Shrimp Yield Research Articles

An Economic Study on Shrimp Production and Value Chain System in Khulna District of Bangladesh

Shrimp farming and related activities contribute significantly to the national economy of Bangladesh. Per hectare half yearly average yield of shrimp was 350 kg and its money value was Tk. 1, 07,900. Variable cost is 61.29% and fixed cost is 38.71% of the total cost (Tk. 92,190). Among the various variable cost items of shrimp production, maximum cost Tk. 20,000 was found on human labor which was about 35.40% and Tk. 14,770 was found on feed which was about 26.14% of the total variable cost. Again among the various fixed cost items of shrimp production, maximum cost (Tk. 24,375) was found on human labor which was about 68.30% of the total fixed cost. Net returns were estimated at Tk. 1, 49,710 and benefit-cost ratio of shrimp farming was 2.62 which indicates that shrimp production is profitable business for the shrimp farmers. The value chain system continues by the active involvement of farmer, faria, aratdar, bepari, retailer, consumers.

Dynamics of Shrimp Farming in the Southwestern Coastal Districts of Bangladesh Using a Shrimp Yield Dataset (SYD) and Landsat Satellite Archives

The shrimp-farming area and shrimp yield are continuously changing in the southwestern coastal districts of Bangladesh. The three southwestern coastal districts, Bagerhat, Satkhira, and Khulna, along with Rampal, a subdistrict of Bagerhat, contribute 75% of the total shrimp yield of Bangladesh. However, the shrimp yield and farming area have declined in Bagerhat district, and the cause of this decline is uncertain. In this research, the differences in the shrimp yield were quantified using a shrimp yield dataset (SYD) and k-means classification. A supervised image classification approach was applied to quantify the spatiotemporal changes and identify the influencing factors behind the declining shrimp-farming area and yield in Rampal, Bagerhat district, using Landsat satellite archives. K-means classification reveals that, between 2015 and 2017, the shrimp yield in Bagerhat district declined significantly compared to Satkhira and Khulna. The satellite-based monitoring results affirm that the shrimp-farming area of Rampal also decreased rapidly, from 21.82% in 2013 to 6.52% in 2018. This research estimates that approximately 70% of the shrimp-farming area was lost in Rampal since December 2013. Hence, the findings of this research might motivate the responsible bodies to declare the shrimp-farming coastal area as a “shrimp zone” and implement an active policy to protect the vulnerable shrimp-farming industry and shrimp farmers, considering it is the second-largest export earning source in Bangladesh after ready-made garments.

Factors influencing yield loss due to diseases in black tiger shrimp (Penaeus Monodon Fabricius, 1798) culture in Soc Trang province

This study aimed to determine the influencing factors on the yield loss due to diseases in black tiger shrimp (Penaeus monodon Fabricius, 1798) cultured in Soc Trang province. Data for the study were collected by interviewing 334 households farming black tiger shrimp in Soc Trang province in 2017. Descriptive statistical analysis was employed to evaluate the current situation of yield, disease and yield loss due to diseases in black tiger shrimp culture of households. Multiple linear regression analysis was used to determine the factors in influencing the yield loss of black tiger shrimp due to diseases. The results showed that the average black tiger shrimp yield fluctuated from 0.54 to 3.28 tons/ha/crop. The household percentage affected by black tiger shrimp diseases was from 33.3% to 90.8%. The percentage of yield loss due to diseases was between 34.6 and 74.2%. The influencing factors (variables) on the yield loss due to diseases included: being a member of black tiger shrimp culturing cooperative; application of trained techniques for shrimp culture and employment of tested post larva (negative correlation with the yield loss in all culture models: reformed extensive culture, semi-intensive culture and intensive culture). For semi-intensive culture and intensive culture, the yield loss due to diseases way negatively correlated with farmer's education degree, employment of accumulation pond and the total pond area for shrimp culture of household whereas farmer's age positively correlated with farmer's age.

Sensitivity of multispecies maximum sustainable yields to trends in the top (marine mammals) and bottom (primary production) compartments of the southern North Sea food-web

In marine ecosystems, maximum sustainable yield considerations are affected by any substantial changes that occur in the top and bottom compartments of the food-web. This study explores how the southern North Sea’s fisheries may need to adjust their fishing efforts to maintain optimum yields of sole, plaice, cod and brown shrimps under increased marine mammal populations and a reduced primary productivity. We constructed plausible scenarios of ongoing food-web changes using the results of Bayesian age-structured population models to estimate carrying capacities of harbour porpoises (Phocoena phocoena) and grey seals (Halichoerus grypus). Losses in primary productivity were predicted by lower trophic level ecosystem models. These scenarios were implemented in a food-web model of the southern North Sea. For each scenario, we sought mixed-fleet fishing efforts that would deliver maximum yields of sole, plaice, cod and brown shrimp combined. We also did so for a baseline run with unaltered mammal and primary production, and compared the differences in optimal fishing strategies, predicted yields, and states of the stocks between the scenarios. We found stocks and yields to be far more sensitive to changes in primary productivity than to increased marine mammal predation. The latter predominantly impacted cod, and even benefitted brown shrimps compared to the baseline run. Under 30% reduced primary productivity, fishing efforts had to be reduced by 50% to still provide maximum yields, whereas the marine mammal scenario induced no need to adjust the fishing regime. This draws attention to the potential gains of incorporating bottom-up processes into long-term management considerations, while marine mammal predation may be less of a concern, in particular for flatfish fisheries in the North Sea, and may even benefit shrimp trawlers because of reduced predation on shrimp from fish predators.

Design, development and analysis of an IoT-based framework for monitoring aquaculture farms

Aquaculture is one of the most popular occupations for the people in the coastal regions of India. Thousands of farmers depend on the yield generated from aquaculture business for their livelihood. Due to various factors, the water in fishery farms gets polluted, which hampers the growth and yield of fish and shrimp. The traditional approaches followed by Indian aquaculture farmers to measure water quality in their farms are slow and inaccurate. This paper highlights the design and development of a wireless sensor network (WSN) for Indian aquaculture farmers for real time assessment and control of the water quality in their farms. Such a system offers flexibility, efficiency, remote monitoring and early warning to the farmers to take preventive measures in time. This paper also presents the power consumption of the sensor node and analysis of the network parameters of the designed sensor network in terms of received signal strength indicator (RSSI) and packet loss (%) for its robust and efficient design and deployment.

Phân tích hiệu quả sản xuất và sử dụng năng lượng điện trong nuôi tôm sú (Penaeus monodon) và thẻ chân trắng (Litopenaeus vannamei) thâm canh và quảng canh cải tiến ở Đồng bằng sông Cửu Long

The study aimed to assess the production efficiency and electricity consuming of white-leg shrimp and black tiger shrimp of intensive and improved extensive farming systems in the Mekong Delta, in order to estimate the demand of electricity to develop the network of electricity supply and use in sustainable shrimp farming. The result indicated that the yield of white-leg shrimp cultured in lining pond was averaged 47±19 ton/ha/crop higher than that of shrimp cultured in earthen ponds (10±11 ton/ha/crop), followed by intensive system culture of black tiger shrimp with shrimp yield of 5±3 ton/ha/crop, and the lowest was the improved extensive system (0,39±0,23 ton/ha/year). White-leg shrimp cultured in lined pond consumed 3,235 kW.h/ton of shrimp (electricity cost of VND 5,085/kg of shrimp) that was higher than that of white-leg cultured in earthen pond 2,914 kW.h/ton of shrimp (VND 4,514/kg of shrimp); but lower than that of intensive black tiger shrimp 4,173 kW.h/ton of shrimp (VND 6,560/kg of shrimp); meanwhile improved extensive of black tiger shrimp did not use electricity.

Influence of variation in water temperature on survival, growth and yield of Pacific white shrimp Litopenaeus vannamei in inland ponds for low‐salinity culture

There is considerable interest in the culture of whiteleg shrimp (Litopenaeus vannamei) in inland low-salinity water in Alabama and other states in the Sunbelt region of the US. However, the growing season is truncated as compared with tropical or subtropical areas where this species is typically cultured, and temperature is thought to be a major factor influencing shrimp production in the US. This study, conducted at Greene Prairie Aquafarm located in west-central Alabama, considered water temperature patterns on a shrimp farm in different ponds and different years; and sought possible effects of bottom water temperature in ponds on variation in shrimp survival, growth and production. Water temperature at 1.2 m depth in 22 ponds and air temperature were monitored at 1-hr intervals during the 2012, 2013, 2014 and 2015 growing seasons. Records of stocking rates, survival rates and production were provided by the farm owner. Correlation analysis and linear mixed model analysis of variance were used. Results showed that hourly water temperatures differed among ponds. The range of water temperature in each pond explained 41% of the variance in average final weight of shrimp harvested from each pond. In conclusion, the results suggest that variation in water temperature patterns has considerable influence on shrimp growth and survival in ponds.

Effect of ice water pretreatment on the quality of Pacific White Shrimps (Litopenaeus vannamei).

Pacific White Shrimps (Litopenaeus vannamei) are an aquaculture species with global importance. For the purpose of this paper, the quality shelling process of Pacific White Shrimps, freshly harvested from farms and stored in a mixture ice water up to 24 hr, was investigated. Both the differences and correlations between the indexes such as peeling time, shrimp yield, chromatic aberration, texture, K value, TBA value, and microstructure were compared and analyzed. The optimal shell peeling time of Pacific White Shrimps was determined by ice water treatment for 8 hr. The shell peeling time was 1.77 min, the elasticity of the shrimp was 0.51 mm, the hardness was 2,124.58 g, K value was 1.33%, and TBA value was 0.004 mg/100 g. Both the smell and color of the shelled shrimp were normal. This study aims to endorse the mechanical shelling of Pacific White Shrimps.

Feed management and the use of automatic feeders in the pond production of Pacific white shrimp Litopenaeus vannamei

The purpose of this study was to examine the effects of using automatic feeding and acoustic feedback systems on the pond culture of Pacific white shrimp Litopenaeus vannamei. This trial was performed using 16, 0.1 ha ponds stocked at 38 shrimp/m2 and grown for 13 weeks. The treatments used were a standard feeding protocol (SFP) fed twice daily, a Timer treatment fed a 15% increase to the SFP offering feed 6 times per day (Timer 15), a timer treatment fed a 30% increase to the SFP offering feed 6 times per day (Timer 30), and the AQ1 acoustic feedback system that fed based on feeding activity (AQ1). At the conclusion of the pond production trial, final individual weights of the shrimp were significantly different for all treatments 19.74 g, 25.15 g, 27.52 g, and 32.04 g for the SFP, Timer 15, Timer 30, and AQ1 treatments respectively. The shrimp yield for the AQ1 treatment (7430 kg/ha) was also significantly higher than the SFP (4843 kg/ha) or Timer 15 (5629 kg/ha) treatments. The AQ1 treatment also produced a significantly higher value of shrimp ($65,587/ha) than the SFP ($32,982/ha) or the Timer 15 ($44,279/ha). No significant differences were seen in FCR (1.07–1.24) or survival (58.5–63.9%). The results of this and previous work, demonstrated that increasing the number of daily feedings from 2 to 6 can allow for a higher daily feeding rate, which translated into higher growth and production. Improvements of feed inputs using feedback technologies improved the production as the number of feedings and quantity of feed was increased, resulting in further improvements in production. The results of this study indicate that increasing the number of daily feedings in the pond production of shrimp has the potential to significantly increase growth and can reduce the labor requirements for feeding.

Reduction of the Phosphate Soaking Time Required for Shrimp Products Using Pulsed Vacuum Condition

ABSTRACTPulsed vacuum (PV) was used to reduce the phosphate soaking time for raw and cooked shrimp, without reducing its quality. The shrimp was soaked in a phosphate solution under cycles of vacuum pressure (15 kPa, 7 min) and atmospheric (ATM) pressure (101 kPa, 3 min). PV-soaked shrimp reached stable absorption faster than ATM-soaked shrimp. At equilibrium absorption, no differences in moisture or phosphate contents were observed between PV- and ATM-soaked shrimp. After cooking, PV-soaked and ATM-soaked shrimp showed no differences in product yield or texture. Therefore, PV soaking reduces soaking time but does not affect the yield of cooked shrimp, increasing production capacity. Moreover, this study suggests that to maximize the yield of raw-soaked shrimp, shrimp should be soaked until the moisture content reaches equilibrium. In contrast, cooked shrimp should be soaked until the phosphate content stabilizes, to produce the highest yield with the lowest soaking time.

Effect of steaming on physical and chemical characteristics White Shrimp (Litopenaeus vannamei) from Indramayu Waters

White shrimp (Litopenaeus vannamei) was a fishery product that has potential to be developed, can be used as ready to eat food or as raw material for various processed products. This study aimed to determine the effect of steaming process on the physical and chemical characteristics of white shrimp collected from Indramayu waters. The research method used was experimental consisting of two treatments (fresh shrimp and steamed shrimp), each treatment was repeated 4 times consisting of three levels (headless, peeled tail on, and peeled undevined). The parameters observed included physical test (yield, cooking loss, color) and chemical test (moisture, protein, fat, and ash content). The results showed that fresh white shrimp yield after peeled completely of 61.92%, whole steamed shrimp 92.76%, and peeled tail on steamed shrimp was 36.02%. Yield of peeled undevined steamed shrimp has the lowest value compared to other that was 54.78%. Cooking loss during shrimp steamed process was 7.24%. The color values of steamed shrimp include L* 68.57, a* 12.17, and b* 47.41. Chemical composition of white shrimp after steaming process decreased water content, while protein, fat, and ash levels increased.

ĐÁNH GIÁ ĐẶC ĐIỂM THỦY HÓA TRONG MÔ HÌNH TÔM SINH THÁI TẠI XÃ TAM GIANG, HUYỆN NĂM CĂN, TỈNH CÀ MAU

This paper clarifies the hydrochemical characteristics of the organic shrimp model certified by Naturland at Tam Giang commune, Nam Can district, Ca Mau province. Pond water was sampled in 8 ponds at 3 points of time of distinct precipitation fluctuations during the year (March, July and November 2015) and hydrochemical parameters related to shrimp were analysed. Results show that salinity, total alkalinity and total hardness are largely dependent on the seasonal precipitation and evapotranspiration, highest in the middle of the dry season (March) and gradually reduced until the wet season-dry season transition (November). Most of the parameters fluctuate within the sampling times but still remain suitable for shrimp. The major constraints include oxygen supersaturation during daylight hours (7.48 ± 0.45 mg/l), low concentrations of soluble nutrients (NH4-N 0.21 ± 0.05 mg/l, NO3-N 0.06 ± 0.02 mg/l, PO4-P 0.02 ± 0.01 mg/l), and high iron contents (Fe2+ 0.08 ± 0.01 mg/l, Fe3+ 0.64 ± 0.14 mg/l) as compared to limits for shrimp aquaculture. The total shrimp yields are very low (355.4 kg/ha water surface/year in which wild shrimp species have accounted for 55%), positively correlated with water depth and temperature but negatively correlated with Fe2+. To improve pond water quality and shrimp yield, it is recommended to increase water depth, nutrient concentrations and restrict the effects of runoff at the beginning of the wet season.

Production characteristics of intensive whiteleg shrimp (Litopenaeus vannamei) farming in four Vietnam Provinces

Whiteleg (Litopenaeus vannamei) and black tiger (Penaeus monodon) shrimp are the most common farm-based shrimp species cultured in Vietnam, but there have been few studies of intensive whiteleg shrimp production. The objectives of this study were to describe production characteristics and to identify factors associated with yield in intensive shrimp production systems in Vietnam. This study included data from shrimp farms in four Vietnam provinces, collected from mid-2014 to early 2016. The data included key production characteristics, such as length of production cycle, number and quality of postlarvae (PL) stocked, feed intake, production yield (kg/m2), harvest size (shrimp/kg), average weight and water quality measurements for some of the crops. We report descriptive statistics for the production parameters and findings from two linear mixed models describing the associations of these parameters with two outcomes: production yield and average weight of shrimp. The average stocking density for the 846 crops included in the dataset was 109 PL/m2, average length of production cycle was 92 days, and average production yield was 1.15 kg/m2. The shrimp gained 0.2 g per day, on average, and consumed an average of 0.17 kg of feed, daily/1,000 PL stocked. The linear mixed models indicated that stocking density, stocking month and region were the main predictors for production yield, while water temperature 4 weeks prior and PL quality were the main predictors for the average weight of shrimp, after accounting for the length of production cycle. This study describes baseline production parameters for whiteleg shrimp production in Vietnam.

The Socio-economic Impact of Climate Change on Marine and Freshwater Fisheries Resources in the Coastal Zone of the Gambia

The fisheries sector is a vital source of overseas exchange and income for the financial and social advancement needs in most part of the world. However, challenges like the low level of research and education on the prospects of this sector to front-runners, business-oriented financiers across the Sub-region has contributed to low investment and development of this sector. Giving the prospects this sector presents, Climate Change (CC) impacts may compromise the Coastal Zone's (CZ) ability to deliver benefits derived from fisheries resources. This study seeks to characterize the trend of artisanal and industrial fisheries catches in The Gambia from 1986-2016 with projected trends to the year 2025. The study will further estimate the effects of climate change on the productivity of fisheries resources in River Gambia and; estimate the effects of climate change on shrimp yield on the sheltered coast of The Gambia to the year 2100. The results of the study reveal industrial fishery catches is decreasing at 534 MT annually over the period 1968- 2014. This observed negative trend is predicted to decrease from 4,770 MT in 2014 to 66.7 MT by the year 2025. The artisanal fisheries sector, contrariwise, revealed a positive trend of 1,611 MT per annum from 1986-2016. It is predicted this trend will increase from 58,261.6 MT in 2016 to 70,651.8 MT by the year 2025; this relates to an increase of approximately 21%. By the year 2100, there will be a potential increase of sustainable shrimp yield in The Gambia by 46%, while the productivity of the River Gambia in support of fisheries resources will increase by 13%. This result reveals that by the end of this century, The Gambia maritime space, and its river framework, will continue to be productive in the support of shrimp and other artisanal fisheries resources under the anticipated impacts of CC on the CZ.

A comparative study on stress resistance and growth among the inbred and hybrid offsprings of wild population F 1 and inbreeding population of Litopenaeus vannamei

PDF HTML阅读 XML下载 导出引用 引用提醒 凡纳滨对虾野生群体F1与近交群体杂交和自交子代的抗逆、生长性状比较 DOI: 作者: 作者单位: 1. 浙江省海洋水产养殖研究所, 浙江 温州 325005;2. 浙江省近岸水域生物资源开发与保护重点实验室, 浙江 温州 325005 作者简介: 冀德伟(1983-),男,工程师,从事对虾选育与养殖生态研究.E-mail:jdw8313@163.com 通讯作者: 中图分类号: S917 基金项目: 浙江省重大科技专项（2016C02055-5）；浙江省省属科研院所专项（2017F30041）；温州市科技计划项目（N20140040，N20160007）. A comparative study on stress resistance and growth among the inbred and hybrid offsprings of wild population F1 and inbreeding population of Litopenaeus vannamei Author: Affiliation: 1. Zhejiang Mariculture Research Institute, Wenzhou 325005, China;2. Zhejiang Key Laboratory of Exploitation and Preservation of Coastal Bio-resource, Wenzhou 325005, China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为了探究野生群体的引入对凡纳滨对虾（（EC）与自建的全同胞兄妹近交群体（ZG）双列杂交，构建了EC♂×EC♀（EE）、ZG♂×ZG♀（GG）、EC♂×ZG♀（EG）、ZG♂×EC♀（GE）4个子代群体，并对4个群体的仔虾进行了急性低盐度、亚硝酸盐暴露下的存活率和急性微囊藻毒素（MC-LR）暴露下的抗氧化酶活性分析，同时进行了养殖生长性状测试。结果显示：4个群体仔虾急性低盐度暴露下的存活率、急性MC-LR暴露下的抗逆性和生长性状都表现为EE > GE > EG > GG，急性亚硝酸盐暴露下的存活率GE > EE > EG > GG；杂交群体GE在急性低盐度、亚硝酸盐暴露和生长性状的杂种优势率分别为31.83%、77.01%和2.77%；而EG群体的杂种优势率分别为-19.21%、-8.01%和-8.14%，性状弱于双亲中值。4个群体的抗逆、生长性状总体表现为EE > GE > EG > GG。研究发现：凡纳滨对虾杂交群体的性状以母本遗传占主导优势，近交群体的性状衰退可能是导致以其为母本的杂交子代性状退化的主因；凡纳滨对虾选育工作可能需要每年补充外源基础群体，才能保持选育群体的优势性状。 Abstract:, which is also known as white shrimp, is one of the main farmed shrimp species in China. It is native to the coastal line of Central and South America and was, instead of , introduced into China in the 1990's. The yield of white shrimp increases annually significantly because of its fast growth, adaptability to a wide range of salt and temperatures, strong disease resistance and low demand for dietary protein. However, in recent years, the success rate of white shrimp farming in China has declined because almost 70% of white shrimp seedlings are from inbreeding produced by hatchery farm without systematic selection, resulting in inadequate growth performance and stress resistance. The very small quantity of quality broodstock imported from abroad is unable to meet market demand. Meanwhile, the dominant trait of broodstock selected by other research institutes in China is not stable. The selection of high-quality broodstock is critical to improving shrimp farming in China. Collection of different basic populations is the basis for white shrimp selective breeding and inbreeding should be avoided. In this study, in order to analyse the effect of wild population introducing on the growth trait and stress resistance of the 1 which was imported from Ecuador (EC) and an inbreeding population (ZG) using a complete diallel cross to construct four F1 populations including EC♂×EC♀ (EE), ZG♂×ZG♀ (GG), EC♂×ZG♀ (EG), ZG♂×EC♀ (GE). The survival rate of post-larvae after exposure to acute low salinity or nitrite, the antioxidant enzymes activities under microcystin-LR (MC-LR) exposure and the growth speed were compared between these four F1 populations. The results showed that the survival rates under acute low salinity (from 30‰ to 2‰) for 24 h to 48 h were significantly different between the four F1 populations (EE > GE > EG > GG, <0.05), with the survival rate of the EE population as the highest and the GG population as the lowest. The survival rates of the four F1 populations under acute nitrite treatment (35 mg/L) after 60 h were different (GE > EE > EG > GG), with GE as the highest and GG again as the lowest. After exposure to 8 mg/L MC-LR, the antioxidant enzyme activities of SOD and CAT were significantly upregulated at 24 h or 36 h; activities of GPX, GST and GR, which are involved in removing secondary metabolites such as H2O2 and ROOH, were also up-regulated; the GSH contents in hepatopancreas decreased because of consumption and the resistance to MC-LR was significantly different between the four F1 populations (EE > GE > EG > GG). The growth trait analysis showed that the growth speed of the EE and GE populations during 0-40 d was slower than the other two populations, while these two populations showed higher growth speed during 40-83 d, and the EE population had the best growth trait after 83 d (EE>GE>EG>GG). The heterosis rates of hybrid population GE under acute low salinity, nitrite or MC-LR treatment were 31.83%, 77.01%, and 2.77%, respectively, and the performance was better than the mean values of the parents. While the heterosis rates of the EG population were -19.21%, -8.01% and -8.14%, the performance was weaker than the mean values of the parents. In conclusion, the stress resistance and growth trait of the four F1 populations was EE > GE > EG > GG. The results revealed that maternal inheritance was dominant for hybrid populations; the trait depression in hybrid offspring could be caused by using female individuals from inbreeding population; and improving the dominant traits depended on more and more basic populations for white shrimp selective breeding. 参考文献 相似文献 引证文献

SPECIES COMPOSITION, DISTRIBUTION, AND POTENTIAL YIELD OF DEEP SEA SHRIMP RESOURCES IN THE WESTERN SUMATERA OF THE INDIAN OCEAN EEZ OF INDONESIAN WATERS

study on the catch composition, distribution and potential yield of deep sea shrimp in the westem off sumarera waters was conducled on June to July 2005 using RV Baruna Jaya lV with trawl net. This study was basicarry caffied out by emproying swept area method

POTENTIAL YIELD OF DEEP SEA SHRIMP RESOURCES IN THE SOUTHERN JAVA OF THE INDIAN OCEAN EEZ WATERS

Study on the potential yield of deep sea shrimp in the south off Java waters (lndian Ocean) was carried out based on data collected from the survey conducted between May and June 2005 using Baruna Jaya IV research vessel. This study was basically conducted by applying swept area method.

Changes of shrimp farming in southwest coastal Bangladesh

Shrimp (Penaeus monodon) farming is a traditional aquaculture in southwest coastal Bangladesh. Changes in both the farming practice and yield of shrimp since the advent of commercial production in this area are evident in scientific studies. We assessed the historical perspective of shrimp farming indicating the major phase changes and present situation of the shrimp farming practice including recent changes in yield and cost-benefit. A systematic random sampling method was employed to conduct a total of 240 questionnaire surveys, 24 focused group discussions, and 60 key informant interviews in six sub-districts (upazila) from southwest coastal Bangladesh. We identified four major phase changes in the history of shrimp farming in southwest coastal Bangladesh and found that shrimp mixed culture is the most preferable form of extensive cultivation at present. Shrimp farmers’ perceptions about changes in shrimp yield and changes in availability of ecosystem services represent declining trends over the last two decades. For 2015, shrimp yield was not significantly different with respect to salinity levels. The net benefit from shrimp mixed culture in 2015 was 121,000 taka/ha, which is 2.35 times higher compared to the net benefit from only shrimp (51,500 taka/ha). In this context, promoting shrimp mixed cultivation could be a management solution for sustainable development of shrimp farming in southwest coastal Bangladesh. The National Shrimp Policy of the government also emphasized on promoting environment-friendly shrimp mixed cultivation for sustainable development of shrimp farming. However, more institutional support such as training, extension support, technical assistance, and credit facility is required to implement the policy.

A novel combined recirculating treatment system for intensive marine aquaculture

This study established a pilot-scale recirculating treatment system that coupled an ecological process with a biological process to achieve adequate water quality and to minimize the water consumption for intensive marine culture. The recirculating treatment system consisted of a settling cell, a biofilter tank, a bivalve tank and gravel beds. The toxic pollutants, threatening the growth of bivalves, were reduced by the settling cell and the biofilter tank, so that the polyculture of shrimp and bivalves could be achieved. The living bivalve tank could function well as a remover of remaining small suspended solids (SS), and other pollutants. As the SS was reduced to a very low level by bivalve tank before the water flowing into the gravel beds, the risk of clogging was prevented. The studies suggested that the system maintained high removal efficiencies of SS, ammonium nitrogen () and nitrite nitrogen () and could contribute to the increase in shrimp yield.

Economics of Sustainable Intensification of Aquaculture: Evidence from Shrimp Farms in Vietnam and Thailand

AbstractThere is growing interest in sustainable intensification of aquaculture production. Yet little economic analysis has been done on farm‐level effects of the economic sustainability of production intensification. Data from 83 shrimp farms (43 in Vietnam and 40 in Thailand) were used to identify (through principal component and cluster analyses) 13 clusters of management practices that reflected various scales of production intensity that ranged from 0–1999 kg/ha/crop to 10,000 kg/ha/crop and above, for both Penaeus monodon and Litopenaeus vannamei in Vietnam and Thailand. The clusters identified reflected sets of management practices that resulted in differing yields despite similarities in stocking densities among some clusters. The enterprise budget analysis developed showed that the more intensively managed clusters outperformed the less intensively managed clusters in economic terms. More intensively managed farm clusters had lower costs per metric ton of shrimp produced and were more profitable. The greater yields of shrimp produced per hectare of land and water resources in more intensively managed shrimp farms spread annual fixed costs across a greater volume of shrimp produced and reduced the cost per metric ton of shrimp. Costs per metric ton of shrimp produced decreased from the lowest to the highest intensity level (from US$10,245 at lowest intensity to US$3484 at highest for P. monodon and from US$24,301 to US$5387 for L. vannamei in Vietnam and from US$8184 at the lowest intensity level to US$3817 at the highest intensity level per metric ton for L. vannamei in Thailand). Costs of pond amendments used in shrimp production were particularly high in Vietnam and largely unwarranted, whereas fixed costs associated with the value of land, production facilities, equipment, and labor were sufficiently high in Thailand so that net returns were negative in the long run. Nevertheless, economic losses in Thailand were less at greater levels of intensification. The study demonstrated a clear value proposition for shrimp farmers to use natural resources (such as land) and other inputs in an efficient manner and supports findings from corresponding research on farm‐level natural resource use efficiency. Additional research that incorporates economic analysis into on‐farm studies of sustainable intensification of aquaculture is needed to provide ongoing guidance related to sustainable management practices for aquaculture.