• Journal of Aquaculture
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• v.17 no.2
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• pp.122-127
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• 2004

On protein equivalence base, fishmeal (FM) was replaced by lysine cell mass (LCM) in selected different diets in Korean rockfish, Sebastes schlegeli (Hilgendorf) Eight experimental diets were formulated to contain 100% FM (LC $M_{0}$), 90% FM+10% LCM (LC $M_{10}$),80% FM+20% LCM (LC $M_{20}$), 70% FM+30% LCM (LC $M_{30}$), 60% FM+40% LCM (LC $M_{40}$ ), 70% FH+30% LCM+lysine (LC $M_{+Lys}$), 60% FM+40% LCM+lysine (LC $M_{40+Lys}$), and 50% FM+50% LCM+lysine (LC $M_{50+Lys}$). Experimental individuals of the fish (12.6 g) were randomly fed on one of the experimental diets. After 6 weeks of feeding trial, weight gain (WG) and feed efficiency (FE) of fish fed LC $M_{0}$ diet was significantly (P〈0.05) higher than those of fish fed LC $M_{20}$, LC $M_{30}$, LC $M_{40}$ , LC $M_{30+Lys}$, LC $M_{40+Lys}$, and LC $M_{50+Lys}$ diets, however, there was no significant difference in WG of fish fed LC $M_{0}$ and LC $M_{10}$ diets. Supplementation of lysine has no effect on WG. There was no significant difference in condition factor (CF) of fish fed LC $M_{0}$, LC $M_{10}$ and LC $M_{20}$ diets. Hemoglobin (Hb) of fish fed LC $M_{0}$, LC $M_{10}$, LC $M_{20}$, LC $M_{30}$, LC $M_{40}$ , LC $M_{30+Lys}$, and LC $M_{40+Lys}$, diets were not significantly different from each other. No significant differences were observed in hematocrit (PCV) and hepatosomatic index (HSI) among all dietary treatments. Apparent digestibility of dry matter (ADM) and protein (ADP) of diets significantly decreased with increase in dietary LCM level, though there was no difference in ADM and ADP between LC $M_{0}$ and LC $M_{10}$. These results indicate that LCM could replace up to 10% of fishmeal in Korean rockfish diets.ish diets.iets.ish diets.s.ish diets.

• Journal of fish pathology
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• v.19 no.2
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• pp.155-164
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• 2006

Tissue distribution and residue depletion of oxytetracycline (OTC) and tetracycline (TC) following dipping administration were evaluated in olive flounder (Paralichthys olivaceus), rockfish (Sebastes schlegeli), and red sea bream (Pagrus major) under field conditions. Fishes were held in floating cages placed in sea water and fed a commercial diet for 15 days to acclimate to a new surrounding. Fishes were dipped in OTC 50 g/ton water for 30min and TC 18 g/ton water for 5 hours. Blood and muscle were sampled from fishes on 0th, 1th, 2th, 3th, and 5th day after administration. After solid-phase extraction, OTC and TC analyses were carried out by HPLC. The recovery rate of OTC in serum and muscle samples was 71-77% and 78-84%, respectively. Also, the recovery rate of TC in serum and muscle samples was 70-79% and 73-78%, respectively. The results of recovery rate were similar to previous studies reported. At the termination of dipping administration of OTC and TC, residue concentration in muscle samples of rockfish was significantly higher than those of olive flounder and red sea bream. At day 5, residue concentrations of all samples were believed to decrease to lower than 0.05 mg/kg, the detection limit. The present study showed that residue concentrations of OTC and TC decreased to below 0.05 mg/kg after treatment 5th day, faster than the established withdrawal period. The tissue reside depletion time of dipping administration of OTC and TC seems to be shorter than those of oral or parenteral administration.

• Journal of Aquaculture
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• v.15 no.3
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• pp.157-163
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• 2002

Thirteen groups, each consisting of 25 juveniles (0.64 g) of the Korean rockfish, Sebastes schlegeli were reared in aquaria after period of one week conditioning. Each group was fed with one of the 13 diets at the rate of 7~10% body weight (on a dry-matter basis) 2 times a day for 6 weeks. Each diet was supplemented with one of the following amino acids at 3g/kg diet: Alanine (Ala), Arginine (Arg), Glycine(Gly), Glutamate (Glu), Histidine (His), Isoleusine(Ile), Lysine (Lys), Methionine (Met), Phenylalanine (Phe), Proline (Pro), Threonine (Thr), Tryptophan (Trp) or Valine (Val). Groups fed with Pro, Thr, Met or Gly-supplemented diet showed significantly (p<0.05) higher weight gain and faster specific growth rate than the groups fed on other diets, while those fed Pro, Thr, Met or Gly were not significantly different each other(P>0.05). Feed efficiency (FE) of fish fed Pro was significantly higher than those fed the other diets except that fed Thr (P<0.05). However, there was no significant difference between FE of fish fed Pro and Thr, and among FE of fish fed Thr, Met and Gly (P>0.05). The requirement of rockfish is higher for Met and Thr. Extra Pro and/or Gly may also stimulate biosynthesis of the nucleic acids (IMP, GMP) which are known as the feed stimulant in fish.

• Journal of Aquaculture
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• v.6 no.2
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• pp.89-105
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• 1993

In order to investigate the effects of dietary n-3 highly unsaturated fatty acids (n-3HUF A) levels on growth and body composition of the Korean rockfish, six experimental diets with various levels of n-3HUFA, which were adjusted by adding squid liver oil and/or soybean oil at $8\%$ dietary lipid level, were fed to the Korean rockfish (6.2g in mean body weight) for 10 weeks. Daily weight gain, feed efficiency and nutrient retention efficiency were the lowest in the fish fed a diet containing 0% n-3HUFA. These parameters were effectively improved by supplementation with n-3HUFA, and showed linear increase up to $1.2\%$ dietary n-3HUFA level (P<0.01). There was no additional response above this level. A higher concentration of nonpolar lipids in the liver was observed for the fish fed insufficient levels of n-3HUFA in the diets. However the liver glycogen content and hepatosomatic index were slightly deareased. The lipid contents of the whole body and vicera showed significantly higher in the fish fed sufficient levels of n-3HUFA in the diets (P<0.05). The fatty acid compositions of polar lipids in the whole body and liver were affected by dietary fatty acid compositions. The contents of n-3HUFA and 18:1 in the liver increased with increasing the n-3HUFA level in the diets, while the 18:2n-6 and 18: 3n-3 decreased. These results suggest that n-3HUFA plays an essential role for normal growth of the Korean rockfish, and the requirement of n-3HUF A is around $1.2\%$ of the diet.

• Journal of fish pathology
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• v.26 no.3
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• pp.173-183
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• 2013

From July to early September 2012, there was mass mortality of fishes, particularly black rockfish, which were being raised in the floating fish cage along the coast of Gyeongsangnam-do. The amount of damage was 1,802,000 fishes and the causes were confirmed to be rapidly rising water temperature and repeated daily changes in water temperature. The water temperature in this area of the sea rose to the maximum $28.4^{\circ}C$ and the daily range of changes in water temperature was maximum $6.5^{\circ}C$. As a result of investigating biological diseases of 194 fishes in 49 fishery areas, major pathogenic organisms such as red seabream iridovirus (RSIV), Vibrio sp. and Vibrio spp. or Microcotyle sp. were detected in rockfish in some fish farms. It is considered that the major causes of the mass mortality were high water temperature accompanied by repeated daily changes in water temperature, it is considered that biological diseases influenced the increase in the perish of fishes.

• Journal of fish pathology
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• v.22 no.2
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• pp.173-177
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• 2009

Lymphocystis disease virus (LCDV) was detected from olive flounder Paralichthys olivaceus, painted glass fish Chanda baculis, gourami Trichogaster leeri and rockfish Sebastes schlegeli, and proteins of the viruses were compared. The major capsid protein (MCP) gene-specific primer sets successfully amplified approximately 1300 bp nucleotides from the olive flounder and 600 bp nucleotides from painted glass fish, gourami and rockfish isolates, respectively. In western blotting analysis using anti-LCDV mouse polyclonal serum, major antigenic proteins had 21, 26, 45, 50, 80, 110 and 120 kDa in olive flounder, 26, 47 and 80 kDa in painted glass fish, 26, 46, 80 and 92 kDa in gourami, 26, 44, 49, 80 and 105 in rockfish, respectively. All the marine and freshwater isolates showed only common antigens of approximately 26 kDa and 80 kDa. These results suggest that antigenic protein profiles of LCDVs may vary depending upon fish species.

• The Journal of Fisheries Business Administration
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• v.45 no.1
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• pp.95-107
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• 2014

This study is aimed to analyze the economic performance of black rockfish aquaculture by standardizing cost structures by region and farming size. The result of survey on farming and sale condition in each region, stocking density, survival rate, juvenile price, and unit production was the highest at Yeosu and Tongyeong, Heuksando showed the lowest. While rearing period was the longest at Tongyeong, the shortest region was Yeosu and Wando. In farming cost structure by region, amount of feeing was the highest at Tongyeong and Yeosu, and the lowest was Heuksando. Cost of medicine was high in Wando and Taean region, Yeosu and Hecksando was low. In case of farm size, feed cost ratio was high in the order of medium(0.75ha), small(0.25ha) and large(1.25ha) size. Standard production cost at every farm size of Heuksando showed the lowest among these regions. Taean and Yeosu was middle, and Tongyeong and Wando was the highest. According to the income, profit rate and investment return of farm size in all regions, as the bigger farm size, the higher income and profit rate was revealed. However, in case of Wando, Taean, and Heuksando which regions has high investment return, medium farm size was higher than large size. The result of economic analysis according to various factors, economic feasibility of black rockfish aquaculture in marine floating cage was showed significant changes by rearing and market condition.

• Journal of fish pathology
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• v.23 no.3
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• pp.323-334
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• 2010

Bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are important components of the mammalian innate defence system against Gram-negative infections. The BPI/LBP cDNA was identified from the black rockfish ConA/PMA or LPS stimulated leukocyte cDNA library. The full-length BR-BPI/LBP cDNA was 2118 bp long and contained an open reading frame (ORF) of 1422 bp that encoded 473 amino-acid residues. The 5' UTR had a length of 57 bp, and the 3' UTR 639 bp. The molecular weight and theoretical isoelectric point (pI) values were calculated 51.4 kDa and 9.72, respectively. Compared with other known BPI or BPI/LBP peptide sequences, the most conserved regions of the black rockfish BPI/LBP peptide were found to be the BPI1 N-terminal, BPI2 C-terminal domains and a LPS binding domain. Phylogenetic analysis based on the deduced amino acid sequence revealed a homologous relationship between the BPI/LBP sequence of black rockfish and that of other teleosts. The black rockfish BPI/LBP gene was predominantly expressed in the PBLs, head kidney, trunk kidney and spleen. The expression of the black rockfish BPI/LBP molecule was induced in the peripheral blood leukocytes (PBLs) from 1 to 24 h following LPS stimulation, with a peak at 12 h post-stimulation.

• Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.118-126
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• 2010

A feeding trial was conducted to investigate the effects of different levels of dietary n-3 highly unsaturated fatty acids (HUFA) (1.1-5.6%) and vitamin E (70 and 400 mg/kg) on the growth and body composition of juvenile rockfish. Six isonitrogenous (45% crude protein) and isolipidic (17% crude lipid) diets were formulated to contain graded levels of n-3 HUFA and vitamin E. Diets 1, 2 and 3 consist of 400 mg vitamin E/kg diet with graded levels of 1.1, 3.0, and 5.6% n-3 HUFA, respectively. Graded levels of n-3 HUFA (1.1, 3.0, and 4.0%) were added in diets 4, 5 and 6, respectively, containing 70 mg vitamin E/kg diet each. At the end of feeding trial, growth performance of rockfish was affected by neither dietary n-3 HUFA nor vitamin E levels. Feed efficiency and hepatosomatic index were slightly decreased (P<0.05) with increment of dietary n-3 HUFA at each dietary vitamin E level. Dietary vitamin E and n-3 HUFA levels did not affect proximate composition and vitamin E concentration in the dorsal muscle of rockfish. Liver moisture and crude protein contents positively related to dietary n-3 HUFA levels. Liver lipid content and hematocrit value were significantly decreased (P<0.05) by increasing dietary n-3 HUFA levels. Eicosapentaenoic acid (20:5n-3; EPA) and docosahexaenoic acid (22:6n-3; DHA) concentrations in the dorsal muscle significantly correlated to dietary n-3 HUFA levels, except for fish fed the diet 6 containing 4% n-3 HUFA and 70 mg vitamin E/kg diet. EPA concentration in the dorsal muscle of fish fed the diet 6 was significantly lower than that of fish fed the diets 2, 3 and 5. The present findings suggest that feeding of diets containing excessive n-3 HUFA level with varying addition of vitamin E may alter fatty acid composition in the dorsal muscle, but do not affect growth of juvenile rockfish.

• Development and Reproduction
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• v.5 no.1
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• pp.39-45
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• 2001

Black rockfish Sebastes schlegeli is one of scopaenid fish giving birth to yolk-sac larvae and distributed around the coast of Korea and Japan, and is one of main species which is cultured in Korea. The difffrentiation of thyroid gland and the changes of thyroid hormones (THs) concentrations in the whole body during early development of this species were examined and the relationship between thyroid gland and their growth will be presented. Total length (TL) and body weight (BW) of the larva at the parturition were 6.3${\pm}$0.1 mm and 3.6${\pm}$0.1 mg, respectively. The larvae transformed to juvenile after 30th day after parturition. According to Hoshiai(1977), they had gown into stage Fl (TL 13.2${\pm}$0.9 mm, BW 46.5${\pm}$1.5 mg) at 50th day. The thyroid gland of black rockfish was first observed histologically in hatching larvae in mother fish. The larvae just after parturition have 1${\sim}$3 of the thyroid follicles diffrentiated between basibranchial bone and ventral aorta, at the base of the first gill arch. In this time, thyroid follic1e number (TFN),thyroid follicle diameter (TFD) and thyroid cell height (TCH) were 1.6${\pm}$0.8 pieces/inds., 18.1${\pm}$0.6 ${\mu}$m and 4.1${\pm}$0.2 ${\mu}$m, respectively. TFN and TFD at 50th day were increased to 32.5${\pm}$6.9 pieces/inds. and 41.5${\pm}$1.7 ${\mu}$m, respectively. These results indicate that they are related to the growth of black rockfish during early development. However, TCH indicates that the activity of thyroid gland appearedat special day, eg. 5, 20 and 50th day, suggesting that TCH may have some role in the physiological activity. L-thyroxine (T$_4$)concentration decreased sharply to 10 days after parturition, and at 25th day (metamorphosis stage) increased markedly to 3.44${\pm}$0.93ng/g fish. After this time, T$_4$ concentration decreased at 35th day, but then increasedagain to the highest concentration, 5.63${\pm}$0.70ng/g fish. 3,5,3'-triiodo-L-thyronine (T$_3$) concentration declined sharply from just after pafurition (4.96${\pm}$1.90 ng/g fish) to 5th day (0.30${\pm}$0.07 ng/g fish). However T$_3$ concentration increased markedly to 0.95${\pm}$0.11 ng/g fish at 30th day and then did not significantly change until 45th day, increased also sharply to 1.67${\pm}$0.23 ng/g fish at 50th day.