TiO2紫外复合消毒机在零污水排放的工厂化养殖系统中杀菌效果研究

在零污水排放的封闭式循环系统中养殖大菱鲆及虹鳟,采用新型TiO2紫外复合消毒机对养殖用水(海水和淡水)中的总菌、弧菌及大肠杆菌的杀灭效果进行试验,并与目前普遍使用的紫外消毒机进行比较.试验结果表明,(1)当通过消毒机的流速低于1.2 t/h时,紫外复合消毒机与紫外消毒机两者对细菌的杀灭率无显著差异(P＞0.05);流速为3～4.2 t/h时,紫外复合消毒机杀菌(总菌及海水中大肠杆菌)效率显著高于紫外消毒机(P＜0.05).(2)2种紫外消毒机对淡水和海水中的总菌和弧菌杀灭率差异不显著.     

封闭循环水养殖哲罗鱼试验

在水温15~17℃下,将5 000尾平均体质量(10±3)g的哲罗鱼Hucho Taimen幼鱼饲养在由24个直径1 800mm×高1 000mm养殖池组成的封闭循环水系统中,以探索工厂化循环水养殖哲罗鱼的主要技术参数。经过8个月的养殖表明:养殖密度达到31.8kg/m~3,成活率96%,肥满度为1.01~1.30,鱼的平均体质量增加350g,体长增加21.3cm,鱼体生长状况良好。生物滤器两天反冲洗一次,有效提高了生物滤器的氨氮转化效率;紫外线消毒方式有效对系统进行了消毒杀菌;监测表明,系统水处理效果显著,其中NH_4~-平均浓度维持在(0.56±0.05)mg/L;NO_2~-含量为(0.15±0.05)mg/L;NO_3~-平均浓度为(41.86±2.62)mg/L;溶解氧为8.37~9.45mg/L;p H8.21~8.63。     

Winter Culture of Yellowleg Shrimp Penaeus californiensis in Aerated Ponds with Low Water Exchange

Abstract— This study was conducted in the semiarid region of Bahia Kino, Sonora, Northwestern Mexico to determine the feasibility of farming yellowleg shrimp Penaeus californiensis during the winter season in ponds with less than 5% daily water exchange and aeration. Four aeration rates (0, 6, 12, and 24 h/d) were used in the study. Mean growth rates ranged from 0.41 to 0.53 g/wk with the highest growth rate in ponds with 12 h of aeration ( P × 0.05). Survival ranged from 50 to 52% and did not differ among treatments. Shrimp yield ranged from 1,012 to 1,208 kg/ha, with the highest yields from ponds with 6 and 12 h of aeration ( P × 0.05). Feed conversion ratios ranged from 2.3 to 2.8, with lower values in ponds with 12 and 6 h of aeration ( P × 0.05). Results suggest that winter culture of yellowleg shrimp is possible and that 6 h of aeration is sufficient to maintain good water quality conditions.     

浅议深水抗风浪大网箱的养鱼效果

大型抗风浪深水网箱是一种新型养殖设备,它是用防腐蚀、防污染、防紫外线的新型材料制成,由于它的应用,使网箱养鱼由小箱到大箱、由近岸到离岸,由内湾到外海、由低效益型变高效益型,代表了当今世界海水养殖技术的先进水平。大型抗风浪深水网箱通常圆形,直径10～20m,底面积约为100～200m2,容积1000～2000m3/个,4个网箱为一组固定。1　大型抗风浪深水网箱与小网箱的比较优势大连市金州区海洋与渔业局、水产科学研究所2002年春从浙江舟山海洋科技有限公司引进周长50m、直径16m、网深10m、容积2000m3/个的浮式抗风浪深水大网箱3组(12个箱),…     

Effects of Inorganic and Organic Fertilization on Physicochemical Parameters,Bacterial Concentrations,and Shrimp Growth in Litopenaeus vannamei Cultures with Zero Water Exchange

To identify ways to improve water quality and shrimp production in closed systems, two parallel experiments (one in tanks and one in ponds) were conducted using Pacific white shrimp, Litopenaeus vannamei, cultures. In both experiments, the effects of inorganic (Nutrilake®) and organic (molasses) fertilization on physicochemical parameters, bacterial concentrations, and shrimp performance under zero water exchange were evaluated. Fertilization with both molasses and Nutrilake enhanced the feed conversion rate, as well as shrimp survival and production. In tanks, the shrimp survival and production rates were highest in the molasses treatment, but this effect was not observed in ponds. In ponds, fertilization with Nutrilake increased nitrogen and phosphorus concentrations more than did the controls and molasses treatments toward the end of the experiment. In tanks, fertilization with molasses reduced ammonia concentrations toward the end of the experiment, but the same effect was not observed in ponds. In ponds, fertilization reduced the proportion of Vibrio spp. bacteria, which most likely reduced the incidence of disease from these potentially pathogenic organisms. In both culture systems, fertilization increased the proportion of Bacillus spp., which most likely enhanced food availability.     

Environmental assessment of boreal rivers using fish data – a contribution to the Water Framework Directive

Abstract A fish‐based assessment method was developed to estimate the ecological status of boreal rivers. Electric fishing data were collected from 902 rapids, together with information on the land use, channel modification and water chemistry. Discriminant function analysis was used to select fish variables that most correctly classified the undisturbed reference sites and human impacted sites into exact classes. The relationship between the level of human alteration and fish metrics was examined. Five metrics were selected for the index: the number of fish species, proportion of sensitive species, proportion of tolerant species, density of cyprinid individuals and the density of age‐0+ salmonids. The value for each metric (between 0 and 1) was calculated according to a point estimate for classical probability. The index is used to estimate the ecological classification of rivers according to the EU Water Framework Directive.     

Intensive Rotifer Production in a Pilot‐scale Continuous Culture Recirculating System Using Nonviable Microalgae and an Ammonia Neutralizer

A study was conducted to test the performance of a high‐density (>3000 individuals/mL) continuous recirculating system for rotifers (B. rotundiformis) fed nonviable Nannochloropsis oculata and using sodium hydroxymethanesulfonate to neutralize ammonia. Three different microalgae feed rates (g of N. oculata [68 × 10⁹ cells/mL] per million rotifers/d) were tested in successive trials. In Trial 1 (feed rate = 1.5), during a 30‐d period, rotifers were harvested daily to 3000 individuals/mL, for an average yield of 178 million/d. Feed efficiency (million rotifers/g/d) was 0.33. In Trial 2 (feed rate = 1.1), during a 32‐d period, an average of 106 million rotifers were harvested daily, and feed efficiency was 0.26. In Trial 3 (feed rate = 1.3), during a 30‐d period, an average of 107 million rotifers was harvested daily, and feed efficiency was 0.23. An economic analysis based on a feed rate of 1.5 showed that production cost was 40% lower than the traditional batch culture method (US$ 0.29 vs. 0.46 per million rotifers/d). The continuous culture system tested reliably produced large quantities of rotifers on a daily basis without the use of a biofilter and with a lower production cost than a batch culture system.     

燕尾草金鱼的选育试验

生物过滤技术是循环水养殖系统中很关键的水处理技术,选择合适的滤料在很大程度上决定着生物过滤效果的好坏和循环水养殖系统能否正常运行。本次试验对一种新型悬浮式滤料在循环水高密度养殖系统中的水处理能力进行了研究,结果表明:(1)该滤料的挂膜性能好,挂膜时间短,且生物膜状态稳定;(2)该滤料的生物过滤能力好,具有较高的氨氮去除率和氨氮负荷,最高分别为57.5%和182.9 g/(m~3·d);其亚硝酸盐去除率平均为45.4%。     

Contribution of Fish Production to Farmers’ Subjective Well‐being in Vietnam – A Logistic Model

There is a growing awareness of the importance of food fish production on human nutrition, employment, poverty, and recreation. However, the role of aquaculture in livelihoods of fish farmers has not been considered rigorously. With 120 farmers interviewed in a field survey and a cumulative logistic model, this study identifies some determinants of subjective well‐being of small‐scale fish farmers in Vietnam and examines the role of earnings from fish production in generating their happiness. The results confirm that the farmers receive satisfaction from their farm working. Subjective well‐being of the farmers increases with their job satisfaction and cash earnings from fish farming. A doubling in cash returns from fish culture relative to household income raises a farmer’s happiness probability by an estimated 10.6%. Education also affects farmers’ life satisfaction. For better educated farmers, when their satisfaction from fish culture increases by one level, happiness probability is estimated to increase by 0.23%. Wild fish plays an important role in Vietnamese farmers as a doubling in relative income from wild fish captures raises their estimated probability of happiness by 139%.     

Replacement of Fish Meal with Soybean Meal,Alone or in Combination with Distiller's Dried Grains with Solubles in Practical Diets for Pacific White Shrimp,Litopenaeus vannamei,Grown in a Clear‐Water Culture System

The objective of this study was to evaluate inclusion of distiller's dried grains with solubles (DDGS) as partial replacement of commercial, solvent‐extracted soybean meal (SBM) in fish meal‐free diets for Pacific white shrimp, Litopenaeus vannamei. Aquaria connected to a recirculating biofiltration system were utilized to evaluate growth, survival, and feed conversion of shrimp during the 8‐wk feeding trial. Each 110‐L aquarium was stocked with 15 shrimp (mean individual weight 0.99 g) and fed one of five diets: a diet containing 20% fish meal (FM), which served as the control (Diet 1); a diet containing 0% FM and 52.5% SBM (Diet 2); and diets containing 0% FM and either 10, 20, or 30% DDGS as partial replacement of SBM (Diets 3, 4, and 5, respectively). Shrimp were fed according to a pre‐determined feeding chart five times daily (0730, 1030, 1330, 1630, and 1930 h) and there were three replicates per dietary treatment. The results from the feeding trial demonstrated that final weight, weight gain (g), and percentage weight gain were significantly higher (P < 0.05) for shrimp fed Diet 1 (10.96 g, 10.01 g, and 1051%, respectively) compared to shrimp fed diets containing DDGS; however, shrimp fed diets containing DDGS had similar (P > 0.05) final weight, weight gain (g), and percentage weight gain as shrimp fed a diet containing 0% FM and 52.5% SBM (Diet 2). Feed conversion ratio (FCR) of shrimp fed Diet 1 (2.84) was significantly lower (P < 0.05) compared to shrimp fed any other diet. Survival (%) was not different (P > 0.05) among treatments and averaged 77.3% for the study. This study demonstrated that practical shrimp diets containing no FM had an adverse impact on growth performance of white shrimp when grown in a clear‐water system and that further research is needed to refine diet formulations when culturing shrimp in these systems when attempting to feed a diet without FM.     

Comparison of Spore Inoculated and Vegetative Propagated Cultivation Methods of <Emphasis Type="Italic">Gracilaria chilensis</Emphasis> in an Integrated Seaweed and Fish Cage Culture

In Chile the integration of Gracilaria chilensis with salmon culture has shown high potential. Seaweed integrated aquaculture is of great interest as it allows waste recycling within fed cage aquaculture. The development of economically feasible suspended methods of seaweed cultivation is therefore of high importance. Hence, production and performance of two suspended Gracilaria cultivation methods, spore inoculated ropes and ropes with twined field collected seaweed, were studied in open water. The production from spore-seeded ropes was comparable to that of twined ropes for the first month of culture. Thereafter, the twined ropes had a significantly higher productivity. Fish farm wastes had no significant fertilizing effect upon Gracilaria growth rate. In addition, spore-originated thalli and field collected thalli were compared under laboratory conditions and in suspended culture using the same cultivation method. Spore-originated thalli had a 50% lower growth rate than the field collected thalli under laboratory conditions; however, no significant differences were detected in the field. Also, the occurrence of spore coalescence growth enhancement was not significant on the spore-seeded ropes. It was concluded that spore-originated cultivation techniques could be of interest for an integrated open seawater aquaculture system due to the high levels of Gracilaria polymorphism. This would result in greater adaptability to environmental variations, and a continuous supply of restocking material.     

Optimum Density of Red Tilapia Oreochromis mossambicus×O. urolepis hornorum in a Pulsed-Flow Culture System

Abstract.— Densities of 9 tilapia (hybrid Oreochromis mossambicus × O. urolepis hornorum)/m³ gave the highest production among five densities (1, 3, 6, 9, and 12 fish/m³) tested in a pulsed-flow culture system. Culture of fish in irrigation ditches may have great potential for integrating fish farming with irrigated agriculture. Each 1,000 meters of ditch could potentially produce up to 1,400 kg of tilapia during a 112-d growing season.     

The Effect of Probiotics in a Litopenaeus vannamei Biofloc Culture System Infected with Vibrio parahaemolyticus

We analyzed the effect of commercial bacterial probiotics on a Litopenaeus vannamei biofloc culture system infected with Vibrio parahaemolyticus. Three replicates of two experimental treatments were conducted: a control system (without probiotic) and a system with the application of a multistrain probiotic containing Bacillus spp., Enterococcus spp., Thiobacillus spp., and Paracoccus spp. applied to the water and another multistrain probiotic containing Bacillus spp., Enterococcus spp., and Lactobacillus spp. added to the feed. Growth and survival rate were significantly higher in the probiotic treatment group (P < 0.05), and the shrimp in the probiotic group also had a lower (P < 0.05) FCR compared to the shrimp in the control group (1.4 vs. 2.7).     

Niche partitioning of fish assemblages in a mountain stream with frequent natural disturbances – an examination of microhabitat in riffle areas

Abstract –  Microhabitat usage by different species of fish was studied to examine the potential for niche partitioning in riffle areas of a mountain river characterised by frequent natural disturbances. We randomly sampled 96 riffle‐area plots (mostly 1 m × 1 m) in a stream in south‐western Taiwan for fish abundance and microhabitat characteristics during the dry season from November 2008 to March 2009. Density and electivity values associated with microhabitat usage indicate the presence of niche partitioning among four major species of fish based largely on flow velocity and water depth. Hemimyzon formosanum, a herbivore, prefers higher velocity and shallower water but avoids sandy substrate. Onychostoma alticorpus, a herbivore, prefers lower velocity and deeper water. Rhinogobius nantaiensis, an omnivore, prefers higher velocity, shallower water and gravel‐sized substrate but avoids boulder substrate. Acrossocheilus paradoxus, an omnivore, prefers lower velocity and deeper water but avoids pebble‐sized substrate. The existence of differentiation of microhabitat preference and overlap of microhabitat usage suggests that interspecific competition is a factor affecting the structure of this fish assemblage, which may remain at early successional stages because of frequent disturbances in the stream. Study results also show that density and electivity detect preference differently. Density detects microhabitat preference for two herbivores while electivity detects microhabitat preference for two omnivores.     

Development of a Model for Describing Accumulation of Color and Subsequent Destruction by Ozone in a Freshwater Recirculating Aquaculture System

The purpose of this study was to develop a mathematical model to assist in the determination of design numbers for color destruction by ozone as a function of feed rate. A mass balance model was developed that takes into account methods of introduction and removal of color, including removal by ozone. Because direct measurement of color mass or concentration is difficult, a representative unit was developed during this study called the color mass equivalent (CME). The CME represents a direct measurement of absorbance at 436 nm, which is a unitless measurement, multiplied by the system volume. The CME is directly proportional to the true concentration of color causing compounds at that wavelength. Once the model was developed, two studies were run to test the model. A 1,500-L recirculating fish system was set up with a 57-L bead filter and six 1-L fluidized sand beds. Approximately 45 kg of channel catfish Ictalurus puncfatus were placed in the system and fed 0.25 kg of 32% protein feed per day (0.55% body wt.). Once the system reached stable conditions, the system was flushed with clean water and samples were taken to estimate the accumulation rate of color in the system. After 5 wk, an ozone unit was activated and samples were taken to determine the destruction rate for color. Once an accumulation rate had been determined, a second study was performed to corroborate this value. The same ozone unit was installed on a 5,000-L recirculating fish system being fed 0.49 kg per day with a 171-L bead filter. Samples were taken to determine the destruction rate for color. The accumulation rate for color was 12.6 CME/kg feed and the destruction rates were 1.7 CME/g O₃ in the first study and 0.82 CMWg O₃ in the second study. This calculates to a range of 7 to 15 g O₃/kg feed to remove the color produced by the feed.     

工厂化养殖半滑舌鳎生长、摄食和水质的变化特征及规律

在封闭循环水养殖条件下,进行6×2双因素随机设计动物试验,即6个体重阶段(45～550 g)和2个密度水平(高密度比正常密度提高20%～30%),共形成12个处理,每处理3个重复,试验期44 d.探寻我国北方工厂化养殖半滑舌鳎生长、摄食和水质的变化特征及规律.结果表明:(1)日增重、日均摄食量、饲料系数等绝对指标与体重阶段呈正相关;氨氮、COD等水质指标相对浓度与体重阶段呈负相关;(2)常规水质条件下,高密度养殖不利于生长、摄食和降低水体有害物,其副作用起初并不明显,随着试验时间的推移不断加大;(3)新发现半滑舌鳎的日摄食率为0.43%～0.92%,对常规鱼类投饲率推荐范围(2%～5%)提出了质疑,为现代海水养殖精准饲喂和清洁生产提供了科学依据;(4)本试验条件下,体重45～550 g阶段半滑舌鳎的特定生长率为(1.42%～0.50%)/d,饲料系数为0.68～0.86,水中氨氮为8.45～1.51 mg/(kg.h).     

Culture of organic tilapia to market size in periphyton‐based ponds with reduced feed inputs

In fish production under organic standards, only organic feeds and manures can be supplied. The cost of organic pelleted feeds is twice that of regular feeds. To support the organic production of hybrid tilapia [Oreochromis niloticus (L.) ×Oreochromis aureus (Steindachner)], a series of experiments in earthen ponds, to improve natural food production for this fish while reducing costs of added feed, are in progress. To improve natural food production for tilapia, plastic substrates equivalent to 50% of the pond surface were introduced into the water column to induce periphyton growth on them. To reduce costs, the feeding rate on pelleted feed was reduced to 60%. Tilapia growth in these periphyton ponds was then compared with ponds without underwater substrates that received the full feed rate. The polyculture consisted of 90% large (320 g stocking weight) hybrid tilapia and small amounts of other fish, at a total stocking density of 13 800 fish ha^?1, during 87 summer days. The results showed improved nitrification and the development of a large autotrophic periphyton biomass that competed with the phytoplankton in the periphyton ponds, and only a 10% and 15% reduction, respectively, in the tilapia daily and specific growth rates, with 40% feed saving. These results point towards periphyton‐based aquaculture as an appropriate technology for the reduction in production costs, allowing economically viable organic tilapia production.     

Lactococcus garvieae outbreaks in Brazilian farms Lactococcosis in Pseudoplatystoma sp. – development of an autogenous vaccine as a control strategy

This study evaluated the control of streptococcosis outbreaks in Brazil, isolated from diseased sorubim and identified as Lactococcus garvieae by genetic sequencing. This report determined the potential for lactococcosis control in sorubim Pseudoplatystoma sp. with two vaccines: an aqueous‐based, whole‐cell inactivated vaccine (bacterin) and an oil‐adjuvanted bacterin. Their efficacy was evaluated at 30 days post‐vaccination (d.p.v.) by challenge with L. garvieae, and the antibody production response at 15, 30 and 60 d.p.v. and the non‐specific immune response were compared amongst treatments. High protection levels (P < 0.05) were achieved with the oil‐adjuvanted vaccine with a relative percentage survival value of 81.7% at 30 d.p.v. Additionally, the oil‐adjuvanted vaccine increased the immunogenicity of the bacterin as indicated by greater agglutination antibody titres from 15 until 60 d.p.v. This is the first report of a positive effect of vaccine administration on the specific immunity of sorubim, and the study showed that a specific antibody plays an important role in sorubim defence against lactococcosis because the innate immune responses were similar in all of the studied animals. These results demonstrated that oil‐adjuvanted vaccine can be an effective alternative for the protection of sorubim from L. garvieae disease.     

Food Production and Water Conservation in a Recirculating Aquaponic System in Saudi Arabia at Different Ratios of Fish Feed to Plants

An indoor aquaponic system (i.e., the integration of fish culture with hydroponic plant production in a recirculating setup) was operated for maximizing water reuse and year-round intensive food production (Nile tilapia, Oreochromis niloticus , and leaf lettuce) at different fish feed to plants ratios. The system consisted of a fish culture component, solid removal component, and hydroponic component comprising six long channels with floating styrofoam rafts for holding plants. Fish culture effluents flowed by gravity from the fish culture component to the solid removal component and then to the hydroponic component. Effluents were collected in a sump from which a 1-horsepower in-line pump recirculated the water back to the fish culture tanks at a rate of about 250 L/min. The hydroponic component performed as biofilter and effectively managed the water quality. Fish production was staggered to harvest one of the four fish tanks at regular intervals when fish attained a minimum weight of 250 g. Out of the total eight harvests in 13 mo, net fish production per harvest averaged 33.5 kg/m³ of water with an overall water consumption of 320 L/kg of fish produced along with the production of leaf lettuce at 42 heads/m² of hydroponic surface area. Only 1.4% of the total system water was added daily to compensate the evaporation and transpiration losses. A ratio of 56 g fish feed/m² of hydroponic surface effectively controlled nutrient buildup in the effluents. However, plant density could be decreased from 42 to 25–30 plants/m² to produce a better quality lettuce.     

蓄水平塘主养建鲤套养网箱高产试验

进行了平塘精养建鲤和用小网箱套养鱼种试验。采取控制理化及生物因子、轮捕轮放等技术措施，获得总产成鱼１４０００ｋｇ，获利２８６００元的成绩。