The silky shark Carcharhinus falciformis regularly associates with floating objects in the open ocean, resulting in relatively high levels of bycatch in industrial tuna purse seine fisheries using drifting fish aggregating devices (FADs). This bycatch has contributed to concerns regarding the sustainability of this fishery and its impact on silky shark populations. To investigate fishery interactions, movements of 28 silky sharks (86–235 cm TL, mean = 118 cm) fitted with pop-up and archival tags in the western Indian Ocean, between 2010 and 2012, were examined. Monthly overlap between probability surfaces of sharks and two fishery metrics (FAD-tuna catches and FAD positions) were calculated. Vertical habitat use overlapped almost entirely with operational gear depth. Horizontal movements were extensive (3–5024 km) and covered large areas of the western Indian Ocean. Monthly overlap with FAD distributions was consistently high (64.03–100%) highlighting the need for compliance with FAD design regulations to avoid entanglement. Monthly overlap with tuna catches was more variable (8.43–51.83%). The observed movement patterns suggest static spatial management measures would be have limited conservation impact, however dynamic approaches could be appropriate. Limiting fishery activities directly will likely have the greatest conservation outcomes for silky sharks in the purse seine fishery.

中文翻译：

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西印度洋热带金枪鱼围网渔业中真鲨（Carcharhinus falciformis）的运动行为和渔业相互作用

丝质鲨鱼 Carcharhinus falciformis 经常与公海中的漂浮物相关联，导致使用漂流鱼聚集装置 (FAD) 的工业金枪鱼围网渔业中的兼捕水平相对较高。这种兼捕引起了人们对这种渔业的可持续性及其对丝鲨种群的影响的担忧。为了调查渔业相互作用，研究了 2010 年至 2012 年间在印度洋西部装有弹出式和档案标签的 28 条丝质鲨鱼（86-235 cm TL，平均 = 118 cm）的运动。计算了鲨鱼概率表面和两个渔业指标（FAD-金枪鱼捕获量和 FAD 位置）之间的每月重叠。垂直栖息地使用几乎完全与操作齿轮深度重叠。水平运动很广泛（3-5024 公里），覆盖了西印度洋的大片区域。与 FAD 分布的月度重叠一直很高（64.03-100%），突出了遵守 FAD 设计法规以避免纠缠的必要性。与金枪鱼渔获量的月度重叠变化更大（8.43-51.83%）。观察到的运动模式表明静态空间管理措施对保护的影响有限，但动态方法可能是合适的。直接限制渔业活动可能会对围网渔业中的丝鲨产生最大的保护效果。与金枪鱼渔获量的月度重叠变化更大（8.43-51.83%）。观察到的运动模式表明静态空间管理措施对保护的影响有限，但动态方法可能是合适的。直接限制渔业活动可能会对围网渔业中的丝鲨产生最大的保护效果。与金枪鱼渔获量的月度重叠变化更大（8.43-51.83%）。观察到的运动模式表明静态空间管理措施对保护的影响有限，但动态方法可能是合适的。直接限制渔业活动可能会对围网渔业中的丝鲨产生最大的保护效果。