• Journal of Aquaculture
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• v.7 no.2
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• pp.109-122
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• 1994

The cultured olive flounder larvae given nutrient enriched rotifer, Artemia nauplii and commertial micro diet were investigated the changes of lipid content, fatty acid composition and vitamin E content in whole body with growth stages in order to compare with those of the wild one. The results obtained are as follows. 1) Lipid and vitamin E contents of the cultured larvae were higher than those of the wild one. 2) Clear differences of fatty acid composition with growth stages, especially 18: 2n-6 and 22 : 6n-3, were recognized between the wild and cultured olive flounder larvae. 3) Changes of lipid content, fatty acid composition and vitamin E content were found to be affected by dietary composition given to fish. 4) The wild olive flounder larvae were found to obtain natural live foods containing of low lipid content and high concentration 22: 6n-3 based on the fatty acid composition of the fish.

• Journal of Aquaculture
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• v.1 no.1
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• pp.1-11
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• 1988

There are many problems to be solved for the establishment of more feasible and simplified method of seed production of marine fishes. One of the most important tasks in seed production is to clarify the feeding ecology of larvae and juveniles under. rearing conditions. In the present study, two groups of postlarvae-juveniles of the flounder, Paralichthys olivaceus were used. One ranging 11.38 to 17.08 mm in mean total length was fed with Artemia nauplii at two different water temperatures (19 to $21^{\circ}C$ and 24 to $25^{\circ}C$) and the other ranging 4.39 to 10.64 cm in mean total length was fed with prepared diet. Time required from the start of feeding to satiation was 45 to 55 minutes at 24 to $25^{\circ}C$ and nearly one hour at 19 to $21^{\circ}C$. Mean numbers of Artemia nauplii in digestive tract were 236 to 375 individuals per fish at 24 to $25^{\circ}C$. The amount of food remained in the intestine was $24.8\%$ of the total food in the digestive tract. In juveniles of 4.39 to 10.64 cm in mean total length, amount of prepared diet consumed at satiation was 0.04 to 0.46 g per fish. Digestive tract index in juveniles was rapidly decreased for 24 hours after satiation and kept nearly constant after 48 hours, showing that the time to completely digest the prepared diet in juveniles was estimated to be about 48 hours.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.2
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• pp.140-146
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• 2008

Marine ecotoxicological standard method using fish larvae was established with the standard test species of Oryzias latipes(Japanese Medaka) and Paralichthys olivaceus(flounder) and with the 7 day $LC_{50}$ as endpoint. Test method referred to the USEPA(1994) with the replacement of test species found in the Korean water. Standard test species were selected in terms of the species supply and ecological importance in Korean waters. Japanese medaka can be reared with small tanks in the lab and has wide tolerance on salinity, and flounder eggs can be easily obtained from commercial fish hatcheries. General conditions for larval fish toxicity test are as follows. The possible salinity ranges for toxicity test were $0{\sim}35\;psu$ for medaka and >20 psu for flounder. Test type was designated as static non-renewal test if the dissolved oxygen in the test chamber does not fall below 4.0 mg/L. Ages of test species were selected as 7 days after hatched for medaka(about 5 mm TL) and 25 days for flounder(about 10 mm TL) because of the low natural mortality after these periods. Test can be accepted when the survival rates are over 80% in control. Also, species sensitivity on standard reference materials(copper, cadmium or zinc) must be provided with the toxicity test results.

• Journal of Aquaculture
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• v.22 no.1
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• pp.105-111
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• 2009

In this study, we carried out an experiment for estimation the larval digestibility in aspects which digestive enzymatic activities and nutrition of the rotifers, Brachionus rotundiformis. Thus we enhanced the digestive enzymatic activity through the addition of starch for the increase of digestibility of rotifer (starch-rotifer), and compared with the feed efficiency through rearing of the olive flounder, Paralichthys olivaceus used rotifer lipid-enriched with Algamac $2000^{(R)}$ (CE-rotifer). The digestive enzyme activities (except for TG-lipase), total protein contents, total essential amino acid, essential amino acids (methionin and phenylalanine) of starch-rotifer (the rotifer used a starch as additive, and enriched not) was assayed significantly higher than CE-rotifer (P<0.05). And total lipid, lipid classes (except for sterol) and fatty acids as DHA and EPA showed higher in CE-rotifer than starch-rotifer (P<0.05). But, sterol contents and ST/TG ratio were shown significantly higher in starch-rotifer (P<0.05). The flounder larvae supplied the two rotifers showed standard length and body weight that not significantly differed with ranges $3.72{\sim}3.79\;mm$ and $32.9{\sim}37.8\;mg$/larva on 6 days after hatching (DAH), respectively (P>0.05). However, these of 12 DAH showed the values of significantly higher to $5.94{\pm}0.249\;mm$, $144.0{\pm}23.86\;mg$/larva and $26.2{\pm}12.13%$ in standard length, body weight and survival in CE-flounder than that of starch-flounder (P<0.05). The hydrolytic enzymatic activities of flounder larvae severally supplied the two rotifers showed the significantly higher activities in acidic -amylase, neutral -amylase, TG-lipase, lysozyme and acidic phosphatase in starch-flounder on 5 DAH (P<0.05). But neutral $\alpha$-amylase, three proteases and two phosphatases of CE-flounder on 11 DAH showed the significantly higher activities than that of starch-flounder (P<0.05). Therefore, for the flounder, Paralichthys olivaceus larvae just depleted yolk was more beneficial to supply the feed, rotifer, enhanced the digestibility than to supply the feed lipid-enriched for aspect of larval digestibility up to 6 DAH, thereafter nutrition of absorption due to the development of digestive organs suggested that enrichment effect appeared with larval somatic growth. Consequently, investigation more detailed about the larval digestive physiological and nutritional requirement variations after 6 DAH will be necessary, thereafter.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.93-97
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• 2000

This study was carried out to investigate the effect of rotifer fed the different diets in high density culture on larval flounder Paralichthys olivaceus. Potifer was enriched with enrichment supplements, Marine ${\alpha}\;and\;{\omega}-yeast$ for 6 hours after being cultured with freshwater Chlorella for 18 hours during high density culture before it was fed to larval flounder. And rotifer was culutured with marine Chlorella and freshwater Chlorella for 24 hours during semi-continuous high density culture before it was fed to larval flounder. Culture tanks(21 working volum) set for rotifer culture in a water bath($28{\circ}C$) were continuously supplied with oxygen gas. The content of n-3 HUFA to fatty acids in rotifer(dry weight ${\%}$) enriched with Marine ${\alpha}$ for 6 hours and cultures with marine Chlorella for 24 hours were higher than that in rotifer enriched with ${\omega}-yeast$ for 6 hours or cultured with freshwater Chlorella for 24 hours. The growth and survival rates of larval flounder fed on rotifer enriched with Marine ${\alpha}$ for 6 hours and cultured with marine Chlorella for 24 hours were higher than those of larval flounder fed on rotifer enriched with ${\omega}-yeast$ for 6 hours or cultured with freshwater Chlorella for 24 hours. And the content of n-3 HUFA of larval flounder fed on rotifer enriched with Marine ${\alpha}$ for 6 hours was higher than that of larval flounder fed on other rotifers, The results from this study indicated that rotifer culture with marine Chiorelia would be suitable for the high density culture and effective diet for the growth of larval flounder.

• Journal of fish pathology
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• v.24 no.2
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• pp.95-102
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• 2011

Normalized resistance interpretation (NRI) analysis for tetracycline was applied to generate information on the epidemiological cut-off value for Vibrio ichthyoenteri isolated from diseased olive flounder (Paralichthys olivaceus) larvae. Thus, 42 strains of V. ichthyoenteri were used to determine minimum inhibitory concentration (MIC) values of tetracycline using Etest. Also, 11 tetracycline resistance related genes were investigated by PCR method. Most tetracycline-resistant strains harbored both tetB and tetM with a few exceptions. NRI-derived mean and 2 SD above the mean of theoretical normal distributions of susceptible isolates were 0.33 mg/L and 1.66 mg/L, respectively. The epidemiological cut-off value for V. ichthyoenteri from the calculations could be set to S ${\leq}$ 2 mg/L. Of the 42 strains, 15 were classified as non-wild type (NWT), and MIC values of the NWT strains vary regardless of tetB and tetM detection, suggesting that there may be other mechanisms involved in tetracycline resistance in this Vibrio species.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.2
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• pp.164-170
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• 2000

This study was carried out to investigate the effect of photosynthetic bacteria to chlorella or ${\omega}-yeast$ on Browth of the rotifer and its dietary value for flounder, Paralicbthys oliraceus. The rotifer fed the chlorella (200,000 cells/ind./day) with the addition of 20 times the photosynthetic bacteria of the chlorella concentration showed the highest growth. But the specific growth rate of 100,000 chlorella/ind./day with the addition of 30 times the photosynthetic bacteria was the most economical feeding regime for mass culture of the rotifer. The rotifer frd ${\omega}-yeast$ with 200,000 cells/ind./days with the addition of 20 times the photosynthetic bacteria of the chlorella conecentration showed the highest growth. Growth and survial rate of the larvae of Paralichithys oiivaceus fed the rotifer reared on both chlorella and ${\omega}-yeast$ with the addition of photosynthetic bacteria were higher than those without the bacteria, and the chlorella had better dietary value than the ${\omega}-yeast$ for the larvae. The larvae fed the rotifer which was cultured with the chlorella of 200,000 cells/ind./day and the photosynthetic bacteria of $4{\times}10^6$ cells/ind./day showed the highest survial rate and growth. The larvae reared with the addition of the photosynthetic bacteris had higher total lipid and the total content of EPA and DHA than those reared without the bacteria. The larvae fed the enriched artemia nauplius with the photosynthetic bacteria also showed higher suurval rate and growth than those fed the nauplius without the enrichment. The optimum enrichment concentration of the photosynthetic bacteria for artemia nauplius was $2{\times}1^7\;cells/ml$. The addition of the photosynthetic bacteria to the chlorella and the ${\omega}-yeast$ was effective to growth of the rotifer and dietary value for the flounder larvae. However, an excessive addition of the bacteria decreased both the growth of the rotifer and the dietary of the larvae.

• Development and Reproduction
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• v.13 no.4
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• pp.239-247
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• 2009

Hatching rate, larval deformation and growth rate of selected olive flounder (Paralichthys olivaceus) for rapid growth were compared to those of the unselected fish. Fish were spawned on the same day and cultured under the similar conditions. The selected fish had a significantly higher eggs hatching rate, and lower larval deformation. The selected fish grew significantly faster, and at the end of the experiment (8 weeks after hatching) averaged 50.49${\pm}$2.67 mm in total length, 16.30${\pm}$0.08 mm in body height, and 1.036${\pm}$0.118 g in weight, compared to 40.55${\pm}$3.13 mm, 13.50${\pm}$0.96 mm, and 0.557${\pm}$0.073 g for unselected fish, respectively. The selected fish had a significantly higher body shape index, however lower condition factor than the unselected fish. The results of the present study demonstrate that the selected fish of the olive flounder for rapid growth had superior growth and improved body shape.

• Journal of Aquaculture
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• v.4 no.2
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• pp.73-84
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• 1991

Underground sea water is widely utilized for land based aquaculture in Cheju province, Korea nowadays. Salinity of this water($20{\~}30$ ppt) is slightly lower than natural sea water but because of its good water quality and temperature which is maintained at $16{\~}18^{\circ}C$ all year-round, many fish farmers are using this water for finfish culture. To evaluate the possibility of utilizing underground sea water for the seed production of the flounder, Paralichthys olivaeceus, hatching rate of fertilized eggs, survival rate of hatched larvae, and growth rate of the juveniles were tested with various salinity levels ranged from 14.1 ppt to 40.2 ppt. The salinity ranges which showed over $70{\%}$ survival rate for fertilized eggs to hatchout were 33.7 ppt${\~}$40.2 ppt, for hatched larvae to 2-day-old were 20.6 ppt${\~}$40.2 ppt, from 10-day-old to 12-day-old were 27.2 ppt${\~}$40.2 ppt, and from 45-day-old to 47-day-old were 20.6 ppt${\~}$40.2 ppt. Two hundred day old fingerlings showed no mortality when exposured to 7.6 ppt${\~}$40.2 ppt for 2 days. All fish died within 3 days when 45-day-old juveniles were transferred directly from normal sea water to 14.1 ppt sea water. However, they were all survived when transferred first to 20.6 ppt for 3 days then to 14.1 ppt sea water. The highest growth rates of fingerlings reared at 4 different salinities (33.7, 27.0, 31.0, or 15 ppt) were obtained at the 27 ppt group followed by 33.7, 21.0, 15 ppt respectively. The relationship between the days of rearing (X) and the total length of the fingerlings were as follows. $33.7\%$ group : Y=8.8109 + 0.1104X(r=0.999) $27.0{\%}$ group : Y=8.6797 + 0.1208X(r=0.997) $21.0{\%}$ group : Y=8.4081 + 0.1052X(r=0.990) $15.0{\%}$ group : Y=8.4309+ 0.0995X(r=0.990)

• Journal of Aquaculture
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• v.7 no.4
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• pp.225-237
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• 1994

Survival and growth rates of flounder larvae fed rotifers and Artemia nauplii enriched by various bio-enrichment techniques were investigated. Enriched materials used in the study were $12\omega-yeast$, 2 commercial emulsified oil and microparticulated products. $\omega-yeast$ were added with one kinds of oils (cuttlefish liver oil, sardine oil, Alaska pollock liver oil, linseed oil) at the level of $5\%,\;15\%\;and\;25\%$. The results are as follows: 1. The growth rate of rotifers cultured with $\omega-yeast$ added $15\%$ cuttlefish liver oil was the best among 12 kinds of $\omega-yeast$ and this performance was almost the same with that of rotifers fed on Chlorella. 2. Survival and growth rates of flounder larvae fed on rotifers and Artemia nauplii enriched with $\omega-yeast$ and the other commercial products were higher than that those of larvae cultured with only Chlorella and non-enriched Artemia. The optimum contents of the cuttlefish liver oil in $\omega-yeast$ for rotifers and Artemia enrichment were $15\%\;and\;25\%$, respectively. 3. Optimum enrichment time and supply amount of $\omega-yeast$ for Artemia nauplii were 6 hr., 1.5 g/g cyst, respectively.