Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands.
Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, the Netherlands.
Sci Total Environ. 2020 Apr 20;714:136818. doi: 10.1016/j.scitotenv.2020.136818. Epub 2020 Jan 21.
Most studies on glass eel (Anguilla anguilla) migration are performed in natural estuaries, where they enter freshwater systems to live there for a period of years before they swim back again to the sea to reproduce. In these natural systems, river flows play a major role in attracting and directing migrating eels. However, coastal areas get urbanized more and more and characterized by anthropogenic barriers and hampered or artificial water flows. The effects of these flows on glass eel migration are poorly understood. Therefore, in this study glass eel were sampled at water pumping stations in a constructed part of the Rhine delta in the Netherlands. A mixed linear-effect model was used to determine effects of freshwater flows from water pumping stations on glass eel catch. We found that freshwater flows from water pumping stations had a significant but small effect on glass eel catch. Pumping activity had no significant effect on glass eel catch at sample locations with a continuous freshwater flow from fish passages. However, a low predictive value of the model and low numbers of individuals per sample prohibited strong conclusions on effects of anthropogenic freshwater flows on glass eel migration. More individual tracking techniques should be used to improve understanding migratory behavior of glass eel.
大多数关于玻璃鳗（Anguilla anguilla）洄游的研究都是在天然河口进行的，在那里，它们进入淡水系统生活数年，然后再游回大海繁殖。在这些自然系统中，河流流量在吸引和引导洄游鳗起着重要作用。然而，沿海地区的城市化程度越来越高，其特点是存在人为障碍物和阻碍或人工水流。这些水流对玻璃鳗洄游的影响还不太清楚。因此，在这项研究中，在荷兰莱茵河三角洲的一个人工部分的水泵站采集了玻璃鳗样本。使用混合线性效应模型来确定来自水泵站的淡水流量对玻璃鳗捕捞量的影响。我们发现，来自水泵站的淡水流量对玻璃鳗捕捞量有显著但很小的影响。在有鱼类通道连续淡水流的采样点，水泵活动对玻璃鳗捕捞量没有显著影响。然而，模型的预测值较低，每个样本的个体数量较少，这使得我们无法对人为淡水流对玻璃鳗洄游的影响做出有力的结论。应该使用更多的个体跟踪技术来提高对玻璃鳗洄游行为的理解。
