Predation risk from piscivorous fish influencing the diel use of macrophytes by planktivorous fish in experimental ponds

Abstract— This study investigated interactions between zooplanktivores (roach and perch) and piscivorcs (pike and large perch) in experimental ponds (16 m²) with open water habitat and three densities of natural macrophytes. Fish habitat selection was determined both day and night and was supported by daytime observations to study anti-predator behavioural patterns. Diel migration out from among macrophytes was seen in the absence of predators, particularly for roach, which changed from 13% of individuals being in open water during the day to 90% at night. The risk of predation from piscivores influenced the habitat selection of the zooplanktivores. Roach seemed to be the most vulnerable to predation from pike and selected the open water (90-92%) during daylight hours, but kept a 1-m distance from the macrophytes edge. The presence of pike thus reduced the use of macrophytes by roach, which in turn may improve macrophytes and the edge area as a refuge for zooplankton. Pike appeared to have less impact on the gross habitat selection of O+ perch, which were associated with the macrophytes (58–89%), though they were still vulnerable to predation. Adult perch, which was a generally less effective predator than pike, showed subdued behavior, concealing them selves in the macrophytes most of the time. No effect of the simultaneous presence of two predator species was found.     

Is scuba sampling a relevant method to study fish microhabitat in lakes? Examples and comparisons for three European species

Abstract – We compared fish microhabitat use patterns in the littoral zone of a lake using a new direct method (point abundance sampling by scuba, PASS) and the widely used point abundance sampling by electrofishing technique (PASE). We collected microhabitat data for age 0+ roach ( Rutilus rutilus L.), perch ( Perca fluviatilis L.), and pike ( Esox lucius L.). The two methods yielded different results for fish assemblage structure and microhabitat patterns. Using PASE, fish were mainly found in "shelter habitats" such as shallow waters and dense vegetation. It is likely that this behavior is caused by the disturbance of the observer stamping around. Using PASS, fish escapement behavior was rarely observed. Therefore, we concluded that this direct and nondestructive sampling technique can be used to provide an accurate microhabitat estimation of a fish community and is assumed to be more suitable than PASE for fish habitat studies.     

温度对黄金鲈(Perca flavescens)耗氧率和排氨率的影响

在不同水温(15、20、25和30℃)下,对体重(46.1±4.5)g黄金鲈(Perca flavescens)的耗氧率和排氨率进行了测定与分析。结果显示:黄金鲈的耗氧率和排氨率均随温度的升高而显著增加(P<0.01);耗氧率和排氨率与温度的关系可用指数方程拟合,其方程分别为:RO=0.0682 e0.0633t,R2=0.9879;RN=2.4593 e0.0904t,R2=0.9703;随着温度的升高氧氮比(O:N)逐渐降低;耗氧Q10值和排氨Q10值均在20~25℃之间最小。结果表明:在各温度水平下黄金鲈基础代谢消耗底物主要均以蛋白质为主,脂肪其次,然而随着温度的升高,黄金鲈利用糖类和脂肪供能的比例逐渐下降,而蛋白质供能的比例逐渐增加。黄金鲈的最适生长温度为20~25℃。     

六种淡水贝类耗氧率的初步研究

通过自制的流水密闭装置,测定了六种淡水贝类耗氧率,研究了起始溶解氧对贝类耗氧率的影响,结果表明:①六种淡水贝类耗氧率大小依次为:圆顶珠蚌、河蚬、扭蚌、背角无齿蚌、三角帆蚌和楔形丽蚌;②水中起始溶氧水平对贝类耗氧率有一定影响,起始溶氧水平与耗氧率呈线性正相关关系,随着起始溶解氧水平的降低,六种贝类耗氧率出现了不同程度的降低;③淡水贝类与其他滤食性鱼类相比具更强耐低氧能力,更适合作为水环境生态修复的工具种。     

温度、盐度、pH对青岛菊海鞘耗氧率的影响

在静水条件下,研究了温度、盐度、pH对青岛菊海鞘(Botryllus tsingtaoensis)耗氧率的影响及其变化规律。结果表明:(1)在13~19℃之间,青岛菊海鞘的单位湿重耗氧率随着温度的升高而增大,高于19℃时其耗氧率急剧降低(P0.01);(2)盐度与青岛菊海鞘耗氧率的关系呈"倒钟"型曲线,在不同温度下盐度在20‰~30‰之间,变化的趋势基本相同,随着盐度的升高,青岛菊海鞘的耗氧率明显增大,在30‰时达到最大值;(3)在pH为8时,青岛菊海鞘表现出较高的耗氧率,而pH低于6和高于8时则明显下降(P0.01)。     

Fixed location hydroacoustic monitoring of fish populations in the tidal River Hull, north-east England, in relation to water quality

Abstract  Fixed location hydroacoustic fish monitoring was carried out at a series of sites in the tidal River Hull, north-east England, in July 1996 during periods of moderate freshwater flows and spring tides. This was followed by a corresponding series during a period of lower freshwater flows and spring tides in autumn 1996. The surveys indicated substantial numbers of fish living upstream and downstream of a depleted oxygen zone which exists in the tidal Hull. Conditions in this zone of poor water quality deteriorated further during low flow periods due to reduced dilution of effluents. Fish populations moved with the tide apparently in response to gradients of dissolved oxygen and salinity. Under conditions of low freshwater flow and high tides, gradients of salinity and oxygen were steeper and fish responses appeared more marked: at higher salinities, the response to increasing salinity overrode the response to decreasing oxygen availability.     

4种石磺水中呼吸耗氧初步研究

在温度22℃、盐度30的密闭容器内,采用WINLKER氏碘量法测定溶氧量,分别对不同规格的4种石磺[瘤背石磺(Onchidium struma)、平疣桑椹石磺(Platevindex mortoni)、里氏拟石磺(Paraoncidium reevesii)、紫色疣石磺(Peronia verruculata)]的水下呼吸耗氧率进行了测定。结果表明:4种石磺的表皮呼吸耗氧率均随体质量的增加而降低;在相同条件下,比较4种石磺的耗氧率发现,紫色疣石磺、瘤背石磺和平疣桑椹石磺在3 h时耗氧率降到最低,分别为(0.126±0.014)mg·(g·h)-1、(0.111±0.011)mg·(g·h)-1、(0.081±0.006)mg·(g·h)-1,里氏拟石磺在4 h时降到最低,为(0.098±0.015)mg·(g·h)-1;紫色疣石磺的耗氧率在各时间段均明显高于其它3种石磺,以下依次为瘤背石磺、里氏拟石磺、平疣桑椹石磺。     

不同温度下青海湖裸鲤的耗氧率、耗氧量与呼吸频率的关系

研究了不同温度(5±0.5)℃、(10±0.5)℃、(15±0.5)℃、(20±0.5)℃和(25±0.5)℃)下青海湖裸鲤(Gymnocypris przewalskii)的耗氧率、耗氧量与呼吸频率的关系。结果表明,耗氧率、耗氧量和呼吸频率均随着温度的升高而升高,且不同温度间差异显著(P<0.01)。呼吸频率在5~10℃较低温度时没有明显差异(P>0.05)。呼吸频率在不同的温度下都存在明显的昼夜差异(P<0.05),白天明显高于夜晚。不同温度下呼吸频率和耗氧率的回归关系为y=63.052e(0.0115x)(R2=0.982 2);呼吸频率和耗氧量的回归关系为y=-1.719 7x2+38.437x-61.914(R2=0.961 8)。在15~20℃间的耗氧率、耗氧量和呼吸频率相对变化较小,为适宜养殖的水温。     

几种常见海鞘的呼吸代谢研究

为了研究网箱、网笼上附着生物耗氧对养殖品种的影响。本文在实验室内采用静水封闭系统,对我国北方常见附着生物－－柄海鞘（Ｓｔｙｅｌａ ｃｌａｖａ）,玻璃海鞘（Ｃｉｏｎａ ｉｎｔｅｓｔｉｎａｌｉｓ）和中国瘤海鞘（Ｓｔｙｅｌａ ｓｉｎｅｎｓｉ）的耗氧率进行了研究,同时,探讨了海鞘体重、温度和氧张力对耗氧率的影响。结果表明：温度和体重对海鞘的耗氧率有明显的影响（Ｐ〈０．０５）。在１２￣２８℃范围内,柄海鞘的     

Relationship between oxygen consumption,growth and survival of larval fish

This work aimed to evaluate the relationship between morphological development, oxygen consumption and reduced mortality in larval fish. We measured the resting metabolic rate (RM), specific metabolic rate (SMR) and the change in the total length during the larval stage of four fish species. Resting metabolism decreased from hatching to mouth opening, and then increased after mouth opening. The changes in the SMR were variable during the larval stage. After hatching, there was no increase in SMR in yolk‐sac larvae. However, SMR increased between mouth opening and the onset of notochord flexion and then decreased during notochord flexion before finally stabilizing. We observed two peaks in mortality during the larval period of all species: between mouth opening to the onset of notochord flexion and from the completion of notochord flexion to the juvenile stage based on the per cent mortality and the number of dead fish collected from the bottom of the rearing tank. Interestingly, the changes in SMR coincided with these periods of mortality. We hypothesize that larvae require more energy during these periods of larval development and are thus more susceptible to mortality when energy is insufficient. Thus, it is important to supply enough nutrition to larvae in during early development to prevent mass larval mortality.     

The effect of feed supply rate on growth of juvenile perch (Perca fluviatilis)

This study investigates the effect of the feed supply rate within a meal on growth of juvenile perch (Perca fluviatilis). Groups of PIT-tagged, feed-trained juvenile perch (12 g) were held in 100-L tanks at 18 °C, under a 24L:0D photoperiod and fed five meals per day in excess. Feed was applied at rates of 1.2 (Low), 4.2 (Medium) and 14.3 (High) pellets fish⁻¹ min⁻¹ during two periods, each of 50 days. Cumulative meal-time per day ranged from 10 to 225 min. Specific growth rates (SGR) in the two periods were positively correlated, indicating a consistent individual growth performance. There was growth dimorphism between the sexes. Females grew about 20% faster than males, resulting in final mean weights of ≈ 87 and 58 g respectively. Autopsy revealed differences in sex ratios between treatments and the effect of feeding rate was analysed according to sex. There was a tendency for fish fed at the lowest rate to have a higher SGR than fish in other treatments, both for females (L = 1.98 ± 0.0, M = 1.84 ± 0.08, H = 1.88 ± 0.19% bw day⁻¹) and males (L = 1.68 ± 0.01, M = 1.55 ± 0.16, H = 1.57 ± 0.02% bw day⁻¹). Fish fed at the lowest rate also tended to have the lowest feed conversion ratio (L = 0.88 ± 0.05, M = 1.02 ± 0.11, H = 1.04 ± 0.10) but the effects were not significant. These results suggest that juvenile perch can feed efficiently under a range of conditions.     

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.     

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。     

Effects of temperature on food consumption, growth and oxygen consumption of freshwater prawn Macrobrachium rosenbergii (de Man 1879) postlarvae

Effects of temperature on food consumption, growth and oxygen consumption were estimated for the freshwater prawn Macrobrachium rosenbergii postlarvae at 23 °C, 28 °C and 33 °C in the laboratory. The results showed that the animal's initial body weight had a close linear relationship with food consumption and growth. Food consumption increased directly with temperature. Consumption rates (C; mg day^?1 ind^?1 ) of the 28 °C and 33 °C groups were much higher than that of the 23 °C group (P < 0.001), and the 33 °C group's consumption rate was higher than that of the 28 °C group (P < 0.05). The relationship of food consumption with temperature and initial body weight (W; mg) could be described as: C = 0.0679W + 0.185t? 3.17. Growth increased significantly with increased temperature. The relationship among specific growth rate, temperature and initial body weight was as follows: SGR = ?0.110W + 0.213t + 0.176. However, temperature showed no effect on growth efficiency. Oxygen consumption increased significantly with temperature (P < 0.01). The weight‐specific oxygen consumption rates (mg O₂ g^?1 h^?1) at 23 °C, 28 °C and 33 °C were 0.83, 1.16 and 1.49 mg O₂ g^?1 h^?1 for 61.92 mg M. rosenbergii.     

千年笛鲷幼鱼耗氧率的研究

千年笛鲷幼鱼的耗氧量随幼鱼体重的增加而增加,耗氧量与体重的关系式为Y=0．756 0．513X。千年笛鲷幼鱼的耗氧率随幼鱼体重的增加而下降,耗氧率与体重的关系式为Y=1246．430X~(-0.036)。幼鱼在遮光条件下的耗氧率比在自然光照条件下要低15．362%～31．675%。在低盐度水环境下幼鱼的耗氧率较高,随着盐度的增加,其耗氧率降低。随着饥饿程度的加深,千年笛鲷幼鱼的代谢水平呈梯度下降。在盐度20和28时,千年笛鲷幼鱼的窒息点分别为0．93和1．17 mg·L~(-1)。     

不同生态因子对日本矶海绵耗氧率的影响

静水条件下,研究了温度、盐度和pH值对日本矶海绵耗氧率的影响。试验结果表明:温度在13~22℃范围内,日本矶海绵的耗氧率随着温度的增大而增大,温度高于22℃,耗氧率则开始减小(P0.05);盐度在20‰~35‰范围内,日本矶海绵的耗氧率随着盐度的增大而增大,盐度高于35‰,耗氧率则开始减小(P0.05);pH在5~8范围内,日本矶海绵的耗氧率随着pH的增大而增大,pH高于8,耗氧率开始减小(P0.05)。     

黑鲷耗氧率昼夜变化及与体重、水温的关系研究

研究了黑鲷(Sparus macrocephalus)耗氧率的昼夜变化规律及其与体重、水温的关系,结果表明,黑鲷耗氧率随水温的升高而升高,随个体的增大而降低;23:00耗氧率最高,为3.16±0.26μg·(g·min)-1,07:00左右耗氧率最低,为0.74±0.59μg·(g·min)-1。黑鲷白天的平均耗氧率为1.98±0.84μg·(g·min)-1,夜间的平均耗氧率为1.96±0.63μg·(g·min)-1,其代谢水平的昼夜变化不明显(n=10,t=0.034相似文献   

军曹鱼幼鱼耗氧率与窒息点的研究

对平均体质量为16.0g～18.4g的军曹鱼在不同水温和盐度条件下的耗氧率进行了测定。结果表明,水温对军曹鱼的耗氧率有显著影响。盐度29‰时,水温从17℃上升到32℃,军曹鱼的耗氧率从0.357mg/g·h增加到0.880mg/g·h,水温(X)与耗氧率(Y)的关系可用幂函数表示:Y=0.0045X1.5197。在水温29℃时,军曹鱼的耗氧率随着盐度的变化而变化。此外,军曹鱼的耗氧率表现出较明显的昼夜变化规律,在中午前和傍晚后较高。水温对军曹鱼幼鱼的窒息点有显著影响。水温从21℃升高到33℃,窒息点从0.74mg/L增加到1.44mg/L。盐度对窒息点的影响不显著。     

波纹龙虾耗氧率和窒息点的研究

采用流水法研究波纹龙虾在不同温度、盐度和pH值条件下的耗氧率和窒息点。结果表明：耗氧率随着水温的升高而增加,25℃耗氧率为0．0645mg／g·h,33℃时上升到0．1879mg／g.h。波纹龙虾耗氧率随盐度的变化则呈“V”字型,盐度为28最低0．1051mg／g。h。波纹龙虾的耗氧率随pH值的升高而降低,pH值7．4～7．7时,耗氧率较高,为0．1426～0．1460mg／g.h;pH值8．0～8．6时,耗氧率从0．1057mg／g。h下降到0．0722mg／g.h。在水温29℃,盐度28,pH值8．0条件下,波纹龙虾的窒息点为0．2341mg／L。     

山女鳟耗氧量与体重、水温的关系的研究

通过对体重0．53g和75．58g的山女鳟，在7℃、10℃、13℃、16℃、19℃，5个范围耗氧的测定，研究了山女鳟耗氧量与体重、水温的关系，结果表明：耗氧量随着体重和水温的增加而增加，耗氧率随着体重的增加而减少，在13℃-16℃水温范围内，水温增加但耗氧率增加不明显，水温在16℃时，耗氧量与体重的关系为：R=0．3621W^7848(R：耗氧量mg／h．尾，W：体重，g)，在体重0．53g时，耗氧量与水温的关系为：R=0．0173T-0．0393，75．58g时，耗氧量与水温的关系为：R=0．825T-1．725(R：耗氧量mg／h．尾，T：水温，℃)。山女鳟耗氧率具有昼夜变化，表现出明显的节律性，在13：00时耗氧率达到最高值，22：00时达到最低值。山女鳟的窒息点在1．2—1．98mg／L。