Production Of Freshwater Prawn Research Articles

Impacts of Training to Member of Society on Production of Freshwater Prawn and Carps Polyculture using Feed in Rural Areas of Kashiganj in Mymensingh

A society of 58 farmers in Kashiganj of Phulpur upazila in Mymensingh district cultured carps and giant freshwater prawn in 59 ponds where 45 people produced carp fishes in 50 ponds, and five farmers with other eight members cultured carps-prawn-poultry polyculture in nine ponds for about nine months. The members of the society received training and technical assistance for polyculture. The fry @ 20000/acre of prawn and carps such as catla, rohu, mrigal, silver carp, mirror carp and silver barb were released in March 2016. The fry of prawn was released with carps in nine ponds in one village – Biska (L05) only. The water quality parameters and pond bottom soil properties were within the productive ranges. Formulated feed (30% protein) used to feed prawn two times daily, and supplementary feed (15% protein) was used to feed carps two times daily and feeds were adjusted fortnightly. Farmers started to harvest prawn (100-150g) and carps (0.80-2.10kg) and silver barb (150-200g) from middle of October up to the end of November. The crude protein of prawn was higher than mirror carp followed by rohu, catla, silver carp and silver barb. The estimated yearly production of carps, prawn of 59 ponds (approximately 35 acres) and poultry birds was about 30 ton which was about six times higher than the past from 59 ponds. Physico-chemical and biological properties of water, and feed had significantly combined effects and percentage contribution (MR2) on the growth and production of prawn (MR2 = 50.84%), and different species of fishes such as catla (MR2 = 80.28%), rohu (MR2 = 69.22%), mrigal (MR2 = 58.52%), silver carp (MR2 = 72.93%), mirror carp (MR2 = 61.62%) and silver barb (MR2 = 55.80%). These factors had almost positively linear correlation with prawn and different species of fishes. The increased production was due to use of fertilizer, feed and proper care taken by owners and the members of the society. Five farmers produced 1000 poultry birds in two lots from five farms which established by the side of ponds. Pond owners shared the benefits with the society at the ratio of 50:50 and kept for the welfare of the society.

Effects of C/N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors

The effects of C:N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors were investigated. The experiment had two treatments: T1 and T2 each with three replications. Stocking density was maintained at 20,000 juveniles ha-1. In T1, only commercially available prawn feed was applied and in T2, a locally formulated and prepared feed containing 24% crude protein with C:N ratio close to 20 was used, and maize flour and bamboo side shoots were provided for maintaining C:N ratio 20.Mean values of water quality parameters did not vary significantly (P>0.05) between treatments. Periphytic biomass in terms of dry matter, ash free dry matter (AFDM) and chlorophyll a showed significant difference (P<0.05) among different sampling months. Individual harvesting weight, individual weight gain, specific growth rates, gross and net yields of prawn were significantly higher (P<0.05) in T2 than T1. Therefore, it was concluded that freshwater prawn might consume periphyton biomass in C:N controlled periphyton based organic farming practices resulted a significantly (P<0.05) higher production of freshwater prawn than traditional farming.

Effects of C/N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors

The effects of C:N controlled periphyton based organic farming of freshwater prawn on water quality parameters and biotic factors were investigated. The experiment had two treatments: T1 and T2 each with three replications. Stocking density was maintained at 20,000 juveniles ha-1. In T1, only commercially available prawn feed was applied and in T2, a locally formulated and prepared feed containing 24% crude protein with C:N ratio close to 20 was used, and maize flour and bamboo side shoots were provided for maintaining C:N ratio 20. Mean values of water quality parameters did not vary significantly (P>0.05) between treatments. Periphytic biomass in terms of dry matter, ash free dry matter (AFDM) and chlorophyll a showed significant difference (P<0.05) among different sampling months. Individual harvesting weight, individual weight gain, specific growth rates, gross and net yields of prawn were significantly higher (P<0.05) in T2 than T1. Therefore, it was concluded that freshwater prawn might consume periphyton biomass in C:N controlled periphyton based organic farming practices resulted a significantly (P<0.05) higher production of freshwater prawn than traditional farming.

An Economic Assessment of Fish and Prawn Health Management in Andhra Pradesh

The assessment of physical and financial losses due to incidence of diseases in aquaculture is essential to strengthen the socio-economic status of fish farmers. This study has been conducted in four districts (Nellore, West Godavari, East Godavari, and Prakasham) of Andhra Pradesh which ranks first in the production of freshwater prawn and second in freshwater fish in India. The study is based on a survey of 120 fish farmers who owned small ( 10 acres) culture ponds. The study has elicited the geographic profile of fish farmers, aqua inputs, fish and prawn diseases, health management costs, and physical and financial losses in carp and prawn production systems in Andhra Pradesh. The study has revealed that health management costs are higher in prawn than those in carps production systems. The physical and financial losses were higher in prawn than carps culture systems. The study has made suggestions to minimize health management costs and losses in aquaculture in Andhra Pradesh.

Impacts of Inclusion of Column Feeder Rohu (Labeo Rohita) at Different Stocking Densities on Growth and Production in Freshwater Prawn-Finfish Polyculture System

Normal 0 false false false EN-US X-NONE BN-BD MicrosoftInternetExplorer4 An experiment was conducted to assess the impacts of inclusion of column feeder rohu ( Labeo rohita ) on growth and production in freshwater prawn-carp-mola polyculture system at the Department of Fisheries Management, Bangladesh Agricultural University, Mymensingh for a period of 172 days (June - December, 2008). Four stocking densities of Rohu were maintained as 500, 1,000, 1,500 and 2,000 ha -1 in treatment R 500 , R 1000 , R 1500 and R 2000 , respectively in triplicates. All ponds each 120 m 2 were stocked with juvenile freshwater prawn ( Macrobrachium rosenbergii ), silver carp ( Hypophthalmichthys molitrix ), catla ( Catla catla ) and small fish mola ( Amblypharyngodon mola ) at the fixed stocking densities of 20,000, 1,500 , 1,000 and 20,000 ha -1 , respectively. Prawns were fed with pelleted feed twice daily started initially with 10% and gradually reduced to 3% of body weight and continued throughout the study period. All fish were fed with mixture of soaked rice bran and mustard oilcake (2:1) at the rate of 3% of the body weight daily. All the water quality parameters such as temperature, transparency, pH, dissolved oxygen, total alkalinity, NH 3 -N, NO 2 -N, NO 3 -N, PO 4 -P and chlorophyll- a did not differed significantly (>0.05) among the treatments. The survival rate, mean individual weight and production of prawn were decreased with increasing density of rohu. Therefore, the density of rohu significantly (P<0.05) influenced the growth and production of freshwater prawn. Catla and Mola production were affected adversely with increasing rohu density. The production of rohu increased with increasing density although the individual weight decreased. The combined production of all finfish was significantly lower in R 0 whereas, the combined production of all species including prawn did not differ significantly (P<0.05) among the treatments. The treatments R 0 and R 500 fetched higher net profit without significant difference between them. Therefore, inclusion of rohu at a density of 500 ha -1 may be recommended for prawn-carp-mola polyculture.

Current status and prospects of farming the giant river prawn Macrobrachium rosenbergii (De Man) and the monsoon river prawn Macrobrachium malcolmsonii (H.M. Edwards) in India

Freshwater prawn production in India that includes farming and wild capture of the giant freshwater prawn, Macrobrachium rosenbergii and the monsoon river prawn, M. malcolmsonii has increased steadily since 1999 reaching a peak output of 42 780 t in 2005, but then declined to 6568 t in 2009–2010. Stunted growth and diseases in ponds because of poor seed quality and the broodstock which had been inbred over several generations; pond water quality issues; and increased cost of production on account of feed, labour and the mandatory certification requirements are suggested to be some of the factors leading to the production declines. While majority of the output occurs in Andhra Pradesh, single crop paddy–prawn production systems in the low-lying fields of Kerala have helped gradual transformation to a sustainable, organic mode of farming of both rice and prawns, suitable for other states of India. Although the trends by June 2011 indicate that the sector is set to a revival, future prospects of freshwater prawn farming in India will also depend on the expansion of whiteleg shrimp Litopenaeus vannamei that was introduced recently in India and provided a more profitable opportunity for farming.

Effects of selective harvesting and claw ablation of all-male freshwater prawn (Macrobrachium rosenbergii ) on water quality, production and economics in polyculture ponds

The effects of selective harvesting (SH) and claw ablation (CA) of blue-clawed (BC) prawns on an all-male freshwater prawn–finfish polyculture system were compared with control (Co) in quadruplicate. Ponds were stocked with all-male freshwater prawn Macrobrachium rosenbergii, silver carp Hypophthalmichthys molitrix, catla Catla catla and mola Amblypharyngodon mola at 12 000, 2000, 500 and 20 000 ha−1 respectively. Prawns were fed with pelleted feed. Ponds were fertilized regularly with urea, triple super phosphate and cow-dung. SH of BC prawns in treatment SH and CA in treatment CA started on the 60th day during a 137-day culture and continued at 15-day intervals until the final harvest. Water quality parameters and plankton abundance did not vary significantly (P>0.05) among the treatments. Treatment SH resulted in a higher (P<0.05) net production of freshwater prawn (437 kg ha−1), with better survival and mean weight, followed by CA (354 kg ha−1) and Co (322 kg ha−1). The combined net production of prawn plus finfish was also higher in SH (1244 kg ha−1) as compared with CA (1161 kg ha−1) and Co (1137 kg ha−1), although the finfish production did not differ significantly. The periodic SH of BC prawns showed a better economic return with a BCR of 1.71.

Effects of carbohydrate source for maintaining a high C:N ratio and fish driven re-suspension on pond ecology and production in periphyton-based freshwater prawn culture systems

The present research investigated the effect of carbohydrate (CH) source for maintaining a high C:N ratio, and tilapia driven bioturbation on pond ecology, production and economical performances in C/N controlled periphyton-based (C/N-CP) freshwater prawn ponds. Two carbohydrate sources (high-cost tapioca starch and low-cost maize flour) were compared in 40 m 2 ponds stocked with 80 freshwater prawn ( Macrobrachium rosenbergii) juveniles (individual weight 0.81 ± 0.03 g) and 20 finfish fingerlings (Nile tilapia, Oreochromis niloticus and Indian major carp rohu, Labeo rohita) in three different combinations: 100% tilapia, 50% tilapia + 50% rohu, and 100% rohu (individual weight 27.7 ± 0.6 g). The CH sources for increasing C:N ratio from 10 (as in feed) to 20 had no significant effect ( P > 0.05) on water quality parameters, abundance of natural food (plankton, periphyton and benthos) and production of prawn and finfish. However, different fish combination had significant effects on pond ecology. The highest PO 4–P ( P < 0.001) and the lowest chlo- a ( P < 0.01) concentrations in water were observed in ponds with 100% tilapia as compared to ponds stocked with 100% rohu. The abundance of phytoplankton, periphyton biomass (dry matter, ash, ash free dry matter and chlo- a) and benthos was significantly higher ( P < 0.05) in 100% rohu ponds than in 100% tilapia ponds indicating the more efficient utilization of natural food items by tilapia than by rohu. The freshwater prawn production was not affected ( P > 0.05) by the different stocking combinations of finfish. The net yield and survival of finfish were significantly higher in 100% tilapia ponds and lower in 100% rohu ponds resulting in 58% higher combined net yield (both prawn and finfish) in the former treatment during a 120-d culture period. This treatment gave the best economic return in terms of benefit–cost ratio while maize flour was used as CH source. In conclusion, maize flour can be used as an alternative cheap on-farm CH source for maintaining a high C:N ratio and tilapia driven re-suspension in C/N-CP system improves culture environment, natural food utilization, production and economic return, further enhancing economic sustainability of C/N-CP freshwater prawn farming system.

Potential of mixed culture of freshwater prawn (Macrobrachium rosenbergii) and self-recruiting small species mola (Amblypharyngodon mola) in rotational rice–fish/prawn culture systems in Bangladesh

The effects of different stocking densities of freshwater prawn (Macrobrachium rosenbergii) on its growth and production in relation to the presence of small self-recruiting species mola (Amblypharyngodon mola) were investigated in modified rice fields after rice harvest at Mymensingh, Bangladesh. Keeping the stocking density of mola fixed at 20 000 ha−1 in each treatment, four densities of freshwater prawn (treatments) were maintained: 10 000, 15 000, 20 000 and 25 000 ha−1 respectively. The rice plots were limed (CaCO3) and fertilized with urea, triple super phosphate and cowdung regularly. The prawns were fed daily with commercial pellets. Water quality parameters such as temperature, dissolved oxygen, transparency, pH, total alkalinity, inorganic nitrogen (nitrate, nitrite and total ammonia), chlorophyll a and orthophosphate were determined fortnightly. Numerical analysis of plankton communities was performed monthly. All water quality parameters were found to be within the suitable range for freshwater prawn culture, except high temperature, in the peak summer months. There was a homogenous abundance of plankton communities in all treatments throughout the experimental period. Mola started to breed in the second month of the original stocking with partial harvesting after the second month and continued until the final harvest. The total production of mola ranged between 124 and 152 kg ha−1 during the 4-month culture period. The average prawn survival ranged from 49% to 57% without any significant difference among treatments. Freshwater prawn production ranged from 294 to 596 kg ha−1 with significantly higher production in the treatment where 20 000 ha−1 freshwater prawn were stocked. This treatment also resulted in a higher net profit margin (74%), indicating that stocking at a combination of 20 000 ha−1 freshwater prawn and 20 000 ha−1 mola could be the optimum proposition for prawn–mola culture in modified rain-fed rice fields after rice cultivation.

Effect of thyroxine immersion on larval survival, growth and postlarvae production of freshwater prawn, Macrobrachium rosenbergii (de Man)

Aquaculture ResearchVolume 37, Issue 13 p. 1378-1380 Effect of thyroxine immersion on larval survival, growth and postlarvae production of freshwater prawn, Macrobrachium rosenbergii (de Man) Paymon Roustaian, Paymon Roustaian Department of Fisheries and Aquaculture, Faculty of Agrotechnology and Food Science, Kolej Universiti Sains dan Teknologi Malaysia (KUSTEM), Kuala Terengganu, Malaysia Department of Fisheries, Faculty of Marine Resources, Khoramshahr University of Marine Science and Technology (KUMST), Khoramshahr, Khozestan, IranSearch for more papers by this authorLim Ai Gaik, Lim Ai Gaik Department of Fisheries and Aquaculture, Faculty of Agrotechnology and Food Science, Kolej Universiti Sains dan Teknologi Malaysia (KUSTEM), Kuala Terengganu, MalaysiaSearch for more papers by this author Paymon Roustaian, Paymon Roustaian Department of Fisheries and Aquaculture, Faculty of Agrotechnology and Food Science, Kolej Universiti Sains dan Teknologi Malaysia (KUSTEM), Kuala Terengganu, Malaysia Department of Fisheries, Faculty of Marine Resources, Khoramshahr University of Marine Science and Technology (KUMST), Khoramshahr, Khozestan, IranSearch for more papers by this authorLim Ai Gaik, Lim Ai Gaik Department of Fisheries and Aquaculture, Faculty of Agrotechnology and Food Science, Kolej Universiti Sains dan Teknologi Malaysia (KUSTEM), Kuala Terengganu, MalaysiaSearch for more papers by this author First published: 25 August 2006 https://doi.org/10.1111/j.1365-2109.2006.01576.xCitations: 5 Correspondence: P Roustaian, Department of Biology, University of New Brunswick, PO Box 5050, Saint John, New Brunswick, Canada E2L 4L5. E-mail: proustai@unbsj.ca Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume37, Issue13September 2006Pages 1378-1380 RelatedInformation

Effects of Two Pelletized Feed Formulations on Experimental Freshwater Prawn, Macrobrachium rosenbergii, Pond Production, Processing, and Costs

With rapid globalization of the aquaculture industry, significant differences in freshwater prawn, Macrobrachium rosenbergii, survival, count, and yield have serious implications to the economic viability of the feed management systems for their production. A grow-out experiment compared the effects of an experimental, sinking, pelletized 35%-pro-tein shrimp diet and a commercially-available sinking, pelletized 32%-protein catfish diet on freshwater prawn production, processing, and costs. Experimental results showed that survival, yield, and feed conversion were not significantly (P > 0.05) different between ponds fed with the experimental shrimp diet and commercially-available catfish diet. The total costs of pond grow-out of freshwater prawns using two feed formulations were estimated assuming a hypothetical risk-free commercial pond production system consisting of 25 adequately-sloped 0.8-ha production ponds. A higher break-even price was estimated for prawns fed with the experimental shrimp diet. The break-even prices were $6.75/kg and $7.49/kg for heads-on and fresh-on-ice prawns raised in ponds fed with catfish diet and shrimp diet, respectively. Further research on prawn diets should be directed toward improving feed conversion.

Towards sustainable freshwater prawn aquaculture - lessons from shrimp farming, with special reference to India

The annual increase in farmed freshwater prawn production in the world during the decade ending 2001 has been estimated as 29% and that during 1999–2001 as 48%, the production in 2001 being about 300 000 mt (all Macrobrachium species). Between 1999 and 2003 the annual increase in farmed Macrobrachium rosenbergii production in India was about 80%, production reaching 30 450 mt in 2002–2003. This log phase of production followed the rise and fall of shrimp farming in the country. Several shrimp farming ventures collapsed in the 1990s, owing to degraded environment and diseases, abetted by lack of awareness and inadequacy of information on the culture systems and their interactions with other human endeavours. This shrimp farming experience has made the aquafarmer and other stakeholders aware that while aquaculture has a high potential in ensuring food and nutritional security and livelihood, besides profit to the farmer and socio-economic benefits to local communities, it is likely to slip from sustainable development pathways if adequate understanding, improved management practices, governmental policies and plans for implementation and regulation to ensure sustainability are not in place. The lessons learned from shrimp farming can help in steering the development of sustainable freshwater prawn aquaculture in India and elsewhere.

Rise and Fall of Freshwater Prawn (Macrobrachium rosenbergii) Culture in Hawaii: 1965–1999

Following Shao-Wen Ling's discovery of larval-rearing requirements for the freshwater prawn Macrobrachium rosenbergii in Malaysia during 1961, Takuji Fujimura developed mass culture technology for the species during the late 1960s. These technological breakthroughs resulted in widespread interest in commercial culture of prawns in many places, including Hawaii. The state of Hawaii actively supported freshwater prawn aquaculaire in many ways. The first commercial production of freshwater prawn in Hawaii began during 1972 and was based on traditional pond culture techniques developed in Hawaii. Those techniques included routine stocking of ponds with prawn seed and harvesting (culling) larger prawns at least monthly. Ponds often were not drained for many years, and only then for maintenance. Freshwater prawn production reached a maximum of 372,700 kg/yr in 1983 valued at $3.3 million, but then collapsed to 47,600 kg/yr in 1987. Prawn prices during that period steadily increased from $7.70 to $l4.17/kg. Production revived briefly in 1991–1992 after prawn prices reached $17.71/kg in 1990, but prices collapsed to $9.79/kg in 1992 and production then fell to 40,200 kg/yr during 1993. Production remained low thereafter and was only 18,300 kg/yr during 1999. We discuss those factors that were most likely responsible for the ultimate collapse of the freshwater prawn culture industry in Hawaii. These factors include biological and physical-chemical conditions that resulted in low yields. The industry was founded on the assumption that pond yields would be 3000–4000 kg/ha/yr, but yields were generally 1000–1700 kg/ha/yr. Those lower yields resulted in high production costs per kg, and made cukured freshwater prawns noncompetitive in the marketplace with imported freshwater prawns and marine shrimp. Unsuccessful marketing attempts with Hawaii farmed prawns and lack of a clear market position for freshwater prawns also contributed to production declines. Many of these same problems still persist, and it is unlikely that freshwater prawn production will do more than fill a small niche market in Hawaii.

Growth, Survival, and Body Composition of Cage‐Cultured Nile TilapiaOreochromis niloticusFed Pelleted and Unpelleted Distillers Grains with Solubles in Polyculture with Freshwater PrawnMacrobrachium rosenbergii

Abstract.—A 12‐wk feeding trial was conducted in cages with juvenile Nile tilapiaOreochromis niloticusto evaluate distillers grains with solubles (DDGS) as a direct feed, the effects of pelleting on its utilization, and the compatibility of caged tilapia and prawns in polyculture. Nine 1.0‐m3cages were stocked with 200 juvenile (26 ± 0.9 g) tilapia. Cages were suspended in a 0.2‐ha pond stocked with juvenile freshwater prawnsMacrobrachium rosenbergiiat 40,000/ha. Three replicate cages were randomly assigned to each dietary treatment. In one dietary treatment DDGS was fed as an unpelleted loose grain ration (26% protein). In a second dietary treatment fish were fed DDGS that had been steam‐pelleted (23% protein). Fish in a third dietary treatment were fed a commercial catfish diet (31% protein) for comparison. After 12 wk, individual weight, individual length, and specific growth rate were significantly higher (P&lt; 0.05) and feed conversion ratio was significantly lower (P&lt; 0.05) for fish fed the commercial catfish diet than for fish fed either unpelleted or pelleted DDGS. Specific growth rate was significantly higher (P&lt; 0.05) for fish fed pelleted DDGS than for fish fed unpelleted DDGS. Survival did not differ significantly (P&gt; 0.05) among treatments (&gt;95%). Although growth was increased in fish fed the commercial diet, their cost of production (&lt;0.66/kg gain) was significantly higher (P&lt; 0.05) than in fish fed unpelleted and pelleted DDGS (&lt;0.26/ kg gain and &lt;0.37/kg gain, respectively). The costs of gain in fish fed unpelleted DDGS was significantly lower (P&lt; 0.05) than in fish fed the pelleted DDGS. Prawn production was 1,449 kg/ha and addition of tilapia in polyculture increased total pond productivity approximately 81 %. These data suggest that DDGS provides economical growth in tilapia when fed as a direct feed and that polyculture of tilapia may improve overall pond efficiency in freshwater prawn production ponds, even at temperate latitudes.

Growth, Survival, Yield, and Size Distributions of Freshwater Prawn Macrobrachium rosenbergii and Tilapia Oreochromis niloticus in Polyculture and Monoculture Systems in Puerto Rico

Abstract.— Tilapia and freshwater prawn production in Puerto Rico for monoculture and polyculture systems were compared. The experiment consisted of three treatments with three replicates each. The stocking rates for the prawn monoculture, fish monoculture and polyculture treatments were respectively: 7 prawns/m2, 1 tilapia/M2, and 7 prawns with 1 tilapia/ m2. The mean stocking size for tilapia and prawn were respectively, 7–8 g and 1–1.3 g. After 145 d of culture, yields and mean weight of tilapia in monoculture and polyculture system were not significantly different. Total yields were 2,942 and 2,769 kg/ha, respectively. Mean weights were 348 g in monoculture and 331 g in polyculture. Yields and mean weight of prawns in monoculture and polyculture were significantly different. Total yields were 1,367 and 951 kg/ha, respectively. Mean weights were 55 g in monoculture and 31 g in polyculture. Total yield in polyculture was 3,720 kg/ha showing an increase over the production separately obtained in prawn and fish monoculture.

Use of egg custard augmented with cod liver oil and Moina micrura on production of freshwater prawn postlarvae

Use of egg custard augmented with cod liver oil (CLO) fed during the day, and of an overnight feed with Moina micrura, were evaluated in terms of its effects on production of freshwater prawn (Macrobrachium rosenbergii) postlarvae (PL). Four levels of CLO (0, 1,3 and 5%) were tested. Significantly higher mean (sd) productions, ranging from 11.27 (1.16) to 13.02 (1.70) PL l−1, were obtained for larvae fed egg custard enriched with CLO compared with that of 7.83 (1.58) PLl−1 for larvae fed egg custard without CLO. The development and survival of larval stages were also higher for the CLO diets. The ω-3 highly unsaturated fatty acid (HUFA) in egg custard increased with increasing CLO level (0–5%). The fatty acid composition of postlarvae reflected the composition of the diet.

Status of freshwater prawn farming: a review

Farmed freshwater prawn production globally expanded by a factor of 3.5 in the 7 years from 1984 to 1991 but declined by 17% to 31 235 tin 1992. This was caused by a 53% reduction in the output of Taiwan due to disease and in-breeding problems, partially compensated by increases elsewhere, notably in India and Vietnam. This paper reviews the scientific literature published between 1989 and 1994 on the culture of the freshwater prawn Macrobrachium rosenbergii (De Man 1879) and summarizes earlier work. Broodstock and larval studies, nutrition, grow-out management, genetics, integrated aquaculture and disease and water quality are covered. Finally, a brief summary of the status and characteristics of prawn culture in the major farming locations is presented, together with some comments on the opportunities and constraints for further development.

Modeling prawn production management system: A dynamic Markov decision approach

This paper describes an attempt to develop a computer-operational bio-economic model for assessing the economics of alternative pond management and marketing strategies for a freshwater prawn production system in Hawaii. The model structure incorporates a biological component, which is represented by a simple Markov process, into a dynamic program for economic analysis. The Markov transition probability matrices are estimated based on 4 months of production data from a commercial facility on Oahu. Price and cost data from the same 4-month period are used as a baseline in the dynamic program. Different price and cost assumptions are used to test the sensitivity of the baseline results. An assessment of the present model structure, its associated data requirements, and results are discussed.