Abstract In recent years, salmon aquaculture has struggled to mitigate the impact of harmful jellyfish species in northern Europe and beyond. Typically, large aggregations of jellyfish are carried by currents through salmon pens, leading to unsustainable mortality levels in some years. One potential solution that has been regularly proposed is the creation of a ‘bubble curtain’ around fish pens. A bubble curtain is created by releasing compressed air from a perforated tube at depth, forming a plume of bubbles that entrain the water to create a vertical current. This study investigated the efficacy of a bubble curtain as a jellyfish barrier at several aquaculture locations in Ireland and in a controlled flume tank. Field tests on bubble curtains provided mixed results: a high air flow 8 m linear bubble curtain set at 5 m depth effectively deflected large compass jellyfish (Chrysaora hysoscella), whereas, a low air flow ca. 800 m circular bubble curtain set at 5 m depth, around a salmon farm, did not significantly impact the abundance of small hydromedusae on either side of the bubble curtain. Flume tank experiments demonstrated that increased wave height and increased air flow increased jellyfish transport through the curtain and the lateral movement was consistent with Stokes drift, i.e. an elliptical motion that includes forward movement with each wave. These results suggest that sites with relatively high wave energy may be unsuitable for bubble curtain use and that the variable size and shape of jellyfish may be an important factor in jellyfish and bubble curtain interactions.

中文翻译：

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野外和水槽水槽实验调查气泡帘防止有害水母进入有鳍鱼围栏的功效

摘要 近年来，鲑鱼养殖业一直在努力减轻北欧及其他地区有害水母物种的影响。通常情况下，大群的水母由水流携带通过鲑鱼围栏，在某些年份导致不可持续的死亡率水平。经常提出的一个潜在解决方案是在鱼栏周围创建一个“气泡幕”。气泡幕是通过从深处的穿孔管中释放压缩空气而产生的，形成一团气泡，夹带水以产生垂直水流。这项研究调查了在爱尔兰的几个水产养殖地点和受控水槽中气泡帘作为水母屏障的功效。气泡帘的现场测试结果喜忧参半：设置在 5 m 深度的高气流 8 m 线性气泡帘有效地偏转了大型罗盘水母（Chrysaora hysoscella），而低气流约。在鲑鱼养殖场周围设置 5 m 深的 800 m 圆形气泡幕并没有显着影响气泡幕两侧的小水螅的丰度。水槽水槽实验表明，增加的波浪高度和增加的空气流量增加了水母通过窗帘的运输，并且横向运动与斯托克斯漂移一致，即包括每个波浪向前运动的椭圆运动。这些结果表明，具有相对较高波能的地点可能不适合气泡幕的使用，并且水母的可变大小和形状可能是水母和气泡幕相互作用的重要因素。