Polyculture of the Giant Malaysian Prawn and the Golden Shiner in Southwestern Louisiana1

Juvenile prawns (Macrobrachium rosenbergii) were stocked at 37,050/ha and golden shiner (Noremigonus crysoleucas) fry at 321,100/ha into 16 earthen ponds at Rockefeller Wildlife Refuge, Grand Chenier, Louisiana. Four replicated treatments were tested: fed prawn monoculture, fed shiner monoculture, fed prawn and fed shiner polyculture, and unfed prawn fed shiner polyculture. The study lasted 149 days. There were no significant differences in growth between prawns fed in monoculture and prawns fed in polyculture (P > 0.05). However, fed prawns grew significantly larger (P < 0.05) than unfed prawns. Prawn survival in all treatments combined averaged 63%. Survival was significantly higher (P < 0.05) for fed prawns than for unfed prawns. Prawn yields averaged 533 kg/ha, when all treatments were combined. Yield was significantly higher (P < 0.05) for prawns grown with shiners and for prawns that received supplemental feed. Growth was significantly higher (P < 0.05) for shiners grown with fed prawns than for shiners grown with unfed prawns. Shiner survival averaged 33% and was significantly higher (P < 0.05) in monoculture than in polyculture. Yield for all ponds averaged 392 kg/ha, with no significant differences between treatments (P > 0.05).     

Effects of Cooking Methods on Proximate Composition and Fatty Acids Profile of Indian White Prawn (Fenneropenaeus indicus)

The effects of baking, boiling, microwaving, and frying on the proximate composition and fatty acid content of the edible portion of Indian white prawns (Fenneropenaeus indicus) were determined. Mean moisture, lipid, protein, and ash contents of raw prawns were 72.1, 4.32, 21.5, and 1.31%, respectively. For all cooking methods, moisture decreased and protein increased, while fatty acid compositions changed uniquely for each method. In fried prawns, the n3/n6 ratio was the lowest and significantly differed from the other treatments. The heat treatment significantly changed the proximate composition and fatty acid content. Baking and microwaving are the best methods of the four for cooking prawn while preserving their nutritional value, especially on the basis of recommended dietary intake of DHA and EPA.     

Impact of marination,pre‐harvest salt acclimation and sodium chloride concentration on the sensory acceptability of freshwater prawn,Macrobrachium rosenbergii

This study was conducted to evaluate the consumer acceptability of post‐harvest freshwater prawns marinated in salt solutions (0.5%, 1%, 1.5% and 2% NaCl in the cooked product), and to compare the sensory acceptability of these treatments against prawns that had been salt acclimated pre‐harvest while still alive. The salt‐acclimated prawns were transferred to 250‐L tanks containing 10 ppt solar salt (NaCl with small concentrations of CaCl₂ and KCl). Salts were increased by 5 ppt in 2 h increments until 30 ppt was reached. After 18 h of salt acclimation, prawns were chill killed. Prawns that were used for post‐mortem marination treatments were transferred to 250 L tanks with freshwater for 18 h prior to harvest and post‐mortem marination. Two consumer‐based sensory tests were conducted (n = 102). Results indicate that flavour, texture and overall acceptability of prawns increased (P < 0.05) as the salt concentration increased from 0.5% to 1.5% in marinated prawns. In addition, marinated prawns that contained 1% sodium chloride after cooking did not differ (P > 0.05) in acceptability when compared to salt acclimated prawns which contained 0.5% sodium chloride in the cooked product. The salt‐acclimated product was preferred (P < 0.05) over the 0.5% salt marination treatment, although they did not differ in final salt concentration. This indicates that salt acclimation enhanced product acceptability through increased salt concentration as well as due to the salt acclimation process, thus lowering the amount of sodium chloride that was necessary to enhance product acceptability.     

Maturation and spawning performance of pond-reared Penaeus merguiensis in different combinations of temperature, light intensity and photoperiod

The combined effects of temperature (23 and 27 °C), light intensity (1100 and 2 lux or ≈ 21.5 and 0.04 μEinst m^?2 s respectively) and photoperiod (10 h light/14 h dark and 14 h light/10 h dark) on ovarian maturation and spawning performance of ablated pond‐reared Penaeus merguiensis were investigated in a 51‐day experiment. The results showed that temperature was the most influential factor, followed by light intensity, whereas the effect of photoperiod was minor. As the maturation process progressed, the effects of temperature and light intensity became stronger while that of photoperiod became less significant. Temperature significantly affected all the reproductive parameters assessed. Prawns in the 27 °C treatments outperformed those in the 23 °C treatments (P < 0.05). The effect of light intensity was found to have a significant effect (P < 0.05) only on the proportion of spawners (prawns that spawned) and spawning rate. More prawns spawned at a higher rate under dim light (2 lux) than under strong light (1100 lux). Photoperiod affected only the proportion of prawns reaching stage III of ovarian development (P < 0.05). There were interactions between temperature and light intensity affecting the proportion of prawns reaching stage III and, although not significantly, the proportion of spawners (P = 0.177), fecundity (P = 0.134) and survival (P = 0.061). Overall, it is recommended that a combination of 27 °C, 2 lux and 10 h light/14 h dark is suitable for the maturation of pond‐reared P. merguiensis. There were indications that temperature can be used to control the rate of ovarian maturation. Also, it is possible to increase light intensity up to 1100 lux in P. merguiensis hatcheries if prawns are ablated.     

Effect of Customized Probiotics on the Physiological and Immunological Responses of Juvenile Western King Prawns (Penaeus latisulcatus Kishinouye, 1896) Challenged with Vibrio harveyi

Juvenile western king prawn P. latisulcatus were fed 10⁵ colony-forming units (CFU)/mL of two probiotics Pseudomonas synxantha and P. aeruginosa for 28 days. P. latisulcatus were then challenged with V. harveyi at 0 (control), 10³, 10⁵, and 10⁷ CFU/mL. During the seven days of challenge, disease resistance of the probiotic-fed prawns was compared with that of prawns not fed probiotics. The immunological responses of the prawns did not improve during the challenge period in terms of total haemocyte count, hyalinocyte, semi-ganulocyte, granulocyte, clotting time, bacteraemia, and intestinal bacterial load. Overall, when prawns were challenged with V. harveyi, the LT₅₀ values got shorter as V. harveyi concentration increased. LT₅₀ values of prawns fed probiotics were significantly longer (P < 0.05) than those not fed probiotics. At a V. harveyi concentration of 10³ CFU/mL, the 100% survival of the prawns fed probiotics was three times more likely than those of the prawns not fed probiotics.     

山东沿海腹洞式毛虾单桩张网试验报告

单桩张网在渤海捕捞毛虾时，损害大量经济鱼虾的幼体，严重地破坏了渔业资源。为保护经济鱼虾的幼体，合理利用毛虾资源，作者根据毛虾和其他经济鱼虾幼体的不同习性和游泳能力，设计了腹洞式毛虾单桩张网。该网的主要特点是，在张网腹部开有一个较大的三角洞，经济鱼虾的幼体受惊后可由此下潜逃逸，或在流速较小时由此外返逃逸。两年来的生产对比试验表明，效果显著。腹洞式毛虾单桩张网比现有生产网的平均网次产量增加20．64％。其中，毛虾增产38．14％，释放经济鱼虾的幼体58．94％。     

Effects of Phosphate Dip Treatment on Quality of Rutilus frisii kutum Fillets During Ice Storage

The use of polyphosphates as a partial replacement of salt in different meat products to improve water holding capacity yield and retard oxidative rancidity has been noticed for many years. Therefore, in this study, effects of polyphosphates dip treatment in 5% solution with three different compounds of phosphate—including tetrasodium pyrophosphate (TSPP), sodium tripolyphosphate (STPP), and a mixture of them on kutum (Rutilus frisii kutum) fillets stored in ice was investigated for 18 days. Phosphate pretreatments showed desirable modal effects on fillets. In particular, the use of TSPP and the mixture of TSPP and STPP solutions were found to delay the fish fillet color changes and improved textural characteristics. An increase in water holding capacity accompanied with a decrease in hardness was observed in samples pretreated with polyphosphates. In total, the results indicated that dipping kutum fillets in polyphosphates solution was the most effective method to improve the quality properties of fillets during ice storage when compared with other phosphate-treated groups.     

A review on the diseases of freshwater prawns with special focus on white tail disease of Macrobrachium rosenbergii

Freshwater prawns, particularly, the Giant Freshwater prawn Macrobrachium rosenbergii, are one of the most economically important farmed species in the world. Faced with increasing disease problems in penaeid shrimp culture, farmers turned to freshwater prawn farming. Freshwater prawns were considered relatively less susceptible to diseases. However, with intensification of culture and increased world trade of the farmed species, emerging diseases are beginning to constitute an increasingly serious health problem in freshwater prawn culture. This article is a review of the important diseases reported in freshwater prawns, with particular emphasis on the white tail disease of M. rosenbergii as it is the most important disease recorded to date and also the most well studied among the diseases of freshwater prawns. Steps to be taken for proper health management in the farming of this species is also touched upon.     

Effects of different feeding regimes on ovarian maturation and spawning of pond-reared giant tiger prawn in Thailand

Large pond-reared Penaeus monodon were used in three maturation and spawning trials lasting 60 days. One group of prawns was fed a fresh diet only; a second group was supplied a fresh diet combined with a formulated pelleted diet; a third group of prawns received the formulated diet only. Total maturation (N = 66 and 55) and spawning events (N = 63 and 48) were much greater for prawns receiving only the fresh diet, and the combined fresh with formulated diets, respectively. Prawns receiving only the formulated diet matured only 12 times, and spawned 11 times. Prawns fed a fresh diet produced significantly more eggs than those given a formulated diet alone. No significant differences were seen in eggs produced per spawning event, % fertilization, % hatch or % metamorphosis from egg to protozoea. Female prawns exhibited greater mortality than did males, while females on the fresh diet only had greater mortality than did other females, presumably due to greater handling and other stress factors. Female prawns on a combined diet had lower mortality than other females. The formulated diet used is suitable for supplementation, but not as a sole maturation food.     

Impact of Substrate Physical Characteristics on Grow Out of Freshwater Prawn, Macrobrachium rosenbergii, in Ponds and Pond Microcosm Tanks

Two independent trials were conducted to evaluate the effects of different physical characteristics of substrate materials on growth and survival of freshwater prawn. In Trial 1, juvenile prawns (0.4 ± 0.2 g) were stocked at 123 prawns/m² of tank bottom into twenty‐one 18,000‐L fiberglass tanks managed as pond microcosms. Six substrate materials were chosen to allow comparisons of surface area, mesh size, color, and texture. A control treatment received no added substrate. There were three replicate tanks per treatment. Substrates were positioned vertically at a rate sufficient to increase the bottom surface area by 100%. Prawns were fed a 32% protein sinking diet according to a feed chart. After 110 d, there was no significant difference (P > 0.05) in survival among treatments, averaging 72.6% overall. Prawns in the control treatment (no substrate) had significantly lower (P ≤ 0.05) average weights (9.5 g), lower production (1342 kg/ha), and higher feed conversion ratio (FCR; 2.5) than those in substrate treatments, which were not significantly different (P > 0.05) and averaged 13.4 g, 2404 kg/ha, and 1.3, respectively. For Trial 2, the least expensive substrate material from Trial 1 (lightweight polyethylene bird netting) was compared with the substrate most commonly used in commercial production (heavyweight orange polyethylene safety fencing) under practical pond conditions. Juvenile prawns (0.8 ± 0.3 g) were stocked at 61,600/ha into six 0.04‐ha earthen ponds. Each was randomly assigned one of the two substrate materials, and there were three replications per treatment. After 101 d, there were no significant differences (P > 0.05) between treatments in terms of survival (91%), average weight (34 g), total production (2150 kg/ha), or FCR (3.1). In these studies, physical characteristics of the substrate materials had little impact. The lightweight netting represents a 68% cost savings compared to the currently recommended substrate material.     

Effects of all‐male,mixed‐sex and all‐female freshwater prawn in polyculture with major carps and molas in the fallow rice fields

This study was conducted to evaluate the effects of all‐male, mixed‐sex and all‐female freshwater prawn (Macrobrachium rosenbergii) in a polyculture with major carps (Catla catla and Labeo rohita) and self‐recruiting small fish molas (Amblypharyngodon mola) in the fallow rice fields of Bangladesh. There were three treatments with three replicates. All ponds were stocked with carps and molas plus either all‐male prawns (treatment MP), mixed‐sex prawns (MFP) or all‐female prawns (FP). Prawn, mola, catla and rohu were stocked 20 000, 20 000, 1750 and 750 ha^?1, respectively, in all treatments. The prawns were fed twice daily, starting at 8% body weight and gradually reduced to 3% body weight. The fish were fed in the morning with mustard oil cake and rice bran (1:2 ratios) at 3% body weight. Significantly higher production of prawns (697 kg ha^?1) was obtained in treatment MP, which yielded 34.7% and 56.2% more production than MFP and FP respectively. Significantly higher total production of 1620 kg ha^?1 and a higher benefit–cost ratio of 2.10:1 were also obtained in treatment MP. It can be concluded that an all‐male prawn culture is economically more viable than all‐female and mixed‐sex prawn cultures, along with other fish like major carps and the nutrient‐dense molas in the polyculture.     

POLYCULTURE OF THE FRESHWATER PRAWN (Macrobrachium rosenbergii) WITH TWO COMBINATIONS OF CARPS IN MANURED PONDS

A study was conducted to 1) evaluate the compatibility of prawns (Macrobrachiurn rosenbergii) with carps, especially the effect of the common carp (Cyprinus carpio); and 2) measure the ability of prawns to utilize the foods available in manured systems. Carps used were the silver (Hypophthalmichthys molitrix), bighead (Aristichthys nobilis), grass (Ctenopharyngodon idella) and common carp (Cyprinus carpio). Four ponds (0.09 to 0.17 ha) were stocked with silver, bighead and grass carps while common carp were stocked in only two ponds. Total fish densities were 8,600/ha where four carps were stocked, but only 6,200/ha when common carp were omitted. Post-larval prawns (wt 0.116 g) were stocked at densities of 17/m². Swine (approximately 60/ha of pond surface area) were housed on pond dikes so that fresh manure continuously entered each pond. Two lots of swine were fattened during the experimental period and loadings of swine manure were calculated based on hog size and feed consumption. Growth periods were 163 days for fish and 107 and 121 days for separate stockings of prawns. Gains in biomass by prawns averaged 714 kg/ha in ponds without common carp and 364 kg/ha in ponds containing common carp. Gains in biomass for both fish and prawns were 3,619 kg/ha (19.8 kg/ha/day) in ponds with common carp and 2,924 kg/ha (18.0 kg/ha/day) in those without common carp. Prawn survival was higher (X = 84.5% vs X = 72.5%), but final average weight of prawns was lower (2.64 vs 5.86 g) in the presence of common carp due to competition for food between common carp and prawns. Competition from carp is believed to have exerted less influence on prawn survival than predation on small prawns by larger, faster-growing prawns.     

Effect of ration size and feeding frequency on the growth and food conversion of juvenile Penaeus merguiensis de Man

When juvenile Penaeus merguiensis were fed four times daily they increased in weight more rapidly and utilized their food more efficiently than when fed once per day. The maximum ration for prawns given a commercial dry pellet was approximately 12.0% of the wet body weight per day and changed very little as the prawns grew from 0.5 to 1.3 g in indoor culture. Food conversion efficiency declined with increasing weight and ration size but the relative loss in efficiency was least when rations were maintained near to the maximum. Evidence is presented for the existence of a negative K-line relationship in P. merguiensis.     

Prawn (Macrobrachium rosenbergii)–plant (Hydrilla verticillata) co‐culture system improves water quality,prawn production and economic benefit through stocking density and feeding regime manage

The effects and commercial implications of aquatic plant addition, and variable prawn stocking density and supply of commercial aquafeed on water quality, prawn production and economic benefit, are investigated in a prawn (Macrobrachium rosenbergii) + plant (Hydrilla verticillata) co‐culture system. Our experimental design includes a control (PM, prawn monoculture without H. verticillata, with 30 prawns/m²) and four treatments with 15% plant cover of total pond area in each replicate. Dissolved oxygen, pH, N, P, total ammoniacal nitrogen, nitrite and nitrate in this co‐culture system were significantly lower than those of PM. Prawn survival (96.2 ± 14.9%), average final weight (68.5 ± 4.9 g) and yield (879.1 ± 102.4 kg/ha) in treatment 20W80%A (20 prawns/m², 80% of control aquafeed) were obviously greater than in PM and other treatments. Despite small males (SM) and immature females (IF) being predominant in prawn + plant cultures, more than 77.2% of prawns reached or exceeded 40 g on completion of trials, and by six months were of appropriate size for market. We report culture of M. rosenbergii with H. verticillata to be both feasible and profitable. The optimal treatment, a stocking density of 20 prawns/m² with these plants, enabled reduction of commercial aquafeed to 20% conventional culture levels. For this optimal treatment, we estimate total gross revenue, profit and internal rate of return to be US$ 6,593.3 ± 103.3 ha^?1, US$ 3,095.5 ± 42.6 ha^?1 and 127.5 ± 20.7% for 20W80%A respectively; we estimate U.S. Dollar (US$) invested generates 3.87 times conventional culture revenue. Co‐culture of M. rosenbergii and plants renders prawn production ecologically and economically feasible on larger farms.     

Alizarin marking of whitefish, Coregonus lavaretus otoliths during egg incubation

Alizarin red S from 200 to 5000 mg L^?1 was used to mark the otoliths of whitefish embryos Coregonus lavaretus (L.) from 5 days after fertilization until shortly before hatching, to develop a method for evaluating the effect of stocking whitefish. Mark quality depended on developmental stage at the time of immersion. The best results were obtained when the otolith primordia had formed and had started aggregating to form the innermost part of the nucleus. This was verified by in vitro staining of otoliths where the primordia were more intensely stained than the remaining part of the nucleus. The volume ratio eggs to ARS solution, which was 1:10 in all but two treatments, must be observed when comparing fluorochrome concentrations, as mark quality decreased at higher ratios of 1:5 and 1:2. An average mortality rate of 35% in the most successful treatments was considered tolerable for a mass‐marking programme being used under commercial hatchery conditions. This method for marking otoliths of whitefish embryos with ARS during egg incubation is recommended for all cases where marking of larvae is not possible.     

A Comparison of Two Feeding Technologies in Freshwater Prawns,Macrobrachium rosenbergii,Raised at High Biomass Densities in Temperate Ponds

ABSTRACT

Recent developments in prawn production technologies (i.e., added substrate, increased stocking densities, size grading, and increased feed rates) have increased production rates from 900-1,000 kg/ha to over 2,500 kg/ha. While prawn can receive substantial nutritional benefit from natural foods at the lower biomass densities, at higher production rates prawn are likely to be more dependent on prepared diets. To ensure that maximum production is being achieved by these new production technologies, production rates must not be nutritionally constrained. This study was conducted to compare the current recommended technology of phase feeding of different quality feedstuffs to prawns of different sizes with the feeding of a high-quality penaeid diet throughout the production season. Two treatments were evaluated: Treatment 1 was phase feeding (current technology-control) where prawns were fed unpelleted distillers' grains with solubles (DDGS) for the first four weeks, then a 28%-protein prawn diet for weeks 5-12, and finally a 40%-protein penaeid diet for weeks 13-16. In Treatment 2, prawn were fed the 40%-protein penaeid diet throughout the entire production period. Feeding rates in both treatments were based upon a feeding table. Three 0.04 ha ponds were used for each treatment. All ponds were stocked at 59,280 juveniles/ha and were provided with artificial substrate in the form of a polyethylene “safety fence” oriented vertically to increase available surface area by 50%. After 106 culture days, no significant differences (P >0.05) were observed between treatments in terms of yield, average individual weight, food conversion ratio (FCR), or survival, which averaged 2,575 kg/ha, 46 g, 2.3, and 94%, respectively, overall. Due to the higher cost of the penaeid diet (US$0.84/kg), feeding costs for the penaeid diet treatment (Treatment 2) were 38% higher than those for Treatment 1. No benefit to using higher protein diets during the first 12 weeks of prawn pond production was observed.     

Effects of different fertilization and feeding regimes on the production of integrated farming of rice and prawn Macrobrachium rosenbergii (De Man)

An experiment was conducted in rice field plots each of 30 m² to determine the appropriate combination of feeding and fertilization regimes for the giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879) cultured along with rice in rice fields. There were four treatments: rice culture only with regular fertilization (A, control); rice–prawn integrated culture with regular fertilization (B); rice–prawn integrated culture with basal fertilization and commercial feed (C) and rice–prawn integrated culture with regular fertilization and commercial feed (D). Juvenile prawns of 1.5‐g size were stocked on the third day after rice transplantation at a density of 2 prawns m^?2 and fed twice daily at 5% reducing to 2% of body weight during the experiment. The rice yield in treatment D (0.42 kg m^?2) was significantly higher than that in other treatments (0.34, 0.36, 0.34 kg m^?2 in treatments A, B, C respectively). Prawns grew significantly faster (P<0.05) in treatments C and D (23.8±0.9 and 22.0±1.7 g prawn^?1 respectively) than in treatment B (14.7±1.6 g prawn^?1). Prawn production in treatment C (347±13 kg ha^?1 crop^?1) was significantly (P<0.05) higher than that (234±30 kg ha^?1 crop^?1) in treatment B, while in treatment D (296±53 kg ha^?1 crop^?1) it was not significantly different from that in treatments B and C (P>0.05). Treatment C gave the highest economic returns among all treatments, followed by treatments D and B, indicating that the combination of basal fertilization and commercial feed is the most appropriate nutrient input regime for the rice–prawn integrated culture system.     

Effects of feeding rates on the growth,water quality and nutrient budget of western king prawn (Penaeus latisulcatus Kishinouye) reared in recirculating aquaculture systems

Feed rate is one of the important variables considered for the improvement in production of prawns. The effects of four feeding rates on growth, water quality and the nutrient budget of Penaeus latisulcatus were investigated for 98 days. The specific growth rate (SGR) at 3.0% feed rate was significantly higher than at all higher feed rates, and there was no significant difference in SGR between 4.5%, 6% and 7.5%. Total ammonia nitrogen concentrations in all treatments remained low in the safe range for prawn culture. Dissolved inorganic nitrogen and nitrate nitrogen were significantly higher (P < 0.05) in prawn tanks received feed rates of 6.0% and 7.5%. Total phosphorus and the soluble reactive phosphorus linearly increased with the progression of the trial and feeding rates. Nutrient conversion rates were significantly higher (P < 0.05) in prawns receiving the feeding rate of 3.0% than feeding rates of 6.0% and 7.5%. The lowest food conversion ratio was recorded at feeding rates of 3% and 4.5%. Nutrient budget showed that 6.01–15.99% nitrogen and 4.53–9.29% phosphorus of the nutrient inputs were retained in the prawn biomass. The results indicated that the growth and nutrient conversion rate may not increase with the increase above 3.0% of biomass per day.     

The effects of densities and feed types on the production of Macrobrachium rosenbergii (de Man) in the rotational rice–prawn system

Postlarvae (PL) of Macrobrachium rosenbergii (de Man 1879) were stocked at 1, 2, 3 and 4 PL m^?2. Prawns were fed only pellets (P) and a combination of pellets and snail meat (PS) with three replications in 100 m² plots in the rotational prawn–rice system. Water levels were 0.3–0.6 m in rice growing areas. The water temperatures at noon in the hot months were higher than the suitable range for prawns. The final mean weights of prawns in treatments 1, 2 and 3 PL m^?2 were significantly higher than in treatment 4 PL m^?2 (P<0.05). The yields from different density treatments ranged from 194±82 to 373±32 kg ha^?1 and increased significantly with the increases in prawn densities (P<0.05). There was no significant difference between the two types of feed on production parameters (P>0.05). The total cost significantly increased at higher densities (P<0.05), but it was not different between feed types (P>0.05). Net profit and cost benefit ratio of treatment PS were significantly higher than in treatment P. In the present study, treatment 3 PL m^?2 and treatment PS offered the optimal results.     

Sperm Quality of Pond-Reared and Wild-Caught Penaeus monodon in Thailand1

Sperm quality, as determined by visual examination and by reaction with “egg-water” was not significantly different (P > 0.05) for sperm obtained by electro-ejaculation from ablated or non-ablated pond-reared Penaeus monodon. Nor was sperm quality different between pond-reared and wild-caught prawns. Normal sperm, determined by appearance, ranged from 17.1 to 21.0%, while reactive sperm ranged from 1.5 to 3.0%. There were, however, significant correlations (P < 0.01) between spermatophore weight and prawn weight (r= 0.73, N= 434). Male prawns weighing 4150 g produced on average spermatophores weighing 22.7 mg and containing 0.8 million sperm, while prawns weighing 61-90 g produced on average spermatophores weighing 56.6 mg with 2.5 million sperm. Ablation did not increase spermatophore size or sperm quality, although it significantly increased mortality of ablated males. Male prawns could be re-ejaculated at about weekly intervals with no change in sperm quality. Wild-caught female prawns artificially inseminated with spermatophores from electro-ejaculated males produced normal spawns with 51% average egg fertilization, and 41% nauplii hatch success. Nauplii hatch success following spawning increased from >60% for newly inseminated females to near zero after 30 days post-insemination, indicating spermatophore depletion and/or deteriorated sperm quality during spermatophore storage in the thelycum. The findings of the present study indicate that electro-ejaculation and artificial insemination are relatively simple and practical methods for improving captive reproduction performance of closed-thelycum prawns such as P. monodon, and that pond-reared and wild-caught males produced sperm of similar quality.