叶轮式增氧机对鱼池溶氧日变化影响的模拟模型初步研究

针对鲜有鱼池溶氧模型考虑增氧机对鱼池溶氧日变化影响的现实,在传统的描述鱼池水温和溶氧日变化多层模型的基础上,通过分析叶轮式增氧机水跃和液面更新对鱼池多层水体中各能量要素和溶氧变化因子的影响,构建了能反映叶轮式增氧机增氧效果的鱼池水温和溶氧日变化模拟模型.通过实验数据对模型的校参和验证,发现溶氧逐小时模拟值与观测数据的均...     

鱼塘溶解氧无线监测与控制系统研究

溶解氧检测在水产养殖中起着至关重要的作用。研制了一套通过无线以太网(WIFI)连接,LabVIEW程序控制,并通过GSM网络使用户远程监控池塘溶解氧的溶解氧无线监测与控制系统。该系统能够在线检测溶解氧、温度等主要环境参数,并根据环境情况实施对增氧机的控制,业主可远程电脑监控或者通过手机远程监测鱼塘水质状况,并发送增氧命令,进行远程手动启停增氧机。在溶解氧超标时,系统可以自动启停增氧机,并向用户发送报告。试验结果表明,该方案提高了水质监控系统的控制性能,且具有应用前景。     

A comparison of constant acceleration swimming speeds when acceleration rates are different with critical swimming speeds in Chinese bream under two oxygen tensions

To investigate the effect of acceleration rates on the constant acceleration test speed (U _cat) and to compare U _cat with the critical swimming speed (U _crit) in Chinese bream (Parabramis pekinensis), the U _cat test at acceleration rates of 0.05, 0.1, 0.2, 0.4 and 0.8 cm s^?2 and the U _crit test in juvenile fish at 20 °C in either normoxia (>90 % saturation oxygen tension) or hypoxia (30 % saturation) were compared. The lactate concentration ([lactate]) of white muscle, liver and plasma and the glycogen concentration ([glycogen]) of white muscle and liver were also measured to identify whether tissue substrate depletion or tissue lactate accumulation correlated with exhaustion. The U _cat decreased with the acceleration rate, and there was no significant difference between U _crit and U _cat at lower acceleration rates. Hypoxia resulted in lower U _cat and U _crit, and the difference increased with decreased acceleration rates of the U _cat test, possibly due to the increased contribution of aerobic components in U _crit or U _cat at low acceleration rates. Hypoxia elicited a significant decrease in muscle [glycogen] and an increase in muscle and liver [lactate] in resting fish. All post-exercise fish had similar muscle [lactate], suggesting that tissue lactate accumulation may correlate with exercise exhaustion. Unlike hypoxia, exercise induced an increase in muscle [lactate] and a significant increase in plasma [lactate], which were worthy of further investigation. The similar swimming speed and biochemical indicators after exercise in the U _crit and U _cat groups at low acceleration rates suggested that U _cat can be an alternative for the more frequently adopted protocols in U _crit in Chinese bream and possibly in other cyprinid fish species.     

卷口鱼的临界水温和溶氧量

卷口鱼 (Ｐｔｙｃｈｉｄｉｏｊｏｒｄａｎｉ)俗名嘉鱼 ,是珠江水系特有的名贵鱼类 ,经济价值高 ,多年来一直是珠江三角洲地区比较高档的河鲜之一 ,因其肉质嫩滑 ,味道鲜美而深受人们喜爱。近两年群众已有人工养殖卷口鱼的尝试 ,但苗种来源不易。因此 ,要发展该鱼的养殖业 ,一方面必须进行人工繁殖的研究 ,另一方面应深入研究其生物学特性。本文对卷口鱼的耐寒能力和呼吸耗氧的某些特点进行了初步的试验观测 ,这一结果对卷口鱼的生产养殖将有一定的理论和实际指导意义。1　材料和方法1 1　试验材料　试验鱼取自江河捕获的野生鱼 ,鱼体健壮无…     

Control of dissolved oxygen levels of water in net pens for fish farming by a microscopic bubble generating system

ABSTRACT:   A microscopic bubble generating system (MBGS) has been developed to control dissolved oxygen (DO) levels suitable for fish farming. The MBGS has been tested to confirm its capability in net pens. Water conditions in a fish farm were monitored every two hours from June to October 2004 by setting an online vertical profiling system (OVPS) close to the net pen. DO in the net pen water decreased to physiologically stressful levels for the fish during the night (4.84–5.51 mg/L), while the DO was kept in saturated conditions during the day, due to oxygen supply from phytoplankton. The MBGS was operated from the evening to the morning of the next day for 16 h, to successfully create DO-saturated conditions in the net pen water at night. By using microscopic bubbles during the warm seasons, DO levels in the net pen water could be improved to a level suitable for fish farming. However, the low DO levels (<5.0 mg/L) of the bottom water occasionally extended to the net pen layers, despite the supply of microscopic bubbles to the water. To maintain the DO of the net pen water at levels suitable for fish farming, DO supply to the net pen water and the bottom water needs to be increased, and the organically enriched sediment just below the net pens needs to be treated.     

A model for oxygen consumption of Atlantic salmon (Salmo salar) based on measurements of individual fish in a tunnel respirometer

A model for oxygen consumption of Atlantic salmon (Salmo salar) including body-weight (BW, kg), temperature (T, °C) and swimming speed (U, bodylengths s⁻¹) was developed. A multiregression analysis of 157 measurement periods on six different fish gave the model:

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(mg kg⁻¹ h⁻¹)=61.6(±6.6) BW^{−0.33(±0.11)} 1.03(±0.10)^T1.79(±0.10)^U. The model is compared with earlier work on oxygen consumption of salmonids.     

褐牙鲆幼鱼能量分配对限制溶解氧供应及恢复的响应

实验采用循环水养殖系统,通过水流量控制溶解氧供给,设计不同溶解氧供应和限制溶解氧供应及恢复两个实验来研究褐牙鲆(Paralichthys olivaceus)幼鱼生长及能量分配等指标的响应。在不同溶解氧供应实验中,溶解氧含量梯度设置为2.24 mg/L,3.14 mg/L,4.27 mg/L,5.38 mg/L,6.94 mg/L,实验结束时褐牙鲆幼鱼体重、日生长系数、摄食率、以湿重表示的饲料转化效率与溶解氧含量呈正相关(P0.05)。单尾鱼的摄食能随着溶解氧含量的下降而减少,生长能的比例在溶氧为5.38 mg/L时最高。排粪能的比例则随着溶解氧含量的下降而上升,排泄能比例随溶解氧含量下降也略有增加,代谢能的比例随着溶解氧含量的下降呈先下降后上升的趋势,在溶解氧含量为5.38 mg/L时最低(37.66%)。单位体重能量收支中,所有指标与溶解氧含量都有明显的正相关关系(P0.05),随着溶解氧含量的提高而显著提高。实验表明,低溶解氧含量下,褐牙鲆幼鱼通过减少能量供应降低摄食率和饲料转化效率,其生长受到抑制。在限制溶解氧供应及恢复实验中,经历10 d低溶解氧含量2 mg/L(S_2)和4 mg/L(S_4)胁迫的褐牙鲆幼鱼生长受到抑制,但在恢复正常溶解氧后10 d内体重即与对照组无显著差异(P0.05)。恢复期间褐牙鲆幼鱼的摄食率明显高于对照组(P0.05),饲料转化效率略高于对照组。恢复阶段不同处理在摄食能、生长能比例和呼吸能比例上没有显著差异(P0.05),但经历低溶解氧胁迫的处理摄食能和生长能比例略高于对照处理,而代谢耗能比例略低于对照处理。S2处理的排泄能比例显著低于其余2个处理(P0.05)。实验表明褐牙鲆幼鱼对短期低溶解氧含量有较强的适应能力,能够通过提高摄食率在较短的恢复期获得完全补偿生长。本研究揭示了褐牙鲆在低溶氧胁迫下的能量分配规律,为深入研究鱼类适应溶解氧波动环境的策略积累资料。     

浅析北方地区越冬池塘冰下应急增氧措施

冰下增氧是北方地区池塘鱼类安全越冬的一项重要措施,如果管理不好或措施不当,会造成全池鱼类缺氧死亡,给养殖户带来巨大损失.目前,北方采用的鱼类越冬技术主要是冰下生物增氧越冬技术,这项技术主要是通过采取各项技术措施,促进冰下水体中的浮游植物的光合作用,释放更多氧气,以满足鱼类的生存需要,提高鱼类越冬的密度和成活率.     

基于统计模型的养殖鱼塘溶解氧预报技术研究

根据武汉市2009-2011年的养殖鱼塘溶解氧数据和对应的气象要素,通过多元逐步回归分析构建鱼塘的溶解氧含量预报预测模型,并在武汉和荆州进行了验证。结果表明:一般鱼塘溶解氧在5-9月期间较低,低值一般出现在清晨6-7时,且较低值出现与天气相关,即闷热型天气突降大雨易导致溶解氧值降低。溶解氧量预报预测模型R2均在0.7以上,拟合效果良好。     

Behavioral responses of tilapia (Oreochromis niloticus) to acute fluctuations in dissolved oxygen levels as monitored by computer vision

Behavioral and ventilatory parameters have the possibility of predicting the stress state of fish in vivo and in situ. This paper presents a new image-processing algorithm for quantifying the average swimming speed of a fish school in an aquarium. This method is based on the alteration in projected area caused by the movement of individual fish during frame sequences captured at given time intervals. The image enhancement method increases the contrast between fish and background, and is thus suitable for use in turbid aquaculture water. Behavioral parameters (swimming activity and distribution parameters) and changes in ventilation frequency (VF) of tilapia (Oreochromis niloticus) responded to acute fluctuations in dissolved oxygen (DO) which were monitored continuously in the course of normoxia, falling DO level, maintenance of hypoxia (three levels of 1.5, 0.8 and 0.3 mg l⁻¹) and subsequent recovery to normoxia. These parameters responded sensitively to acute variations in DO level; they displayed significant changes (P < 0.05) during severe hypoxia (0.8 and 0.3 mg l⁻¹ level) compared with normoxic condition, but there was no significant difference under conditions of mild hypoxia (1.5 mg l⁻¹ level). There was no significant difference in VF between two levels of severe hypoxia 0.8 and 0.3 mg l⁻¹ level during the low DO condition. The activity and distribution parameters displayed distinguishable differences between the 0.8 and 0.3 mg l⁻¹ levels. The behavioral parameters are thus capable of distinguishing between different degrees of severe hypoxia, though there were relatively large fluctuations.     

Water quality fluctuations under floating net cages for fish culture in Lake Cirata and its impact on fish survival

ABSTRACT:   Vertical profiles of water quality were surveyed before and after mass mortality of fish cultured in cages in Lake Cirata, a man made lake in Indonesia. The first survey was performed 4 months before the mass mortality and the second survey was carried out 4 days after the mass mortality. In the first survey, the conditions below 8 m depth were reductive and anoxic, although at 8 and 10 m depth, the water became oxidative in spite of low oxygen concentration in the second survey. These changes were probably caused by strong mixing of surface water with deeper water. Eight months after the mass mortality, when the redox potential at 8 m became reductive again, exposure tests of fish were performed in different layers in the water column around the cage. During the exposure tests the redox potential of the water was less than −100 mV and 93% of carp died within 6 h of exposure at 8 m depth. These results indicated that the mass mortality was caused by the strong mixing of surface water with reductive water in deeper layers.     

工厂化养鱼中氧气锥的增氧规律

控制养殖水体溶氧是工厂化养鱼水处理主要技术之一.介绍一种工厂化养鱼氧气锥的结构、原理及增氧效果.为了掌握氧气锥增氧规律,对氧气锥进行了氧气流量单因素等差梯度试验.结果表明,在循环水流量为65 m3/h,水温24.5℃,氧气流量为0,1,2,……,10 L/min的条件下,溶氧与氧气流量回归方程为y=0.100 9x2+0.059x+5.958 8(r=0.992 7);根据物料平衡原理,推算出氧气锥的最大氧气利用率为84.56%;在最大氧气利用率的条件下,依照尼罗罗非鱼的耗氧率计算模式,推算出工厂化养鱼系统需配置氧气锥的台数.     

Monitoring of oxygen fluctuations in seabass cages (Dicentrarchus labrax L.) in a commercial fish farm in Greece

Dissolved oxygen and temperature were monitored in cages stocked seabass at a commercial fish farm in Greece during summer and autumn. During the first part of the study, October–November 2012, current velocity monitoring outside the cages supported the sampling program. The latter sampling took place during May–July 2014. Including both periods, temperature fluctuated within the range 18–26°C while the current velocity, dominated by the tidal flow, varied from 0 to 28 cm/s in autumn. During sampling, seabass of 400–550 g individual weight was stocked at a density of 10–15 kg/m³. Within the cages, dissolved oxygen (DO) saturation decreased by 10% to 50% compared with outside levels. In‐cage oxygen concentrations seemed to be affected by current speed, temperature and diurnal fluctuations due to the fish stock's activity and the day‐night rhythm of algae. Hypoxia within the range 40%–70% of oxygen saturation was shown in several cases, despite the fact that the feeding intensity was quite low in the farm. The diurnal pattern of DO saturation showed that minimum levels coincided with feeding of the fish, while photosynthesis played a minor role in this case. This level of DO saturation although does not result in any mortalities may have other severe implications, especially at high temperature, such as lower feed utilization, increased metabolic expenses due to osmo‐respiratory compromise, increased stress level, lower disease resistance and diminished fish welfare.     

Influence of diurnal behaviour rhythms and water-level fluctuations on the migratory activities of fish in a backwater of the River Danube:a hydroacoustic study

This paper reports the results from three fixed-location acoustic surveys carried out in August and September 1996 to analyse the influence of diurnal behaviour rhythms and water-level fluctuations on the migratory activities of fish in the mouth of the Regelsbrunn-arm east of Vienna, Austria. A BioSonics 105 dual-beam echosounder (420 kHz), with a circular transducer (6°/15°) beaming nearly horizontal across the arm was used, with acoustic ranges of between 20 and 30 m. All surveys were conducted during day and night. The fish density was highest during the first observation period with low water level, lowest during the second sampling period with increasing water level, and intermediate during the third period with decreasing water level. The fish density was always higher during night than during day. Diurnal behaviour rhythms influenced the fish density as well as the size-frequency distribution. Increasing or decreasing water-gauge superposed the influence of diurnal behaviour rhythms on the size-frequency distribution for immigrating fish of certain length classes. Fish within the length group 10–15 cm tended to migrate upstream during decreasing water-gauge. Fish above 400 mm total length tended to move upstream during increasing water-gauge.     

方斑东风螺的耗氧率及饲养水中溶氧变化的初步研究

为对方斑东风螺养殖生产提供参考依据,试验测定了饥饿和饱食状态下方斑东风螺幼螺在不同水温(25℃、28℃、30℃)时的耗氧率,测定了幼螺摄食后水中溶解氧浓度的变化。结果表明,饱食后幼螺的生理代谢活动加强,耗氧率增加;随着水温的升高,耗氧率也增加。幼螺摄食后水中的溶解氧浓度随着时间的延长不断下降。试验观察发现,在方斑东风螺养殖的正常水温范围内(25℃~30℃),DO高于3mg/L时,幼螺生活正常;DO在2.40mg/L~2.35mg/L时,幼螺表现为缺氧状态;DO在1.5~1.0mg/L时,幼螺表现为严重缺氧状态。     

凡纳滨对虾高氨氮和低溶氧抗逆性状的杂交配合力分析

该研究利用3 个凡纳滨对虾( Litopenaeus vannamei) 引进群体, 采用完全双列杂交交配设计, 建立9 个自繁和杂交组合F1 代, 比较幼虾对高氨氮和低溶解氧的耐受性, 分析各交配组合杂种优势, 采用线性模型均数加权二乘分析法估算凡纳滨对虾高氨氮和低溶氧抗逆性状的配合力, 评估亲本及子代的耐受性能。结果表明, 9 个群体对氨氮( NH3-N) 和溶解氧( DO) 胁迫的耐受性均存在显著差异, 杂交子代耐高氨氮和耐低溶氧性状的中亲优势和超亲优势范围分别为14.09 42.57 和1.860～26.18、52.48～31.39 和54.34～24.66; 杂交后代耐受性的表现受到父本、母本一般配合力以及杂交组合特殊配合力共同影响, 美国夏威夷SIS 群体( UH) 耐高氨氮和低溶氧性状的一般配合力较高, 分别为0. 44 2 和0. 89 9; 特殊配合力分析表明, 美国迈阿密SIS 群体( UM) 和美国夏威夷SIS群体的杂交组合( UMUH) 为强优势组合, 存在较强的抗逆非加性效应, 杂交优势明显, 可为进一步家系选育提供候选材料。     

Redox profile in liver of Leporinus macrocephalus exposed to different dissolved oxygen levels

Aquatic organisms are continuously exposed to environmental variations, which can lead to physiological and biochemical alterations. Leporinus macrocephalus, known as piavu?u, is a migratory species that may be exposed to variations in dissolved oxygen levels. Studies evaluating oxidative changes undergone by this species in these conditions are scarce. Therefore, this investigation aimed at evaluating oxidative alterations in L. macrocephalus exposed to different oxygen levels for 96?h: 6.12?±?0.18, 3.99?±?0.17, 3.22?±?0.17, 2.47?±?0.30 and 0.710?±?0.07?mg?L(-1). At the end of the experimental period, fish were euthanized and livers used to determine lipid hydroperoxides, thiobarbituric acid reactive substances, catalase, glutathione-S-transferase, superoxide dismutase and thiol groups, which are an indirect measure of reduced glutathione. Results indicated a decrease in the studied parameters in hypoxic situations, suggesting a possible metabolic depression.     

春季鱼病发病的原因及防治措施

越冬后的鱼池,鱼类体质普遍下降,抗病能力也随之降低,进入春季水温逐渐上升,鱼类开始慢慢恢复活力,并逐渐开始摄食,同时各种能使鱼体致病的细菌、寄生虫也开始大量繁衍,各类养殖池塘容易暴发鱼病,引起池鱼大量死亡,给养殖者造成较大经济损失。为此,笔者认为加强春季养殖管理,切实做好鱼病防治工作是春季生产管理的关键。通过多年的生产实践,总结出春季常发鱼病主要有:烂鳍病、细菌性烂鳃病、水霉病、疖疮病、竖鳞病、锚头鳋病、车轮虫病以及三代虫病等。     

Responses of phosphate solubilizing bacteria to qualitatively different fertilization in simulated and natural fish ponds

The growth of phosphate solubilizing bacteria (PSB) was examined inresponse to pond fertilization with poultry dropping (PD) (12,500 kgha^–1 y^–1), cattle manure (CM) (25,000 kg ha^–1 y^–1), inorganic fertilizer (IF) consisting of urea (10.83 kg ha^–1 y^–1) and single super phosphate (43.52 kg ha^–1 y^–1) and inorganic-organic mixed fertilizers (PD:CM:IF – 1:1:1) in simulated fish ponds under alluvial and laterite soil conditions as well as in natural pondslocated in alluvial soil zone. The high correlation between dissolved oxygenand density of PSB implied the contribution of the latter in the aerobicorganic decomposition. The PSB were maximal in the PD, and minimal in theIF treatments. The distribution pattern of PSB was related to theautochthonous C/N ratio and the N/P ratios of water. Relatively low C/N ratios caused greater abundance of PSB. Increased fish production in PD treatments was clearly due to increased primary productivity and higher zooplankton abundance resulting from nutrient-grazing-detritus-microbial-food chain complex pathways.