• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.50-55
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• 1999

The proximate composition, mineral content, fatty acid composition, ATP related compounds, amino acid composition, color and texture were investigated with dorsal and ventral muscle from olive flounder, spotted flounder and hybrid (olive flounder m $\times$spotted flounder f). Spotted flounder and hybrid were higher in moisture content, and lower in crude protein content than those of olive flounder, Potassium content in hybrid was higher than that in olive flounder and spotted flounder. Hybrid was lower in calcium, iron, manganese content, and higher in magnesium content than olive flounder and spotted flounder. The contents of saturated fatty acid, unsaturated fatty acid and docosahexaenoic acid (DHA) in hybrid were intermediate level of spotted flounder and olive flounder. Fatty acid composition of dorsal muscle was slightly similar to ventral muscle. Adenosine triphosphate (ATP) and its related compounds contents and amino acid content in hybrid were intermediate level of spotted flounder and olive flounder, and these compounds of dorsal muscle were slightly similar to those of counterpart. The major amino acids such as aspartic acid, glutamic acid, leucine and Iysine were very similar to all the samples. Total amino acid and essential amino acid contents in dorsal muscle were slightly higher than those in ventral muscle. Free amino acid content and composition in hybrid were similar to spotted flounder, and free amino acid content in dorsal muscle was higher than in ventral muscle, The lightness of hybrid and spotted flounder was stronger than that of olive flounder, and was stronger in dorsal muscle. The breaking strength of hybrid was slightly lower than that of spotted flounder, and was stronger in dorsal muscle.

• Fisheries and Aquatic Sciences
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• v.4 no.2
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• pp.70-74
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• 2001

To examine the production of steroids with potential oocyte maturation-inducing activity in the spotted flounder, Verasper variegatus, we have incubated post-vitellogenic oocytes (0.82­0.95mm in diameters) with radiolabeled pregnenolone and $17\alpha-hydroxyprogesterone$. The resulting metabolites were analyzed by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). The two main metabolites (progestogens) found in both incubations co-migrated with $17\alpha-hydroxy$, $20\alpha-dihydroprogesterone$ $(17\alpha, 20\alpha OHP)$ and $17\alpha-hydroxy,\;$20\beta-dihydroprogesterone$ (17 a20{30HP). Additional chromatography by HPLC and TLC confirmed the presence of radioactive $17\alpha, 20\alpha OHP$ and a large amount of unknown metabolite. The present study did not reveal in vitro formation of $l7\alpha 20\beta OHP$. Although 1$l7\alpha 20\beta OHP$ was found in a small amount, the synthesis of this steroid suggests that it may play a role in regulating the oocyte maturation process in the spotted flounder.

• Journal of Aquaculture
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• v.8 no.1
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• pp.69-76
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• 1995

Hybrid fish were induced between olive flounder (Paralichthys olivaceus) female and spotted flounder (Verasper variegatus) male by artificial inseminations. Survival, growth and morphological changes in larval stage of hybirds were examined and compared to their parental species. Survival and growth up to 25 days after hatching of the hybrids were more similar to those of olive flounder than to those of spotted flounder (P<0.05). The ratio of yolk length to yolk width in hybrids was similar to that of female parents (P<0.05). The oil globule were resorbed within 18 days after hatching in hybrids and 14 days after hatching in olive flounder, and spotted flounder has no oil globule. These results indicated that survival, growth and morphological changes in larval stage of hybrids were similar to those of maternal olive flounder.

• Journal of Aquaculture
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• v.6 no.3
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• pp.221-233
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• 1993

Cell size, DNA content, chromosome and PCR-based mitochondrial 12S rRNA gene analyses were conducted to obtain basic informations for genetic stock identification of spotted flounder (Verasper variegatus) from Yeocheun, Korea. The mean erythrocytic and nuclear volumes of spotted flounder were $211.10{\mu}m^3$ and $23.03{\mu}m^3$, respectively. The haploid DNA content of this species was 0.79 pg/cell which correspond to $46.5\%$ of carp and to $22.6\%$ of mammals. Spotted flounder had the 2n = 46 acrocentric chromosomes but no heteromorphic sex chromosomes was found. Mitochondrial DNA gene for 12S ribosomal RNA was amplified by polymerase chain reaction (PCR) and the PCR products were subjected to digestion with 15 restriction endonucleases. Restriction enzyme analyses revealed that Ava I, Mae II, Sma I and Xba I had one restriction site in the mitochondrial 12S rRNA gene segment of spotted flounder, while Mae I had two. Segments of 12S rRNA gene from mitochondria in spotted flounder were sequenced and compared with channel catfish and human as controls. The 12S rRNA gene of this species was more similar to that of channel catfish than to human's.

• Journal of Aquaculture
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• v.10 no.2
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• pp.179-187
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• 1997

Early development growth and sexual phenomena of the hybrid between male spotted flounder (Verasper variegatus) and female olive flounder (Paralichthys olivaceus) were investigated. The hybrid produced was newly called the "Bumnupchi" in Korean name, "Mottled flounder" in English name. Fertilization rate, hatching rate and early survival rate of the mottled flounder were 56.9~72.3%, 86.7~92.5% and 89.1~96.0%, respectively. At 50th day and 240th day after hatching, they were 2.1$\pm0.2cm\;and\;22.9\pm2.1cm\;in\;total\;length, \;0.10\pm0.002g\;and\;179.0\pm38.5g$ in body weight, respectively. Eye position of the mottled flounder was mixed with both dextral (77.7%) and sinistral type (22.3%). Gonads were differentiated into ovarian type and testis type at 80th day after hatching, and its ratio was 1:1 (P>0.05). Most Gonads seemed to be sterile without having germ cell, whereas only 3.6% of investigated indiciduals turned out to have oocytes in the gonad. When the induction of sex reversal were attempted by daily oral administration of $17\beta$-methyltestosterone (0.5mg/kg fish) andestradiol-17$17\beta$(0.5mg/kg fish)from 40th to 100th day after hatching, both testis and ovary type were induced 81.9% and 87.7% of each hormone-treated fish, respectively.fish, respectively.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.338.2-339
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• 1998

• Fisheries and Aquatic Sciences
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• v.6 no.4
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• pp.180-186
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• 2003

The full-length cDNA encoding the pre-protein growth hormone (sfGH) from spotted flounder (Verasper variegatus) was amplified by the rapid amplification of cDNA ends (RACE) using degenerated oligonucleotide primers derived from conserved growth hormone sequences. It consists of 901 nucleotides in length, including the coding region of 609 nucleotides, 111 nucleotides of a 5' untranslated region, and 181 nucleotides of a 3' untranslated region. The conserved polyadenylation signal (AATAAA) lies 12 bases upstream from the poly (A) tail. The deduced amino acid sequence shows an open reading frame encoding a pre-protein of 203 amino acids and a putative signal peptide of 17 amino acids, suggesting that the mature hormone consists of 186 amino acids. The analyses of sfGH reveal some unique structural features. The repetitive sequences are located in the 5' untranslated region of sfGH cDNA and consist of tandem arrays of imperfect direct repeat monomers. Moreover, sfGH contains six Cys residues, as opposed to four or five in other GHs, and it is clearly distinguishable from olive flounder (Paralichthys olivaceus) GH, which lacks a region corresponding to residues 175-188 in alignment positions. It has important implications from an evolutionary standpoint, suggesting possible divergence among flatfishes.

• Environmental Analysis Health and Toxicology
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• v.22 no.1 s.56
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• pp.19-26
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• 2007

Accumulation of tributyltin (TBT) in serum, liver and muscle of olive flounder (Paralichtys olivaceus) was investigated in a 60-d static renewal exposure at $0.1{\mu}g$ TBT/L. Tributyltin accumulated rapidly from 83 ng Sn/g to 2,227 ng Sn/g on a wet weight basis in the serum of the olive flounder and to a greater extent than in the other tissues. The accumulated TBT concentrations in tissues were in the order of serum>liver>muscle on wet or dry-weight basis. High concentrations of dibutyltin (DBT: 990 ng Sn/g dry wt) and monobutyltin (MBT: 141 ng Sn/g dry wt), degradation products of TBT were found in liver of olive flounder at the end of exposure. On the other hand, DBT and MBT was below the detection limits in muscle during the exposure, and only low concentration of DBT (56 ng Sn/g) were detectefd in serum. Butyltin compounds were also quantitatively determined in feral fine-spotted flounder (Pleuronichthys cornutus) collected from Gwangyang Bay as one of polluted area and Sori Island as a reference site. All three butyltin compounds were detected from the fine-spotted flounder from Gwangyang Bay up to 3,107 ng Sn/g of total butyltins in liver, while 120 ng Sn/g of total butyltin concentration was found in the liver of fish from Sori Island.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.3
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• pp.473-479
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• 1997

The yolk protein of spotted flounder, Verasper variegatus was purified by precipitation wit cold distilled water, followed by Sepharose CL-6B column chromatography. The purified protein was identified as vitellin by Ouchterlony's immunodiffusion test and immunoelectrophoresis. The purified vitellin from ovarian crude extracts has same antigenic determinants with the female specific serum protein, vitellogenin. The molecular weight of purified vitellin was estimated about 550 kD by gel filfration. The vitellin was composed of three major subunits with molecular weight of about 108, 85 and 31 kD, and two minor subunits. The vitellin was identified by western blot analysis using anti-vitellin antibody.

• Korean Journal of Ichthyology
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• v.10 no.2
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• pp.191-199
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• 1998

The ovary of the spotted flounder Verasper variegatus is a conical bag in shape and is bilateral structure develops lengthily from the posterior of the abdomen to the end of the anal fin. The testis also is bilateral in structure, usually located in small size in the abdomen. In females, the gonadosomatic index (GSI) showed very low from March to July, and then began to increase from August, thereafter reached the maximum in January through out the year. In males, the GSI reached the maximum (1.7) in January through out the year, as seen in females. Compared with the male GSI in other fishes, the maximum GSI of this species were very lower than those of other fishes. According to the distributions of egg diameter in the spawning season, it is assumed that the spotted flounder spawn four times or more in the spawning season. The total length of female and male reached 50% first sexual maturity were 42.0~44.0 and 28.0~30.0cm, respectively and total length of female and male reached 100% maturity were 44.0 and 32.0cm, respectively. The reproductive cycle could be classified into four successive developmental stages: growing stage (August~October), mature stage (November~December), ripe and spent stage (December~February), degenerative and resting stage (March~July).