Department of Aquatic Resource Management, Faculty of Fisheries, Sylhet Agricultural University, Sylhet 3100, Bangladesh; Department of Ecology and Coastal Management, Institute of Marine Sciences of Andalusia (CSIC), Campus Río S. Pedro, 11510 Puerto Real, Cadiz, Spain.
Department of Ecology and Coastal Management, Institute of Marine Sciences of Andalusia (CSIC), Campus Río S. Pedro, 11510 Puerto Real, Cadiz, Spain.
Sci Total Environ. 2019 Feb 25;653:504-511. doi: 10.1016/j.scitotenv.2018.10.375. Epub 2018 Oct 29.
Aquatic ecosystems receive run-off and discharges from different sources that lead to the accumulation of contaminants such as copper. Besides producing lethal and sub-lethal effects, copper has shown to be aversive to zebrafish (Danio rerio) by triggering avoidance response. The primary aim of the present study was to evaluate how a copper gradient could affect the spatial distribution of D. rerio by triggering avoidance, preventing recolonization and isolating populations. Secondly, to what extent the food availability in a previously avoided environment could make it a less aversive environment was assessed. A non-forced, multi-compartmented exposure system with a copper gradient (0-300 μg·L), through which fish could move, was used for the avoidance and recolonization assays. To test the effect of copper on population isolation, two uncontaminated connected zones were separated by a chemical barrier with a copper concentration of 90 μg·L (a concentration producing an avoidance of 50% - AC). Zebrafish avoided copper and the 2 h-AC was 90.8 μg·L. The recolonization was in accordance with avoidance and the relationship AC/RC (RC: recolonization concentration) was around 2.5. When food was provided in the highest copper concentration, the recolonization pattern was altered, although the distribution of the fish was not statistically different from the scenario without food. The chemical barrier formed by copper (90 μg·L) impaired the migratory potential of the fish population by 41.3%; when food was provided in the last compartment, no statistically significant trend of fish moving towards that concentration was observed. Copper might act as an environmental disruptor by triggering spatial avoidance, preventing recolonization and isolating populations in zebrafish. The present study allows simultaneously including three ecological concepts to ecotoxicological studies that have received little attention: habitat selection, recolonization and habitat chemical fragmentation.
水生生态系统接收来自不同来源的径流和排放物，导致污染物如铜的积累。除了产生致死和亚致死效应外，铜还通过触发回避反应被证明对斑马鱼（Danio rerio）具有厌恶感。本研究的主要目的是评估铜梯度如何通过触发回避、防止再殖民化和隔离种群来影响 D. rerio 的空间分布。其次，评估在先前避免的环境中食物供应的程度如何使其成为一个不那么厌恶的环境。使用具有铜梯度（0-300μg·L）的非强制、多隔室暴露系统，鱼可以通过该系统移动，进行回避和再殖民化测定。为了测试铜对种群隔离的影响，两个未污染的连接区域被化学屏障隔开，化学屏障的铜浓度为 90μg·L（产生 50%回避的浓度 - AC）。斑马鱼回避铜，2 小时的 AC 为 90.8μg·L。再殖民化与回避一致，AC/RC（RC：再殖民化浓度）约为 2.5。当在最高铜浓度下提供食物时，再殖民化模式发生了变化，尽管鱼的分布与没有食物的情况没有统计学差异。铜（90μg·L）形成的化学屏障使鱼类的迁徙潜力降低了 41.3%；当最后一个隔室提供食物时，没有观察到鱼向该浓度移动的统计上显著趋势。铜可能通过触发空间回避、防止再殖民化和隔离斑马鱼种群，作为一种环境干扰物发挥作用。本研究允许同时将三个生态概念纳入到生态毒理学研究中，这些概念很少受到关注：栖息地选择、再殖民化和栖息地化学碎片化。
