Energy use in controlled temperature marine aquaculture

Temperature control offers benefits in land‐based marine aquaculture: stock growth rates may be enhanced by heating in winter; mortality rates in summer may be reduced by cooling. However, if the plant is not well designed, temperature control may create very large energy demands. This paper describes the application of temperature control in abalone aquaculture in New Zealand, with a focus on energy considerations in plant design. An abalone farm using a semi‐closed water conditioning system is used as a case study for which an energy model, based on a heat pump system, is developed. The model is used to determine the impact of plant design and tank conditions on the economics of the operation. Copyright © 2002 John Wiley & Sons, Ltd.     

Radiation transmission through a composite pure water layer of uniform and depth-dependent extinction characteristics

The paper describes the calculation of the beam solar radiation transmission across the uniform salinity upper convecting zone (UCZ) and the salinity stratified gradient zone (GZ), when the extinction coefficient is not only wavelength but also salinity-concentration dependent, assuming that the effect of scattering to be negligible. The results are useful in determining the effects of dissolved salt ions on pure water transmission, at least according to the existing measured data in the literature.     

Stability analysis of double-diffusive solar ponds with non-constant temperature and salinity gradients

In this communication, the stability of the double-diffusive solar ponds with non-uniform temperature and salinity gradients has been investigated. This is a further generalization of our approach to this problem initiated in Ref. [7]. Using a stochastic approach, the linearized system of basic equations of motion is reduced to a single integro-differential equation. For convective motion, this equation reduces to a time-independent Schrödinger equation for a particle moving in a potential field ƒ(Z) characterized by the non-uniform temperature and salinity gradients. This equation can, in general, be solved (exactly or approximately depending on the form of the gradient profile) by methods commonly used in quantum mechanics.

In the Appendix, we show that, for a quadratic gradient profile, the above equation has an analytical solution similar to that obtained by Zangrando using numerical computations.     

Wastewater reuse and exposure to Legionella organisms

Eight hundred and fifty-two (852) blood sera were drawn in 1980 and 1981 from populations residing in 30 agricultural settlements (having a total population of 16,240). These sera were tested for the presence of antibodies against 15 different antigens of Legionella species (L. pneumophila serogroups 1–8 and seven other Legionella, i.e. bozemanii, gormanii, micdadei, jordanis, dumoffii, longbeacheae and oakridgensis). The results indicate a significant (P < 0.02) excess in the percentage of sera positive for L. pneumophila (serogroups 1–8) among sewage and non-sewage irrigation and fish pond workers as compared to the control group (4.5% vs 1.5%). For the other Legionella species, there was no difference among the above groups. The isolation of L. pneumophila serogroup 4 and five organisms resembling Legionella spp from one oxidation pond used for irrigation strengthens the seroepidemiological findings.     

基于遥感案例推理的海岸带养殖信息提取

目前基于目视解释或光谱分类的养殖信息提取效率低,难以克服由于地物混杂带来的“椒盐”噪声现象且难以融合地学知识。针对养殖信息提取中存在的问题,首先在分析现有养殖信息提取方法和案例推理CBR(Case\|Based Reasoning)用于遥感图像处理的基础上,提出基于遥感案例推理的海岸带养殖信息提取的研究思路;其次,结合养殖区域的空间特征和属性特征,构建案例的表达模型以及CBR相似性推理模型;最后,对不属于案例构建区的粤西沙田镇进行养殖信息提取的CBR实验,精度达到84.56%。对比CBR方法和传统监督分类方法可知,CBR方法是实现海岸带养殖信息快速准确提取的一种有效手段。     

Rancidity development during the chilled storage of farmed Coho salmon (Oncorhynchus kisutch)

Coho salmon (Oncorhynchus kisutch) is a fatty fish species whose farming production has greatly increased in recent years. Lipid damage produced during Coho salmon chilled storage was studied for up to 24 d. Lipid hydrolysis (free fatty acids, FFA) and oxidation (conjugated dienes; peroxide value, PV; thiobarbituric acid index, TBA‐i; fluorescent compounds formation, FR; browning development) were determined and compared to lipid composition (polyene index, PI; astaxanthin, AX) changes and sensory assessment (rancid odour development) results. Most lipid damage indices developed slowly during storage; thus, values obtained for FFA, PV, TBA‐i and FR were in all cases under 1.5 g/100 g, 4.0 meq oxygen/kg lipid, 0.40 mg malondialdehyde/kg muscle and 0.40, respectively. Odour assessment showed a significant (p <0.05) rancidity development at day 10, when compared to starting fish material; then, non‐acceptable values were obtained at days 19 and 24. The PI analysis showed not many differences during the storage time, with the lowest mean value at day 19. AX analysis indicated a relatively high content in the white muscle, which was maintained till the end of the experiment. A low oxidation development is concluded for Coho salmon lipids when compared to other fatty fish species under the same chilling conditions. AX was found to contribute to the oxidation stability of Coho salmon lipids, due to its free radical scavenger properties.     

乌江渡水电站水库网箱养殖对环境的影响及对策措施研究

文章从对水体富营养化的影响、对水质的影响、对水生生物的影响、对底质的影响、对库湾水文条件的影响5个方面分析了乌江渡水电站水库网箱养殖对环境的影响,以及对解决这些问题的对策措施进行了介绍和探讨.     

渠塘供水模式下灌区信息管理系统的设计

以引大灌区为对象研究了渠塘供水模式下灌区信息管理系统的设计。该设计以充分利用渠塘联控调水模式、最大限度提高灌区水资源的利用率为目标,由监测子系统提供塘群、渠系水情等实时信息,基于B/S结构的信息管理系统将完成动态配水、GIS查询等功能,实现对塘水、渠水的信息化管理和调度,突出渠塘供水模式的特色,充分发挥塘的二次调蓄功能。     

基于ExcelVBA实现山塘堰上水头计算的自动化

分析山塘综合整治工程中堰上水头计算现状,针对存在的问题,提出将Excel的二次开发工具VBA语言应用于堰上水头计算。编写计算程序、将可视化窗口作为用户操作界面,实现山塘综合整治工程堰上水头计算的自动化。将本程序应用于山塘实例,结果表明该程序可实现堰上水头计算的自动、准确、高效进行。     

智慧生态水产养殖系统

针对工厂化海参养殖信息化低的现状,设计并实现了具有养殖环境水质监测、养殖环境水质分析评价、水下视频观测、养殖知识普及等功能的系统.该系统经测试,水质检测准确,水下视频观测实时清晰,可以满足海参养殖的实际需要.系统的推广可以帮助养殖企业进行养殖决策,提高养殖的智能化水平.利用工业化和智能化在水产养殖业领域的纵向扩散和深度融合,来探索现代化养殖模式,提升智能技术在渔业经济发展中的贡献率.