• Journal of Aquaculture
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• v.13 no.3
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• pp.253-258
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• 2000

Monthly samplings were made at Yongho-dong, Pusan, on the south eastern coast of Korea from May 1998 to April 1999 to investigate population growth and regeneration pattern of C. okanurae. The growth of erect branches was dependent mainly on the habitat water temperature. Maximum length of an erect branch was 13.4 cm in July and the minimum was 5.1 cm in March; during the corresponding months maximum and minimum weights of the alga were 2.2 and 0.7 g, respectively. During this investigation, gametangia did not occur. Regeneration of excised ramuli was dependent on irradiance. Regeneration rate was the highest under 50 ${\mu}$molm$^{-2}$s$^{-1}$ at 2$0^{\circ}C$. Under the conditions of different combinations of temperature (18, 22, 25, 28 and 1$^{\circ}C$) and irradiance (10, 20, 40, 60 and 100 ${\mu}$molm$^{-2}s$ $^{-1}$) regimes, regeneration of excised erect branch was highly affected by temperature and irradiance. The highest regeneration occurred at 25 $^{\circ}C$ and 20 ${\mu}$molm$^{-2}s$$^{-1}$, whereas the highest growth in length (4.5${\pm}$1.0 cm) and fresh weight (1.2${\pm}$0.7 g) was attained after 15 days of culture.

• Journal of Aquaculture
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• v.19 no.1
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• pp.7-13
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• 2006

In this study, environmental parameters of natural habitat were measured to find out suitable place for release and improve the productivity of Protothaca jedoensis in Gamak Bay. Water temperature, salinity of the habitat ranged from 5.4 to 27.6 and from 26.5 to $34.5\%_{\circ}$, respectively. Range of pH, DO, COD, Chl-a, T-N and T-P were $7.82{\sim}8.39,\;5.31{\sim}11.28mg/L,\;0.13{\sim}1.38mg/L,\;3.05{\sim}11.55mg/L,\;0.005{\sim}0.180mg/L\;and\;0.007{\sim}0.028mg/L$ respectively. Dominant grain size was fine silt and the IL of sediment was ranged from $0.75{\sim}7.26%$. The water content was $20.16{\sim}53.65%$ and highest value was observed in Baegyado. The COD and AVS in the sediments ranged from $0.53{\sim}8.67mg/g-dry$ and $0.002{\sim}0.113mg/g-dry$ respectively. The bottom condition of Baegyado was higher than other area.

• Journal of Aquaculture
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• v.19 no.1
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• pp.57-63
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• 2006

This study was conducted to investigate the effects of dietary supplementation of spirulina (SPI) and asthaxanthin (AST) on growth performance and antioxidant activity in juvenile olive flounder (Paralichthys olivaceus) in low temperature season. Total 180 fish ($27.8{\pm}0.3g$, average weight ${\pm}S.D.$) were randomly divided into 12 groups, and 3 groups were fed one of four isonitrogenous (52% CP) and isocaloric $(18.3\;MJ\;kg^{-1})$ diets containing no SPI and AST, 0.5% SPI, 0.5% AST, and 0.5% each SPI and AST (designated by diets Control, SPI, AST and SPI+AST, respectively). After 6 weeks of feeding trial, the growth performance, feed utilization, whole body composition and survival of fish were not significantly affected by the experimental diets. There were no significant differences in hematocrit, hemoglobin, alanine aminotransferase and aspartate aminotransferase of fish fed all the experimental diets. The DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical scavenging assay indicated numerically increased antioxidant activity in liver of fish fed the SPI diet compared to that of fish fed the control diet, even though it was not significant. The present study shows that a low level (0.5%) of dietary supplementation of SPI and/or AST does not affect growth and feed utilization and intake of juvenile olive flounder in low temperature season.

• Journal of Aquaculture
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• v.19 no.4
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• pp.281-287
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• 2006

Intraspecific diploid androgenesis was achieved in mud loach (Misgurnus mizolepis) by the inhibition of the first mitotic division using combined thermal treatment. A combined thermal treatment (heat shock at $40.5\;^{\circ}C$ for 120 sec followed by cold treatment at $1\;^{\circ}C$ for 45 min) applied to the 1st metaphase of cell division (28 min post insemination at $25\;^{\circ}C$) successfully recovered viable androgenetic diploidy. Mean hatching success of the androgenetic diploid group was 29.6%, and the average yield out of total eggs taken was about 7% assessed at 1 week of age. However, relatively large variations in the yield of diploid androgenesis were observed among different egg batches used as cytoplasmic donors. Successful diploidization was confirmed by flow cytometric analysis, and parthenogenic reproduction in a paternal exclusive manner was verified with transgene dosage. Significant mortality was found in most androgenetic groups especially from hatch to 1 month of age, although such mortality was stabilized later.

• Journal of Aquaculture
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• v.19 no.4
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• pp.261-266
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• 2006

This study was conducted to evaluate the effect of dietary supplementation of paprika and spirulina as carotenoid sources with three different levels on survival and skin color development of swiri. Fish (initial mean weight 4.4 g) were fed the diets containing different levels of paprika (2, 5 and 10%), spirulina (5, 10 and 20%) and mixture of 5% paprika and 10% spirulina and without supplementation (con) for 9 weeks. Survival of fish fed diets containing the various levels of spirulina was 100% and higher than that of fish fed the other diets. Total carotenoid contents of the skin and fin in fish fed the diets containing the various levels of paprika and spirulina were higher than those in fish fed the control diet. Total carotenoid contents of skin and fin in fish fed the diets containing 5% and 10% paprika tended to be higher than that in fish fed the diet containing 2% paprika. Total carotenoid contents of fish fed the diets containing 10% and 20% spirulina tended to be higher than that of fed the diet containing 5% spirulina. The apparent color definition of skin and fin in fish fed the diets containing paprika and spirulina was better than fish fed the control diet. The results of this study suggest that dietary supplementation with paprika and spirulina can improve skin coloration of swiri.

• Journal of Aquaculture
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• v.19 no.4
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• pp.231-235
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• 2006

The effects of mycelium cultural extract supplemented diet, hematology and disease resistance against Vibrio anguillarum in juvenile flounder, Paralichthys olivaceus were evaluated. Fish were fed the Phellinus linteus with Coriolus militaris versicolor mixed mycelium cultural extract supplemented diet, Phellinus linteus mycelium cultural extract supplemented diet and Coriolus militaris tmycelium cultural extract supplemented diet a commercial diet for 12 week. The body weight and length gain from the fish fed on daily the phellinus with coriolus versicolor mixed mycelium cultural extract supplemented diet, phellinus linteus mycelium cultural extract supplemented diet and Coriolus versicolor mycelium cultural extract supplemented diet of each mycelium cultural extract were higher than the control and the Glutamic oxalacetic transaminase (GPT) were of lower than the control. The relative precent survival rate (RPS) after an artificial challenge with $7{\times}10^5\;CFU$ of Vibrio anguillarum per fish was higher than the control.

• Journal of Aquaculture
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• v.19 no.4
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• pp.225-230
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• 2006

A long-term (26 weeks) feeding experiment was conducted to examine the essentiality and requirement of inositol in diets for olive flounder because no information is available in the species. Five casein-gelatin based semi-purified diets were formulated to contain four different levels of myo-inositol (0, 0+antibiotic, 400, 800, and 1600 mg/kg, designated as M0, M0+, M400, M800, and M1600, respectively). One (M0+) of the control diets contained tetracycline hydrochloride (0.4%, wt/wt) as an antibiotic to inhibit biosynthesis of inositol by micro-organism in intestine of fish. Olive flounder at the early juvenile stage (initial body weight 1.22 g) were randomly distributed into fifteen 35 L tanks (48 fish/tank) and fed with one of the experimental diets (3 replicates per diet). At the end of the feeding trial, the weight gain, feed intake, specific growth rate, and protein efficiency ratio of fish fed diets containing higher levels of myo-inositol (M800 & M1600) were significantly higher than those of fish fed the other diets (P<0.05). Feed conversion ratio, survival, hematocrits, and hemoglobin of fish fed experimental diets were not significantly different among all the fish groups. Whole body compositions of fish were not different except for lipid content. The lipid content was significantly different between M0 and M400 diet groups. These results indicate that juvenile olive flounder requires dietary supplementation of myo-inositol in diets for normal growth and its optimum level seems to be approximately 800 mg myo-inositol/kg diet.

• Journal of Aquaculture
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• v.19 no.4
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• pp.315-322
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• 2006

The objective of the present study was to investigate the expression of heat shock protein 90 (HSP90) and 70 (HSP70) mRNA as cellular stress responses, the levels of plasma cortisol with glucose as neuro-endocrine stress responses during water temperature rising in freshwater adapted black porgy, Acanthopagrus schlegeli. A cDNA fragment of 891 (HSP90) and 465 (HSP70) bp was cloned from black porgy testis by Reverse transcription-polymerase chain reaction (RT-PCR) with primers designed from the conserved regions of other teleost. The PCR product of HSP90 showed very high homology to red seabream (99%), rainbow trout (95%), Atlantic salmon (94%), zebrafish (94%) HSP90, HSP70 of black porgy was also highly similar to those of rainbow trout (96%), silver seabream (95%), zebrafish (95%) HSP70. Water temperature rising ($20{\sim}30^{\circ}C$) induced elevation of HSP90 mRNA in black porgy gonad, liver, brain, intestine and kidney, whereas it resulted in an induction of the HSP70 mRNA expression in gonad only. Plasma cortisol levels increased significantly at $30^{\circ}C$ in the fish compared to those at $20^{\circ}C$. Glucose levels of the fish showed a tendency of co-increase with cortisol during water temperature rising. These results suggest that increased HSP90 mRNA in liver with plasma cortisol following heat shock may be related to increasing glucose for homeostasis in this species.

• Journal of Aquaculture
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• v.19 no.4
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• pp.310-314
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• 2006

This study was carried out to investigate grazing of brackish water cyclopoid copepod Paracyclopina nana on four microalgae species (Tetraselmis suecica, Isochrysis galbana, Phaeodactylum tricornutum and Dunaliella tertiolecta) and different food concentrations raging from 5 to 55 ng chl a/ml. The grazing of P. nana was examined by the analysis of decreased number of microalgae and chlorophyll a content in rearing water and pigment content in the gut of P. nana. The maximum content of decreased chlorophyll a and gut pigment in P. nana varied with microalgae species and concentrations. It appeared at the food concentration 30 ng chl a/ml in T. suecica, 40 ng chl a/ml in I. galnaba and D. tertiolecta, and 45 ng chl a/ml in P. tricornutum, respectively. The grazing rate of a P. nana per hour also varied with different microalgae species and concentrations. The maximum grazing rate per hour of P. nana fed T. suecica with 39.3 ng chl a/ml was the highest with 0.63 ng chl a/h, but lowest with 0.52 ng chl a/h. From these results, it can be concluded that T. suecica is the best species among four microalgae species for the mass culture of P. nana and daily optimum food concentration of P. nana is $25{\sim}39$ ng chl a (approximately $10{\sim}15{\times}10^4$ cells).

• Journal of Aquaculture
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• v.19 no.4
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• pp.305-309
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• 2006

This study was carried out to examine the anesthesia and recovery time of the male and gravid female of marine benthic copepod Tigriopus japonicus at 500, 750, 1,000 ppm of MS-222. We also investigated the survival (%) and the nauplii production of T. japonicus for 14 days, which was anesthetized with MS-222. As the concentration of MS-222 was higher, the anesthesia time of the copepod was shorter and the recovery time was longer. The survival (%) of male T. japonicus was significantly higher than that of the gravid female both in anesthetized and control group. But the survival (%) of the male treated with MS-222 did not show the different survival (%) with the control (0 ppm). In contrast, the survival (%) of the gravid female treated with 750 and 1,000 ppm was significantly lower than that of 500 ppm and control. With regard to hatching, as the concentrations was higher, the number of hatching and total nauplii were lower and interval of hatching was longer. However, the gravid female treated with 500 ppm did not show the significant difference with control. We suggest that 500 ppm of MS-222 is the suitable concentration in isolation of T. japonicus.