征订启事

罗氏沼虾商品虾的养殖，要坚持因地制宜根据虾种来源、饵料状况，水域环境及养殖技术等，采用科学的养殖方法，来提高产量，增加养殖效益。     

印度马氏沼虾的繁殖和养殖

印度所有河流都有大量的马氏沼虾资源，但作为亲本，其质量较低，且数量不多又不稳定。这就是为什么在孵化、幼体培育及成虾养殖方面的技术尚未突破，也是马氏沼虾大面积的养殖示范未获得象罗氏沼虾那样成功的原因所在。马氏沼虾的发育有四个阶段，而这四个阶段完全与培育条件和措施有关。亲虾、幼体和商品虾是决定性的阶段，这期间需要精心照料。目前，这方面的技术已日臻成熟。马氏沼虾亲虾是沼虾育种的关键材料。虾种的性成熟会随自然环境的改变而有较大改变，而这种环境又取决于农业化肥施用的流失和污染的程度。在池塘养殖的情况下，马…     

商品活虾的运输

大量的商品虾，采用活体运输是比较困难的，因为，南美白对虾体小壳薄、不耐低溶氧，运输中虾易死亡并恶化水质，影响其他活虾的存活。但随着水产品流通市场的不断发展，市场价格决定了上市商品虾必须保持鲜活，广大养虾户和销售户面临着如何进行批量活虾运输的难题。山东高青渔场近年来摸索出一种运输方法，可供参考：     

罗氏沼虾养殖高产技术

罗氏沼虾养殖高产技术陈凌云（杭州市水产技术推广站）罗氏沼虾又名马来西亚大虾，是一种优良的淡水养殖对象。我们通过近几年的养殖，亩产可达１５０千克以上，最高达２５０千克，成虾商品规格在３５—４０尾／５００克，亩净收益在４０００元，经济效益显著。现将养殖过...     

斗门罗氏沼虾养殖发展迅速

罗氏沼虾又名淡水长臂大虾，原产地在东南亚，最大个体重600克，虾头充盈膏脂，甘香可口，虾身肉厚脆甜，含蛋白南20．4％，是国内大力推广养殖的优质水产品种。从1厘米体长的虾苗养成每公斤50尾的商品虾通常只需要120天，亩产可达数百公斤，目前每公斤收购价50元。养殖罗氏沼虾技术讲究，尤其是虾苗生产难度较大，     

活虾运输四法

1．活水船运虾。在普通船的船舱前后开孔．让河水因船的前进而由前孔进水，后孔出水，使船舱内的水由“死”变“活”。在河水环境不污染的地区和温度低的季节，装载密度和成活率都较高。此法适宜水网地带运输商品虾、幼虾和亲虾。     

斑节对虾高产养殖试验

斑节对虾俗称草虾、花虾,在我国浙江以南沿海广泛公布。斑节对虾耐高温，具广盐性，适宜于我省沿海尤其珠江口海区高温、低盐且盐度变化大的特殊环境，是对虾养殖的优良品种。斑节对虾个体大、食性杂、生长快、耐干性强能销售活虾，故养殖斑节对虾具有较高的经济效益。     

罗氏沼虾育苗中几个问题的探讨

罗氏沼虾人工育苗技术已有较多报道，本文根据199O年到1998年间利用天然海水和人工配制海水进行罗氏沼虾育苗工作的经验总结，对几个较为突出的问题进行分析讨论，提出相应对策，以供参考。1育苗过程中主要出现的问题及原因1．1抱卵虾卵脱落和孵化率低抱卵亲虾挑选出后，常有卵脱落和卵死亡造成孵化率低，甚至孵化不出幼体的现象，尤其是每年的第一批抱卵虾。笔者认为，引起这种现象的原因是：（1）亲虾越冬期间没有管理好，亲虾受过伤。（2）交配时雄虾较少，或精子质量低。（3）抱卵虾在孵化过程中长时间在水质较差的水中。（4）抱卵虾在…     

虾（罗氏沼虾）鱼混养初试和效益

虾（罗氏沼虾）鱼混养初试和效益１９９３年４月１０日，水库渔业研究所在广西扶绥汪庄水库坝下池塘进行虾鱼混养试验。结果亩产罗氏沼虾６８．４２公斤，商品鱼１０４．２１公斤，饲料系数２．５０，取得了较好的经济效益。现将试验过程中所采取的措施和经济效益总结如下...     

鱼虾鳖池塘混养技术

鱼、虾、鳖池塘混养不但可以提高池塘利用率和商品鱼、虾、鳖的质量，而且可大大提高池塘养殖经济效益。现根据近年来的生产实践，介绍池塘鱼、虾、鳖混养技术，供养殖者参考。     

Phenoloxidase and peroxidase activity in the shrimp Litopenaeus schmitti,Pérez‐Farfante and Kensley (1997) exposed to low salinity

Phenoloxidase and peroxidase activity were analysed in haemolymph of juvenile shrimp, Litopenaeus schmitti, exposed to different salinity levels (35%, 18%, 8%) for 48 h. A significant reduction (P<0.05) in total glucose and phenoloxidase activity in animals exposed to lower salinities (18% and 8%) was recorded, while peroxidase activity and total protein concentration did not vary. Histology revealed the occurrence of oedema in gills in shrimp exposed to 8%. The work demonstrates for the first time that in L. schmitti, low salinities can decrease glucose levels in haemolymph and create an immunosuppressive state by reducing phenoloxidase activity.     

中国对虾产业现状及相关研究综述

中国对虾产业在国际上具有重要地位，但近年来中国对虾出口形势面临从未有过的巨大挑战，因此，了解我国对虾产品、产业的现状，加大我国对虾产品与产业的研究，对我国对虾产业增强竞争能力和可持续发展具有一定意义。     

Microalgal bacterial flocs originating from aquaculture wastewater treatment as diet ingredient for Litopenaeus vannamei (Boone)

Microalgal bacterial flocs (MaB‐flocs) in sequencing batch reactors are a novel and promising technology to treat aquaculture wastewater. To improve the economics of this technology, the harvested MaB‐flocs should be valorized. Therefore, we investigated if MaB‐flocs from an outdoor pilot reactor treating pikeperch (Sander lucioperca L.) wastewater can be used as a colour enhancing ingredient for shrimp diets. Considering the nutritional composition and high ash content of MaB‐flocs, five iso‐nitrogenous and iso‐lipidic shrimp diets were formulated by replacing 2–8% of the basal diet ingredients by MaB‐flocs. These diets were continuously fed to juvenile Pacific white shrimps Litopenaeus vannamei (Boone) cultured in a hybrid recirculating aquaculture system. The addition of these relatively low amounts of MaB‐flocs to shrimp diets significantly increased the pigmentation (redness and yellowness) of cooked shrimp tails. The diet modifications did not affect the shrimp survival, weight gain, size distribution and food conversion rate, nor did they affect the proximate composition and fatty acid profile of the raw shrimp muscle. This shows that MaB‐flocs originating from treatment of pikeperch wastewater can substitute 8% of diet ingredients of Pacific white shrimp while enhancing its pigmentation.     

Dietary β-Glucan and Nucleotide Effects on Growth,Survival and Immune Responses of Pacific White Shrimp,Litopenaeus vannamei

Effects of dietary supplementation of β-glucans and nucleotides on growth, survival and immune responses of the Pacific white shrimp (Litopenaeus vannamei) at a low salinity (5 ppt) were evaluated during a 30 d feeding trial. Final mean weight of shrimp fed nucleotides at 0.5%?was highest and significantly different from those fed the basal diet or diets supplemented with β-glucans. Survival was significantly higher for shrimp fed the diet with 0.2%?β-glucans compared to all other diets and was lowest for shrimp fed the basal diet. Shrimp fed diets containing β-glucans and nucleotides had generally better immune responses than shrimp fed the basal diet with higher total hemocyte count (THC) recorded for shrimp fed 0.2%?β-glucans followed by those fed 0.2%?nucleotides. Shrimp fed diets with 0.2%?and 0.5%?nucleotides and 0.2%?β-glucans had significantly higher respiratory burst values than shrimp fed the basal diet. These results indicated that dietary supplementation of either nucleotides or β-glucans has beneficial effects in improving shrimp performance when cultured at low salinity.     

Rearing of the Pacific white shrimp,Litopenaeus vannamei in a biofloc system: The effects of different food sources and salinity levels

The present study assessed the effects of different types of feeds and salinity levels on water quality, growth performance, survival rate and body composition of the Pacific white shrimp, Litopenaeus vannamei, juveniles in a biofloc system. Shrimp juveniles (2.56 ± 0.33 g) were cultured for 35 days in 300 L fibreglass tanks (water volume of 180 L) with a density of 1 g/L in six treatments. Three sources of feed (100% formulated feed, mixture of 66.6% formulated diet and 33.3% wet biofloc, and 100% wet biofloc) and two levels of salinity (10 and 32 ppt) were considered in two control groups and four biofloc treatments. Water quality parameters in the biofloc treatments were significantly better than control groups (p < .05). The highest increase in growth performance and survival rate were obtained in salinity of 32 ppt and mixed feed sources. Analysing the proximate composition of body shrimp indicates an increase in lipid and ash levels in biofloc treatments, which was more evident in the salinity of 32 ppt. In addition, the proximate analysis of shrimp body showed significant differences between biofloc treatments and control groups (p < .05). The highest FCR was found in the treatment with salinity level of 10 ppt and fed only with floc. Overall, it was found that the artificial diet supplemented with biofloc at the salinity of 32 showed better performance in the juvenile stage of Pacific white shrimp.     

Tolerance of the shrimp Litopenaeus stylirostris, Stimpson 1894, to environmental stress: interindividual variability and selection potential for stress-resistant individuals

Our study showed that osmoregulatory capacity (OC) of shrimp from the same clutch displayed interindividual variability. When environmental salinity decreases, this variability increases. Thus, at isoosmotic point (sea‐water salinity ≈26), the coefficient of variation calculated for measured OC was 2.7%, whereas it was 8.2% for sea‐water salinity ≈1.5. In terms of haemolymph osmolality, the interindividual difference can reach up to 45.8% for the same water salinity level. The mean OC of individuals that have survived a series of salinity and temperature shocks is significantly greater than the mean value recorded within their original population. This increase in OC was maintained beyond the one or two moulting periods that these shrimp experienced during our experiment.     

The Effects of Air Exposure on Hemolymph Osmoregulatory Capacity of Brown Tiger Shrimp,Penaeus esculentus,and Western King Shrimp,Penaeus latisulcatus,Reared at Different Salinities

Abstract

Hemolymph osmolality and osmoregulatory capacity (OC) of brown tiger shrimp, Penaeus esculentus (0.94±0.04 g mean initial weight) and western king shrimp, P. latisulcatus (5.37±0.10 g mean initial weight) from four salinities (10, 22, 34 and 46 ppt) were determined following 7, 14 and 21 minutes of air-exposure. Hemolymph osmolality of both species increased with increasing salinity. Isosmotic points of brown tiger shrimp calculated from regression lines between hemolymph and medium osmolality were 30.9, 31.9, 32.1 and 31.1 ppt at 0, 7, 14, and 21 minutes of air-exposure, respectively. Isosmotic points of western king shrimp were 33.8, 33.3, 32.8 and 33.1 ppt at 0, 7, 14, and 21 minutes air-exposure, respectively. OC of brown tiger shrimp at salinity of 34 ppt did not change when exposed to air for any length whereas OC of shrimp at other salinities (10, 22 and 46 ppt) were significantly different (P < 0.05) when exposed to air for 21 minutes. OC of western king shrimp at salinity 10 ppt was reduced (P < 0.05) when exposed to 14 and 21 minutes of air when compared to control and 7 minutes of air exposure. The results indicate that both species spent less energy (P < 0.5) for osmoregulation from 30 to 34 ppt. Furthermore, salinities 10 and 46 ppt were unsuitable for rearing brown tiger shrimp and salinity 10 ppt was unsuitable for growing western king shrimp.     

虾池水环境因子与虾病爆发的相关性分析

2001～2002年在对瓦房店市和庄河市等虾池水环境因子的连续监测中,运用多元分析研究了水环境因子与对虾病害爆发的相关性,主成分分析结果表明,NO3-N、COD、NO2-N、盐度、NH3-N和水温是显示对虾疾病爆发的关键因子。     

Effect of salinity on natural community and production of Litopenaeus vannamei (Boone), within experimental zero-water exchange culture systems

Recent efforts have been made to culture marine shrimp in systems operating under low or zero‐water exchange and with decreased water salinity. The aim of this study was to investigate the impact of various salinity levels on qualitative and quantitative characteristics of the natural community and, more particularly, ciliated protozoa, and compare this information with shrimp growth and survival. Tanks with 9‰ salinity were characterized by a higher pH, but also by a significantly higher concentration of chlorophyll a (Chl a) per weight of suspended matter (1.93 ± 0.72 µg Chl a/mg TSS) than tanks with 18‰ (1.29 ± 0.68 µg Chl a/mg TSS) or 36‰ (1.37 ± 0.61 µg Chl a/mg TSS) salinity. Concentrations of ciliates (max 6000 cells mL^?1) showed considerable fluctuations over the sampling period, reflecting the impact of water salinity, dynamic interactions between ciliates and their diverse roles within the shrimp production system. There was no significant difference between survival rates of shrimp reared at 9‰, 18‰ or 36‰, but decreasing salinity from 36‰ to 9‰ led to a significant decrease in final shrimp body weight (from 13.40 ± 0.26 g to 10.23 ± 2.72 g). Future work should address the potential of ciliates as an indicator of aquaculture water quality, as is currently being done in the wastewater industry, and the contribution of ciliates as food sources.     

Effect of salinity on survival, growth, oxygen consumption and ammonia-N excretion of juvenile whiteleg shrimp, Litopenaeus vannamei

In this study, we tested the lower salinity tolerance of juvenile shrimps (Litopenaeus vannamei) at a relatively low temperature (20 °C). In the first of two laboratory experiments, we first abruptly transferred shrimps (6.91 ± 0.05 g wet weight, mean ± SE) from the rearing salinity (35 000 mg L^?1) to salinities of 5000, 15 000, 25 000, 35 000 (control) and 40 000 mg L^?1 at 20 °C. The survival of L. vannamei juvenile was not affected by salinities from 15 000 to 40 000 mg L^?1 during the 96‐h exposure periods. Shrimps exposed to 5000 mg L^?1 were significantly affected by salinity, with a survival of 12.5% after 96 h. The 24‐, 48‐ and 96‐h lethal salinity for 50% (LS₅₀) were 7020, 8510 and 9540 mg L^?1 respectively. In the second experiment, shrimps (5.47 ± 0.09 g wet weight, mean ± SE) were acclimatized to the different salinity levels (5000, 15 000, 25 000, 35 000 and 40 000 mg L^?1) and then maintained for 30 days at 20 °C. Results showed that the survival was significantly lower at 5000 mg L^?1 than at other salinity levels, but the final wet weight under 5000 mg L^?1 treatment was significantly higher than those under other treatments (P<0.05). Feed intake (FI) of shrimp under 5000 mg L^?1 was significantly lower than those of shrimp under 150 00–40 000 mg L^?1; food conversion efficiency (FCE), however, showed a contrasting change (P<0.05). Furthermore, salinity significantly influenced the oxygen consumption rates, ammonia‐N excretion rates and the O/N ratio of test shrimps (P<0.05). The results obtained in our work provide evidence that L. vannamei juveniles have limited capacity to tolerate salinities <10 000 mg L^?1 at a relatively low temperature (20 °C). Results also show that L. vannamei juvenile can recover from the abrupt salinity change between 15 000 and 40 000 mg L^?1 within 24 h.