Coagulation of phosphorous and organic matter from marine,land-based recirculating aquaculture system effluents

Saline effluents from marine land-based aquaculture production can neither be disposed in common municipal wastewater treatment plants, nor disposed as landfill. Furthermore, stricter environmental regulations require the reduction of phosphorous and organic matter levels from marine environment discharges to minimize eutrophication. Chemical coagulation with FeCl₃ and AlSO₄ is commonly used for removing phosphorous and suspended solids in wastewater treatment. The capacity of these coagulants for creating particle aggregations depends on the characteristics and chemistry of the treated wastewater, such as the ionic strength or mixing conditions. Marine water has a higher ionic strength than fresh or brackish water, which may be beneficial when using chemical coagulants to treat the effluents from farms operated at high salinities. The following study compared the application of FeCl₃ and AlSO₄, to treat the two effluents discharged from a marine land-based recirculating aquaculture system (RAS) producing salmon (Salmo salar). The aim of the study was to determine; 1) in what effluent (sludge flow vs. exchange water overflow) at the end-of-pipe treatment the coagulant application is more efficient for the removal of PO₄³⁻-P, total suspended solids (TSS), total phosphorous (TP) and total chemical oxygen demand (TCOD); and 2) the optimal coagulant dose to apply and its associated chemical sludge production. The results show that more than 89 % removal of TCOD, TSS and TP is achieved when treating the sludge flow, arguably because the sludge flow contained the largest fraction of the target masses (P and organic matter) discharged from the system. Up to 80 % of TSS removal was achieved by simple sedimentation, and with the highest coagulant dose tested, up to 95 % of TSS could be removed from the effluent. To remove 90 % of PO₄³⁻-P, FeCl₃ and AlSO₄ need to be dosed at a molar ratio of 2.6:1 Fe:PO₄³⁻-P and 5.7:1 Al: PO₄³⁻-P, respectively. Dosing above 90 % removal efficiency did not significantly affect removal of PO₄³-P and TSS, but substantially increased the volume of chemical sludge produced. Finally, FeCl₃ is proposed as a better overall alternative for P removal at the end-of-pipe treatment in marine land-based RAS.     

辽宁海水养殖业发展现状及可持续发展对策

辽宁海水养殖业在全国具有重要地位.随着城市化、工业化进程推进,多元用海矛盾问题凸显,养殖空间萎缩,受技术、管理等因素制约海域资源利用效率不高,养殖生产方式传统粗放,近岸环境监控压力增大,水产品质量存在安全隐患.解决这些问题需要合理规划布局,优化海域空间资源配置,加强技术创新,改变传统生产方式,提高病害防控能力,保护海域生态环境,提高养殖产品质量.     

The use of a geographical information system for land-based aquaculture planning

Site selection for aquaculture planning is a complex task involving the identification of areas that are economically, socially and environmentally suitable, available to aquaculture and commercially practicable. This paper reports upon a study into the use of a geographic information system (GIS) to assist in aquaculture planning. Using a case study in the site selection for land‐based shrimp farming within the Australian coastal zone, we demonstrate that a GIS has potential to assist aquaculture planning. Our analysis is based on a sequential, two‐stage approach. The first stage eliminates the grossly unsuitable portion of the study area through a preselection with low resolution, cheap and easily available data. The second stage then focuses on and ranks the remaining area using high resolution, possibly more expensive data. Finally, we use the GIS to present the results of the analysis in an easily accessible form.     

Biotechnology in marine aquaculture

Intensification of production, modernization of technique, and improvement of cultivars are needed to increase the economic efficiency of marine aquaculture industries. To help achieve such improvements, modern methods of biochemical and genetic engineering can be adapted to control biological processes which intrinsically limit the efficiency and yield of production. Such applications now have been developed for improved production of molluscs. Critical life-cycle stages of several species of abalones and other commercially valuable molluscs which thus far have proved amenable to improved control by these means include reproduction, larval settlement, metamorphosis, and acceleration of early growth.

Analysis of the physiological and molecular mechanisms which control reproduction in molluscs reveals a prostaglandin-dependent regulation of spawning in abalones and certain other species. Spawning of gravid adults can be induced by the addition of prostaglandins to the surrounding seawater, or, more reliably and inexpensively, by activation of the endogenous enzymatic synthesis of prostaglandin-related spawning triggers in response to added hydrogen peroxide. Peroxide activation of the prostaglandin-dependent spawning reaction has been found widely useful for obtaining synchronous and copious release of fully competent gametes in a large number of species of abalones, oysters, scallops, mussels, clams, and other valuable molluscs; a number of these species had not been successfully spawned by other methods.

Settlement and metamorphosis of many molluscan species can be brought under similar biochemical control. Most efficiently and inexpensively, the natural biochemical requirement for induction of these critical developmental processes can be met by providing competent larvae with unique amino acid constituents associated with the naturally required inducing molecules. Thus, γ-aminoburyric acid (GABA) can be used simply, safely and inexpensively to induce complete and rapid larval settlement and metamorphosis — with minimal mortality — in many commercially important abalone species. This and similar neurotransmitter-related, amino-acid-derived compounds are proving comparably effective for the reliable induction of settlement and metamorphosis in a number of other valuable molluscan species.

Recent analyses of the requirements for rapid early juvenile growth in abalones reveals a mechanism of growth-control which is susceptible to exogenous hormonal acceleration. Genetic cloning and amplification of recombinant-DNA templates for the efficient production of essential growth-regulating hormones, and substances required for enhanced nutritional efficiency and resistance of cultivars, are now in progress. Genetic engineering for the direct improvement of cultivated species soon will be within reach.     

Macro policies to promote sustainable commercial aquaculture

Aquaculture has been the world's fastestgrowing source of food, with fin fish andshellfish production expanding by an averagecompound rate of growth of 10.9%. This is arate of growth faster than that of terrestrialmeat production. The paper describes policiesthat can promote aquaculture. The focus is oncommercial (for profit) aquaculture, butsubsistence aquaculture is indirectly includedon the assumption that the two systems arecomplementary, rather than mutuallyexclusive.     

水产养殖业可持续发展及管理的研究进展

水产养殖装备是高效发展现代水产养殖,促进水产养殖产业结构改革的重要技术支撑。基于养殖装备、信息技术和自动控制等多学科协同发力的智慧水产养殖模式已成为现代渔业高质量发展的新趋势与重要抓手,这也对水产养殖现有装备及其相关技术提出了更高的智能化要求。本文梳理了池塘、工厂化、网箱、筏式和底播养殖等5种主要养殖方式装备发展现状,从数字化和智能化角度分析了环境监测、对象感知、饲料投喂、分级计数等养殖环节中常用装备的研究进展,指出了制约我国水产养殖智能装备与技术发展的关键问题,提出了“机械化、自动化、智能化”的水产养殖装备与技术发展的新思路,旨在实现我国从水产养殖大国向水产养殖强国的历史转变。

     

水产养殖业可持续发展及管理的研究进展

全球水产养殖业在过去的几十年内得到了迅速发展,但同时也带来了诸多的环境、经济和社会问题,因此可持续发展水产养殖理念的提出得到了国内外众多学者的认可。本文简单介绍了全球水产养殖业近年的发展情况及可持续发展水产养殖业的理念发展进程,重点分析了可持续发展水产养殖管理涉及的六大步骤,介绍了水产养殖指标体系构建及评估的研究成果,以期为我国水产养殖可持续发展提供借鉴。     

Benthic dynamics within a land-based semi-intensive aquaculture fish farm: the importance of settlement ponds

The present work aims to assess the importance of settlement ponds (SP) in semi-intensive fish farms by studying benthic dynamics in an aquaculture fish farm, more specifically in the water reservoir (WR) and SP and also in production (P) and nonproduction (C) ponds during a 16-month period. In Portugal, a SP is only mandatory for intensive fish farms, and another objective of the present study is to assess the importance of these areas in semi-intensive fish farms. The WR was the area with highest diversity and evenness, as well as the higher number of exclusive taxa and taxa sensitive to organic enrichment. P and SP samples showed signs of higher disturbance levels, emphasized namely by the association of the opportunistic annelids Capitella spp. and Tubificidae. However, the benthic data from SP points to lower disturbance levels than P both due to an increase in the percentage of sensitive taxa observed in June and October 2004 and by the association of this latter sample with water reservoir samples as evidenced by canonical correspondence analysis. Moreover, a higher and increasing number of taxa when compared with the P area were also observed. Therefore, in semi-intensive fish farms, where effluents from P ponds are directly discharged to the lagoon, the potential environmental impacts would be more severe. In conclusion, the imposition of SP in semi-intensive fish farms should be considered, especially because most fish farms are located within relevant wetland areas.     

陆基圆池循环水条件下养殖密度对大口黑鲈生长及养殖效能的影响

为研究陆基圆池循环水养殖条件下大口黑鲈(Micropterus salmoides)适宜的养殖密度,设置55、65、75、85、95尾/m²等5种养殖密度(分别标记为A1、A2、A3、A4、A5组),进行了63 d的大口黑鲈养殖试验,通过测定和分析试验鱼的体质量日增长率、体长日增长率、饲料系数、体质量均匀度和单位面积产量等指标,评价不同养殖密度对大口黑鲈生长和主要养殖效能的影响。结果显示:(1)从次低密度的A2组(65尾/m²)至密度最高的A5组(95尾/m²),试验鱼的体长日增长率基本上随着养殖密度的提高而下降,最高的A2组比A3、A4和A5组分别高了31.6%、82.9%和92.3%,并且差异显著(P<0.05);(2)从A2组至A5组,试验鱼的体质量日增长率和特定生长率均随着养殖密度的提高而下降;(3)A2组的饲料系数比A1、A3、A4和A5组分别降低了16.7%、28.6%、55.4%和56.9%;(4)单位面积产量和产品均匀度均在A2组达到最高。基于生长性能及养殖效能的综合评价,陆基圆池循环水养殖条件下大口黑鲈成鱼养殖阶段较适宜的养殖密度为65尾/m²。     

Development of a marine aquaculture research complex

The new Environmental Systems Laboratory of the Woods Hole Oceanographic Institution was designed to be capable of performing a wide spectrum of research in the fields of marine aquaculture, water pollution control and coastal biology.Discussed are the setting of requirements, approaches adopted, design problems encountered, experiences to date and the unique physical plant.     

系统功能视角下的水产养殖业可持续发展

水产养殖系统具有食物生产、价值增殖和环境维持三大基本功能.目前,国际和国内水产养殖业在功能实现上存在着食物生产功能的弱化、价值增殖功能遇到阻力、环境维持功能遭遇挑战等问题.水产养殖业可持续发展就是要平衡水产养殖系统的基本功能,实现综合效益的最大化,关键是要解决"粮食"生产与价值增殖、环境保护与价值增殖的矛盾.中国水产养殖产业肩负着保障未来全国16亿人口食物安全的重任,即食物生产的任务,同时,该产业的发展还要遵循市场经济规律.因此,水产养殖业的发展离不开政府的引导和支持.     

小头鲔幼鱼陆基循环水养殖日周期性运动规律研究

为实现小头鲔(Euthynnus affinis)陆基循环水养殖,优化养殖设施和完善养殖技术参数,开展了陆基循环水驯化养殖条件下,小头鲔口径与全长的关系、非摄食期间幼鱼运动速度、摄食期间幼鱼运动速度、幼鱼摄食深度与时间的关系及非摄食期间幼鱼水层分布等一系列研究。结果显示:小头鲔幼鱼45°和90°口径均随着全长的增长而增大,呈线性关系;在非摄食状态下,小头鲔幼鱼主要做巡航游泳运动;摄食阶段,初始发现食物时,小头鲔幼鱼做爆发性游泳运动,游泳速度与摄食游泳速度和摄食后游泳速度差异显著(P<0.05);捕食时和捕食后,小头鲔主要做巡航游泳运动,两者间差异不显著(P>0.05)。在摄食状态下,小头鲔幼鱼的游泳深度会随食物的深浅变化而变化;而在非摄食状态下,小头鲔幼鱼的游泳深度变化与时间有一定的关系。本研究为小头鲔陆基养殖、繁育等提供基础数据,也为后续开展南海金枪鱼陆基驯化养殖及人工繁育提供参考。     

Safety issues and sustainable development of European aquaculture: new tools for environmentally sound aquaculture

Sustainable and long-term growth of the aquaculture industry should involve both ecologically sound practices and appropriate resource management. The increasing economic dimension of Mediterranean aquaculture is opening new economic niches and may be a valid support to reduce the pressure of traditional fisheries. Aquaculture practices can also lead to modifications of coastal habitats through the impact of wastes of land-based and open-sea mariculture facilities. In addition to these aspects which place a direct pressure on aquatic ecosystems and wild fishery resources, a wide range of environmental contaminants, such as chemicals used in farming operations, can accumulate in farmed organisms and put fish health and quality at risk. Thus, as aquaculture makes its transition to a major food-producing sector, proper assessment and control of environmental impacts and food safety awareness are becoming increasingly important. The development of simple tools able to monitor the extent of environmental and biological impacts associated with farming operations at various levels of biological complexity from the ecosystem to the organism level is required. Although a number of techniques for assessing the environmental and biological impact of pollutants in natural ecosystems are available, the development of practical and validated tools is sorely needed in aquaculture.     

克氏螯虾的生物学和生态养殖模式

生物絮凝技术可以通过在养殖水体中调节碳氮比而维持良好水质,促进养殖品种健康生长,产生的生物蛋白可实现蛋白的多级利用,节约经济成本。实验从摄食环境(曝气、无曝气、水草)、摄食时间以及生物絮凝质量浓度等角度,探讨了克氏原螯虾 (Procambarus clarkii) 幼虾摄食絮凝的适宜条件。结果显示,絮凝质量浓度为500~600 mg·L^–1可满足幼虾的摄食需求,并在摄食4 h之后幼虾肠道达饱和状态。相同摄食时间,絮凝曝气组幼虾摄食量最大,显著高于水草组(P<0.05),但与无曝气组差异不显著(P>0.05),比较幼虾肠道的充塞度,可见曝气组在摄食4 h后肠道食糜较多,肠道更为饱满,优于其他各组。综合生物絮凝培养条件、水化指标以及幼虾的摄食情况,认为生物絮凝技术应用到克氏原螯虾的养殖具有可行性。     

Nitrogen removal techniques in aquaculture for a sustainable production

As the aquaculture industry intensively develops, its environmental impact increases. Discharges from aquaculture deteriorate the receiving environment and the need for fishmeal and fish oil for fish feed production increases. Rotating biological contactors, trickling filters, bead filters and fluidized sand biofilters are conventionally used in intensive aquaculture systems to remove nitrogen from culture water. Besides these conventional water treatment systems, there are other possible modi operandi to recycle aquaculture water and simultaneously produce fish feed. These double-purpose techniques are the periphyton treatment technique, which is applicable to extensive systems, and the proteinaceous bio-flocs technology, which can be used in extensive as well as in intensive systems. In addition to maintenance of good water quality, both techniques provide an inexpensive feed source and a higher efficiency of nutrient conversion of feed. The bio-flocs technology has the advantage over the other techniques that it is relatively inexpensive; this makes it an economically viable approach for sustainable aquaculture.     

小头鲔幼鱼陆基循环水养殖日周期性运动规律研究

为实现小头鲔(Euthynnus affinis)陆基循环水养殖,优化养殖设施和完善养殖技术参数,开展了陆基循环水驯化养殖条件下,小头鲔口径与全长的关系、非摄食期间幼鱼运动速度、摄食期间幼鱼运动速度、幼鱼摄食深度与时间的关系及非摄食期间幼鱼水层分布等一系列研究。结果显示:小头鲔幼鱼45°和90°口径均随着全长的增长而增大,呈线性关系;在非摄食状态下,小头鲔幼鱼主要做巡航游泳运动;摄食阶段,初始发现食物时,小头鲔幼鱼做爆发性游泳运动,游泳速度与摄食游泳速度和摄食后游泳速度差异显著(P<0.05);捕食时和捕食后,小头鲔主要做巡航游泳运动,两者间差异不显著(P>0.05)。在摄食状态下,小头鲔幼鱼的游泳深度会随食物的深浅变化而变化;而在非摄食状态下,小头鲔幼鱼的游泳深度变化与时间有一定的关系。本研究为小头鲔陆基养殖、繁育等提供基础数据,也为后续开展南海金枪鱼陆基驯化养殖及人工繁育提供参考。     

海洋生物多糖在水产养殖中的应用

介绍了海洋生物多糖的种类——海洋动物活性多糖、海洋植物活性多糖、海洋微生物活性多糖,阐述了海洋生物多糖对水产动物的生理功用,指出了海洋生物多糖在水产养殖中的应用前景和展望,这对配制、推广应用高效环保型、功能性水产配合饲料,促进水产养殖业的健康、可持续发展,具有参考意义。     

Biodegradation potential of aquaculture chemotherapeutants in marine sediments

The commercial chemotherapeutant formulations SLICE^® and AlphaMax^® [active ingredients emamectin benzoate (EB) and deltamethrin respectively] are used in fin fish aquaculture to control parasitic sea lice. In some regions, the use of these substances has drawn concern from the commercial fishing industry regarding potential adverse effects on non‐target organisms. In the present work, biodegradation of EB and deltamethrin, and their commercial formulations, was investigated over 135 days at 4 and 10°C in fresh marine sediments collected from underneath an active open net‐pen salmon farm. EB incubated as either pure substance or commercial formulation was recalcitrant at both temperatures under abiotic and biotic conditions. Deltamethrin incubated alone or as its commercial formulation degraded slowly at 10°C (t_1/2 = 330 ± 107 and 201 ± 27.1 days respectively). At 4°C, deltamethrin degradation was only significant following incubation as commercial formulation (t_1/2 = 285 ±112 days). Degradation rates of EB and deltamethrin as pure substances versus their commercial formulations were not statistically different. Depletion of deltamethrin was observed in 10°C inactive sediments indicating that transformation occurred (at least in part) via an abiotic pathway. Overall, these data provide further insight into the fate and persistence of EB from the ongoing use of SLICE^® in British Columbia's salmon aquaculture industry. AlphaMax^® is not registered in Canada but is used in other salmon farming countries to control sea lice.     

海水增养殖业对于低碳经济的促进作用

低碳经济是以“低能耗、低污染、低排放”为基础的新的经济模式。多年来,由于二氧化碳等温室气体的排放使得气温升高、灾害不断发生,直接影响到人们正常的生产、生活。因此,节能减排、控制碳含量、保护生态已非常紧迫。