网箱养殖智能投饲监控系统的设计

针对浑水海域网箱养殖中的投饲量控制问题,提出了一种采用回声探测方法进行智能投饲监控的系统原理及软硬件设计。在网箱底部安装一套收发合置的回声探测声纳,监测通过网箱饲料反射的声信号能量值,将其作为反馈量来调整饲料流量,使得过剩饲料维持在预设量,以实现智能饲量控制。为简化投饲监控系统并降低成本,可采取1套回声探测系统同时监控4个网箱的设计,并将各个监控节点组成WLAN后接入公网,以实现大型网箱养殖场的远程智能投饲监控。     

一种新型养鱼自动投饲机

四川省双流县研制成功了一种新型自动投伺机，为自动投饲机家族增添了一名新成员，受别了养鱼农民的欢迎。该投饲机采用220V农用电，由控制器和抛料器两部分组成，两者之间用电线连接。控制器安装在室内，抛料器安装在鱼塘水面上空。抛料器在控制器控制下工作，一个控制器可以分别控制l～5个抛料器独立工作，满足l～5个鱼塘分别投饲。抛料器由机座、支架、装料斗、电机、抛料盘等组成。在支架与机座连接处设置活动的锁定装置、便于在岸上添加饲料，在鱼塘内悬空水面投饲，抛撒高度低，不受天气影响，并不损坏饲料颗粒，减少饲料浪费。控制…     

水产养殖投饵中“四定”的定量投饲方法

准确掌握投饲量是水产养殖成功的保证。它既能使养殖对象吃饱吃好,又不至于造成饲料浪费。在介绍定量投饲方法前,首先让我们了解一下饵料系数的概念:评价饲料质量最常用的指标是饵料系数。饵料系数是指鱼体增加单位体重时所消耗饲料的重量。饵料系数以低为好,计算公式:饵料系数=饵料消耗量/鱼体增重量。常用方法有以下几种:1.定量投饲方法一:以鱼类净增重倍数和饵料系数计算年投饲量、月投饲量、日投饲量。年投饲量:根据鱼类净增重倍数和饵料系数来进行推算,即鱼种放养量×净增重倍数×饵料系数。鱼类净增重倍数一般为4～5。全价配合饲料饵…     

养殖池塘大型智能投饲系统的工艺设计

为研发符合国情、操作简便、经济性好、性能高的大型智能化投饲设备,提高我国水产养殖行业的设施装备水平和劳动生产率,对养殖池塘大型智能投饲系统的工艺技术进行了研究探索。采用气力输送和水体增氧一元化工艺技术,这一工艺设计能解决池塘养殖生产中智能化集中投饲需求,实现集中供料、饲料预处理、多点位(多池塘)同步投饲、投饲区域增氧、远程管理控制等目的。     

高密度养殖池塘自动气力投饲机的设计试验

为解决池塘高密度养殖过程中的投饲机承载量小、投饲不均匀、投饲范围小、饲料利用率低等问题,提出一种基于气体输送原理的自动投饲机。根据其工作原理,对投饲机的供料系统、输送系统、抛料系统和控制系统进行了设计与分析,采用气力作为供料能源,管道作为输送机构,撒料盘作为抛料机构,西门子S7-200PLC作为系统控制单元。结果显示,该自动投饲机能同时满足6个池塘的投喂,并能单独控制,满足池塘的投饲需求;投饲距离达20 m,平均投饲速度400 kg/h,破碎率低于0.9%,基本满足设计要求。与传统池塘投饲机相比,该投饲机具有结构简单、操作方便,饲料不易破碎、饲料利用率高等特点,并可实现对投饲量精确调节与控制。     

养虾的间断投饲法浅议

近些年来,国内外在对虾养殖技术中,试用一种“规则性停食投饲法”(也叫“规则性绝食”或“周期性停食”——Periodic starvation),即改变原来每日连续投饲的传统习惯,采用有规律的间断性安排,以日为单位,试行几日投饲、几日停投的办法,使养殖的对虾既满足营养需要和增加体重,又节省饲料和劳力,对于成本经济核算来讲颇有益处。一般来说,对于养殖小、中虾阶段是适宜的。由于停投饲料期间,对虾并不排除摄食剩余饲料和其它有机物质,并非真正的“绝食”或“停食”。所以更确切地讲,采用这种投饲方法,称为“间断性投饲”比提为     

精养鲤成鱼投饲技术

目前,随着养鱼业的不断发展,集约化精养已成为主要养鱼模式,在一个养殖周期中,每日里渔民们做得最多的是投饲,看起来枯燥无味的投饲,其实在养鱼中是一个很重要的技术环节。役饲包括最适投饲量、投饲方法、投饲次数、时间与速度等。一、投饲且影响投饲量的因素主要是鱼的摄食量和消化速度、水质、水温等环境因素和饲料的营养价值、加工方法等。鲤鱼的消化速度在１０℃、１５℃、２０℃、２５℃时食物通过消化管的时间分别为１６－１８、１０、６．５和４、５小时,温度越高,通过时间越短．日摄食量越大。投饲量过大、过频势必加快自物…     

基于六轴传感器的鱼群摄食规律与投饲方法研究

随着水产养殖的发展，对水产品的需求量逐年增加，大多数养殖手段是遵循传统的人工经验，人工投饲存在投饲量控制不精准、自动化程度低以及人工成本大等问题，需要一种精准化、智能化的投饲方法提升饲料的利用率。利用六轴传感器对鱼池水面波浪进行分析，通过传感器获取鱼群进食状态函数曲线，利用主成分分析选择具有代表性的特征参数，对比不同间隔下特征参数的贡献率。结果显示：间隔60 s时的分析结果更贴近实际情况，选择6个贡献率更高的参数作为是否继续投饲的判断指标，如果连续3次测得2个特征参数低于所设阈值，则视为投饲结束。基于鱼群摄食规律研究的投饲方法使投饲过程更加符合鱼群的摄食需求，饲料利用率达到85%以上，节约养殖成本并降低了污染。研究表明，该方法可以实现鱼群的精准化投饲，为实现鱼群的自动化投饲提供参考。     

欧鳗投饲技术

一、投饲与鳗鱼规格的关系欧鳗规格大小是决定投饲率的前提之一。众所周知，规格越小投饵率越高，但究竟要达到多高的投饵率才能保证其健康生长，又保持较高的生长速度和饲料效率。一般认为，在水温适宜、鳗体健康、饲料品质保证、放养密度适宜时，应保持的投饲率为：白仔阶段投喂红虫时期，可不控制投饲率，尽量让白仔吃饱。在转为白仔后期和黑仔期时投饲率可参照表１：表１白仔后期与黑仔期投饲率在３０尾／公斤以内，许多教科书或文章提倡应低于２．５％，在１０尾／公斤以内应低于２％，在５尾／公斤以内应低于１．５％。但从本人几年的…     

浅论在水产养殖中怎样掌握投喂技术

在渔业生产过程中,投饲技术是直接影响饲料系数和养殖生产效果的重要因素。饲料的投喂技术在水产养殖生产中十分重要,是现代水产养殖生产者必须熟练掌握的一项实用技术。1、投饲原则     

Effects of stocking density on the performance of brown shrimp Farfantepenaeus californiensis co‐cultured with the green seaweed Ulva clathrata

The brown shrimp Farfantepenaeus californiensis and the seaweed Ulva clathrata, both native to north‐west Mexico, were co‐cultured in lined ponds during 18 weeks. The aim of this study was to evaluate different stocking densities (10, 20, 30, 40 and 50 per m²) in terms of shrimp yield to see if the co‐culture method results in shrimp yields suitable for commercial production. The presence of Ulva results in good water quality and allows culture of brown shrimp with low water exchange (10% weekly) and with low nitrogen and phosphorus content in discharged water. The final weight and specific growth rate (SGR) in shrimp between 10 and 30 per m² were significantly higher (12.5–12.0 g and 4.56–4.53% day⁻¹ respectively) than 40 and 50 per m² (9.1 and 8.6 g, and 4.31% and 4.26% day⁻¹ respectively). Total shrimp biomass generated in 30 or more shrimp per m² was significantly higher (2.7–3.1 t ha⁻¹) compared with 10 and 20 shrimp per m² (1.0 and 2.0 t ha⁻¹ respectively). The lowest feed conversion ratio (FCR) (0.97) was shown in the 10 shrimp per m² case, and the highest FCR was seen with 50 shrimp per m² (1.37). Shrimp survival ranged between 71% and 81%, where the highest mortality was shown in 50 shrimp per m². The results show that the co‐culture method can result in commercially interesting yields, suggesting that 30 shrimp per m² is the best stocking density for co‐culturing F. californiensis with U. clathrata, based on the shrimp performance.     

Semi‐continuous mass culture of rotifers (Brachionus plicatilis) using an automatic feeder

This study describes the rotifer mass culture protocol developed at the Institute of Aquaculture (HCMR) in Crete. Rotifers were cultured semi‐continuously at a density of 257.6 ± 2.6 ind. mL^?1, with a daily dilution rate of 25%. An automatic feeder was used to administer dry feed (Selco Sparkle^®) every 10 min. A number of factors were investigated so as to provide an in‐depth analysis of the advantages and disadvantages of the two systems, especially when compared with traditional protocols such as batch culture. The use of these two systems resulted in a culture of considerable duration (41 days) and daily yield (0.21 ± 0.01 ind. 10⁶ day^?1 L^?1), using exclusively dry feed. Both systems can be easily applied in hatcheries, requiring few modifications on existing protocols and contribute to a stable and predictable production. Further improvements include manipulation of the dilution rate, food ration, culture volume and duration, as well as choice of a phytoplankton‐based diet.     

RNA/DNA ratio is an early responding,accurate performance parameter in growth experiments of noble crayfish Astacus astacus (L.)

Recent intensification efforts of astacid culture considerably depend on the appropriate assessment of the animal's physiological condition both for research and application. We conducted a 4 weeks feeding experiment to assess temporal resolution and accuracy of different response parameters (RNA/DNA ratio, RNA per wet weight, carapace length, wet weight, specific growth rate). Juvenile noble crayfish were exposed to five feeding regimes that differed in feeding frequency and food availability. Continuous growth was detected in all feeding regimes with individual increase up to 90% (wet weight) and 17% (carapace length), respectively. Morphometric parameters allowed separation of three weight‐groups or two length‐groups. During the experimental period RNA/DNA ratios showed both decrease (?17%) and increase (+35%), with superior accuracy than morphometric parameters, separating four groups. Based on RNA/DNA ratios, different feeding regimes were detected earlier, with two groups separated already after 3 weeks. RNA/DNA ratio was clearly superior to RNA per unit wet weight, as the latter failed to detect any differences between groups. In conclusion, RNA/DNA ratio is a valuable tool in nutritional studies with freshwater crayfish if overall growth is the key variable of interest.     

The effect of demand feeding on swimming speed and feeding responses in Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages

Abstract Using underwater cameras, data were collected on the feeding behaviour and swimming speeds of Atlantic salmon Salmo salar L., gilthead sea bream Sparus aurata L. and European sea bass Dicentrarchus labrax L. in sea cages. Comparisons were made between the behaviours of fish fed on demand using interactive feedback systems and those of fish fed under the standard feeding practice of each farm (control). In all three species, swimming speeds were similar before feeding , but they were significantly higher in the control regimes during feeding. When fed on demand, sea bass had reduced swimming speed just before and during feeding compared with that observed during the non‐feeding periods. Higher proportions of feeding fish were observed in the control regime cages than in fish fed on demand for all three species, indicating a greater feeding intensity during meals in the control regimes. This was further supported by observations of an increase in the density of sea bass in the upper water in the control cages during feeding. The results suggest decreased levels of competition between the on demand‐fed fish during feeding, which might be hypothesized to lead to improved growth and production efficiency in aquaculture.     

Influence of feeding regime on intraspecific competition, fin damage and growth in 1+ Atlantic salmon parr (Salmo salar L.) held in freshwater production cages

The feeding behaviour, growth and feed conversion ratio (FCR) of cage‐held Atlantic salmon parr (Salmo salar L.) were studied when in 576 m³ (12 m × 12 m × 4 m) commercial freshwater cages under ambient water temperature (8.84±3.53°C) and photoperiod (11.02±2.05 h) for 205 days. The effect of feeding regime on fin damage was also investigated. Six groups (n=31 234±2051 fish group⁻¹, initial stocking density 1.25±0.14 kg m⁻³) were fed to satiation using either (a) an imposed regime involving scheduled, fixed ration feeding every 10 min from dawn till dusk or (b) on demand from dawn till dusk using commercial interactive feedback systems. During feeding, there were no significant differences in aggression although swimming speeds and turning angles were significantly higher in fish under the imposed regime. On‐demand feeding significantly reduced the incidence of dorsal fin damage. There was no clear relationship between fish size, feed regime and the incidence of fin damage until 1 week before the fish were transferred to marine cages, when the smallest fish under each feeding regime had the highest incidence of fin damage. Interestingly, growth did not differ between regimes, but fish under the imposed regime were significantly overfed and achieved higher FCRs.     

水产养殖自动投饵装备研究进展与应用

自动投饵系统可应用于大型网箱养殖和高密度工厂化养殖等，是提高饲料利用率，控制养殖成本和强化产品质量控制的重要手段。文章概述了国内外自动投饵装备的发展进程，着重介绍了国外深水网箱自动投饵装备的研究进展与应用情况，分析了国内自动投饵装备研究使用现状，对国内自动投饵装备的发展提出了建议。     

香鱼咸淡水工厂化养殖试验

在浙江宁海凫溪人海口附近海堤内采用咸淡水工厂化养殖香鱼，1400平方米水泥池，总产量5．65t，总产值59．33万元，纯利润40．46万元，每平方米产香鱼4．71kg，养成成活率65．52％。     

Laboratory and field investigations on the effect of scheduled meal timings on growth performance and nutrient retention in an Indian major carp,Cirrhinus mrigala (Ham) fingerlings: Effect on nitrogen retention and excretion of metabolites

To investigate the effect of scheduled meal timings on growth performance in Cirrhinus mrigala fingerlings, two experiments were conducted. The first experiment was conducted under laboratory conditions and the fish were submitted to schedule meal timings (at 08:00, 12:00,16:00, 20:00, 00:00 and 04:00). A control on continuous feeding was also maintained. ANOVA had revealed a significant (p < .05) increase in live weight gain (g), growth per cent gain in body weight, specific growth rate, PER, GPR, GER and APD (%) values in fingerlings fed between 12:00 and 16:00 hours. A decline in growth parameters, nutrient retention and an increase in FCR values were observed in the group fed at 20:00, 00:00 hours and also in the control group. Studies have further revealed that meal timings had also significantly (p < .005) affected protein digestibility, nitrogen retention and excretion of metabolites . Fish carcass composition had significantly (p < .05) higher accumulation of protein (14.82 ± 0.032), fat (5.51 ± 0.006) and energy (5.95 ± 0.004) in the group fed at 16:00 hours. The second experiment was conducted under field conditions and the fish were submitted to schedule meal timings (at 08:00, 12:00, 16:00 and 20:00). A control on continuous feeding was also maintained. Significantly (p < .05) higher values in growth parameters were observed in the group fed at 16:00 hours and lower values in the group fed at 20:00 hours and also in controls. Water quality, nutrients and productivity status of ponds revealed favourable levels and appears to have been affected by meal timings. Thus, in C. mrigala, timings of food intake can serve to optimize the utilization of ingested calories.     

A review of diet formulation strategies and feeding systems to reduce excretory and feed wastes in aquaculture

Significant efforts should be devoted to reducing waste outputs from aquaculture operations in order to lower the environmental impacts of aquaculture in many parts of the world. Since most aquaculture wastes are ultimately from dietary origin, reduction of waste outputs should first be through improvements of diet formulation and feeding strategies. The first step in the production of feeds producing less solid waste is to eliminate poorly digestible ingredients (such as whole grain or grain by-products used as binders and fillers in the feed formulae) and to use highly digestible ingredients with good binding properties. Further reduction of solid waste can then be achieved through careful selection of the ingredients to improve apparent digestibility and the nutrient balance of the feed. Nitrogen waste outputs can be reduced through the reduction of the digestible protein to digestible energy (DP/DE) ratio of the diet. Phosphorus waste outputs can be reduced through careful selection of the ingredients and optimization of the digestible phosphorus content of the diet to meet the requirement of the fish but avoid greatly exceeding this required level. Finally, feeding practices that minimize feed wastage should be adopted since feed wastage can have a very significant impact on waste outputs from fish culture operations.     

Validation of a feeding strategy to deliver bacterially expressed dsRNA to marine amoeba from the genus Neoparamoeba

RNA interference (RNAi) mediated by double stranded RNA (dsRNA) has emerged as one of the most promising techniques to study gene function of non‐model protozoan parasites. We have previously demonstrated that bacterially expressed dsRNA delivered by immersion elicited successful knockdown in Neoparamoeba pemaquidensis, the non‐infective species closely related to the causative agent of salmonid amoebic gill disease (AGD). However, considering that amoebae naturally feeds on microorganisms, direct ingestion of bacteria designed to express dsRNA could allow rapid and low‐cost analysis of gene function on a large‐scale. Therefore, the main objective of this study was to investigate whether ingestion of bacteria‐expressing dsRNAs would also induce suppression of N. pemaquidensis β‐actin and EF1α. Despite effective bacterial uptake, no significant variation in EF1α relative copy number was triggered by dsRNA ingestion. β‐actin, on the other hand, presented similar silencing efficiency to what was observed in our previous soaking study. However, the observed RNAi response was delayed by at least 72 h. The present work provides evidence that delivery of bacterially expressed dsRNA through feeding can be successfully achieved in N. pemaquidensis, albeit not as efficiently as by soaking. Therefore, further investigation is required to develop more efficient and specific RNAi delivery systems in Neoparamoeba species. To our knowledge, this is the first time that RNAi‐mediated knockdown through ingestion was attempted to manipulate gene function of a marine amoeba.