鱼虾混养模式优势分析与注意问题

近几年来,对虾养殖业迅猛发展,随之而来的各种养殖模式和实用技术也不断涌现。针对目前对虾精养风险大,养殖成本不断走高的状况,采用鱼虾混养模式被越来越多的养殖户所采用。为此,本文针对当前鱼虾混养模式的优势进行分析,并提出具体注意措施,以期为我国虾类健康养殖提供参考。1优势分析     

选择优质南美的对虾虾苗的学问

虾苗的质量优劣是直接影响养虾者的切身利益,当前无论养什么虾,采用那种养殖模式,都要进行无公害建康养殖,这是今后水产养殖的唯一出路,首先是以健康的种苗为前提,养虾的虾苗必须是SPF虾苗。当然无公害健康养殖系统是整个养殖系列工程的生产与管理等构成，健康虾苗是确保养殖安全与食品安全的前提。所以每个养殖者都希望能购到最好的虾苗，[第一段]     

日本囊对虾地膜覆沙池高产技术

日本囊对虾是我国海水养殖的重要品种之一，目前主要采取粗养和半精养，产量相对较低，而且养殖成功率较低，在华南广东、广西和海南三省养殖成功率低于10％。如何开发出日本囊对虾高产、安全和高效的养殖模式，成为调整对虾养殖品种结构，增加经济效益，维持海水对虾养殖业健康可持续发展的一个关键问题。高位地膜养殖模式是华南地区对虾精养的主要模式，笔者1998年在海南琼山三江首次采用地膜进行斑节对虾的养殖试验，并采用地膜改造老化虾池取得成功并犬面积推广，高位地膜养殖模式用于南美白对虾养殖也取得成功，     

对虾养殖水环境无公害高效调控技术（上）

水产养殖的关键在于养水,养水的根本在于降解养殖代谢产物,调节水质,营造良好养殖水环境。对虾养殖水环境无公害高效调控系列技术是遵循对虾生态生理特性和养殖池塘生态特点,应对当前养殖环境污染、病害频繁发生、质量安全隐患等因素所提出的。其技术模式如图1所示。     

斑节对虾精养技术

正斑节对虾(Penaeus monodon)俗称草虾,属节肢动物门、甲壳纲、十足目、对虾科、对虾属,属于广温广盐热带虾类,是养殖对虾中体形最大、经济价值最重要的种类之一。近年来,由于环境污染、种苗退化、病害频发等原因,凡纳滨对虾的养殖难度增大,斑节对虾作为一个轮养品种,养殖产量稳步提升。笔者以高位池养殖模式为例,介绍斑节对虾的精养技术。     

对虾常见传染性疾病的防治方法

养殖对虾各种传染性疾病的防治,应贯彻“以防为主,防重于治”的健康养虾理念。首先,应当注意选择不携带病原的种苗养殖;其次,要注意在优化养殖环境的基础上,慎重选择使用药物防治的措施。实践经验证明,优化养殖环境对于对虾的健康养殖是极为重要的,除了采用一些消毒药物杀灭养殖环境中的病原体之外,在对虾养殖过程中采用生物制剂调节水质,     

几种健康高效对虾养殖模式

正对虾是我国水产养殖的支柱性品种,养殖对虾已经成为市场供应的主要来源。近几年对虾高密度精养造成病害多发、产品质量低下的问题凸显,养殖成功率降低。因此,不同池塘基础条件、区域优势等特点下的健康养殖模式被不断探索,多种健康养殖模式已经取得了成功。成功的对虾健康养殖模式主要有以下几种。1南美白对虾双茬轮作模式该模式适应于华北地区,南美白对虾生长的水温是22~28℃,在华北地区适宜时间较短,多     

南美白对虾无公害健康养殖技术

21世纪是我国对虾养殖业进入新的持续发展的重要阶段,南美白对虾已成为当前我国从南到北对虾养殖的重要品种之一,而且发展相当快。从各地养殖的情况看来,当前在南美白对虾养殖上存在不少问题,如种苗质量差,虾苗供过于求,商家竞争激烈、苗价低,虾农超密度养殖;造成虾病流行,滥用药物非常突出,养殖技术混乱,造成养殖水域富营养化和环境污染,造成公害。直接影响产品的质量和食品安全问题。因此,当前对虾养殖不论采用哪种养殖模式,养什么虾,都面临着两个“安全”问题,即养殖安全和食品安全的问题。所以,养殖业者要面对现实,许多对虾养殖专家已意…     

基于生态足迹评估的凡纳滨对虾可持续发展养殖模式

在中国对虾养殖产业格局中,传统半精养模式仍占着很大的比重,新型精养模式普及程度不高,两种模式各有优劣。为了比较两种养殖模式的可持续性,本研究采用生态足迹和生态足迹指数对两种不同养殖模式进行比较分析。结果表明:1)对虾半精养模式的生态足迹为28.278 ghm~2,精养模式的生态足迹为44.596 ghm~2,其中饲料项目对生态足迹的贡献最大,比重达到60%~80%。2)半精养模式的人均水产品消费生态足迹为0.040 10 ghm~2,生态足迹指数为-0.24%,为不可持续发展模式;精养模式的人均水产品消费生态足迹为0.033 23 ghm~2,生态足迹指数为16.93%,为可持续发展模式,精养模式比半精养模式具有更大的可持续发展潜力。本研究针对水产养殖的特性对渔业生态足迹的定义和模型进行优化,解决了小尺度研究领域中人均渔业生态足迹难以明确和核算的问题,并结合生态足迹指数模型对对虾养殖可持续发展进行量化评估,从因素分析和生产模式优化等方面为小尺度水产养殖业的可持续发展策略提供权衡和比较。     

第二茬大棚接力精养斑节对虾试验

正针对近年来南美白对虾大棚第二茬养殖排塘率高、养殖成功率低、半年空塘资源浪费等问题,从2016年起,象山县开展了第二茬大棚接力精养SPF斑节对虾试验,2019年斑节对虾取得亩产1 645千克的好成绩。大棚第二茬接力精养斑节对虾的成功对调整当前我县对虾产业品种单一结构、促进渔民稳产增收等方面具有重要意义。     

对虾工厂化养殖的系统结构

对虾工厂化养殖是在人工控制条件下,利用有限水体进行对虾高密度养殖的一种生产方式,它依托一定的养殖工程和水处理设施作为技术支撑,融合无公害生产的管理模式,是一种高效的环境友好型养殖。文章就构建对虾工厂化养殖平台中的各系统环节及该种生产模式的概况作系统综述。     

Comparison of microbial community structures in intensive and extensive shrimp culture ponds and a mangrove area in Thailand

ABSTRACT:   A pelagic bacterial community structure was examined in experimental intensive shrimp culture ponds that have a shrimp–mangrove complex aquaculture system, an extensive shrimp culture pond and a mangrove area in Thailand by denaturant gradient gel electrophoresis analysis of polymerase chain reaction amplified partial 16S rRNA genes. Bacterial community structure in the intensive shrimp culture ponds was distinguishable from that of the mangrove area. In the extensive shrimp culture pond, the bacterial community structure resembled that in the mangrove area, but bacterial abundance was as great as that in the intensive shrimp culture ponds. Among the intensive shrimp culture ponds, the bacterial community structure was different between a closed culture system and a shrimp–mangrove complex culture system. Moreover, the bacterial community structure in mangrove planted ponds was close to those in the intensive shrimp culture ponds when shrimp culture was conducted, but it was close to those in the mangrove areas without shrimp culture. These results suggest that intensive shrimp culture with shrimp feed input affects the bacterial community structures in pond water.     

Evaluation of carrying capacity for shrimp pond culture with integrated bioremediation techniques

The integrated multi‐trophic aquaculture (IMTA) is a semi‐artificial habitat optimization ecosystem by co‐culture species from multiple trophic levels, in which farm waste produced by species of a higher trophic level is a nutrition source for species of a lower trophic level. However, in system construction it is essential to distinguish the roles of aquaculture organisms from different trophic levels and optimize the aquaculture capacity allocation. With this objective, a carrying capacity evaluation model for shrimp culture with integrated bioremediation techniques was developed, and the efficiency to repair the aquaculture pond environment was evaluated. Scenario simulations were conducted to assess the shrimp culture capacity for optimal economic and ecological benefits. The sensitivity analysis of the model indicated that changes in bivalve biomass had no significant impacts on the concentration of total nitrogen (TN) in the system, and macroalgae were more sensitive to the changes in TN than biofilters did. In conclusion, 1,500,000 Litopenaeus vannamei co‐cultured with 15,000 kg Crassostrea gigas and 1,125 kg Gracilaria lemaneiformis per hectare would bring maximum integrated benefit, and the use of integrated bioremediation techniques can make shrimp pond culture a virtuous cycle incorporating both production and restoration.     

Harvest time optimization considering the stocking density and heterogeneity of sizes in the culture of white shrimp in freshwater

ABSTRACT

The control and management of production factors have been of great economic interest for the aquaculture industry. In this study, the optimal harvesting time that maximizes the net benefits of shrimp cultured in freshwater was determined using a bioeconomic model fitted to six stocking density strategies (90, 130, 180, 230, 280 and 330 shrimp m^?2). A model was constructed which included the size heterogeneity of the culture and the results obtained were compared with the traditional model which assumes size homogeneity for all individuals. The results from both models indicated that the stocking density of 90 shrimp m^?2 was the best management strategy for optimizing net benefits. The economic importance of taking into account size heterogeneity in the culture of the white shrimp in freshwater is discussed.     

A comparison of development opportunities for crab and shrimp aquaculture in southwestern Bangladesh, using GIS modelling

The present study identifies and quantifies appropriate sites for brackish water aquaculture development in southwestern Bangladesh using remote sensing, GPS and geographical information systems (GIS). A colour composite Landsat TM image from 1996 covering the southwestern part of Bangladesh was used to identify the extent of brackish water and to classify land use. The remotely sensed data were complemented by secondary data digitised from a range of sources, including hard copy maps, to create a spatial database that included environmental and infrastructural data. A series of GIS models were developed in order to identify and prioritise the most suitable areas for brackish water shrimp and crab farming. Using qualitative and quantitative output from the models, the benefits of shrimp and crab farming and alternative land uses in the Khulna region were compared, based on gross production, economic output and employment potential. Comparisons were made of brackish water shrimp and crab culture with moderately saline-tolerant tilapia and prawn culture, freshwater carp culture and traditional rice production systems. Shrimp was identified as the most capital intensive and risky production system. Earnings per hectare were a little higher for shrimp culture than for crab culture. The present study demonstrates the usefulness of GIS as an aquaculture planning tool in a region where natural resources are already under considerable pressure.     

Economics of risk and uncertainty of alternative water exchange and aeration rates in semi‐intensive shrimp culture systems

Abstract

Reducing water exchange in shrimp aquaculture to minimize discharge of pollutants is a search for sustainability. In desert regions, like most of northwest Mexico, low water exchange must be complemented with artificial aeration to compensate for low levels of oxygen in warm and highly saline water. The economic yield of a low‐water‐exchange production system is compared against yield from a typical water‐exchange‐without‐aeration system for Penaeus vannamei culture. The difference between two systems is centered on pumping and aeration rates for a 100 ha semi‐intensive farm in northwest Mexico.

A bioeconomic model was built to compare the systems. Risk analysis is adopted to account for uncertainty of seed price, shrimp growth rate, survival rate, and shrimp prices.

The typical system was slightly more profitable than the low‐water‐exchange, aerated system. The latter used less electricity than the former in all of the three mortality‐rate scenarios. However, the difference in profitability is so small that for practical purposes both production systems provide similar economic yield. For a typical system, the probability of reaching a positive net present value (NPV) is high, therefore under the assumed risks, a 100 ha semi‐intensive shrimp farm in northwest Mexico is a good investment choice.     

Pyocyanin as a safe aquaculture drug for the control of vibriosis in shrimp recirculating aquaculture system (RAS)

Diseases are one of the most critical limiting factors in aquaculture. Recirculating aquaculture systems (RAS) are one of the most functionally viable sustainable aquaculture production systems adopted world over. In the event of any eventuality caused by bacterial pathogens, antibiotics or other antibacterial agents cannot be applied due to the vulnerability of biological filters which form an integral part of the RAS. Because of this, newer drugs are required for the effective control of diseases in RAS which would not interfere with the activity of nitrifying bacteria used in the biological filters. The antagonistic activity of pyocyanin, a bioactive compound produced by Pseudomonas aeruginosa, against vibrios is well established. The purpose of this study was to prove the effectiveness of pyocyanin as an aquaculture drug for application in RAS by employing a pilot-scale shrimp culture under RAS. It was noted that at the concentration of 5 mg L^?1, pyocyanin could significantly bring down the population of Vibrio spp. in RAS without affecting noticeably the other natural heterotrophic bacteria. Also, pyocyanin at this concentration did not inhibit the activity of nitrifying bacterial consortia used in the SBSBR (stringed bed suspended bioreactor) of RAS. The reared shrimp (Penaeus monodon) showed 100% survival after the application of pyocyanin, besides exhibiting normal health signs. Pyocyanin was non-toxic to the shrimp hybrid cell line (PmLyO-Sf9) at the concentration required for its application in disease management (IC₅₀?=?419.26 mg L^?1). The present study has demonstrated that pyocyanin is effective as an environment-friendly and safe aquaculture drug for the application in RAS-based shrimp culture to control Vibrio spp. without impeding nitrification established through the deployment of nitrifying bioreactors.

     

对虾高密度养殖过程中水质的周期变化与分析

通过对对虾高密度养殖池中水质的连续监测，得出养殖水体水质污染状况及一般规律。养殖水体的污染主要是含氮废物的污染，在高密度养殖池养殖后期，养殖水体中氨氮首先达到峰值2.32m/L，随后亚硝酸盐的含量也迅速达到峰值0．773mg／L，在高密度养殖池中活性磷的含量较高，没有显示出明显的磷缺乏现象。     

Development of a Model to Simulate Nitrogen Dynamics in an Integrated Shrimp–Macroalgae Culture System with Zero Water Exchange

The effluents of traditional shrimp monoculture cause pollution and promote eutrophication and hypernutrification of the receiving coastal ecosystems. Integrated aquaculture and a recirculating aquaculture system (RAS) have been proposed as an alternative to address these problems. In this study, we developed a dynamic model to simulate the concentration of total ammonia nitrogen (TAN), nitrite, and nitrate in an integrated culture of whiteleg shrimp, Litopenaeus vannamei, and seaweed, Gracilaria vermiculophylla, in a recirculating and zero water exchange system, and the effect of nitrifying and heterotrophic bacteria was also included. The experiments demonstrated that a dynamic model can explain the concentrations of dissolved inorganic nitrogen and variations in these concentrations over time in the integrated culture. The results also suggest that nitrifying and heterotrophic bacteria play an important role in the transformation of dissolved nitrogenous compounds; therefore, these bacteria should be considered within the dynamics of nitrogen in integrated systems with low water exchange.     

Protozoans and Meiofauna Inhabiting a Bead Filter: A Preliminary Investigation of Their Role as Potential Bioindicators of Shrimp Production System Health

Abstract.— Protozoans are used as bioindicators of system health in wastewater treatment plants. The objective of this study was to determine if protozoans or meiofauna could be useful bioindicators of shrimp production system health. Specifically, we noted the relative abundance of protozoans and meiofauna inhabiting a propeller-washed bead filter (PBF) used in a recirculating aquaculture system for intensive shrimp production during a 12-wk grow-out trial. Based on microscopic analysis of PBF backwash, results indicate that (1) the presence of nematodes and rotifers may reflect the age and/or organic loading of the filter; (2) feed quantity affects protozoan biomass, whereas feed quality impacts the nutritional group of protozoans that survive; (3) free-living amoeba typically are surface associated in their active feeding state and were present in most PBF samples; and (4) ciliates likely play an important ecological role in PBF used in intensive shrimp culture.