Chemical and Physical Properties of Shrimp Pond Bottom Soils in Ecuador

Chemical and physical analyses were conducted on bottom soil samples from 74 brackish-water ponds representing 40 shrimp farms in Ecuador. Most ponds had soils with pH > 6 and total carbon concentrations < 2.5%. Carbon was mostly in organic form, for the average concentration of carbonate carbon was 0.06%. The C: N ratio was 8 to 10 in soils with < 2.5% carbon. In ponds built in former mangrove areas, soil carbon was > 2.5% and C: N ratios were 25 to 30. Ponds soils in former mangrove areas also tended to be high in total sulfur and low in pH. Lack of correlation between carbon and sulfur in mangrove soils suggested that most of the sulfur was inorganic and presumably in sulfides. Soils containing above 0.4% free carbonate (as equivalent CaCO₃) had pH values > 7. Although carbonate concentration was a major factor controlling soil pH, calcium hardness of pond waters was strongly influenced by salinity (and calcium) in the water supply. Total phosphorus concentrations averaged 898 mg/kg, and dilute acid extractable phosphorus usually accounted for 25–35% of the total. Concentrations of major cations and minor elements varied greatly in soils and exhibited ranges of up to three orders of magnitude. Contrary to opinions of shrimp producers, many pond soils in Ecuador are not acidic and few soils have a high organic matter content. Proper use of soil and water testing could greatly improve the efficiency of liming and other soil management practices.     

The Impact of Aquaculture Pond Engineering Design on the Returns to Shrimp Farms

The effects of pond design on the internal rate of return of a 40 ha shrimp farm is evaluated. The influence of four pond construction parameters (pond size, pond shape, levee crown size and canal bank slope) on the total amount of earth moved and construction costs is determined using an engineering design model. The bioeconomic model, MARSIM, calculates returns to farms with the design modifications. Of the four parameters, the pond shape is the most influential over the range considered (from 17% to 8%). Pond size is the second most important parameter (from 17% to 21%). Levee width and canal bank slope influence are of lesser importance (<1% change).     

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

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

Possible Potassium and Magnesium Limitations for Shrimp Survival and Production in Low‐Salinity,Pond Waters in Thailand

Low‐salinity waters of inland shrimp ponds in Nakhon Nayok, Chachoengsao, Prachin Buri, and Samut Sakhon Provinces of Thailand often had concentrations of potassium and magnesium below those expected for normal seawater diluted to the same salinity. However, in Samut Sakhon Province – where the sampling area was nearer the coast – ponds typically had higher concentrations of these two cations than did ponds in the other three provinces. Studies of inland, shrimp ponds at Banglane in Nakhon Pathom Province revealed that magnesium additions to maintain a target concentration near 100 mg/L resulted in greater (P < 0.05) shrimp survival, size, and production than obtained in control ponds. Although potassium additions to ponds (75 mg/L target concentration) did not improve shrimp survival or production, the control ponds had potassium concentration higher than those previously reported for ponds in Alabama where potassium treatment was highly beneficial to shrimp survival and production. A study conducted using laboratory, soil‐water systems with soil from one site did not remove potassium and magnesium from the water, while soil from two other sites removed potassium and magnesium from water – but at different rates.     

Using Experimental Microcosms in Shrimp Research: The Growth-Enhancing Effect of Shrimp Pond Water

After preliminary six week experiments showed that shrimp pond effluent from an intensive culture growout pond had the capacity to nearly double shrimp growth in laboratory tanks, an 18 day experiment was designed to determine if similar results occurred in the presence of high quality feeds. The results presented here corroborate the hypothesis that autochthonous factors in shrimp pond water stimulate shrimp growth. These results revealed that performance of currently available shrimp feeds is greatly improved in the presence of pond effluent, regardless of feed quality. Increased feed performance did not appear to be an artifact of supplemental feed availability in pond effluent. The implications from these experiments are that, even in intensive culture systems (above 40 shrimp per m²), in-situ sources of nutrition play an important role in shrimp growth.     

Accumulation of Chemical Elements in Texas Shrimp Pond Soils

Abstract— This study evaluated changes in chemistry of shrimp pond soils over one production cycle. Several soil nutrients, pH, organic matter, and total soluble salts were analyzed in the upper 10 cm of pond-bottom soil on two Texas shrimp farms in two consecutive years. Soil concentrations of S, P, Ca, Mg, K, Na, Mn, and Zn increased from one year to the next, S increased by 400 ppm. Organic matter did not accumulate. The pH decreased in all pond soils, owing perhaps to the oxidation of organic matter and/or inorganic compounds. There was no statistical difference in shrimp yield between the two consecutive years. These results indicated that the accumulation of S and soluble salts derived from seawater and feed should be monitored and evaluated to prevent excessive chemical element loading of pond soil and discharge water.     

普通虾池对虾无公害(Non-Pollution)健康养殖试验

为寻求无公害健康养殖的途径,我们进行了普通虾池无公害对虾健康养殖试验。经过114d的养殖,试验池塘收获成虾总产量27,505kg,平均单产8,595．31kg／hm^2;对比池塘收获成虾总产量12,157kg,平均单产7,598．13kg／hm^2;试验池塘总产值66．01万元,获利27．04万元,平均每亩池塘获利5,633元;试验池塘总产值26．75万元,获利7．1万元,平均每hm^2池塘获利44,370元。试验池塘与对比池塘相比,平均单位面积获利增长90．43％。试验池塘由于采用了无公害养殖技术,成品虾各项规定指标均符合食品卫生安全标准,达到无公害食品要求。     

杂色蛤与对虾混养技术

赣榆县1999年对虾(Penaeus chinensis)与杂色蛤(Ruditapes variegata)混养面积380 hm2,收获杂色蛤4 800 t,对虾125 t,取得了较好的经济效益和社会效益.本项生态农业技术模式适宜在硬泥或沙泥底质的虾塘泥滩推广,其技术要点如下:     

Disinfection, Microbial Community Establishment and Shrimp Production in a Prototype Biosecure Pond

Plankton community establishment and shrimp production in a prototype biosecure pond were compared to three control ponds. The biosecure pond was enclosed and intake water was disinfected, while control ponds were neither enclosed nor disinfected. All ponds were managed with no water exchange and stocked with 100 postlarvae/m², Litopenaeus vannamei . Residual oxidant concentrations in the biosecure pond dropped rapidly after cessation of chlorinated water addition. This was followed by a sharp increase in water column bacterial abundance, after which the pond was fertilized and inoculated with cultured Chaetocerous gracilis . After crash of the initial C. gracilis bloom in the biosecure pond, this species was not observed again. Following initial large fluctuations in biosecure pond bacterial abundance, phytoplankton biomass, oxygen consumption and nitrification rates, these parameters appeared to stabilize at levels similar to the control ponds. Early season compositional differences in phytoplankton, zooplankton, and bacterial communities were observed. No differences were seen in late-season phytoplankton and bacteria; however, zooplankton biomass tended to be lower in the biosecure pond than in the control ponds throughout the season. Shrimp production in all ponds was greater than 9,000 kg/ha. Production in the single biosecure pond was not a significant outlier compared to production in the triplicate control ponds.     

分段养殖模式在凡纳滨对虾(Litopenaeus vannamei)养殖过程中的应用

通过测定凡纳滨对虾(Litopenaeus vannamei)生长性能和监测池塘水质变化,研究分段养殖模式在对虾养殖过程中的应用价值.养殖实验在6口池塘内(0.267 hm2/口)进行,首先在其中2口池塘内进行对虾的中间培育,养殖密度为300×104尾/hm2.经过36 d和48 d的中间培育后,将对虾先后转移到其他4口池塘内,养殖密度为60×104尾/hm2,分别记为T1和T2组.剩余的对虾继续养殖在中间培育池塘内,记为C组.结果显示,经过分段养殖的T1和T2组对虾,在分池养殖阶段7d内,生长速度均明显增加,其特定生长率(SGR)分别达到9.36 ％/d和6.76 ％/d;养殖期间,T1组具有最大的SGR (9.36 ％/d)和饲料投喂量,然而其饲料系数(FCR) (1.053)高于T2组(0.822);经过分段养殖的对虾FCR均低于C组(1.082).在分池养殖阶段的大部分时间,T2组对虾的SGR高于T1组;C组NH4+-N、NO2-N和Chl-a浓度低于T1组和T2组,而颗粒物含量(TPM)和总磷(TP)高于T1组和T2组;T2组Chl-a含量明显高于T1组和C组.结果显示,经过48 d中间培育后,即对虾体重约为2 g时进行分池养殖仍可保证对虾在较长时间内保持较大的生长速度,对于饲料的节约具有重要意义.由于分池养殖阶段具有较多的饲料投喂,经过36 d中间培育后的对虾具有最大产量.分池养殖池塘内饲料投喂少于全期养殖,有利于养殖系统的稳定,然而单位时间内投喂量增加则会影响水质.分段养殖模式在提高分池养殖阶段对虾的生长速度和保持水质稳定方面具有重要的应用价值.     

精养虾池的水色培养及调控方法

“养虾先养水”是业内人士都认同的观点 ,它说明了水色在对虾养殖生产中的重要性。在整个养殖过程中 ,要营造良好而稳定的水色是养虾技术的重点和难点。说起来容易 ,做起来难度很大。现针对对虾高产养殖生产中经常碰到一些有关水色调控的问题 ,提出一些处理方法 ,以供参考或共同探讨 :1　虾池水色的标准及作用水色是虾池水体理化因子的综合反映 ,它与水中浮游生物的种类和数量有密切关系。对虾养殖生产中通常以池水的颜色、透明度的大小和清爽度来衡量池水水色的好坏 ,良好的水色应是黄褐色、黄绿色 ,清爽而亮泽 ,硅藻和绿藻同时成为优势种…     

淡水青虾土池人工育苗技术

在土池中架设敞口式网箱，箱内放养抱卵青虾进行强化培育及幼虾孵化，通过适时培养生物开口饵料，及时投喂人工饲料，保持中度肥水等技术措施和20余天的培育，经验收小组确认，每亩生产1cm以上的虾苗 140余万尾。并对适宜青虾育苗的池塘生态条件及饵料生物培养，水质调节提出了自己的看法。     

世界五国对虾养殖场附近海域环境管理实况

关于对虾养殖场附近海域环境管理，是水产养殖学研究的课题。本文是作者根据韩国(水产养殖)杂志2000年第6期翻译整理的一篇译文。简要介绍了世界对虾联合会对巴西、泰国、美国、洪都拉斯、尼加拉瓜五国对虾养殖场沿岸水质监测情况的调查的内容。     

几种对虾池塘放养模式的生态效益评价

从生态效益角度对我国对虾池塘的几种放养模式进行了评价,综合放养模式符合生态平衡、物种共生互利以及对物质多层次利用等生态学原理,较之于单品种放养模式具有较高的生态效益,在我国具有强大的生命力和广阔的发展前景。     

日本沼虾水泥池育苗试验

选取450只平均抱卵量为960粒/尾健康活力强的抱卵虾作为亲本进行育苗试验,并对日本沼虾蚤状幼体分期进行系统观察。结果在孵化期间共获得蚤状幼体408 240尾,孵化率为94.5%,育苗后期共获得仔虾242 086尾,蚤状幼体发育到仔虾的成活率为59.3%,蚤状幼体可分为Ⅴ期。本试验结果为今后日本沼虾人工育苗技术推广提供参考。     

Estimates of Bottom Soil and Effluent Load of Phosphorus at a Semi-intensive Marine Shrimp Farm

A phosphorus budget for a single crop was prepared for a 685‐ha semi‐intensive shrimp farm that consistently has produced about 3000 tonnes/yr of black tiger prawn, Penaeus monodon. Phosphorus inputs were shrimp stock, 0.31 kg/ha; triple superphosphate, 1.38 kg/ha; incoming water, 25.8 kg/ha; and feed, 65.3 kg/ha. Phosphorus outputs were harvested shrimp, 5.43 kg/ha, and outflow for water exchange and draining, 42.7 kg/ha. The high clay‐content soil in pond bottoms adsorbed 45.2 kg/ha of phosphorus. Water was taken from and released back into the same estuary and bay. The phosphorus contribution of shrimp farming to the receiving water body was the difference between the amount of phosphorus in effluent and that in the incoming water, which was 16.9 kg/ha. Bottom soil accumulated 67.8% of phosphorus added to the ponds. Another estimate of soil phosphorus uptake based on the relationship between cumulative phosphorus applied to ponds as fertilizer and feed and soil phosphorus concentration suggested that 63.2% of fertilizer and feed phosphorus had accumulated in pond bottoms. The farm effluent phosphorus load was 23.5 tonnes/yr. The estuary and bay system has an estimated volume of 4.8 × 10⁹ m³, and the annual phosphorus input from the farm had a concentration equivalent of 0.005 mg/L, and there were no other major inputs of phosphorus. The estuary and bay are flushed by freshwater inflow and tidal action, and the farm input is not likely to cause eutrophication.     

微生态制剂对虾池水质影响的研究

以虾为研究对象来探讨微生态制剂对虾池水质的改良效果。在养虾池中分别加入光合细菌、芽孢杆菌以及不同浓度的微生态制剂,待其生长繁殖后测定氨氮、亚硝酸盐、溶解氧、COD值和pH值等各项水质指标。结果表明,微生态制剂对虾池水质具有较好的改善作用,其最适使用浓度约为2 0×1010个/m3。     

Regression Analysis of Soil Chemical Composition for Two Shrimp Farms in Texas

Several nutrients, pH, organic matter, and total soluble salts of surface soil from 81 ponds on two Texas shrimp farms were measured. The relationship between shrimp yield and soil characteristics was analyzed statistically. Shrimp yield was negatively correlated with soil concentrations of S, P, NO₃^-, B, Ca, Mg, K, Na, Cu, and total water-soluble salts. Shrimp yield was directly correlated with soil concentrations of Fe, Mn, and organic matter. Stepwise multiple regression analysis indicated that Ca and S concentrations explained 54% of the variation in shrimp yield.     

Biochemical Composition of Pond Biota, Shrimp Ingesta, and Relative Growth of Penaeus vannamei in Earthen Ponds

Indigenous pond biota contribute to the nutrition of shrimp grown in semi-intensive and extensive earthen ponds. Penaeus vannomei ingesta was used to assess the nutritional contribution of pond biota and applied feed in model 225 m² nominally managed earthen ponds. Biochemical analyses were also performed on representative pond biota and pond environment samples. Average dry matter shrimp ingesta composition ( N = 64) was: available carbohydrate, 4.2%± 1.8%; lipid, 4.8%± 2.3%; available protein, 9.6%± l.0%; carbon, 9.6%± 1.0%; nitrogen, 5.9%± 2.9%. Ingesta carbon decreased from 27.0%± 3.9% on week 2 to 16.3%± 3.3% on week 8, and nitrogen content decreased from 9.5%± 4.3% to 3.6%± 0.8% during the same interval. The decrease of ingesta C:N ratio from weeks 2 to 8 may indicate changing nutritional requirements of the shrimp. Ingesta essential amino acids varied by less than 10% from short-neck clam protein. Except for several samples which were low in arginine, pond biota and environment samples contained amino acid profiles which were close to short-neck clam. Essential fatty acid composition of shrimp ingesta was highly variable. Ingesta 22:6 fatty acid was present in populations of shrimp from ponds experiencing the highest weekly growth rates. Ingesta 22:6 fatty acid was not present in measurable amounts in shrimp experiencing the lowest growth. The unsaturated fatty acids 20:5 and 22:6 were absent from some pond biota and environment samples and abundant in others. The applied diet contained no measurable 20:5 or 22:6. The management implications of shrimp ingesta biochemical analyses are that diets may be fed which nutritionally complement pond biota consumed by the shrimp.