• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.70-70
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• 2003

This study was conducted to determine the effects of the dietary microbial phytase (P) supplementation on growth performance and bioavailability of phosphorus in juvenile olive flounder, Paralichthys olivaceus and juvenile Korean rockfish, Sebastes schlegeli fed soybean meal-based diets. Nine experimental diets were formulated to be isonitrogenous and isocalolic to contain 50.0%crude protein (CP) and 16.7kJ, 48.6% crude protein (CP) and 16.0kJ available energy/g without the dietary phytase supplementation for olive flounder and Korean rockfish, respectively : 100% fish meal (FM); 70% FM ＋ 30% soybean meal (SM); 70% FM ＋ 30% SM ＋ Phytase(P) 1000U/kg diet; 70% FM ＋ 30% SM ＋ P 2000U/kg diet; 70% FM ＋ 30% SM with phytase-treated (Ptre) P 1000U/kg diet; 60% FM ＋ 40% SM; 60% FM ＋ 40% SM ＋ P 1000U/kg diet; 60% FM ＋ 40% SM ＋ P 2000U/kg diet; 60% PM ＋ 40% SM with Ptre P 1000U/kg diet. After two weeks of the conditioning period, triplicate groups of 25 fish initially averaging 6.15$\pm$0.04g, was randomly distributed into the aquarium for olive flounder, and 20 fish initially averaging 7.25$\pm$0.04g was randomly distributed into the aquarium for Korean rockfish. After 8 weeks feeding trials, there was no significant difference on weight gain fish fed between 100% FM and 70% FM＋30%SM with Ptre P 1000U in olive flounder and Korean rockfish. Apparent phosphorus digestibility fish fed phytase supplemental diets were significantly higher than those of fish fed phytase non-supplemental diets in olive flounder and Korean rockfish. Therefore, these results indicated that pre-treated soybean meal with phytase 1000U could replace fishmeal up to 30% for the maximum growth of juvenile olive flounder and Korean rockfish. Phytase supplementation could improve apparent digestibility of phosphorus in olive flounder and Korean rockfish fed soybean meal based diets.

• The Journal of Fisheries Business Administration
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• v.28 no.2
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• pp.39-66
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• 1997

The objective of this study is to suggest the improvement method of the profitability in our marine fish culture business. So I investigated the actual condition for aquaculture farms in South Sea coast by the question and actual survey. 1 recognized the following facts; 1) The marine floating netcage system are a great portion in two province - Kyeongnam and Cheunnam, 2) The rockfish are reared absolutely much more than the olive flounder, 3) The polyculture by various species are more carried out than the monoculture of the olive flounder or rockfish, etc. I analyzed the profitability in olive flounder monoculture, rockfish monoculture, olive flounder and rockfish polyculture, and rockfish polyculture taking turns year by year respectively. At a result I comfirmed that the net income to net sales was the highest in the olive flounder monoculture bacouse the olive flounder,s sale price was higher than rockfish price. But internal rate of return(IRR) and net present value(NPV) were high in the olive flounder and rockfish polyculture or the rockfish taking turns polyculture. The reasons were alttributed to their high utility of a netcage and to reduction of a capital cost. So, I suggest 1) to feed the bigger product in short term, 2) to reduction of a feed and seed cost, 3) to increase a survival rate of fish and 4) to enlarge production by highly utilizing a netcage. And I recognized that a aquaculture manager should make constantly an effort to gain more profit by rearing more good products and by reducing a production cost.

• The Journal of Fisheries Business Administration
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• v.47 no.4
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• pp.65-75
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• 2016

The purpose of this study was to analyze the production and marketing control effects of aqua-cultured flounder required for stable income growth of aqua-cultured household. We analyzed the supply and demand structure of cultured flounder using the partial equilibrium model approach. And we estimated the optimal yield of cultured flounder and analyzed the effect of marketing control through constructed model. The main results of this study are summarized as follows. First, the fitness and predictive power of the estimated model showed that the RMSPE and MAPE values were less than 5% and Theil's inequality coefficient was very close to 0 rather than 1. It was evaluated that the prediction ability of the aqua-cultured flounder supply and demand model by dynamic simulation was excellent. Second, dynamic simulation based on policy simulation was conducted to analyze the price increase effect of production and shipment control of cultured flounder. As a result, if the annual production volume is reduced by 1%, 5%, and 10% among 32,852~37,520 tons, it is analyzed that the price increase effect is from 1.2% to 12.5%. Finally, this study suggests that the production and marketing control can increase the price of aqua-cultured flounder in the market. In this paper, we propose a policy implementation of the total supply system instead of conclusions.

• Journal of fish pathology
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• v.16 no.1
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• pp.51-59
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• 2003

Streptococcal infection is one of the most serious disease of cultured olive flounder, Paralychthys olivaceus in Korea and caused by more than one species. However, there has been considerable confusions about the taxonomic position of the fish pathogenic streptococci. In this study, We performed the randomly amplified polymorphic DNA(RAPD) pattern analysis to evaluate the possible classification in 8 streptococci isolated from diseased olive flounder and reference strains based on their DNA structure. RAPD PCR with DNA solution prepared by simple boiling and 10-mer random primer was appeared to be a good tool for discrimination of different streptococcal strains. Phenotypical characters by simple biological test and API 20 Strep corresponded well to the specific profiles of RAPD in streptococcal isolates of this study. Therefore, the RAPD profile was considered as one of differential characters to discriminate the streptococcal isolates from diseased olive flounder.

• The Journal of Fisheries Business Administration
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• v.47 no.1
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• pp.1-20
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• 2016

The purpose of this study is to assess the effects of outlook project for olive flounder, from the view point of price stabilization, market efficiency, and causality of the prices in different distribution channels. Analytical results show that the volatility of producer price of olive flounder has been significantly mitigated after the implementation of the outlook project. The market efficiency is estimated to be improved after implementing the outlook project although there is an inefficiency on price determination process in some producing regions. The causality test on the producer and wholesale price shows that producing stage leads the wholesale stage in forming the prices. It is found that Jeju leads the flounder price on the size of 500g and 2kg, while Wando leads the price of 1kg size. These estimation result as whole indicate that outlook project for olive flounder has accomplished the intended goals.

• Fisheries and Aquatic Sciences
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• v.22 no.7
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• pp.14.1-14.8
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• 2019

Olive flounder (Paralichthys olivaceus) is the major species developed for aquaculture in South Korea. Over the long history of olive flounder aquaculture, complex and diverse diseases have been a major problem, negatively impacting industrial production. Vibriosis is a prolific disease which continuously damages olive flounder aquaculture. A bacterial disease survey was performed from January to June 2017 on 20 olive flounder farms on Jeju Island. A total of 1710 fish were sampled, and bacteria from the external and internal organs of 560 fish were collected. Bacterial strains were identified using 16 s rRNA sequencing. Twenty-seven species and 184 strains of Vibrio were isolated during this survey, and phylogenetic analysis was performed. Bacterial isolates were investigated for the distribution of pathogenic and non-pathogenic species, as well as bacterial presence in tested organs was characterized. V. gigantis and V. scophthalmi were the dominant non-pathogenic and pathogenic strains isolated during this survey, respectively. This study provides data on specific Vibrio spp. isolated from cultured olive flounder in an effort to provide direction for future research and inform aquaculture management practices.

• Journal of Aquaculture
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• v.19 no.2
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• pp.95-98
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• 2006

This study was performed to determine possibility of compensatory growth of juvenile olive flounder fed a commercial feed during the summer season. Five treatments of fish with triplicates were prepared: C, S1, S2, S3 and S4. Fish in the control group (C) was hand-fed with the commercial feed to apparent satiation twice daily for 6 days a week during 6 weeks. Fish in S1, S2, S3, and S4 experienced 1, 2, 3, and 4 weeks of starvation before fed to satiation twice daily for 5, 4, 3, and 2 weeks, respectively. The feeding trial lasted far 6 weeks. Survival of flounder in C, S1 and S2 was significantly (P<0.05) higher than that offish in S4. Weight gain and specific growth rate (SGR) of flounder in C and S1 were significantly (P<0.05) higher than those of fish in S2, S3 or S4. And weight gain and SGR of flounder in S2 and S3 were significantly (P<0.05) higher than those of fish in S4. Feed consumption of flounder tended to increase with weeks of feeding. Feed efficiency ratio and protein efficiency ratio for flounder in C, S1, S2 and S3 were significantly (P<0.05) higher than those for fish in S4. Moisture content of the whole fish in C was lowest, but highest for fish in S4, respectively. Crude protein content of the whole fish in C was highest, but lowest far fish in S4, respectively. Crude lipid content of the whole fish in C, S1 and S2 was significantly (P<0.05) higher than that of fish in S4. In conclusion, full compensatory growth was obtained in juvenile olive flounder fed for 5 weeks after 1-week feed deprivation during the summer season. Compensatory growth of fish was well supported by improvement in feed efficiency ratio and protein efficiency ratio.

• 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.

• The Journal of Fisheries Business Administration
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• v.52 no.1
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• pp.47-63
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• 2021

The purpose of this study is to identify the leading price between Jeju and Wando's oliver flounder producer price and to analyze the dynamic effect of the regional producer price using the panel VAR model. In the process of analysis, it was confirmed that there are unit roots in the monthly data of Jeju and Wando's oliver flounder producer price. So, in order to avoid spurious regression, the rate change of producer price which carries out log difference was used in the analysis. As a result of the analysis, first, the panel Granger causality test showed that the influence of the change rate of producer price in oliver flounder in Jeju was slightly larger than that in Wando, but it was found that each region all leads the change rate of the producer price in oliver flounder. Second, the panel VAR estimation showed that the rate change of producer price in Jeju and Wando a month ago had a statistically significant effect on the change rate of producer price of each region. Third, the impulse response analysis indicated that other regions are affected a little more than the same region in case of the occurrence of the impact on the error terms of the change rate of produce price in Jeju and Wando oliver flounder. Fourth, the variance decomposition analysis showed that the change rate of producer price in the two regions was higher explained by Jeju compared to Wando. In conclusion, it is expected that the above results can not only be useful as basic data for the stabilization of oliver flounder producer price and the establishment of policies for easing volatility but can also help the oliver flounder industry operate its business.

• Fisheries and Aquatic Sciences
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• v.25 no.8
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• pp.441-449
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• 2022

In this study, we investigate the physiological response of olive flounder, Paralichthys olivaceus and Japanese croaker, Nibea japonica, on a series of rising water temperatures (WT). At 1, 9, and 17 days, WT increased from 23℃ (control) to 26, 29 and 32℃ within 6 hours, respectively, and then maintained for 96 hours. At 5, 13, and 21 days, WT decreased from each WT to 23℃ within 6 hours and was maintained at 23℃ for 96 hours. Blood were collected at 0, 1, 5, 9, 13, 17, 21, and 60 days. In both species, hematocrit, red blood cell and hemoglobin of stressed groups were lower than non-stressed group at 13 days. The osmolality of stressed group was lower than non-stressed group at 21 and 60 days. In olive flounder, hemoglobin of stressed groups was lower than non-stressed group at 21 and 60 days, respectively, but osmolality of stressed group was higher than non-stressed group at 9 days. In Japanese croaker, hematocrit, red blood cell and hemoglobin of stressed groups were higher than non-stressed group at 21 and 60 days, respectively, and osmolality of stressed group was higher than that of non-stressed group at 1 day. At 1, 17, and 21 days, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of stressed group were higher than non-stressed group in olive flounder. In Japanese croaker, AST and ALT of stressed group was lower than non-stressed group at 17, 21, and 60 days. The cortisol of olive flounder increased with increasing WT, but those of Japanese croaker increased with decreasing WT. In both species, the glucose increased with increasing WT. After changing WT, lactic acid of olive flounder and Japanese croaker were not significantly different. The physiological response of olive flounder increased directly to the increase in WT, and Japanese croaker contrasted with olive flounder.