Study on the effects of aquatic vegetation on foraging behaviour of planktivores in lakes

湖泊水生植被对浮游动物觅食行为的影响研究

基本信息

批准号：
10450179
负责人：
ASAEDA Takashi
金额：
$ 8.51万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In littoral zones of lakes, macrophytes have considerable structural variation and that provides protection to prey communities by hindering predator foraging. The swimming and feeding behaviour of a planktivore (Pseudorasbora parva) with their prey (Daphnia pulex) were studied in a series of laboratory experiments with varying densities of simulated submerged vegetation. Prey availability was varied from 0.5, 1, 2, 5, 10 and 25 prey.lィイD1-1ィエD1. As the stem density gradually increased, the predator's foraging efficiency decreased considerably relative to feeding in open water. Moreover, a good relation in feeding rate and swimming speed existed with the average stem distance to fish body length ratio. Abrupt reduction in feeding and swimming was recorded when fish body length ratio was near 0.7, which is approximately equal to one stride length of a fish.In fish, hunger increases the motivation to feed and also efficiency of feeding. After 36 hours of food deprivation, the feeding and swimming behaviour of Pseudorasbora parva was studied under different prey densities. The initial feeding rates showed marked variations in relation to prey availability. Under high densities the initial feeding rate of fish was higher and subsequently decreased faster, when compared to those feeding under low prey densities. At high prey densities, two factors are involved : that of high prey encounter rates and also the attainment of food satiation at a faster rate. Across all prey densities, the feeding rates of fish reached a plateau after satiation. The swimming speed was noted as being directly related to the level of satiation. After satiation, the fish fed at a steady rate irrespective of prey density. However, the swimming speed of fish varied significantly in relation to prey density. It was found that the maximum feeding rates depend upon and show a marked variation with average prey distance.

在湖泊的沿海区域中，大型植物具有相当大的结构变化，并通过阻碍捕食者觅食为猎物群落提供保护。在一系列的实验室实验中，研究了浮游生物（pseudorasbora parva）的游泳和喂养行为，并研究了模拟淹没的植被的一系列实验室实验。猎物的可用性与0.5、1、2、5、10和25猎物不同。LィイD1-1ィエD1。随着茎密度逐渐增加，相对于在开水中的进食，捕食者的觅食效率降低了。此外，饲喂速率和游泳速度的良好关系与平均茎距离与鱼体长度的比率存在良好的关系。当鱼体长度比接近0.7时，记录了进食和游泳的突然减少，大约等于一条鱼的长度。经过36个小时的剥夺，在不同的猎物密度下研究了伪虫的喂养和游泳行为。最初的喂养率显示了与猎物可用性有关的标志变化。在高密度下，与低猎物密度下的饲料相比，鱼的初始进食率更高，随后降低了。在较高的猎物密度下，涉及两个因素：高猎物遇到的速度以及以更快的速度达成食物饱食的因素。在所有猎物密度中，满意后的鱼类饲料率达到了平稳状态。游泳速度被认为与满意度直接相关。满意后，无论猎物密度如何，鱼都以稳定的速度喂食。但是，鱼的游泳速度与猎物密度相关。发现最大进食率取决于并显示出平均猎物距离的明显变化。