Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Department of Estuarine and Delta Systems, PO Box 140, 4400AC, Yerseke, the Netherlands; Ghent University, Department of Biology, Marine Biology Section, Krijgslaan 281/S8, 9000, Ghent, Belgium.
Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700CC, Groningen, the Netherlands.
Mar Environ Res. 2020 Jul;159:104964. doi: 10.1016/j.marenvres.2020.104964. Epub 2020 Mar 26.
In this study, we analysed the benthic effects of two in situ fisheries disturbance experiments using a combination of side-scan sonar, high definition underwater video, sediment profile imagery, and box core sampling techniques after conventional beam trawling and box core sampling after electric pulse trawling in a southern North Sea habitat. Acoustic and optical methods visualised the morphological changes induced by experimental beam trawling, showing the flattening and homogenisation of surface sediments. Video transects found a 94% decrease in epibenthos in beam trawled sediments compared to an untrawled control site and a 74% decrease in untrawled sediments of the same transect. Box core samples taken 5.5 h, 29 h and 75 h after trawling detected a downward trend in infaunal densities and species richness that continued after the initial impact with small-bodied and juvenile taxa being especially prone to depletion. Data from shallow sediment samples showed trawl resilience in large mud shrimps and evidence of their upward movement towards the sediment surface after disturbance. Both trawl gears induced significant changes to infaunal communities, with no differential effect between the two gears. Our results suggest that in the Frisian Front, trawling may favour the survival of deep burrowers while removing surficial macrofauna.
在这项研究中，我们结合使用侧扫声纳、高清水下视频、沉积物柱状图像和箱式芯采样技术，对两个原位渔业干扰实验的海底效应进行了分析。这两个实验分别是在北海南部栖息地进行的传统桁拖网和电脉冲拖网之后。声学和光学方法直观地显示了实验桁拖网引起的形态变化，使表层沉积物变得平坦和均一。视频横切发现，与未拖网的对照点相比，桁拖网沉积物中的底栖生物减少了 94%，而同一横切线上未拖网的沉积物减少了 74%。在拖网后 5.5 小时、29 小时和 75 小时采集的箱式芯样本显示，底栖动物密度和物种丰富度呈下降趋势，在最初的冲击后仍在继续，小型和幼年类群特别容易耗尽。来自浅层沉积物样本的数据表明，桁拖网对大型泥虾具有恢复力，并且在受到干扰后有向上移动到沉积物表面的证据。两种拖网渔具都对底栖动物群落产生了显著的影响，但两种渔具之间没有差异。我们的研究结果表明，在弗里斯兰前缘，拖网可能有利于深穴生物的生存，同时去除表层大型动物。
