• 한국수산과학회지
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• 제43권3호
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• pp.262-269
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• 2010

Seventeen fish species were counted in an underwater visual census, and the most common species, Sebastes inermis and Halichoeres poecilopterus, were released. More than 60% of the released S.inermis occurred near a fish farm 5 days after release, but they moved to a distant rocky area, and decreasing numbers were seen near the farm 90 days after release. In pots, a total of 722 individuals belonging to 43 species occurred, and released S.inermis dominated with 174 individuals recaptured during the study period. The other common fish species were Stephanolepis cirrhifer and Acanthopagrus schlegeli. The percentage of recapture was 0.23%, but declined to 0.12% at 90 days after release. The potential predators of released S.inermis included Lateolabrax japonicus and Sebastes schlegeli.

• 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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• 제6권4호
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• pp.209-212
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• 2003

Lucigenin (Lg)- and luminol (Lm)-dependent chemiluminescence (CL) was used to compare the respiratory burst of rockfish (Sebastes schlegeli) phagocytes after stimulation with phorbol myristate acetate (PMA). To establish which reactive oxygen species (ROS) contributes to the observed CL, the modulators of ROS metabolism, such as superoxide dismutase (SOD), catalase, and sodium azide $(NaN_3)$ were used. Although LgCL responses were inhibited significantly by the addition of either SOD or catalase, in comparison to the control, significantly lower LgCL responses were recorded by SOD than catalase. LmCL also showed significantly decreased responses by the addition of SOD and catalase. However, there were no statistical differences in CL responses between SOD and catalase additions. More profound and significant decrease of LmCL responses were recorded by simultaneous addition of SOD and catalase. Sodium azide markedly enhanced LgCL responses, while it significantly inhibited LmCL responses. These results indicate that LgCL and LmCL can be used to measure extracellular $O_2$ production and myeloperoxidase (MPO)-mediated ROS production in fish phagocytes, respectively. Furthermore, LmCL can be used for analyzing intracellular ROS production by simultaneous addition of both SOD and catalase.

• Asian-Australasian Journal of Animal Sciences
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• 제27권5호
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• pp.690-699
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• 2014

Three feeding trials were conducted to evaluate the effects of feeding rate and water temperature on growth and body composition of juvenile Korean rockfish, Sebastes schlegeli rearing at 3 different water temperatures. A total of 270 fish (each experiment) individual body weight (BW) averaging $16{\pm}0.3g$ ($mean{\pm}SD$) were fed a commercial diet for 4 wk at $16^{\circ}C$, $20^{\circ}C$, and $24^{\circ}C$. At each temperature, triplicate tanks were assigned to one of 6 feeding rates: 1.5%, 2.5%, 2.8%, 3.1%, 3.4%, and satiation (3.7% BW/d) at $16^{\circ}C$, 1.9%, 2.9%, 3.2%, 3.5%, 3.8% and satiation (4.1% BW/d) at $20^{\circ}C$ and 1.7%, 2.7%, 3.0%, 3.3%, 3.6%, and satiation (3.9% BW/d) at $24^{\circ}C$ water temperature. Weight gains of fish in satiation and 3.4% groups at $16^{\circ}C$, in satiation and 3.8% groups at $20^{\circ}C$ and in satiation and 3.6% groups at $24^{\circ}C$ were significantly higher than those of fish in the other treatments (p<0.05). A broken line regression analysis of weight gain indicated that optimum feeding rates of juvenile Korean rockfish were 3.41% at $16^{\circ}C$, 3.75% at $20^{\circ}C$ and 3.34% at $24^{\circ}C$ water temperature. Results of the present study indicate that the optimum feeding rate could be >3.1% but <3.41% at $16^{\circ}C$, >3.5% but <3.75% at $20^{\circ}C$ and >3.0% but <3.34% at $24^{\circ}C$. As we expected results suggest that fish performed better at $20^{\circ}C$ than $16^{\circ}C$ or $24^{\circ}C$ water temperature and the optimum feeding rate could be 3.1% BW/d to 3.7% BW/d in 16 g of juvenile Korean rockfish.

• Asian-Australasian Journal of Animal Sciences
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• 제27권9호
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• pp.1319-1327
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• 2014

Two feeding trials were conducted to determine the optimum feeding frequency in growing Korean rockfish, (Sebastes schlegeli) reared at the temperatures of $15^{\circ}C$ and $19^{\circ}C$. Fish averaging $92.2{\pm}0.7$ g (mean${\pm}$standard deviation [SD]) at $15.0{\pm}0.5^{\circ}C$ and $100.2{\pm}0.4g$ ($mean{\pm}SD$) at $19.0{\pm}0.5^{\circ}C$ water temperature were randomly distributed into each of 15 indoor tanks containing 250-L sea water from a semi-recirculation system. A total of five feeding frequency groups were set up in three replicates as follows: one meal in a day at 08:00 hour, two meals a day at 08:00 and 17:00 hours, three meals a day at 08:00, 14:00, and 20:00 hours, four meals a day at 08:00, 12:00, 16:00, and 20:00 hours, and one meal every 2 days at 08:00 hour. Fish were fed at the rate of 1.2% body weight (BW)/d at $15^{\circ}C$ and 1.5% BW/d at $19^{\circ}C$. At the end of 8 wks of feeding trial weight gain and specific growth rate were significantly higher at the fish fed groups of one meal a day and two meals a day at $15^{\circ}C$ and fish fed groups of 1 meal every 2 days at $19^{\circ}C$ were significantly lower than those of all other fish fed groups. Glutamic oxaloacetic transaminase and glutamic pyruvic transaminase of fish fed group at 1 meal every 2 days was significantly higher than those of all other fish fed groups in both experiments. Weight gain, specific growth rate and condition factor were gradually decreased as the feeding frequency increased. The results indicate that growing Korean rockfish 92 and 100 g perform better at $15^{\circ}C$ than $19^{\circ}C$ water temperature. As we expected, current results have indicated that a feeding frequency of 1 meal a day is optimal for the improvement of weight gain in growing Korean rockfish grown from 92 g to 133 g at $15^{\circ}C$ and 100 g to 132 g at $19^{\circ}C$ water temperature.

• 한국수산과학회지
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• 제46권6호
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• pp.746-752
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• 2013

An 8-week feeding experiment was conducted to evaluate three types of squid Sepia esculenta liver powder (SLP) as a dietary protein source for replacement of fish meal (FM) in the juvenile black rockfish, Sebastes schlegeli. For replacement of FM, six experimental diets were formulated with 5 or 10% of either of three types (A, B, C) of SLP: SLP-$A_5$, SLP-$A_{10}$, SLP-$B_5$, SLP-$B_{10}$, SLP-$C_5$, and SLP-$C_{10}$. One of the control diets contained 100% FM as the protein source, and the other was a commercial diet (Com). Fish with an average body weight of $6.50{\pm}0.03g$ ($mean{\pm}SD$) were allocated randomly in triplicate groups of 50 to aquaria and fed the experimental diets until satiation. The weight gain (WG) and specific growth rate (SGR) of fish fed the FM, SLP-$A_5$, SLP-$A_{10}$, and SLP-$B_5$ diets were higher than those of fish fed the Com, SLP-$B_{10}$, SLP-$C_5$ and SLP-$C_{10}$ diets. No significant differences were observed in WG and SGR among the diet groups, with the exception of the SLP-$C_{10}$ diet group. The feed efficiency (FE) and protein efficiency ratio (PER) of fish fed the SLP-$A_5$, SLP-$A_{10}$, and SLP-$B_5$ diets did not differ from those fed the control diet. However, fish fed SLP-$B_{10}$ and SLP-$C_{10}$ had lower FE and PER than the fish fed the FM, commercial, SLP-$A_5$, SLP-$A_{10}$, and SLP-$B_5$ diets. Both the SLP-A and SLP-B diets, but not the SLP-C diets, replaced up to 10% and 5% of FM for juvenile black rockfish, respectively. The results of this experiment provide information that will assist in formulating an inexpensive and practical diet containing SLP for juvenile black rockfish.

• Molecular & Cellular Toxicology
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• 제2권4호
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• pp.251-256
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• 2006

The exploration of genes which expressions are changed by exposure to ecotoxicants or pollutants can provide the important information about the reaction mechanisms in the body as well as adaptation to exterior stimulus or environmental changes. Also they can be developed as biomarkers for the detection of environmental pollution. Differential display polymerase chain reaction (DD-PCR) technique has been usefully used to hunt the clones which expressions are up-regulated or down-regulated by exterior changes and this study aimed to search for those clones in diesel oil-exposed rockfish (Sebastes schlegeli) using DD-PCR. The RNA isolated from liver of 20 ppb diesel oil-exposed rockfish was used for screening of the differentially displayed genes and total 44 differentially expressed genes (DEG) are detected then their nucleotide sequences were analyzed. The present data provided the general information about the effect of diesel oil contamination on marine organism and further more the primary step in development of new biomarkers for marine environmental pollution or ecotoxicological stresses.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2000년도 춘계수산관련학회 공동학술대회발표요지집
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• pp.233-234
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• 2000

Formalin, 37% formaldehyde, has been employed as a chemical for controlling ectoparasites and aquatic fungi responsible for infectious fish of diseases in hatcheries and culture facilities (Roberts, 1978; Schnick, 1991; Rach et al., 1997). Regarding the commercial usage of formaldehyde in the aquaculture industry, the U.S. Food and Drug Administration (FDA) approved three commercial products as parasiticides in a species-specific manner: Paracide-F and Formalin-F for bluegill, catfish, largemouth bass, salmon, and trout and Parasite-S for all finfish (FDA, 1998). Withdrawal time for these products was legally zero when used as permitted under the regulations. With the increased production of cultured fish in Korea, such as olive Hounder Paralichthys olivaceus and black rockfish Sebastes schlegeli, application of formalin to diseased fish has become more frequent. Moreover, there is still some concern about environmental exposures caused by effluents from fish culture facilities. The purpose of the present study was to evaluate residues in fish resulting from therapeutic usage of formalin in the aquaculture industry and to document the rate of disappearance of formaldehyde in seawater treated with formalin. (omitted)

• 한국양식학회지
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• 제18권2호
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• pp.92-97
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• 2005

This study examined the partial replacement of the fish meal with meat meal in practical diets for juvenile rock-fish. Five isonitrogenous (48% CP) diets were prepared to contain meat meal at 0% (control), 10%, 20%, 30% and 40% with substituting the mackerel meal in the control diet. Three replicate groups of fish (initial average weight, 4.1g) were hand-fed to visual satiety two times daily for 8 weeks. Survival (>93%) and daily feed intake were not significantly different (P>0.05) among treatments. The best weight gain, feed efficiency and protein efficiency ratio were obtained from fish fed the diets containing 0% and 10% meat meal, and were not significantly different (P>0.05) to those of fish 134 diet containing 20% meat meal. Condition factor, visceralsomatic index and hepatosomatic index were not influenced by dietary meat meal levels. The contents of crude protein and ash of whole body were not significantly affected (P>0.05) by dietary meat meal levels, whereas crude lipid content of fish fed the diets containing 30% and 40% was lower than that of fish fed the control diet. Proximate composition of liver was not influenced by dietary meat meal level (P>0.05). The data obtained in this study indicate that a diet containing $10{\sim}20%$ meat meal could be used for least-cost formulation in juvenile rockfish diet.

• 한국어병학회지
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• 제21권2호
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• pp.129-137
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• 2008

We constructed a black rockfish (Sebastes schlegeli) leukocyte cDNA library and a total of 386 expressed sequence tag (EST) clones were generated. Gene annotation procedures and homology searches of the sequenced ESTs were locally done by BLASTX for amino acid similarity comparisons. Of the 386 EST clones, 199 different ESTs showed significant homology to previously described genes while 97 ESTs were unidentified, hypothetical, or unnamed proteins. Encoding 38 different sequences were identified as putative bio-defense genes or genes associated with immune response.