• The Journal of Fisheries Business Administration
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• v.47 no.4
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• pp.1-13
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• 2016

Fish mortality is the most important success factor in aquaculture management. To analyze the effect of mortality considering biological and economic condition is a important problem in land-based aquaculture. This study is aimed to analyze the effect of mortality for duration of cultivation in land-based aquaculture. This study builds the mathematical model that finds the value of decision variable to minimize cost that sums up the water pool usage cost, sorting cost, fingerling cost and feeding cost under critical standing corp constraint. The proposed mathematical model involves many aspects, both biological and economical: (1) number of fingerlings (2) timing and number of batch splitting event, based on (3) fish growth rate, (4) mortality, and (5) several farming expense. Numerical simulation model presented here in. The objective of numerical simulation is to provide for decision makers to analyse and comprehend the proposed model. When extensive biological and cost data become available, the proposed model can be widely applied to yield more accurate results.

• 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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.908-913
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• 1998

The productivity of land based seawater fish farm has been decreased because of unexpected outbreaks of diseases caused by the contaminated inlet seawater. Sometimes unfiltered/untreated outlet seawater from the land based seawater fish farm has created serious environmental problem. In the needs of treatment systems for the inlet and outlet seawater, the researchers have developed two different systems, The purpose of this study is to design and test two treatment systems, the screen filter for inlet seawater and drum filter for outlet seawater, on the basis of concept of system design and automatization. After developing two systems, an experiment has been conducted with two systems and collected data to improve design and efficiency of the system. In this study, detailed design and efficiency of the system could be improved by the programmable logic controller (PLC).

• 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.

• Journal of Aquaculture
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• v.16 no.1
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• pp.15-23
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• 2003

We have investigated water quality of the coastal saline groundwaters utilized for fish farms in Jeju Island. The water quality investigation included the spatial observations for 75 fish farms during March-May, 1994 and the hi-monthly observations for both coastal saline groundwaters and seawaters at four fish farms from August 1994 to December 1995. Water temperature of the saline groundwaters ranged from 16 to 18$^{\circ}C$ over the study period. Salinity of the saline groundwaters varied between 20.60 ppt and 34.02 ppt, slightly lower than that of the coastal seawaters(26.47~34.53 ppt). This salinity variation must be associated with local precipitation conditions in Jeju Island. The oxygen saturation for most saline groundwater samples was lower than 80%, ranging from 24.7 to 89.8%. The COD and pH values for the saline groundwaters were similar to those for the coastal seawaters. The concentrations of DIP for the saline groundwaters varied between 0.021 mg/L and 0.121 mg/ L, and seasonal variation of DIP in the saline groundwater ranged from 0.014 to 0.077 mg/L, which were higher than that of the coastal seawaters(0.000~0.015 mg/L). Nitrate in the saline groundwaters accounted for more than 90% of the DIM. The maximum concentrations of ammonia, nitrite, nitrate and DIN in the saline groundwaters were 0.085, 0.012, 2.294 and 2.309 mg/L, respectively. These concentrations of the saline groundwaters were considerably lower than those affected culture organisms. Overall, the saline groundwaters utilized for fish farms in Jeju Island appear to maintain good waterquality for fish farms.

• The Korean Journal of Malacology
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• v.31 no.2
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• pp.129-136
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• 2015

To introduce an oyster rack culture in tidal flat of Wando-gun, Korea, we investigated sanitary conditions from 2012 April to 2013 March in oyster growing waters and adjacent area in Wando. Average seawater temperature and salinity ranged $8.6-28.0^{\circ}C$ and 26.2-33.6 psu, respectively. The coliform group and fecal coliform of seawater ranged < 1.8-13.0 MPN/100 mL each. Only one of 60 samples was exceeded in the European criteria of fecal coliform. Influence of adjunct basin's pollution load on cultural waters was negligible, which half radius of dilution was not above 300 m. According to our observation, however, landing of oyster should be banned for at least 5 days after the heavy rainfall. Our findings meet the sanitary seawater criteria for domestic use and export of shellfish and classified as 'Class A' in European Community regulations for bivalve culture.

• Journal of Life Science
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• v.7 no.1
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• pp.1-9
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• 1997

For the recent years, considerable efforts have been made to rationalize the techniques of research and monitoring of biological effects of marine pollutants such as heavy metals, polychlorinate biphenyls (PCBs), organochlorine pesticides, polycyclic aromatic hydrocarbons (PAHs), organophosphorus pesticides. This study was designed as a part of efforts to investigate the biochemical pollutant markers for diagnosis of marine pollutions by the changes in lipid components of the flounder (Paralichthys olivaceus) in Yellow Sea of Korea. Homoglobin levels in serum of cultured and wild flounders in Yellow Sea were significantly lower (5 - 15% and 20 -25 % , respectively) than those of wild flounder in Pohang. Triglyceride (TG) contents in serum of cultured flounders in Yellow Sea were 10 - 40% higher than those of wild flounder in Pohang. Total and low density lipoprotein (LDL)-cholesterol contents in serum of flounders in Yellow Sea were significantly 10-15% and 30-35% (cultured), and 10-20% (wild), respectively, higher than those of wild flounder in Pohang. Atherogenic index (AI) and T-Chol/PL rations in serum of cultured and wild flounders in Yellow sea were significantly 20-45% and 10-!5%, 6-35% and 15-35%, respectively, higher than those of wild flounder in pohang. These results suggest that near-coastal waters as well as neritic waters of the Yellow Sea might be affected by pollutant input.

• Journal of Aquaculture
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• v.8 no.3
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• pp.221-229
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• 1995

Two long term feeding trials using moist pellet diet were conducted to study the growth pattern of Korean rockfish (Sebastes schiegeli). Two groups of the fish with initially averaging of 6.8g and 11.0g were stocked in the indoor FRP tanks, and were fed with moist pellet for 22 months and 10 months, respectively. It took approximately 11 months and 23 months after parturition to grow up to 200g and 500g of average body weight, respectively. Average body weight of fish increased almost linearly, and no significant growth stagnation was observed even in winter (the lowest water temperature was $11^{\circ}C$) and summer (the highest water temperature was $25^{\circ}$) seasons. Growth rate, feed intake and protein intake decreased gradually with fish size up to approximately 200g of average body weight, and these values were remained relatively consistent afterward.

• Korean Journal of Ichthyology
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• v.24 no.1
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• pp.41-47
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• 2012

In the present study, we investigated the characteristic of growth and the tolerance of cold temperature in small yellow croaker and yellow drum. The results shows that the growth of yellow drum were faster than those of small yellow croaker with high food convergency efficiency. In condition factor (CF), the results shows that the values of yellow croaker and yellow drum were significantly higher in September, respectively. In mortality according to cold shock, two fishes was died under $4.7^{\circ}C$ in slow temperature descending test, but was both died under $9^{\circ}C$ in acute temperature descending test.

• Journal of Korea Water Resources Association
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• v.46 no.7
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• pp.783-794
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• 2013

Saline groundwater, in addition to fresh groundwater, is actively developed for inland aqua culture in Jeju Island where groundwater is practically the only source of freshwater. In this work we analyzed impacts of saline and fresh groundwater development on groundwater systems in Sungsan subwatershed in Jeju. A sharp-interface model was used to simulate fresh and saline groundwater flows. Withdrawal of freshwater imparted adverse impacts by lowering groundwater level and inducing saltwater encroachment. Withdrawal of saline water imparted mixed results: on one hand it lowered groundwater level, on the other hand it reduced saltwater encroachments. However, freshwater development lowered groundwater level much more than salinewater development did. Modified Ghyben-Herzberg ratio was developed for a transition zone with finite width. Comparison against observed data resulted in fair agreement.