Non-indigenous species (NIS) establish and thrive on floating artificial substrata along mid-latitude shores, which might serve as propagule reservoirs and stepping stones for their dispersal. However, often, the NIS are not able to colonize the adjacent seafloor, where high predation pressure by benthic predators might inhibit them. To test this hypothesis, we quantified and compared consumption rates of standardized bait (squidpops) in four water depth zones (sea surface, sub-surface, midwaters, seafloor) in five representative regions in the Southeast Pacific, covering oceanic Rapa Nui (Easter Island; 27°S, 109°W; November 2022) as well as the Chilean continental coast (29–41°S, 71–73°W; March–June 2022). We found a strong overall effect of water zonation, with significant bait consumption being limited to the seafloor and occurring only sporadically in other depth zones. Consumption frequencies also differed between experimental regions but were not influenced by latitude or mean sea surface temperature. An analogous experiment with the NIS Ciona robusta, conducted at one sampling site, showed that the occurrence or absence of predation per site and water depth zone, but not the exact consumption rates, concurred between both bait types. Our results confirm that predation in SE Pacific temperate shallow waters mainly depends on benthic predators that cannot reach higher zones of the water column. These findings have far-reaching implications, as they indicate that predation rates in mid-latitude systems might be underestimated through commonly used water column-based experiments. For a comprehensive estimation of predation pressure in a given system, future studies should consider differences between vertical water zones.

非本土物种（NIS）在中纬度海岸的漂浮人工基质上定居并繁衍生息，这些基质可能作为繁殖体的储存库和扩散的垫脚石。然而，NIS 通常无法在邻近海底定居，底栖捕食者的高捕食压力可能会抑制它们。为了检验这一假设，我们量化并比较了东南太平洋五个代表性区域的四个水深区域（海面、次表层、中层水域、海底）标准化鱼饵（鱿鱼）的消耗率，其中包括拉帕努伊（复活节岛）海洋；南纬 27°，西经 109°；2022 年 11 月）以及智利大陆海岸（南纬 29–41°，西经 71–73°；2022 年 3 月至 6 月）。我们发现水域分区具有很强的整体影响，大量的诱饵消耗仅限于海底，而在其他深度区域仅零星发生。不同实验区域的消费频率也有所不同，但不受纬度或平均海面温度的影响。在一个采样点对 NIS Ciona robsta进行的一项类似实验表明，两种饵料类型之间是否存在每个地点和水深区域的捕食情况，但不是确切的消耗率。我们的结果证实，东南太平洋温带浅水区的捕食主要依赖于无法到达水体较高区域的底栖捕食者。这些发现具有深远的影响，因为它们表明通过常用的基于水柱的实验可能会低估中纬度系统的捕食率。为了全面估计给定系统中的捕食压力，未来的研究应考虑垂直水域之间的差异。