• Environmental Analysis Health and Toxicology
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• 제17권1호
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• pp.13-19
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• 2002

Effects of Formalin treatment on embryogenesis and larvae growing in fertilized eggs and hatched larvae of olive flounder, Paralichthys alivaceus were investigated. Fertilized eggs and hatched larvae were exposed to aqueous solution with 100, 200, 400, 800 and 1,000 ppm of nominal formalin concentration. They were kept in sea water of 16, 18 and 22$^{\circ}C$, respectively. Survival rate and hatchability of fertilized eggs were high in control groups more than formalin treated groups in 16, 18 and 22$^{\circ}C$, respectively (P<0.05). A similar effect that survival rate of hatched larvae was also observed for control and treatment groups. On the other hand, fertilized eggs treated with 400 ppm formalin, were all death in kept in 22$^{\circ}C$. These results suggest that high-dose of formalin in fertilized eggs and hatched larvae in olive flounder, Paralichthys olivaceus was inhibited the normal embryogenesis for fertilized eggs and growing for hatched larvae. Also, these inhibited effects was promoted in higher temperature.

• Environmental Analysis Health and Toxicology
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• 제17권1호
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• pp.1-6
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• 2002

Effects on nonylphenol (NP) treatment on early development of fertilized eggs and survival of larvae in olive flounder, Paralichthys olivaceus were investigated. Fertilized eggs and hatched larvae were exposed to aqueous solutions of NP at nominal concentrations of 50, 100, 150 and 200 $\mu\textrm{g}$/L. In the control I and II (methanol-carrier control) groups, the hatchability of fertilized eggs were 90.7$\pm$7.02 and 90.0$\pm$5.29％ (P <0.05), respectively. However, treatments of NP concentrations at 50, 100, 150 and 200 ug/L were reduced to 78.7$\pm$4.16, 46.0$\pm$9.17, 48.0$\pm$3.46 and 33.3$\pm$11.02% (P<0.05), respectively. The time to hatching of fertilized eggs was delayed in high-dose NP treatment groups rather than control groups. Fertilized eggs of NP immersed group could not hatch normally, and also vertebra of the larvae observed as abnormal shape. Cumulative mortality of hatched larvae after 26hr NP treatment was 38.3, 78.3, 88.3 and 100% in NP 50, 100, 150 and 200 ug/L treatment groups, respectively. Whereas, control I and II were 11.7, 16.7% (P<0.05). Hatched larvae showed most death at the embryonic development stage with abnormalities. These results suggest that NP treatment in fertilized eggs and larvae was inhibited as normally development for fertilized egg and growing of larvae.

• 수산해양교육연구
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• 제28권6호
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• pp.1828-1833
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• 2016

The purpose of this research was to investigate the bacterial flora of healthy olive flounder larvae (Paralichthys olivaceus) and live feeds (Rotifer spp. and Artemia spp.). The total bacteria counts were $9.2{\times}10^7$ and $1.2{\times}10^{10}cfu/g$ and Vibrio sp.(82.8%) was dominant in rotifers. The total bacteria counts were $3.8{\times}10^6$ and $9.2{\times}10^6cfu/g$ and Vibrio sp.(73.3%) was dominant in artemia. In olive flounder larvae, the total bacteria counts were $1.4{\times}10^6{\sim}8.3{\times}10^7cfu/g$ and V. harveyi (38.5%) was dominant. It might be potential marker of disease outbreak in olive flounder larvae.

• Fisheries and Aquatic Sciences
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• 제8권4호
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• pp.228-234
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• 2005

Despite the relatively high production of fingerlings of the olive flounder Paralichthys olivaceus, its larval rearing in terms of first feeding has not been fully analyzed. We evaluated the variations of amino acids and fatty acids of starved larvae over 96 hr after hatching. We also investigated depletion of the yolk and oil globule of starved larvae and those fed the rotifer Brachionus plicatilis. In addition, the optimum size of the rotifers according to the mouth size of the larvae, and the point of no return with delay of the first feeding, were also examined. The amino acids in the egg decreased abruptly during embryo development. At 48 to 72 hr after hatching, the amino acids of starved larvae decreased by $30-40\%$ from the level in newly hatched larvae. The concentrations of fatty acids in newly hatched larvae were lower than those of floating eggs and dropped sharply at 48 hr after hatching, when the yolk disappeared. The starved larvae depleted their yolksacs and oil globules earlier than the fed larvae did. At 84 hr after hatching, rotifers were detected for the first time in the guts of the larvae, which were about 3 mm in total length. The point of no return appeared to be close to the fourth day from the first feeding. For a high survival rate of P. olivaceus larvae, the first feeding should occur before the third day after hatching.

• 한국수산과학회지
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• 제48권5호
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• pp.696-703
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• 2015

We investigated the characteristics of embryonic and abnormal organ development in haploid olive flounder, Paralichthys olivaceus, by comparing egg development and histological sections in haploid and diploid individuals. After the mid-blastula transition, abnormal development was observed in haploid fish, including delayed epiboly and malformation of the germ ring and embryonic body. In haploid flounder, Kupffer’s vesicles are irregularly shaped and of variable size compared to diploids. The embryonic body of haploids was shorter and broader than that of diploids and the tail length and size were variable. Most haploid embryos failed to hatch and the few larvae that did, did not survive for more than 6 h. The histological analysis of haploid larvae revealed deformed development in diverse organs, including the eye, otic vesicles, notochord, and neural tube. These results may be related to an abnormality in the axial system of haploid larvae. This study confirmed that the abnormalities of haploid olive flounder were similar to the reported characteristics of haploid syndrome. The abnormalities are caused by delayed epiboly and involution and deformity of Kupffer’s vesicle during egg development.

• Fisheries and Aquatic Sciences
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• 제16권4호
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• pp.253-260
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• 2013

We investigated the toxicological effects of Aroclor 1254 on the fertilized eggs, embryos and larvae of the olive flounder Paralichthys olivaceus. The survival rate and hatching success of the embryos decreased significantly in treated groups in an Aroclor 1254-dose-dependent manner. Significant differences were found at ${\geq}5{\mu}g/L$ Aroclor 1254 compared to the control group. Hatching success occurred at ${{\leq}}10{\mu}g/L$ Aroclor 1254, which was not significantly different to the control. Embryo malformation increased significantly at ${\geq}1{\mu}g/L$, and included yolk-sac and tail-flexure abnormalities. There was a significant decrease in the survival rate of the larvae at ${\geq}5{\mu}g/L$, which was accompanied by the malformations described above. Notably, concentrations as low as $1{\mu}g/L$ caused a significant increase in abnormalities in the larvae, including incidences of multi-focal hemorrhages, pericardial and yolk-sac edema, inhibition of swim bladder inflation and severe developmental delay. The responses to Aroclor 1254-induced toxicity were generally similar among fertilized eggs, embryos and larvae from three separate flounder hatcheries: Cheju Island, Yeosu and Chungnam, South Korea. These results indicate the high acute toxicity of Arolcor 1254 concentrations of which as low as $1{\mu}g/L$ in olive flounder larvae can affect unhatched embryos. To conclude, the average $LC_{50}$ values for Aroclor 1254 in the embryos and larvae were 50.92 and $3.08{\mu}g/L$, respectively. Additionally, the average $EC_{50}$ values, based on the rate of damage were 14.72 and 5.6$1{\mu}g/L$, respectively.

• 한국어병학회지
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• 제26권1호
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• pp.11-17
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• 2013

The cadmium (Cd) toxicological effects on the fertilized eggs, embryos and larvae were investigated in olive flounder, Paralichthys olivaceus water-borne exposed to Cd. The survival rate and hatching success of the embryos significantly diminished in treated groups in dependence of the Cd concentration. Significant differences were found at ${\geq}30{\mu}g\;L^{-1}$ exposed groups compared to the control group. A significant increase of malformation of the embryo was observed at ${\geq}20{\mu}g\;L^{-1}$ exposed groups. They usually include such symptoms as clouded yolk-sac abnormality, fin erosion and spinal curvature. A significant reduction in the survival rate of the larvae was observed in ${\geq}20{\mu}g\;L^{-1}$ exposed groups with accompanied by the disorder. Notably, in larvae, a concentration as low as $10{\mu}g\;L^{-1}$ exposed groups caused significant elevated abnormalities that is incidences of spinal cord deformation, abnormal eyes, deformation of the head region and severe developmental delay.

• 한국어병학회지
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• 제20권3호
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• pp.257-267
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• 2007

The hypo-salinity effects on fertilized eggs, embryos and larvae were investigated in olive flounder (Paralichthys olivaceus) obtained from hatcheries in Cheju-Island, Yeosu and Chungnam. Those were treated to eight concentration; 0, 3.4, 6.7, 10.1, 13.4, 20.2, 27.4 and 33.6 ‰. It was not discrepancy in the survival rate and hatching success rate of fertilized embryos obtained from different regions. Also, in the larvae, the regional difference was not appeared. The survival rate and hatching ability of embryos significantly diminished in the lower groups than 13.4 ‰ compared to 33.6 ‰. After fertilization, namely embryos are tolerant of a wide range of salinity (13.4 - 33.6 ‰). Reduced salinity induced an increase of the malformed embryo and larvae including various deformities; irregular embryos membrane (or yolk sac depression), fin erosion and swim bladder inflation in the flounder embryo. The hatching success of embryos was significantly reduced in lower salinity than 13.4 ‰. Notably, the reduction of larval survival rate significantly was observed in ≤10.1 ‰ treated groups with the same manner of survival rates of the embryos. Additionally, olive flounder was found to be adequate model for measuring external impulses because there are no the regional differences.

• Fisheries and Aquatic Sciences
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• 제16권2호
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• pp.125-129
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• 2013

Vibrio ichthyoenteri is a facultatively anaerobic gram-negative bacterium with straight or slightly curved rod morphology. The bacterium is an etiological agent of bacterial enteritis of Olive flounder Paralichthys olivaceus. Only a handful of studies, using a limited number of isolates, have investigated the phenotypic and genetic characteristics of V. ichthyoenteri. We isolated 40 V. ichthyoenteri strains, identified based on the 16S rRNA gene sequence, from the diseased flounder larvae and investigated the API 20E and ZYM profiles. The isolates exhibited highly divergent phenotypic characteristics regardless of sampling time point and location, and fish age. Essential enzymes produced by V. ichthyoenteri seemed to be alkaline phosphatase, leucine arylamidase, and N-acetyl-${\beta}$-glucosaminidase. This study reveals a much greater enzymatic and biochemical phenotype diversity than has been evident to date. These results suggest that a given population of V. ichthyoenteri could be heterogeneous in terms of its phenotypic characteristics.

• 한국양식학회지
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• 제21권3호
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• pp.125-132
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• 2008

Seed production of olive flounder Paralichthys olivaceus was performed in a pilot RAS. The growth of juvenile olive flounder and changes in water quality were monitored for the entire production period. The pilot RAS consisted of 8 circular culture tanks($4.0mD{\times}1.0mH$), 2 trickling biofilters($1.7mD{\times}2.0mH$), 2 protein skimmers ($0.8mD{\times}2.5mH$), and 4 sedimentation chambers($0.7mD{\times}1.5mH$). The culture surface area was about $100.5m^2$ and the actual working volume was about $106.9m^3$. As many as 300,000 fertilized olive flounder eggs were initially distributed into 2 culture tanks with the water temperature at $19.0^{\circ}C$. Live feeds such as rotifers and Artemia nauplii were fed until the 32nd day after hatching, and a commercial diet was fed from the 19th day to the end of the experiment. After 70 days, 150,256 juveniles with a body length of $65.8{\pm}3.9mm$ were produced in the RAS, with a daily growth rate for body length of 4.7%/day. At this time, the final culture density was 1,495 individuals $m^{-2}$, and 13.6 L of makeup water, 0.071 kW of electricity and 0.025 L of diesel fuel were used to produce a juvenile olive flounder. During metamorphosis of the larvae, the TAN concentration increased to 0.99 mg/L, which made the larvae sensitive to result in some mortality. However no more massive mortality occurred at the juvenile stage after metamorphosis even at a TAN concentration of 4.25 mg/L and a ${NO_2}^{-}-N$ concentration of 2.45 mg/L.