases prevalence and serological constituents and HSI of korean rockfish, Sebastes schlegeli grown in two commercial-scale aquaculture farms from June to December in 2009. The growth of MP-fed rockfish was slightly faster than EP-fed rockfish during experimental period, but did not show significant differences. The levels of TCHO, TG, Glucose and TP in the MP-fed rockfish group were higher than those of EP-fed group, whereas there was no significant difference in other biochemical factors of blood between two groups. In addition, bacteria and virus were not detected in both MP- and EP-fed rockfish groups, and the infection rates of gill fluke between two groups did not show clear difference. In conclusion, there was no comparable difference in growth and the health extents of one year rockfish by administration of the commercial mixed extruded pellet(EP) and raw fish moist pellet(MP) diets.

• 대한수의학회지
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• 제48권3호
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• pp.287-293
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• 2008

The cDNA of the aquabirnavirus, GC-1 isolated from rockfish Sebastes schlegeli in Korea, was synthesized using the reverse transcriptase-polymerase chain reaction. The nucleotide and deduced amino acid sequences were determined from cDNA of the VP2-NS-VP3 coding region of genome segment A. The nucleotide sequences of the segment A were 3,086 base pairs (bp) in length and contained large open reading frame (ORF) and terminal sequences. The large ORF was comprised of 2,916 bp nucleotides and composed of 972 deduced amino acid sequences. Pairwise comparisons were made with other aquabirnavirus sequences published previously. The study of genetic relationships between GC-1 and aquabirnaviruses in the large ORF and VP2 coding regions demonstrated that the GC-1 has the nearest genetic relationship with the marine birnaviruses (MABV strains), and the GC-1 and MABV strains can be clustered as the same genogroup. GC-1 can be included in MABV, which is the 7th genogroup of family Aquabirnaviridae.

• 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.