Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understanding their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Significant vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps towards incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasising the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.明晰板鳃亚纲动物（elasmobranchs）的三维运动模式，对理解其生态角色与人为压力暴露风险至关重要。迄今为止，全球尺度下的物种间比较研究大多聚焦于水平运动。本研究通过整合针对38种板鳃亚纲动物部署的989个生物遥测标记（biotelemetry tags）所获数据，首次完成了板鳃亚纲动物垂直栖息地利用情况的全球综合分析，填补了垂直运动相关的研究空白。板鳃亚纲动物的垂直运动模式存在显著的种内与种间变异。诸多大洋表层（epipelagic）板鳃亚纲动物存在显著的垂直空间重叠，这意味着它们更易出现空间重合、产生生物交互，并面临类似的、随垂直梯度变化的人为威胁风险。本研究强调了将垂直运动纳入板鳃亚纲动物全球管理与监测策略的关键后续方向，并着重指出，需解决标记部署中的地理与分类学偏差问题，同时统筹水平与垂直运动的综合监测与管理。