• 한국수산과학회지
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• 제37권2호
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• pp.91-97
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• 2004

Applications of probiotics to shrimp ponds were carried out to determine their effects on water quality. Fermented solutions consisting of Bacillus spp. and Nitrosomonas spp. were applied to a 4 ha shrimp (Fenneropenaeus chinensis) pond from July to September, 2000. In the pond treated with probiotics, daily variations of DO and pH, and concentrations of DIN and DIP were lower than those in the ponds without probiotic treatment. Concentration of phytoplankton was less variable and the number of species was more variable in the probiotic-treated pond than those in the control pond. Variation of bacterial numbers and the number of Vibrio spp. were lower in the treated pond than those in the control pond. It is confirmed that the probiotics can be used to improve water quality of the shrimp ponds.

• Fisheries and Aquatic Sciences
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• 제11권4호
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• pp.195-204
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• 2008

Viral diseases are major emerging problems of shrimp that have affected the production, and even complete losses for shrimp farms. In this study, we developed a sensitive TaqMan real-time PCR method to quantify white spot syndrome virus (WSSV) and hepatopancreatic parvovirus (HPV) in the shrimp and pond water in which fleshy shrimp, Fenneropenaeus chinensis, and Pacific white shrimp, Litopenaeus vannamei, are reared. WSSV and HPV in pond seawaters ranged from $1.65{\times}10^3$ to $2.43{\times}10^9$ and from 0 to $4.43{\times}10^5$ copies/L of seawater, respectively. Of 20 ponds analyzed, all pond water and shrimp were positive for WSSv. L. vannamei showed higher susceptibility to WSSV than F chinensis. HPV was detected only in the pond water for F chinensis. In shrimp tissue, however, HPV was found in both species, with 23-times higher infection rate in F chinensis than L. vannamei. The total bacterial counts in the pond water ranged from $2.23{\times}l0^3$ to $1.98{\times}l0^5\;CFU/mL$. The variations in total bacterial count for each pond appeared to correlate to the variations of the WSSV load. Statistical analysis indicated that there was no significant difference (P>0.05) between the WSSV load in pond water and shrimp, and there was no relationship between total bacterial load and viral load in the pond water. However, a significant difference (P<0.01) was found between HPV load and L. vannamei and F chinensis pond water.

• 한국수산과학회지
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• 제37권1호
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• pp.24-32
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• 2004

A mathematical model is used to investigate nitrogen dynamics in the intensive aquaculture ponds in the western coast of Korea. Parameters associated with water quality, sediments and growing of shrimp (Fenneropenaeus chinensis) are measured to calibrate the model for feeding ponds A and B and storage ponds. The model describes the fate of nitrogen including loadings of ammonia from feeds, phytoplankton assimilation, nitrification, sedimentation, volatilization and discharge. The model obtains good agreements with the measured values of TAN $(NH_4,\;NH_3),\;NO(NO_2,\;NO_3)$ and Chl (chlorophyll a). Impacts of water exchange on TAN and Chl are investigated, showing that the range of 0.01-0.2 (/day) cannot effectively reduce TAN but reduces Chl. Nitrogen in the ponds A is removed by sedimentation $66\%,$ volatilization $8\%,$ discharge of particulate and dissolved $8\%.$ The pond B shows $56\%\;and\;26\%$ of sedimentation and volatilization, respectively, to yield $10\%.$ decrease and 8c/o increase compared to those in the pond A. While the pond A has larger area (1.02:0.66 ha) and same stocking density (0.025 md./L) at the beginning of culture, the pond B obtains higher stocking density (0.0065:0.0091 md./L), longer feeding period (103:121 day) and resultant higher shrimp production (1.15:2.13 t/ha/cycle) at harvest. This is possibly due to the hydraulic characteristics driven by paddlewheels. At low ratio of the low speed area and the pond area, the rate of sedimentation is high, while the rate of gas exchange is low. Thus, the measurement and model analysis suggest that water quality and shrimp production are positively correlated with the hydraulic characteristics in the shrimp ponds.

• 한국양식학회지
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• 제14권1호
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• pp.43-50
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• 2001

To study the effect of paddle wheel on water circulation, velocity components were measured in shrimp ponds both along the longitudinal direction from a single paddle wheel and at 25 grid points of two ponds, which have mean water depth of 1.2m and aspect ratio (length/width) 1.05 and 0.68, respectively. An analysis of factors related to water quality and circulation showed that I) a single paddle wheel has an effective distance of 33m for de-stratification, 16m for particulate suspension and 25m for removal of organic material, dispersion of DO and prevention of bed sediment disturbance and ii) with doubling the number of paddle wheels at the pond corners, the flow speed increased by 13% over the ponds, while it reduced by 8.5% around the pond centres. Contrary to expectation, increasing the number of paddle wheel did not generate strong circulation around the pond centre and improve water quality.

• 한국수산과학회지
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• 제43권4호
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• pp.331-339
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• 2010

Shrimp farming is the most important mariculture industry on the west coast of South Korea. However, it has suffered from mass mortality due to viral disease outbreaks and coastal pollution due to water discharge. This study developed an intensive shrimp culture method for outdoor ponds, without water exchange, which minimizes the chance of viral transmission from the environment, reduces coastal pollution by water discharge and enhances shrimp production. A culture trial was conducted in two high-density polyethylene (HDPE)-lined ponds with a $550\;m^2$ surface area. The ponds were stocked with postlarvae of Litopenaeus vannamei, the major farmed shrimp species in Korea, on July 10, 2007, and cultured for 90 days with no water exchange. The stocking density of the postlarvae (B.W. 0.0015 g) was $272\;ind./m^2$, which is eight times higher than in traditional pond culture in Korea. At harvest, the total production of ponds 1 and 2 was 1,362kg ($2.48\;kg/m^2$) and 1,282 kg ($2.33\;kg/m^2$), respectively. This is 20~22 times higher than the mean farmed shrimp production ($0.112\;kg/m^2$) in Korea and about eight times higher than in traditional ponds with a good harvest. Although there was no water exchange throughout the culture period, the mean concentrations of unionized ammonia and nitrite-nitrogen were as low as 0.038 and 6.0 mg/L, respectively. The feed conversion rate (FCR) was 1.38, which is 20~45% lower than that of traditional pond cultures. The high efficiency of the diet in this study is thought to be due to a well-managed feeding strategy and well-developed bioflocs used as diet additions for the shrimp. The final body weight of the shrimp at harvest was low (12.2~12.5 g), compared with that of traditional pond culture. This may have resulted from the combination of a short culture period, high density of shrimp, and low temperature. This study suggests that a super-intensive shrimp pond culture method using biofloc technology with no water exchange can minimize viral transmission via water exchange, reduce coastal pollution, and enhance shrimp production.

• 스마트미디어저널
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• 제12권3호
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• pp.112-119
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• 2023

Shrimp farming has been becoming a new source of income for fishermen in South Korea. It is often necessary for fishers to measure the size of the shrimp for the purpose to understand the growth rate of the shrimp and to determine the amount of food put into the breeding pond. Traditional methods rely on humans, which has huge time and labor costs. This paper proposes a deep learning-based method for calculating the size of shrimps automatically. Firstly, we use fine-tuning techniques to update the Mask RCNN model with our farm data, enabling it to segment shrimps and generate shrimp masks. We then use skeletonizing method and maximum inscribed circle to calculate the length and width of shrimp, respectively. Our method is simple yet effective, and most importantly, it requires a small hardware resource and is easy to deploy to shrimp farms.

• 한국양식학회지
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• 제13권1호
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• pp.39-46
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• 2000

우리나라의 대하양식은 먹이생물이 대체로 풍부한 연안 및 만을 중심으로 제방을 쌓거나 폐쇄된 염전 등을 이용하여 극히 한정된 장송에서 실시되고 있다. 본 조사 대하 양식장인 남해의 갈화 양식장은 조석차이를 이용한 해수교환이 주기적으로 실시되고 있으나, 서해의 운호 양식장은 단지 양수에 의한 해수보충이 가끔 실시되고 있을 뿐이다. 따라서, 본 연구는 갈화와 운호양식장의 환경특성을 파악하였고, 이에 따른 성장을 비교.검토하다. 갈화양식자의 저질성상은 사질이 약 70%를 차지한데 비해 운호 양식장은 대부분 펄이 차지하고 있었다. 저질중의 황화물은 갈화 양식장에서 1.8mgS/g-dry, 운호 양식장에서 4.7mgS/g-dry가 측정되어 약 3배의 차이를 나타내었다. 해수중의 ammonia-N 및 $H_2S$ 농도는 갈화 양식장에서 각각 0.10mg/${\ell}$ 및 10.8 ${\mu}$g/${\ell}$가 측정된 반면, 운호 양식장에서는 약 2배 이상 높은 0.31mg/l 및 21.2${\mu}$g/${\ell}$이 측정되었다. 또한, DO는 7월부터 8월에 걸쳐 갈화 양식장에서 6.0mg/${\ell}$이하, 운호 양식장에서는 5.0mg/${\ell}$이하가 관찰되었다. 대하의 체장과 체중은 10월 갈화 양식장의 158.2mm 및 28.9g에 비해 운호 양식장에서는 138.3mm 및 22.9g로 유의하게 낮은 성장을 보였다. 또한, 대하의 일일 성장률도 양식기간을 통해 갈화 양식장에 비해 운호 양식장에서 낮게 나타났다/ 따라서, 운호 양식장의 저층수에서 측정된 ammonia-N, $H_2S$ 및 DO는 대하의 성장에 영향을 미쳤다는 것을 의미한다.

• Journal of Microbiology and Biotechnology
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• 제28권6호
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• pp.946-956
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• 2018

The gut microbiota of aquatic animals plays a crucial role in host health through nutrient acquisition and outcompetition of pathogens. In this study, on the basis of the high-throughput sequencing of 16S rRNA gene amplicons, we examined the bacterial communities in the gut of freshwater shrimp (Macrobrachium nipponense) and in their living environments (sediment and pond water) and analyzed the effects of abiotic and biotic factors on the shrimp gut bacterial communities. High bacterial heterogeneity was observed in the freshwater shrimp gut samples, and the result indicated that both the surrounding bacterial community and water quality factors (particularly dissolved oxygen and temperature) could affect the shrimp gut bacterial community. Despite the observed heterogeneity, 57 genera, constituting 38-99% of the total genera in each of the 40 shrimp gut samples, were identified as the main bacterial population in the gut of M. nipponense. In addition, a high diversity and abundance of lactic acid bacteria (26 genera), which could play significant roles in the digestion process in shrimp, were observed in the shrimp gut samples. Overall, this study provides insights into the gut bacterial communities of freshwater shrimp and basic information for shrimp farming regarding the application of probiotics and disease prevention.

• The Korean Journal of Ecology
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• 제15권3호
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• pp.257-265
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• 1992

The effects of insecticide dimilin including the technical grade(tg) and wettable power(wp-25), inhibiting the synthesis of chitin in the cuticle of insect larvae, and herbicides alachlor and atrazine on the development of shrimp caridina denticulata denticulata were investigated in various concentrations. This species is abundant in the freshwater such as river and pond. The shrimp larvae were reared at dimilin solutions(tg and wp 2), alachlor solutions, and atrazin solutions. the concentrations of dimiline were 0, 1, 5, 10 and 25 ppb dimilin solutions, and those of alachlor and atrazin were 0, 1, 5, 10 and 25ppm, respectively.mortality was high at 10 ppb when the larvae were exposed to dimilin and at 25ppm in the case of alachlor and atranzine solutions. If lethal concentration is defined as a concentration in which less than 10% of larvae to the post larval stage from hatching it can be concluded that the lethal concentration of dimilin is 5ppb, and that of alachlor and atrazin is 25 ppm.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1248-1254
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• 2006

The effect of Spirulina platens is and probiotics as feed additives on the growth of the shrimp Fenneropenaeus chinensis was investigated in comparison with a control. The shrimp were cultured in rearing tanks in a seawater pond for 35 days from September 1, 2004. As regards the water quality, the probiotic treatment (T2, commercial diet and 3% probiotics) produced a lower TDN (total dissolved nitrogen) and TDP (total dissolved phosphorus), making it effective in water quality improvement. Nonetheless, the phytoplankton flora succeeded from diatoms to cyanobacteria, regardless of the feed additives. Treatment T3, including 3% S. platensis, produced the highest mean body weight, which was 39% higher than that for all the other treatments (P<0.05). Accordingly, it was found that the use of Spirulina and probiotics as feed additives increased the shrimp body weight and improved the water quality, respectively.