Phenotypic and genetic parameters for body traits in the giant freshwater prawn (Macrobrachium rosenbergii) in India

Phenotypic and genetic parameters were estimated for three body traits (harvest weight, carapace length and standard length) and for adult male morphotypes of the giant freshwater prawn Macrobrachium rosenbergii in a fully pedigreed synthetic population in India. The data set included 9,173 progeny produced over four generations from 162 sires and 234 dams. Variance components and genetic parameters were estimated fitting an animal model using the residual maximum‐likelihood methodology. The heritabilities for harvest body weight (HW), carapace length (CL) and standard length (SL) were moderate (0.22 ± 0.056, 0.22 ± 0.055 and 0.25 ± 0.059 respectively). The common environmental effects for HW, CL and SL were 0.10 ± 0.020, 0.08 ± 0.018 and 0.10 ± 0.021 respectively. As M. rosenbergii is sexually dimorphic, we estimated heritabilities within each sex. Heritability of HW in females (0.27 ± 0.068) was greater than that in males (0.15 ± 0.057). CL and SL followed the same pattern. The occurrence of male morphotypes is a unique characteristic of adult populations of M. rosenbergii. Populations from culture ponds exhibit a wide range of sizes. To examine whether there was a heritable component in male morphotype frequencies, we treated male morphotypes as traits. The additive genetic variance (and hence the heritability) was zero for male morphotype, indicating that selective breeding to increase the proportion of desirable male morphotypes would not be effective. The genetic correlations among body traits were all positive, high and approaching unity. The results are discussed in relation to selection plans for the giant freshwater prawn.     

Effect of probiotics on immune competence of giant freshwater prawn Macrobrachium rosenbergii

This study evaluates the effect of probiotics, Zymetin, on the immune efficiency of Macrobrachium rosenbergii juvenile against pathogenic Vibriospp. and Aeromonasspp. The experiment was conducted in glass aquaria with same level of feeding under different treatments, that is, negative control (Cn), positive control with Vibrio spp. (Cv) and Aeromonasspp. (Ca), prawn juveniles fed with probiotics (Zymetin) at 5 g/kg of feed but without pathogen (T1), probiotic fed prawn challenged with Vibrio spp. (T2) and Aeromonasspp. (T3). The results demonstrated that T1 showed higher survival rate, total haemocyte count, non‐granular haemocyte count, phagocytic activity, and clearance efficiency compared to other treatment groups. In contrast, decreased number of small and large granular haemocyte was observed in T1. Despite that, THC was found to be significantly different (p < 0.05) among all the controls and lowest was in Cv, followed by Ca. Besides, phagocytic activity and clearance efficiency against Vibrio spp. and Aeromonasspp. decreased significantly in Cn, Ca, and Cv fed M. rosenbergiijuvenile, while the values were found to be higher in T1 followed by T2 and T3, in that order. In addition, the challenge test showed an increasing trend of total and beneficial bacterial density as well as declining trend of some harmful bacteria in the water and gut of prawn in all the groups tested (p < 0.05).     

Growth performance and survival of giant freshwater prawn Macrobrachium rosenbergii larvae fed coloured feed

This study examined the behavioural response on the preference and acceptance, growth performance and survival of Marcobrachium rosenbergi larvae fed with isonitrogenous and isolipidic yellow (YCF) and blue (BCF) coloured feed. In the behavioural response test, single and paired feed drop test of YCF and BCF were introduced at the middle of a tank about 15–20 cm from the edge of the white colour tank wall to larvae zoea IV–VI. The number of larvae attracted to each coloured feed was recorded. For the growth and survival performance, each coloured feed was fed to triplicate groups of larvae (zoea V–VI) at stocking density of 30 larvae/L in 12 ppt brackish water for 28 days until they reached postlarval (PL) stage. In the behavioural test, the number of larvae that attracted and accepted the BCF was significantly higher than those fed YCF (p < 0.05). The body weight and length of PL fed BCF was 28% and 5.6% bigger than those fed YCF respectively. However, the survival of the PL was almost similar in both treatments. This study shows that the freshwater prawn larvae were attracted more to the BCF and able to detect and capture the preferred BCF by vision and this contributed to higher growth of the larvae.     

Heritability for growth traits in giant freshwater prawn,Macrobrachium rosenbergii (de Mann 1879) based on best linear unbiased prediction methodology

In this study, heritability was estimated for growth‐related traits of giant freshwater prawn (Macrobrachium rosenbergii) before and after morphological sexual differentiation. Estimation was made on data from 16 full‐sib and eight half‐sib families. The variance estimation was performed using a univariate mixed linear animal model and variance components were analysed following an animal model using restricted maximum likelihood procedure using average information algorithm. Heritability estimates (h²) varied considerably with ages. At 2 months old, h²for carapace length (CL; 0.35±0.15) and body weight (BW; 0.26±0.13) were higher than those estimated at 5 months old, based on mixed sex data. However, when data were sorted by sex, h² calculated from data of females were higher than those of males for CL (0.26±0.16 vs. 0.10±0.06), BW (0.28±0.17 vs. 0.12±0.08), body length (0.40±0.17 vs. 0.11±0.07), total length (0.47±0.18 vs. 0.11±0.07) and claw length (0.29±0.16 vs. 0.03±0.04). The same trend was observed for traits at 6 months old in both bulk and individual rearing.     

Hatchery seed production of giant freshwater prawn,Macrobrachium rosenbergii using inland ground saline water in India

The suitability of inland saline water (ISW) from the Lahli‐Baniyani Fish Farm, Rohtak was investigated for the larval rearing of giant freshwater prawn (GFP), Macrobrachium rosenbergii. Six experiments were conducted. In Experiment‐I, 54% of the larvae metamorphosed to postlarvae (PL) in constituted seawater (CSW) whereas total mortality occurred at larval stages (LS)‐II and LS‐III in ISW with salinity of 12 g L^?1. Larvae survived to LS‐IV in Experiment‐II, when ISW was supplemented with K⁺~ SW. In Experiment‐III, total hardness in ISW was reduced serially, but K⁺ ~ SW was supplemented. The larvae did not survive beyond LS‐V. In Experiment‐IV, ISW was amended with different ratios of Mg²⁺/Ca²⁺ and K⁺ ~ SW. The larvae successfully metamorphosed to postlarvae with highest survival of 51.6% in Mg²⁺/Ca²⁺ ratio of 2.5. In Experiment‐V, eight larval cycles were run with water quality used in Experiment V, where all the cycles produced PL's with a survival rate of 20–67%. In Experiment VI, the larvae were reared in Mg²⁺/Ca²⁺ ratio of 2.5 and different levels of K⁺ to optimize its requirement. The ISW amended with K⁺ 80% ~ SW and Mg²⁺/Ca²⁺ ratio of 2.5 was found to be commercially suitable for the seed production of GFP.     

Resistance to vibriosis,production performance and tolerance to stress of the selected giant freshwater prawn (Macrobrachium rosenbergii)

The purpose of this study was to evaluate the resistance to vibriosis, growth, survival and tolerance to stress of the selected prawn, second generation, compared to a non‐selected control. The first generation of selected giant freshwater prawn, which has 10.4% higher of resistance, was used to attain disease resistant freshwater prawn (Macrobrachium rosenbergii) generation through challenge test‐based selection. Resistance test was conducted by infecting the prawn (mean body weight of 10.29 ± 1.40 g) with pathogenic Vibrio harveyi (5 × 10⁵ cfu prawn^?1). The growth and survival of the prawn were evaluated by rearing the two populations of prawn in both nursery and grow‐out phases. Stress tolerance test was done by evaluating the viability of postlarvae exposed to environmental stressors, i.e. temperature, salinity, NH₃ and formaldehide. Post‐challenge survival of the selected prawn (55.0 ± 5.0%) was about 46% higher than that of the control (37.5 ± 7.5%). The survival of the selected prawn in nursery culture (77.16 ± 0.841%) was significantly higher (p < .05) than that of the control (51.31 ± 2.938%), while the survival in grow‐out culture was similar (p > .05). The growth of selected prawn (4.99 ± 0.03% day^?1) was significantly higher than that of the control (4.81 ± 0.05% day^?1). There was no difference between treatments on the tolerance level against the tested environmental stressor. Overall data suggested that the selected prawn showed better performance in growth and resistance against vibriosis.     

Expression and functional characterization of glutamine synthetase from giant freshwater prawn (Macrobrachium rosenbergii) under osmotic stress

The freshwater prawn, Macrobrachium rosenbergii naturally lives in the freshwater, though it migrates to the brackish water environment during spawning that claimed to be resistant on a broad range of saline fluxes. However, little is known about the osmoregulatory patterns and the effect of an enzyme glutamine synthetase (GS) in M. rosenbergii under stress. Here, we described the identification and functional characterization of GS from M. rosenbergii (Mr‐GS) at molecular and protein levels. The identified Mr‐GS was comprised of 361 amino acids that phylogenetically shared the highest identity with other crustaceans and predicted to contain Gln‐synt_C and Gln‐synt_N domains at the respective terminal regions. Tissue distribution analysis in M. rosenbergii revealed that the Mr‐GS was highly expressed in muscle, and commonly existed in other examined tissues in the following order gills > heart > stomach > brain > haemolymph. Whereas, the mRNA of Mr‐GS was significantly up‐regulated in the muscle and gill tissues following challenges with either hyper (0 → 13‰), or hypo (13 → 0‰) osmotic stress at 3, 6 and 12 hr. Furthermore, the level of Glutamine concentration was positively correlated with the GS mRNA and protein expression patterns in hyper‐osmotic stress, whereas in hypo‐osmotic stress a slight decrease in the gills and maintained a level in the muscle tissues at 3, 6 and 12 hr post‐treatments. Our findings suggest that Mr‐GS potentially exhibited the osmoregulation responses in the gill and muscle tissues of M. rosenbergii throughout the time of osmotic stress, which will benefit for future study on osmoregulation.     

Histopathological changes in giant freshwater prawn Macrobrachium rosenbergii (de Man 1879) fed with probiotic Bacillus licheniformis upon challenge with Vibrio alginolyticus

The effect of dietary supplementation of probiotic bacterium Bacillus licheniformis on the histopathological changes in Macrobrachium rosenbergii juveniles (4.0 ± 0.02 g) challenged with known pathogenic strain of Vibrio alginolyticus are reported. Two isocaloric basal diets supplemented with probiotic bacteria B. licheniformis (1.0 × 10⁹ cfu/g feed) and other without probiotic supplementation were fed to the M. rosenbergii juveniles for 45 days. The histological observations revealed no significant changes in the hepatopancreas and gut tissues of both the experimental and the control groups which indicate that the present bacterium is a safe candidate probiont for the host. Prawns were challenged with V. alginolyticus after 45 days of feeding with probiotic diet. The histopathological studies of the hepatopancreas revealed that M. rosenbergii fed with probiotic‐supplemented diet showed less changes as compared to the prawns fed with control diet on second and fourth day of post‐experimental challenge with V. alginolyticus. Histopathological observations revealed that the gills of the prawns fed with control diet were severely affected in comparison to the prawns fed with probiotic‐supplemented diet after challenging with V. alginolyticus. Results from this study revealed the improved protection by dietary incorporation of B. licheniformis in reducing the histopathological manifestations due to V. alginolyticus infection in freshwater prawn.     

Dynamics of glucose in the haemolymph of female giant freshwater prawn,Macrobrachium rosenbergii,influences reproductive and non‐reproductive moulting cycles

Glucose, when measured in haemolymph, has been found to reflect a useful predictor of energetic investment. This study evaluated the pattern of glucose in the haemolymph, with an attempt to gain a better insight into the role of glucose as nutritional source of ovarian development and energy reserves during reproductive and non‐reproductive moulting cycles. The haemolymph of female giant freshwater prawn, Macrobrachium rosenbergii, was obtained at eight different moulting stages, and levels of glucose were determined using an enzymatic colorimetric glucose‐oxidase method in parallel with a histological examination of ovarian development. Glucose levels were relatively low (0.15 ± 0.02 mg mL^?1) at D₀ stage, an abrupt increase (0.52 ± 0.13 mg mL^?1) during premoult D₁ stage and declined (0.32 ± 0.10 and 0.31 ± 0.09 mg mL^?1) during premoult D₂ and D₃ stages, respectively; thereafter, a slight increase (0.43 ± 0.09 mg mL^?1) occurred at post‐moult A stage. The progression of ovarian growth, marked by an increasing gonadosomatic index (GSI) pattern during the reproductive moulting cycle (C₀–D₃ stages), was directly proportionate to fluctuations in glucose levels. GSI was significantly positively correlated with glucose (R = 0.40; P < 0.05). In contrast, glucose was notably higher at post‐moult A and premoult D₂ stages during non‐reproductive moulting cycle, the period during which glucose is crucial for exoskeletal chitin synthesis. At this particular stage, a negative correlation between body weight and glucose (R = ?0.36; P < 0.05) was observed. The dynamics of glucose in the haemolymph of female M. rosenbergii correlated with ovarian growth, which signify that glucose as nutritional source for vitellogenesis, and affects the body weight of this species.     

Immunomodulatory effect of recombinant RNA‐dependent RNA polymerase protein of Macrobrachium rosenbergii nodavirus in giant freshwater prawn M. rosenbergii

The present study evaluated the role of recombinant RNA‐dependent RNA polymerase (RdRp) protein of Macrobrachium rosenbergii nodavirus (MrNV) in modulating the immune response and in reducing MrNV load in infected prawn. In the first experiment, prawns (25–30 g) were injected with recombinant RdRp protein (RP) at a concentration of 0, 1.0 and 10 μg, and immune parameters and expression of some immune‐related genes were measured up to 14 days post injection (p.i.). In the second experiment, early juveniles were injected with a similar dose of RdRp and animals were challenged by immersion with MrNV. The infection status was detected in muscles by nested RT‐PCR up to 21 days post challenge. Prawn injected with higher concentration of RP showed significantly higher total haemocyte count at different period post injection. Significant up‐regulation of immune‐related genes was observed within 24 h in prawn treated with lower dose of RP and after 7 days p.i. at higher level of RP injection compared with adult control. Most of the tested samples (63%) were found to be RT‐PCR positive for MrNV at 48 h of post‐immersion challenge. After 14 days, MrNV was detected only in control prawn, while both RP‐injected groups were MrNV negative. This study elucidated the potential viral load reduction role played by RdRP in MrNV‐infected prawn.     

Effect of thermal stress on Hsp70 gene expression and female reproductive performance of giant freshwater prawn,Macrobrachium rosenbergii

Using Hsp70 as a biomarker, thermal stress impinges on reproductive organs, ovary and hepatopancreas were being analyzed by determining the expression of Hsp70 mRNA inside the organs after the adult inter‐molt females were subjected to thermal treatment at 35, 30 and 28°C (Control). Results showed the expression of Hsp70 mRNA under thermal treatment of 35°C after 2 hr recovery in ovary were upregulated at 2, 4, 6, 12, 24 hr and 30 days compared to control whereas in hepatopancreas under similar treatment, the expression of Hsp70 mRNA were significantly higher than control at 6, 24 hr and 30 days. Frequency of reproductive molt at 35°C showed the ovary of females were failed to develop and only entered common molt along three consecutive molt cycles. For 30°C thermal treatment, the expression of Hsp70 mRNA was significantly higher than control after 2 hr recovery but returned to normal afterwards until 30 days’ thermal treatment. Maternal heat shock for 2 hr at 35°C were found to give significantly lower frequency of reproductive molt and longer duration of ovarian development and incubation period whereas maternal heat shock for 2 hr at 30°C gave lower frequency of reproductive molt, slower development of embryo and lower hatching success compared to untreated control. This study suggests that short and long‐term thermal stress at 30 and 35°C were found to affect the induction of Hsp70 mRNA in reproductive organs of Macrobrachium rosenbergii and also influence their reproductive performance.     

Immunomodulatory effect of Cynodon dactylon against white tail disease of giant freshwater prawn,Macrobrachium rosenbergii (de Man, 1879)

The giant freshwater prawn, Macrobrachium rosenbergii, is an economically important and extensively cultured crustacean worldwide. The viral pathogens, Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV) are responsible for causing severe mortalities in the hatchery and nursery phases. This study investigates the protection of postlarvae of freshwater against white tail disease (WTD) using plant extract derived from Cyanodon dactylon and the modulation of the prawn non‐specific immunity. To determine the immunomodulatory effect of C. dactylon extract, the prawn was injected with plant extract and various immunological parameters were estimated. The immunological parameters such as proPO, SOD, THC and clotting time were found to be significantly higher in the plant extract‐injected prawn when compared with control groups. The results of real time PCR analysis revealed up regulation on the expression proPO, SOD and lysozyme genes in MrNV and XSV challenged prawn postlarvae treated with C. dactylon extract. Infectivity experiment showed high relative per cent survival in MrNV and XSV‐challenged prawn postlarvae treated with C. dactylon extract. These results strongly indicate that the administration of C. dactylon plant extract enhances immunity of the prawn. Based on the results, this study recommends that the immersion of postlarvae in C. dactylon plant extract is a potential prophylactic agent against WTD.     

Current status & prospects of farming the giant river prawn (Macrobrachium rosenbergii de Man 1879) in Thailand

Thailand was second only to P.R.China in annual production of giant river prawn. This article briefly describes the seed production of giant river prawn technology in Thailand and notes that broodstock management has paid scant attention to genetic issues. There are, however, ongoing selective breeding programmes on giant river prawn aimed to improve growth and disease resistance. In the conventional culture technology, postlarvae are stocked at a high density and prawns are harvested partially. The cropping period is long and the practice has led to disease outbreaks and deteriorated pond bottoms that result in frequent detection of antibiotic residue. The improved culture technology involves manual sexing of the prawns at 3 months and restocking only the male prawns into new ponds at low density. The technique gives higher yield and reduces incidence of disease and thus the need for prophylactics. The constraints to giant river prawn culture business in Thailand include low yield and a limited export market. The article describes three ways to expand and sustain the business of giant river prawn farming in the country: development of more genetically improved strains; culture of all‐male stock, and new culture techniques.     

罗氏沼虾养殖群体表型性状间的相关性及类群差异分析

为研究罗氏沼虾(Macrobrachium rosenbergii)养殖群体表型性状间的相互关系及不同类群间的性状差异,本研究对人工养殖的罗氏沼虾雌、雄及“老头虾”3个类群共490个个体的体重、体长、全长等12个表型性状进行了相关分析、形态性状对体重影响的通径分析等。结果表明, 3个类群除上、下额刺数2个可数性状外,其他9个可量形态性状与体重都呈极显著的正相关(P<0.01);影响体重的关键形态性状在3个类群中各不相同,但体长、头胸甲长、第二步足长在3个类群中均是影响体重的关键指标;分别建立了各类群体重与关键形态性状的多元回归方程。聚类分析和主成分分析结果表明,雌、雄2个类群表型上更为相似,“老头虾”与雌性个体的差异最大。腹部轮廓特征(包括腹长、腹宽、腹高)、全长、体长及第二步足长对3个类群的差异贡献较大。雌性个体腹部发达,“老头虾”则第二步足尤为发达。本研究结果可为罗氏沼虾的选择育种、基础生物学及行业标准的制定提供数据资料。     

Multiple dietary administrating strategies of water hyacinth (Eichhornia crassipes) on enhancing the immune responses and disease resistance of giant freshwater prawn,Macrobrachium rosenbergii

The different products of Eichhornia crassipes leaves including dried E. crassipes powder (DEP), hot‐water treated E. crassipe (HTE), hot‐water extract of E. crassipe (ECE) and dreg of hot‐water extract of E. crassipe extract (dECE) were produced and incorporated into the diet of the prawn, Macrobrachium rosenbergii, as an immunostimulant. Results showed that prawn fed the HTE‐, ECE‐ and dECE‐containing diets for 4 months had increased total haemocyte count, different haemocyte count, phenoloxidase activity, respiratory bursts, superoxide dismutase activity, glutathione peroxidase activity especially in HTE and ECE treatments. The phagocytic activity and clearance efficiency against Lactococcus garvieae of prawn fed the HTE‐ and ECE‐containing diets were significantly higher than those of prawn fed the control diet at 2–4 months. The relative percentage survival of prawn fed the DEP‐, HTE‐, ECE‐ and dECE‐containing diets for 4 months following 144 h challenging with L. garvieae were 19.0%, 38.1%, 38.1% and 33.3%. It was concluded that E. crassipes leaves containing an active component which was easily extracted by hot water can enhance innate immunity and resistance against pathogen of M. rosenbergii by dietary long‐term administration, and the administration of HTE in the diet was the best strategy due to the availability and convenience.     

Growth and immune response of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae fed diets containing Chlorella vulgaris (Beijerinck)

A 50‐day growth trial was conducted to evaluate the efficacy of Chlorella vulgaris (Beijerinck) as an ingredient in the diets of giant freshwater prawn Macrobrachium rosenbergii (De Man) postlarvae (PL30). Immune response (total haemocyte count and prophenoloxidase activity) was also assessed by subjecting postlarvae to a challenge test against Aeromonas hydrophila (Chester) for 14 days. Iso‐nitrogenous and iso‐lipidic test diets were prepared using a fishmeal‐based‐positive control diet (D0) and four basal diets with inclusion levels of 2% (D2), 4% (D4), 6% (D6) and 8% (D8) C. vulgaris. Postlarvae of M. rosenbergii were randomly stocked (mean initial body weight of 0.19 ± 0.02 g) in 30‐L tanks in three replicates per dietary treatment for evaluation of growth performance. Another set of postlarvae (mean initial body weight of 1.25 ± 0.02 g) was randomly distributed in 95‐L tanks in three replicates per dietary treatment for the assessment of immune response. Results showed that specific growth rate was significantly higher (P < 0.05) in postlarvae fed D4 and D6. Variations in values for carcass protein, lipid, moisture and ash were also evident. Postlarvae fed diets with Chlorella showed increased prophenol oxidase activity and total haemocyte counts. Moreover, survival rate after challenge with A. hydrophila was significantly increased (P < 0.05). Inclusion of C. vulgaris in diets enhanced immune response and resistance of M. rosenbergii postlarvae against A. hydrophila infection.     

Growth performance,muscle biochemical constituents,amino acid and fatty acid compositions of the giant freshwater prawn,Macrobrachium rosenbergii,fed with herb‐incorporated diet

This study was conducted to evaluate the influence of herbs such as Ocimum sanctum, Phyllanthus amarus and Solanum trilobatum on the freshwater prawn, Macrobrachium rosenbergii, postlarvae (PL). These herbs were powdered and incorporated at 5% with the basal diet separately and in a combination. The M. rosenbergii was fed with these feeds for a period of 90 days. Results indicated that significant (P < 0.05) improvements were observed in the survival, nutritional indices (weight gain, specific growth rate and protein efficiency ratio), proximate muscle biochemical constituents (total protein, amino acid, carbohydrate and lipid), profiles of essential amino acids and fatty acids of prawns fed with herb‐incorporated feeds. Among these herbs supplemented, P. amarus produced significantly (P < 0.05) better performance followed by S. trilobatum and O. sanctum. However, prawns fed with these herbs combination showed an insignificant (P > 0.05) improvement in survival and growth performance when compared to individual supplementation. Hence, this study suggests that the herbs (O. sanctum, P. amarus and S. trilobatum) can be used as a supplementary feed for a sustainable development of freshwater prawn culture.     

Current status of the giant freshwater prawn ( Macrobrachium rosenbergii) industry in China,with special reference to live transportation

The giant freshwater prawn Macrobrachium rosenbergii was first introduced into mainland China by the Chinese Academy of Agricultural Sciences from Japan in 1976. It was cultured at the Guangdong Province Fishery Institute (now as Pearl River Fishery Institute, Chinese Academy of Fishery Sciences). Following these early efforts, giant freshwater prawn culture has gradually spread to northern and inland areas. At this time (2011), China has become the largest producer of giant freshwater prawn in the world. Due to a preference of cooking with fresh aquatic products, Chinese retail markets have developed which have special live‐holding counters. From small rural shops to urban supermarkets and specialty restaurants, live seafoods are commonly available whereby customers pick out the products they wish to purchase and consume. Giant freshwater prawns are produced in over 35 countries throughout the world. They are usually sold either fresh, on‐ice, or frozen. What makes the Chinese prawn industry unique is its focus on a live transportation and marketing model. As a result, numerous innovative live‐transport technologies have been developed which have been key to the success of this expanding domestic industry. In this article, we would like to give a general overview of the giant freshwater prawn industry, its status in China, and the special role live‐transportation has for expanding production of giant freshwater prawns.     

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.