• Ocean and Polar Research
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• v.23 no.3
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• pp.285-290
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• 2001

The strength of juvenile black rockfish, Sebastes schlegeli, raised in different hatcheries for wild stock enhancement was evaluated in terms of resistance to an anesthetizing agent, tricaine methane-sulfonate (MS-222), and exposure to drying. The working dosage of MS-222 varied significantly with fish size and hatchery population. Smaller fish were less resistant to the chemical than larger ones. MS-222 effects also differed with fish growth history. The fish cultured in embanked populations showed stronger resistance, earlier recovery, and lower mortality, compared to those cultured in land-based tanks or collected from wild stocks. Similar results were seen in juveniles challenged to dry exposure. These results suggest that an embanked population of black rockfish is more resistant to anesthetic stress, expressed as anesthesia recovery and mortality, and that this population is healthier than others.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.3
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• pp.35-46
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• 2023

It was in the 1982 that artificial seed production research for olive flounder (Paralichthys olivaceus) farming was first conducted in Korea (Currently, National Institute of Fisheries Science, Fish Breeding Research Center). In 1985, fertilized eggs were obtained from natural olive flounder adapted to land tanks, and artificial seed production technology was established and fertilized eggs were distributed. In the late 1980s, halibut aquaculture began to prosper in land-based tank farming in Jeju Island and Busan's Gijang region, where water temperatures are relatively high in winter. Currently, aquaculture is being carried out all over the country, centering on Jeju Island and Wando, Jeollanam-do. However, olive flounder farming, which started with a small group in the 1980s, reduced genetic diversity through inbreeding over generations, resulting in side effects such as slow growth, reduced resistance to disease and environmental conditions. In order to solve these genetic problems of farmed olive flounder in Korea, the Fish Breeding Research Center of the National Institute of Fisheries Science introduced a wild-caught parent fish group to the existing aquaculture group from 2003 to 2004. Genetic diversity was secured and KingNupchi with fast growth and improved body shape was developed. In this study, the current status of breeding technology development of olive flounder, a major aquaculture breed in Korea, is reviewed and future research directions are suggested.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.4
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• pp.395-406
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• 2020

The objectives of this study were to develop the optimal structures of recirculating aquaculture tank for improving the removal efficiency of solid materials and maintaining water quality conditions. Flow analysis was performed using the CFD (computational fluid dynamics) method to understand the hydrodynamic characteristics of the circular tank according to the angle of inclination in the tank bottom (0°, 1.5° and 3°), circulating water inflow method (underwater, horizontal nozzle, vertical nozzle and combination nozzle) and the number of inlets. As the angle in tank bottom increased, the vortex inside the tank decreased, resulting in a constant flow. In the case of the vertical nozzle type, the eddy flow in the tank was greatly improved. The vertical nozzle type showed excellent flow such as constant flow velocity distribution and uniform streamline. The combination nozzle type also showed an internal spiral flow, but the vortex reduction effect was less than the vertical nozzle type. As the number of inlets in the tank increased, problems such as speed reduction were compensated, resulting in uniform fluid flow.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.660-665
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• 2002

In Korea, an olive flounder is very popular fish food item. However, due to the increasing human population, the present catches of the olive flounder may not be sufficient to satisfy the present demand. To increase the supply of the olive flounder, aquaculture has been begun. An interest in the aquaculture of the olive flounder has been increased recently because of its characteristics of good growth and high price in the market, However, the productivity of the olive flounder aquaculture depends on economic inputs such as fuels, facilities, and labor. The rapid growths of the olive flounder aquaculture and the concerns about economic and ecological sustainability have focused peoples attention on the aquaculture industry. In this study, an energy systems model was built to simulate the variation of sustainability on the aquaculture of olive flounder, The results of simulation based on calibration data in 1995 show that olive flounder production yield and asset slowly increase to steady state because of the law of supply and demand. The results of simulation based on the variation of oil price show that the more increase the oil price, the more decrease the olive flounder economic yield and asset. Energy sources required for systems determine the sustainability of systems. Conclusionally, the present systems of the olive flounder aquaculture should be transformed to ecological-recycling systems or ecological engineering systems which depend on renewable resources rather than aquaculture systems which depend on fossil fuels, and be harmonized with the fishing fisheries by the sustainable use of renewable resources in the carrying capacity.

• Journal of Aquaculture
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• v.15 no.4
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• pp.261-266
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• 2002

The effluent sediment from the land-based seawater fish farms of Jeju consists of proteins, fats, ash and moisture. An evaluation of the effluent sediment as substrate for growth of phototrophic or lactic acid bacteria revealed that the sediment supported the growth of phototrophic bacteria but could support lactic acid bacteria only on supplementation with sugar. The possibility of using phototrophic bacteria for recycling the land-based seawater fish farm effluent is shown.

• Ocean and Polar Research
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• v.45 no.3
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• pp.103-111
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• 2023

To evaluate the impact of effluents from land-based fish farms on the coastal ocean of Wando, Korea, we analyzed inorganic nutrients, particulate organic carbon (POC), dissolved organic carbon (DOC), and colored dissolved organic matter (CDOM) in the effluent and influent of land-based fish farms during the summer (July) of 2021. The average concentrations of nutrients (Dissolved inorganic nitrogen, phosphorus, and silicate; DIN, DIP, and DSi, respectively) in the effluents of this study area were 17±3.7 μM, 1.4±0.7 μM, and 14±1.6 μM, respectively. The average concentrations of POC and DOC were 37±22 μM and 81±13 μM, respectively, with POC accounting for about 30% for total organic carbon in effluents. The Reduced Dissolved Inorganic Nitrogen/Total Dissolved Inorganic Nitrogen ratio (0.7), potential short-period index, indicates that the discharge of nutrients excreted by the fish and unconsumed feed into coastal water results in such nutrients being deposited and accumulated in the sediment. Subsequently, this continuous accumulation triggers the release of ammonium ions during organic matter decomposition, and the ammonium-enriched waters that encroach on fish farms as influent seem to be due to the diffusion of high concentrations of ammonium from bottom sediment. Furthermore, we used fluorescence indices to examine the characteristics of organic matter sources, obtaining mean values of 1.54±0.19, 1.06±0.06, and 1.56±0.06 for the humification index, biological index, and fluorescence index, respectively, in the effluent. These results indicate that the organic matters had an autochthonous origin that resulted from microbial decomposition, and such organic matters were rapidly generated and removed by biological activity, likely supplied from the sediment. Our results suggest that the effluent from land-based fish farms could be a potential source of deoxygenation occurrence in coastal areas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.716-720
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• 2023

This study was designed to analyze the effects of reducing water turnover in olive flounder Paralichthys olivaceus farms, focusing on olive flounder growth, decreasing electricity costs, and developing measures to ensure business stability. Daily water turnover was set at 18 in the control group and six in the experimental group. Juvenile fish were reared for 12 months. No significant differences in mean weight were observed between groups until five months. After five months, the mean weight of the control group grew significantly faster than that of the experimental group. Maintaining water turnovers leverl at six turnovers for the first five months after stocking juvenile fish and then increasing water turnover resulted in a 34.4% reduction in electricity costs compared to the control group. This approach presents a potential method to enhance the profitability of olive flounder farms and ensure stable productivity and profitability without sacrificing olive flounder growth.

• Journal of fish pathology
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• v.18 no.2
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• pp.187-195
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• 2005

Effluent of aquaculture industry has caused a growing concern regarding its environmental impact. We assessed the use of flounder farming sewage as supplement of diet, to minimize the impact of aquaculture on the environment or also establish the technique for the recycling of effluent sediment derived from land-based seawater fish farm. In order to investigate the effects of a fermented aquaculture waste on biochemical responses of olive flounder (Paralichthys olivaceus), fermented products of aquaculture wastes were used as test compounds that cause hepatic and renal stress through the induction of oxidative stress in liver and kidney. Hepatosomatic index (HSI), glutathione content and glutathione dependent enzyme were not significantly different and no correlation was found within the different types of fermentation condition or supplement concentration, except for significant increases in 50% fermentation group and 50% concentration group in case of glutathione peroxidase activity and HSI value, respectively. These results showed addition of fermented aquaculture sewage may be an economic artificial sources of diet for fish aquaculture practices without affecting the function and safety in view of biochemical examination.

• The Journal of Fisheries Business Administration
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• v.46 no.1
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• pp.1-13
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• 2015

This study is aimed comparative analysis for business performance of land-based ezo abalone (Haliotis discus hannai) seed farms by standardizing cost structures by region and farming size. The result of survey on average farming incomes by region showed that farming incomes in Haenam and Jindo regions were much higher than those in other regions. Followed by Wando region, incomes in other regions were analyzed to be relatively lower. It is shown that farming incomes became higher as farm size increased. Farming incomes per unit size which were modified from farming incomes by region were highest in Jindo region, followed by East sea region, Wando and Haenam regions. Incomes in Jeju and Yeosu regions were analyzed to be relatively lower. Results on farming incomes per unit size ($m^2$) showed that both farming incomes and profits became higher as size increased. It implies that a scale effectiveness might exist in case of land-based abalone culture system. Impacts of major factors on farming profits and returns on investment in abalone seed aquaculture are summarized as follow. First, only if the survival rate increased by 10% with improvement of component ratio, variable effects became largest. In variable effects of other factors, a variation in Jindo region was largest and on the other hand, a variation in Yeosu region was shown to be smallest.

• Journal of fish pathology
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• v.17 no.1
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• pp.57-66
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• 2004

Effects of oral administration with fermented product from sewage in land-based seawater fish farm on haematological disturbance in the olive flounder, Paralichthys olivaceus was investigated. After 4 weeks of conditioning with a basal diet, fish were divided into 4 groups and provided experimental diet (0.1, 0.5, 1.0 and 2.0%) supplement of fermented sewage for 80 days. Proximal analysis was performed for the product of sewage which was fermented by lactic acid and yeast. RBC count, hemoglobin concentration and hematocrit value were increased according to the treated periods, however, no statistical difference was observed between control and treatment groups. There were no significant difference in serum organic, inorganic compounds and enzyme activities between control and treatment groups. This study hypothesized that the supplement of fermented product from sewage in land-based seawater fish farm might be an additive supplement for source of fish diet in view of haematological examination. Recycling of the sewage may be an economic artificial sources of diet for fish aquaculture practices.