• 한국양식학회지
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• 제14권2호
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• pp.67-71
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• 2001

Phosphorus is an essential element for growth and metabolism in fish. However high levels of phosphorus in the feed can lead to poor water quality of pond, and can also be a potential source of pollution, when pond water is released to the environment. In this study phosphorus supplemented diets containing 0.0, 0.9 or 1.9% of (dicalcium) phosphate were offered to channel catfish and changes in water quality of ponds and phosphorus levels in fish were measured. Higher level of (1.9%) supplementation of phosphorus in diet resulted in higher concentration of T-P and SRP in pond waters. Also it produced negative effects on fish production by lowering feed coefficient and rate of increment in body weight. Surplus phosphorus can affect fish growth and water quality of pond.

• 수산경영론집
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• 제13권1호
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• pp.85-97
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• 1982

This study involves a blending of intensive and extensive shrimp culture techniques for a hypothetical shrimp farm which uses a combination of heated raceway nurseries and extensive grow-out ponds per year. The present value method of economic analysis is used to determine economic feasibility. The biological data in this reports were obtained from published or personal communications from leaders in the field of shrimp aquaculture. The proposed system showed economic feasibility using the present value method with discount rates of 10% and 12%. The most profitable scenario, the culture of three crops of Penaeus vannamei showed a 1.26 year payback period and 120% annual average rate of return. The breakeven price was ＄1.25/1b., which is ＄1.52 less than the market price of ＄2.77. Breakeven production was 724 1bs/acre, which is 8761bs. less than the assumed 1,600 1bs/acre. All other scenarios 1.2 and 3 crops for P. stylirostris and P. setiferus showed economic feasibility also.

• 한국조경학회지
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• 제23권2호
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• pp.167-181
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• 1995

An Ecocomplex is proposed for ecological design of the estuarine environment of Han River, which is designed upon an alternative mamagement concept of estuarine environment. The concept reveals interrelationships among estuary, delta region and urban inland with inputs/outputs and feedbacks among them. The Ecocomplex emphasizes an integration of wastewater treatment with aquaculture, agriculture and recreation, and carries out ecological treatment, recycling, and harvest processes. A module of wastewater treatment pond system is employed in the Ecocomplex, which treats a flow of 3,786 ㎥/day and is composed of a four-facultative-pond series. Treatment ponds stabilize wastewater discharged from the urban area, and concurrently produce algae for commercial or recreational fish farming. Effluent from treatment and fish ponds is reused for agricultural production. Through the waste-algae-fish-vegetable-recreation processes, wastewater from the urban settlement is recycled back to the urban ecosystem. This resource-conserving design approach can maintain a sustainable urban ecosystem, managing an estuarine environment more naturally, healthly, and economically.

• Fisheries and Aquatic Sciences
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• 제20권11호
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• pp.30.1-30.10
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• 2017

Small-scale fish farmers in developing countries are faced with challenges owing to their limited information on aquaculture management. Nile tilapia farmers in Teso North Sub-County recorded lower yields than expected in 2009 despite having been provided with required inputs. Water quality was suspected to be the key factor responsible for the low yields. This study sought to assess the effects of earthen pond water physico-chemical parameters on the growth of Nile tilapia in six earthen fish ponds under semi-intensive culture system in Teso North Sub-County. The study was longitudinal in nature with pond water and fish being the units of analysis. Systematic sampling was used to select five ponds while a control pond was purposively selected based on its previously high harvest. Four ponds were fed by surface flow and two by underground water. Each pond was fertilized and stocked with 900 fry of averagely 1.4 g and 4.4 cm. Physico-chemical parameters were measured in-situ using a multi-parameter probe. Sixty fish samples were randomly obtained from each pond fortnightly for four months using a 10 mm mesh size and measured, weighed and returned into the pond. Mean range of physico-chemical parameters were: dissolved oxygen (DO) 4.86-10.53 mg/l, temperature $24-26^{\circ}C$, pH 6.1-8.3, conductivity $35-87{\mu}S/cm$ and ammonia 0.01-0.3 mg/l. Temperature (p = 0.012) and conductivity (p = 0.0001) levels varied significantly between ponds. Overall Specific Growth Rate ranged between 1.8% (0.1692 g/day) and 3.8% (1.9 g/day). Ammonia, DO and pH in the ponds were within the optimal levels for growth of tilapia, while temperature and conductivity were below optimal levels. As temperature and DO increased, growth rate of tilapia increased. However, increase in conductivity, pH and ammonia decreased fish growth rate. Temperature and DO ranging between 27 and $30^{\circ}C$ and 5-23 mg/l, respectively, and SGR of 3.8%/day and above are recommended for higher productivity.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1104-1116
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• 2019

In this study, we investigated the potential of using sediment bioelectrochemical systems (SBESs) for in situ treatment of the water and sediment in brackish aquaculture ponds polluted with uneaten feed. An SBES integrated into a laboratory-scale tank simulating a brackish aquaculture pond was established. This test tank and the control (not containing the SBES) were fed with shrimp feed in a scheme that mimics a situation where 50% of feed is uneaten. After the SBES was inoculated with microbial sources from actual shrimp pond sediments, electricity generation was well observed from the first experimental week, indicating successful enrichment of electrochemically active bacteria in the test tank sediment. The electricity generation became steady after 3 weeks of operation, with an average current density of $2.3mA/m^2$ anode surface and an average power density of $0.05mW/m^2$ anode surface. The SBES removed 20-30% more COD of the tank water, compared to the control. After 1 year, the SBES also reduced the amount of sediment in the tank by 40% and thus could remove approximately 40% more COD and approximately 52% more nitrogen from the sediment, compared to the control. Insignificant amounts of nitrite and nitrate were detected, suggesting complete removal of nitrogen by the system. PCR-DGGE-based analyses revealed the dominant presence of Methylophilus rhizosphaerae, Desulfatitalea tepidiphila and Thiothrix eikelboomii, which have not been found in bioelectrochemical systems before, in the bacterial community in the sediment of the SBES-containing tank. The results of this research demonstrate the potential application of SBESs in helping to reduce water pollution threats, fish and shrimp disease risks, and thus farmers' losses.

• 한국해양바이오학회지
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• 제3권1호
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• pp.1-6
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• 2008

Angola has a coastline of about 1,650 km long. Two diverging current namely, the Angola current with its warm water from the north and the cold Benguella Current in the south create a strong up-welling with a high productive ecosystem for marine resources. The area from Lobito to the mouth of the Cunene River, also known as the Southern fishing zone is by far the most productive of Angola's fishing zones. In 1977, the total potential of its marine fisheries sector was estimated at more than 700,000 tonnes per annum. In 2003, the Total Allowable Catch (TAC) established for demersal species was 57,600 tonnes and 160,000 tonnes for pelagic species. The most important resources are various marine demersal and pelagic fish including pilchard and the Cape and Cunene horse Mackerel (Tranchurus capensis and T. trecae). Sardinellas (Sardinella aurita and S. maderensis) are fished in parallel with horse mackerel. The rest of the catches are mainly demersal spp. and some deep water crustaceans. The demersal sppecies consist of Hake (Merluccius polli and M. capensis) and the large eye dentex spp. Tunas are caught at certain times of the year whilst some marine shrimp are also harvested from the Angolan waters. Angola also has several high value freshwater fish species, exploited by about 255 fishers. Tilapia sp. is among the most important and abundant fresh water fish found in Angola. Other species include the catfish (Clarias gariepinus) and fresh water prawns (Macrobrachuin rosenbergii). Some aquaculture ponds have been established in the country side, but due to lack of investment, proper training and the impact of civil war have seriously limited developments in the sub sector.

• 한국양식학회지
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• 제8권4호
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• pp.285-294
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• 1995

프랑스 굴 축양지의 하나인 Bouin 간척지에서 인공기질을 매주 수하시켜 생체량을 정량하고, 기상자료와 해수의 이화학적 성분을 분석한 결과를 상관계수, 상관원, 주성분분석을 통하여 지서미소주류의 변동양상을 나타내었다. 기상요인인 일조시간, 강우량, 바람 중 일조시간의 증가에 따라 미세조류의 생체량 증가와 그에 따른 질산염 소비 등이 높아지고 따라서 해수중의 질산염 농도는 감소되었다. 일조량과 함께 영양염 중 질산염이 생체량 변동에 가장 중요한 기여자이며 생체량이 증가하는 여름철 고수온기에 인산염과 규산염은 오히려 증가하는 경향을 보였다.

• 한국양식학회지
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• 제9권1호
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• pp.65-71
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• 1996

PVC 파판에서 초기전복치패의 먹이생물인 저서미소조류의 변화를 추정하기 위해 1984년 1월부터 12월까지 France Bourneuf만의 굴 양성지에 파판을 수하하여 파판에 부착 발생된 저소미소조류의 엽록소 a와 갈색소를 분석하였다. 저서미소조류의 생체량을 엽록소의 양으로 추정하고, 생리상태를 갈색소의 백분율로 나타낼때 생체량은 제절에따라 겨울에는 파판의 수하시간에 따라 비례하여 증가하였으나, 고수온기인 여름에는 저서미소조류의 군집이 빠르게 노쇠되어 매 2주마다 최대치를 나타내는 양상을 보였다. 갈색소의 백분율은 봄과 가을에 낮은 비율을 나타내었으나, 여름 고수온기에는 군집의 빠른 노쇠로 인하여 백분율은 최대치를 나타내어 군집의 활성이 저하되었으며, 생체량과 갈색소의 백분율을 고려할 때 5, 6월과 9, 10월에 전복의 산란이 이루어지는 것은 저서미소조류를 먹이로 하는 초기부착치패에게 영양적으로 종은 균형을 이루게 한다.

• 한국양식학회지
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• 제20권4호
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• pp.278-288
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• 2007

새우양식은 90년대 서해안을 중심으로 빠르게 발달하여 2001년에는 2,605ha의 면적에서 3,268톤이 생산되었으나 2004년에는 2,368톤으로 해마다 감소되고 있다. 이러한 원인 중의 하나는 흰반점바이러스(WSSV)에 의한 대량폐사에 기인하는 것으로 알려져 있다. 흰반점바이러스는 현재 세계적으로 새우양식산업에 심각한 피해를 입히는 바이러스로 우리나라에는 1993년 처음 보고된 후 해마다 새우양식장에 반복적인 대량폐사를 유발시킨다. 축제식 새우양식장의 질병 피해를 감소시키기 위한 방법의 하나로서 새우와 어류, 패류, 해조류를 함께 복합양식하는 방법이 많은 연구되어 있으며 또한 육식성 어류와의 복합양식은 질병새우를 선택적으로 포식함으로써 새우의 바이러스 발병을 지연 혹은 억제시키는 것으로 알려져 있다. 새우양식장에 육식성 어류인 황복 Takifugu obscurus을 복합적으로 사육함으로써 바이러스 억제 효과를 조사하기 위하여 수면적 $1,616{\sim}1,848\;m^2$의 4개 축제식 양식장에 각각 흰다리새우($46.9/m^2$), 흰다리새우($43.4/m^2$)+황복($0.22/m^2$), 대하($24.6/m^2$), 대하($30.3/m^2$)+황복($0.25/m^2$)의 밀도로 입식하고 95일간 사육하였다. 대하 단독구와 복합구는 각각 51일, 57일째 WSSV 발병으로 전량 폐사하였다. 흰다리새우 단독구의 생존율은 18.2%인 반면 복합구의 생존율은 32.4%이며 단위생산량은 단독구에 비해 69.2%가 높아 흰다리새우는 황복과 복합양식이 단독양식에 비해 훨씬 유리한 것으로 나타났다. 사육수의 영양염(TAN, $NO_2-N,\;NO_3-N$) 농도는 복합구가 단독구에 비해 2배 이상 높았으나 전체적으로 새우의 성장에 적정범위를 유지하였다. 대하는 흰다리새우에 비해 WSSV에 대한 감수성이 높은 것으로 나타났으며 따라서 대하와의 복합양식은 이러한 점이 충분히 고려되어야 할 것이다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2008년도 International Symposium on Remote Sensing
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• pp.320-323
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• 2008

This study attempts to establish a system extracting and monitoring cultural grounds of seaweeds (lavers, brown seaweeds and seaweed fulvescens) and abalone on the basis of both KOMPSAT-2 and Terrasar-X data. The study areas are located in the northwest and southwest coast of South Korea, famous for coastal cultural grounds. The northwest site is in a high tidal range area (on the average, 6.1 min Asan Bay) and has laver cultural grounds for the most. An semi-automatic detection system of laver facilities is described and assessed for spacebome optic images. On the other hand, the southwest cost is most famous for seaweeds. Aquaculture facilities, which cover extensive portions of this area, can be subdivided into three major groups: brown seaweeds, capsosiphon fulvescens and abalone farms. The study is based on interpretation of optic and SAR satellite data and a detailed image analysis procedure is described here. On May 25 and June 2, 2008 the TerraSAR-X radar satellite took some images of the area. SAR data are unique for mapping those farms. In case of abalone farms, the backscatters from surrounding dykes allows for recognition and separation of abalone ponds from all other water-covered surfaces. But identification of seaweeds such as laver, brown seaweeds and seaweed fulvescens depends on the dampening effect due to the presence of the facilities and is a complex task because objects that resemble seaweeds frequently occur, particularly in low wind or tidal conditions. Lastly, fusion of SAR and optic spatial images is tested to enhance the detection of aquaculture facilities by using the panchromatic image with spatial resolution 1 meter and the corresponding multi-spectral, with spatial resolution 4 meters and 4 spectrum bands, from KOMPSAT-2. The mapping accuracy achieved for farms will be estimated and discussed after field verification of preliminary results.