Effects of Intensification of the Amazon River Prawn,Macrobrachium amazonicum,Grow‐out on Effluent Quality

Studies to determine suitable levels of intensification are essential for developing sustainable aquaculture. The objective of this study was to evaluate the quality of effluents discharged from ponds stocked with 10 (D10), 20 (D20), 40 (D40), and 80 (D80) postlarvae of Macrobrachium amazonicum/m². Intake and effluent water samples were taken throughout a 5.5‐mo grow‐out cycle. In that study, twelve 0.01‐ha earthen ponds were stocked postlarvae with 0.01 g. Average water exchange rate was 15%/d; water was discharged from the bottom of the ponds. Prawns were fed a commercial feed with 38% crude protein according to their biomass (3–10%) and the concentration of dissolved oxygen (DO). In our research, temperature, turbidity, total suspended solids, conductivity, DO, pH, biochemical oxygen demand (BOD), chemical oxygen demand (COD), N‐ammonia, N‐nitrite, N‐nitrate, N‐Kjeldahl nitrogen, total phosphorus, and soluble orthophosphate were measured every 15 d throughout the experiment in the early morning (0630 to 0730 h). Turbidity was lower in D10 than in D20 and D40 and total phosphorus was higher in D80 than in D10 and D20. An analysis of principal components comparing treatments and intake water showed three groups: intake, D10 and a cluster of D20, D40, and D80. On the basis of the water characteristics found in our study it appears that the farming of M. amazonicum is likely to have a low environmental impact, at least up to a stocking density of 80 prawns/m².     

Effect of Intensification on Grow Out of the Amazon River Prawn, Macrobrachium amazonicum

The effects of intensification on growth, survival, productivity, population structure, and distribution of harvested biomass in individual size classes of Macrobrachium amazonicum in semi‐intensive culture were evaluated. Postlarvae (0.01 g) were stocked in 12 ponds at densities of 10, 20, 40, and 80/m² (three replicates per treatment) and raised for 5.5 mo. Average individual weight significantly decreased and productivity significantly increased as stocking density increased (P < 0.001), while survival was not affected (P > 0.05). Prawn mean weight at harvest ranged from 3.6 (80/m²) to 7.0 g (10/m²). Average survival ranged from 65.5% (40/m²) to 72.8% (20/m²), while productivity ranged from 508 (10/m²) to 2051 kg/ha (80/m²). Harvested biomass showed a clear bimodal distribution in individual size classes indicating the occurrence of heterogeneous growth, which may affect management and market strategies. Harvested biomass of prawns weighing more than 7 g (the best market size) increases for stocking densities up to 40/m² and stabilizes between 40 and 80/m². Growth reduction was associated with a decreasing frequency and average weight of green claw 1 and green claw 2 male morphotypes and adult females as density increased. Thus, the distribution of male morphotypes and sexually mature females are affected by density‐dependent factors. Results suggest that prawn density plays an important role on M. amazonicum grow‐out phase, as has been demonstrated for other species of the genus Macrobrachium. M. amazonicum tolerates grow‐out intensification and may be raised in both semi‐intensive and intensive systems stocked at very high densities yielding high productivity.     

４种微生态制剂对虾池水质及青虾生长性能的影响

在测定养殖水体pH值、溶解氧、氨态氮、亚硝态氮等水质指标和养殖青虾肥满度、平均规格、饲料系数等生长性能指标的基础上,比较研究了全池泼洒复合芽孢杆菌、EM菌、类球红细菌、超浓缩光合细菌微生态制剂对养殖水质的改善情况及提高杂交青虾"太湖1号"生长性能的效果。结果表明,4种微生态制剂均可改善水质;其中,芽孢杆菌与EM菌具有较强的降亚硝态氮功能,类球红细菌和EM菌具有较强的降氨态氮作用。4种试验菌剂的调水效果排序为:类球红细菌>EM菌>复合芽孢杆菌>超浓缩光合细菌。4种菌剂不同程度提高了青虾的生长性能;其中,类球红细菌效果最为显著,其次为EM菌、复合芽孢杆菌,而光合细菌的效果不显著。     

复合型活菌生物净水剂对改善虾池水质的作用

研究了复合型活菌生物净水剂在南美白对虾室内饲养试验中对水质的影响。结果表明：试验组平均透明度比空白对照组高41．25％，COD比空白对照组低26．81％，NH4-N比空白对照组低28．84％，pH与空白对照组无明显差异，异养菌总数、弧菌总数与空白对照组无明显差异。科新牌复合型活菌生物净水剂应用于水产养殖具有明显改善水质的作用。     

Effects of Ambient Nitrite on Amazon River Prawn,Macrobrachium amazonicum,larvae

The effects of nitrite concentration on larval development of Amazon river prawn, Macrobrachium amazonicum, were studied in laboratory. In Experiment 1, larvae were reared in 600‐mL glass beakers filled with 300‐mL water with nitrite concentration of 0, 0.2, 0.4, 0.8 and 1.6 mg/L NO₂‐N. In Experiment 2, total ammonia nitrogen (TAN, NH₃‐N + NH₄‐N) excretion were analyzed in zoea (Z) I, III, VII and IX exposed to 0, 0.4, 0.8 and 1.6 mg/L NO₂‐N. In both experiments each treatment was conducted in five replicates. The experiments were carried out in test solutions at 10 salinity, constant temperature 30 C and 12:12 h daylight : darkness regime. Survival, productivity, weight gain and larval stage index decreased linearly with increasing ambient nitrite concentration. However, there was no significant difference among larvae reared at concentration ranging from 0 to 0.8 mg/L NO₂‐N by ANOVA in all variables. Individual ammonia‐N and mass‐specific ammonia‐N excretion increased in ZI and ZIX, was almost constant in ZIII and decreased in ZVII from 0 to 1.6 mg/L NO₂‐N. The relationship between individual TAN and body mass suggested that 1.6 mg/L NO₂‐N stress the larvae. Despite of the effects of nitrite on larvae follow a dose‐dependent response and shows large variability among individuals, levels below 0.8 mg/L may be used as a general reference in commercial hatcheries, which should be applied carefully.     

河口低盐区罗氏沼虾养殖试验报告

利用对虾养成池，在盐度为５．９８～９．０的半咸水中，单养罗氏沼虾，平均亩产１０８．ｇｋｇ，平均体长７．７８ｃｍ；罗氏沼虾与梭鱼混养，亩产罗氏沼虾１０２．３ｋｇ，平均体长８．１７ｃｍ，亩产梭鱼２６．３ｋｇ，平均体长１８．７８ｃｍ。与当地养殖中国对虾相比，每亩经济效益高６８．３％。专家鉴定认为：本研究技术成果达国内先进水平。     

泼洒糖蜜对池塘养殖罗氏沼虾生长和水质的影响

将单口面积1.33~2.33hm~2、环境相似的6口罗氏沼虾养殖池塘分为2组,3口池塘投喂蛋白质水平为35.4%的饲料,且每日适量泼洒糖蜜(试验组),3口池塘投喂蛋白质水平为41.9%的饲料,不泼洒糖蜜(对照组),常规管理。养殖期间,每隔15d取水样检测氨氮和亚硝态氮含量。156d的饲养结果表明,对照组和试验组罗氏沼虾的产量分别为6600kg/hm~2和6427.5kg/hm~2,降低饲料中的蛋白水平结合泼洒糖蜜不影响罗氏沼虾的生长(P0.05),养殖效益亦无显著差异(P0.05)。但试验组池塘水中氨氮较对照组低54.0%,亚硝态氮低21.0%,泼洒糖蜜显著降低了池塘氨氮和亚硝态氮含量(P0.05)。     

Effect of Water Exchange Rate on Waste Production in Semi-Intensive Shrimp Ponds During the Cold Season in New Caledonia

An experiment was conducted in six earthen ponds with 20 shrimp/m² ( Litopenaeus stylirostris ) during the cold season in New Caledonia to determine the effect of water exchange rate on characteristics of effluents and pond sediment. The nitrogen budget was established, taking into account the different forms of nitrogen in the water, sediment, feed, and shrimp. Mean water exchange rates ranged from 10 to 23% per day. Increasing water exchange rate did not cause any significant change in the average quality of the rearing environment (water and sediment) during the whole growout period. However, the results showed that increasing exchange rates boosted primary productivity. Compounds produced by the mineralisation and metabolism of organic matter (feces, uneaten feed) were exported as particulate, rather than soluble matter. The nitrogen budget showed that the amount of exported wastes from the pond into the coastal environment was only 40–50% of nitrogen inputs due to nitrogen accumulation in the pond sediments and/or release to the atmosphere. The highest accumulation of dry material, as well as the highest Δ N (concentration of total N at the end of rearing - concentration of total N before rearing), was observed in ponds with the highest WER.     

Effect of Water Exchange Rate on Production, Water Quality, Effluent Characteristics and Nitrogen Budgets of Intensive Shrimp Ponds

Water exchange is routinely used in shrimp culture. However, there are few, if any, systematic investigations upon which to base exchange rates. Furthermore, environmental impacts of pond effluent threaten to hinder further development of shrimp farming in the U.S. The present study was designed to determine effects of normal (25.0%/d), reduced (2.5%/d) and no (0%/d) water exchange on water quality and production in intensive shrimp ponds stocked with Penaeus setiferus at 44 postlarvae/m². Additional no-exchange ponds were stocked with 22 and 66 postlarvae/m² to explore density effects. Water exchange rates and stocking density influenced most water quality parameters measured, including dissolved oxygen, pH, ammonia, nitrite, nitrate, Kjeldahl nitrogen, soluble orthophosphate, biochemical oxygen demand, phytoplankton and salinity. Reduced-exchange and no-exchange treatments resulted in reduced potential for environmental impact. Mass balance of nitrogen for the system indicates that 13–46% of nitrogen input via feed is lost through nitrification and atmospheric diffusion. Growth and survival were excellent in ponds with normal exchange, reduced exchange, and a combination of low density with no water exchange. A combination of higher stocking density and no water exchange resulted in mass mortalities. Mortalities could not be attributed to a toxic effect of any one water quality parameter. Production was 6,400 kg/ha/crop with moderate stocking density (44/m²) and reduced (2.5%/d) water exchange and 3,200 kg/ha/crop with lower stocking density (22/m²) and no water exchange. Results indicate that typical water exchange rates used in intensive shrimp farms may be drastically reduced resulting in a cost savings to farms and reduced potential for environmental impact from effluent.     

Effects of Aeration, Alum Treatment, Liming, and Organic Matter Application on Phosphorus Exchange between Soil and Water in Aquaculture Ponds at Auburn, Alabama

Application of readily-oxidizable organic substrate to laboratory soil-water systems and fish ponds caused anaerobic conditions in bottom soil and water, and concentrations of soluble reactive phosphorus (SRP) increased. Aeration of ponds increased total phosphorus (TP) concentrations by suspending soil particles in the water, but SRP concentrations declined because of increased oxy- genation of bottom water and soil, Alum [Al₂(SO₄)₃·14H₂O] treatment of ponds reduced SRP and TP concentrations in ponds, but the low concentration of alum used, 20 mg/L, had little residual effect on phosphorus concentration. Application of agricultural limestone at 0.2 kg/m² to ponds with soil pH of 5.5 and Ca²⁺ concentration of 5 mg/L did not affect SRP and TP concentration. Unless pond soils were anaerobic at their surfaces, a condition not acceptable in thermally-unstratified fish ponds, soils released little phosphorus to the water. Strong adsorption of phosphorus by soils in intensive ponds with feeding is beneficial, because removal of phosphorus by aerobic soils is a control on excessive phytoplankton growth. In fertilized ponds, phosphorus must be applied at frequent intervals to replace phosphorus removed from the water by soils.     

Grow‐out performance of Kuria labeo,Labeo gonius (Hamilton), with major carps in carp polyculture system

A year‐long grow‐out carp polyculture trial was conducted in nine earthen ponds to study the growth performance of Kuria labeo (Labeo gonius) with the different major carps such as catla (Catla catla), silver carp (Hypophthalmichthys molitrix), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala). Suitable water quality parameters were maintained in ponds through intermittent liming, manuring and fertilization. Three different species combinations of carps were evaluated using silver carp and catla as the common species and varying other carp components as rohu–Kuria labeo, mrigal–Kuria labeo and rohu–mrigal in the three treatments. The ponds were stocked at a combined density of 7500 fingerlings ha^?1. Silver carp and catla showed similar growth performances in all the three combinations, suggesting that other carps in the combination do not have any differential influence on their growth. Kuria labeo was compatible with rohu, while competition was observed with mrigal. Although growth performance of Kuria labeo was inferior to that of mrigal, better compatibility of Kuria labeo with rohu helped this combination to yield a biomass equivalent to the mrigal–rohu combination, suggesting feasibility to use Kuria labeo as an alternative species to mrigal in the major carp polyculture system without compromising the total biomass yield.     

珠江三角洲密养池塘的水质特点分析

对珠江三角洲的几个典型基塘进行了一个养殖周期的跟踪调查,发现密养池塘中的NH4-、TN、COD、Chla等指标均有明显的升高,而NO3-、TP、SRP、BOD等指标无明显升高,DO没NO2-也占约 比例上升,占50%以上,NO2有明显下降。密养池塘无机氮的组成发生了明显的变化:NH4-比例,降到40%以下。池塘是以P为浮游植物生长的限制性因子。P的限制因素解除,浮10%,NO3游植物将迅速增长。池塘底泥中TP、TN、有机质明显高出基面堆叠土,以P的富集最为强烈。富营养化评价结果表明,珠江三角洲密养池塘达到了重度富营养化水平,而且养殖年限越高,富营养化程度越高。     

Magnesium Budget for Inland Low‐Salinity Water Shrimp Ponds in Alabama

A magnesium budget was prepared for a commercial low‐salinity shrimp farm in the Blackland Prairie region of Alabama for one production cycle. Ponds had previously been used for production and fertilized with magnesium; two ponds (S‐5 and S‐6) for four previous years and one pond (N‐9) for one previous season. Fertilization with sulfate of potash magnesia (K₂SO₄·2MgSO₄ or K‐Mag^®) was applied to these ponds to obtain the concentrations of 20 mg/L, averaging 1274 kg Mg²⁺/ha. Additional inputs of magnesium included groundwater, rainfall, and runoff averaged 441.5 kg/ha. A water budget for ponds indicated that 292.6 kg/ha of magnesium in outflows. The difference in inputs and magnesium outputs resulted mainly from adsorption of magnesium by pond bottom soils. However, the increase in exchangeable magnesium in the upper 15‐cm layer of pond bottom soils was not great enough to account for the difference in total magnesium inputs and magnesium outputs in water and shrimp. Possible explanations for this discrepancy are magnesium precipitation, nonexchangeable fixation of magnesium by clay minerals, incomplete extraction of magnesium, and analytical error. The decreased uptake of magnesium by older ponds, S‐5 and S‐6, indicate that the soils had a diminishing affinity for the cation or an equilibrium concentration is being established.     

虾池基础生物饵料的培养技术及其种类,数量的研究

为解决虾苗入池后的前期饵料，降低养虾成本，对对虾美成池基础生物饵料的培养技术及其种类，数量进行了研究。对试验池２４０个水样进行生物定性，定量分析的结果：浮游植物有７４种，隶属７门８纲４１属；浮游动物有５３种，隶属７纲１４目；平均生物量为７４．４７×１０＾６个／Ｌ或３８．３９ｍｇ／Ｌ。基础生物饵料的种类和数量随着水温的升高而增多。通过合理施肥使池水保持自然生态平衡，不用投喂任何代用饲料，便可使对虾长     

Winter Culture of Yellowleg Shrimp Penaeus californiensis in Aerated Ponds with Low Water Exchange

Abstract— This study was conducted in the semiarid region of Bahia Kino, Sonora, Northwestern Mexico to determine the feasibility of farming yellowleg shrimp Penaeus californiensis during the winter season in ponds with less than 5% daily water exchange and aeration. Four aeration rates (0, 6, 12, and 24 h/d) were used in the study. Mean growth rates ranged from 0.41 to 0.53 g/wk with the highest growth rate in ponds with 12 h of aeration ( P × 0.05). Survival ranged from 50 to 52% and did not differ among treatments. Shrimp yield ranged from 1,012 to 1,208 kg/ha, with the highest yields from ponds with 6 and 12 h of aeration ( P × 0.05). Feed conversion ratios ranged from 2.3 to 2.8, with lower values in ponds with 12 and 6 h of aeration ( P × 0.05). Results suggest that winter culture of yellowleg shrimp is possible and that 6 h of aeration is sufficient to maintain good water quality conditions.     

Effects of Diet and Organic Fertilization on Water Quality and Benthic Macroinvertebrate Populations in Ponds Used to Culture Freshwater Prawn,Macrobrachium rosenbergii

ABSTRACT

Effects of three diets: (1) complete diet; (2) supplemental diet (vitamin and mineral supplements not added); and (3) the supplemental diet with an adjunct organic fertilization regimen (using distiller's dried grains with solubles [DDGS]) on benthic macroinvertebrate populations and water quality in experimental ponds used to culture freshwater prawns, Macrobrachium rosenbergii were investigated. Benthic samples were taken from deep (1.5 m) and shallow (1.0 m) areas of each of nine 0.02-ha ponds every three weeks, using a 0.09-m² Ekman dredge. The abundance of gastro-pods, oligochaetes, total non-insects, chironomids, total dipterans, total insects, and total macroinvertebrates was significantly higher (P <0.05) in ponds receiving the complete diet, possibly due to lower predatory pressure by prawns or direct benefits of micronutri-ents. Total macroinvertebrate abundance was significantly decreased (P <0.05) in ponds receiving supplemental diet (with and without organic fertilization), possibly due to increased predation by prawns to supplement the nutrition not provided by the lower quality diet. Organic fertilization significantly increased (P <0.05) the abundance of oligochaetes and total macroinvertebrates. These data suggest that M. rosenbergii can adjust to reduced feed quality by increasing consumption of benthic fauna.     

Constructed wetlands for treatment of harvest effluents from grow‐out ponds of the Amazon river prawn

Effluent discharges from aquaculture can reduce water quality in receiving water bodies and that strategies or practices to reduce this are necessary. One possibility is to reduce, or eliminate, water renewal in grow‐out ponds. In this study, we eliminated water renewal in grow‐out ponds associated with the culture of 40 individuals m^?2 of Amazon river prawn (Macrobrachium amazonicum). At the end of the culture period it was, however, necessary to drain the pond to harvest the prawns. An experiment was performed in triplicate, in which the water supply characteristics and harvest water characteristics of ponds were evaluated. To reduce these concentrations of total N and P, an aquatic macrophyte (Eichhornia crassipes, water hyacinth) treatment system (CWs) was adopted. The water characteristics in the CWs were evaluated after 1, 3, 7, 14 and 21 days. The water supply of ponds presented the average concentrations of 0.67 ± 0.32 mg L^?1 and 17.4 ± 14.7 μg L^?1 of total‐N and total‐P respectively. The harvest effluent of ponds had elevated concentrations of different forms of nitrogen (4.44 mg L^?1 of total‐N) and phosphorous (100.9 μg L^?1 of total‐P). After 1 day of the experiment we found the following reductions in key nutrients in treatment system containing E. crassipes: 90%, 78% and 45% reductions in the concentrations of particulate matter, orthophosphates and nitrates respectively. We noted that after 3 days the nitrates had been reduced by 53%. We concluded that 3 days of this treatment was sufficient for the removal of the additional nutrients that had accumulated in the Amazon river prawn ponds.     

Effects of Major Water Quality Variables on Shrimp Production in Inland,Low‐Salinity Ponds in Alabama

Common water quality variables in nine, inland low‐salinity shrimp ponds in Alabama exhibited wide variation in concentrations among ponds and over time. Shrimp performance also varied considerably among ponds in 2008 as follows: survival, 16–128%; production, 928–5950 kg/ha; feed conversion ratio (FCR), 1.18–2.89. Measured water quality variables were not at concentrations high enough to be lethal to shrimp; but water temperature, dissolved oxygen, carbon dioxide, total ammonia nitrogen, calcium, and magnesium were occasionally outside optimum ranges for shrimp production and may have stressed shrimp. Survival and production both were positively correlated (P < 0.05) with increasing concentrations of methyl orange alkalinity, total alkalinity, and calcium hardness. Negative correlations (P < 0.05) between production and higher pH and water temperature may have resulted from lower water temperature and pH during final days of the crop in ponds harvested in October rather than from an actual effect of temperature and pH on growth. Nevertheless, those variables that were outside optimal ranges or correlated with shrimp survival or growth should be further investigated to ascertain whether or not excursions outside optimum ranges are harmful and to determine if observed correlations are causal.