Aggregation sites represent important sources of environmental heterogeneity and can modify the movement behavior of animals. When these sites are artificially established through anthropogenic actions, the consequent alterations to animal movements may impact their ecology with potential implications for their fitness. Floating objects represent important sources of habitat heterogeneity for tropical tunas, beneath which these species naturally aggregate in large numbers. Man-made floating objects, called Fish Aggregating Devices (FAD), are used by fishers on a massive scale to facilitate fishing operations. In addition to the direct impacts that fishing with FADs has on tuna populations, assessing the effects of increasing the numbers of FADs on the ecology of tuna is key for generating sound management and conservation measures. This study investigates the effects of increasing numbers of FADs (aggregation sites) on the movements of tunas, through the comparison of electronic tagging data recorded from 146 individuals tunas (yellowfin tuna, Thunnus albacares, and skipjack tuna, Katsuwonus pelamis) tagged in three instrumented anchored FAD arrays (Mauritius, Oahu-Hawaii and Maldives), that differed according to their distances among neighboring FADs. The effect of increasing inter-FAD distances is studied considering a set of indices (residence times at FADs and absence (travel) times between two visits at FADs) and their trends. When inter-FAD distances decrease, tuna visit more FADs (higher connectivity between FADs), spend less time travelling between FADs and more time associated with them. The trends observed for the absence (travel) times appear to be compatible with a random-search component in the movement behaviour of tunas. Conversely, FAD residence times showed opposite trends, which could be a result of social behavior and/or prey availability. Our results provide the first evidence of changes in tuna associative behavior for increasing FAD densities. More generally, they highlight the need for comparing animal movements in heterogeneous habitats in order to improve understanding of the impacts of anthropogenic habitat modifications on the ecology of wild animals.

中文翻译：

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栖息地改变对动物运动行为的影响：以鱼聚集装置（FAD）和热带金枪鱼为例

聚集点代表了环境异质性的重要来源，可以改变动物的运动行为。通过人为行动人为地建立这些场所时，随之而来的动物活动变化可能会影响其生态，并对它们的适应性产生潜在影响。漂浮的物体是热带金枪鱼栖息地异质性的重要来源，在这些物种之下，这些物种自然会大量聚集。渔民广泛使用人造鱼漂浮物，称为鱼聚集装置（FAD），以便利捕鱼活动。除了使用FADs捕捞对金枪鱼种群产生直接影响外，评估增加FADs数量对金枪鱼生态的影响对于制定合理的管理和保护措施也很关键。这项研究通过比较在三种仪器中标记的146个个体金枪鱼（黄鳍金枪鱼，白金枪鱼和skip鱼，skip鱼，白鳍金枪鱼）记录的电子标签数据的比较，研究了FAD（聚集部位）数量增加对金枪鱼运动的影响。固定的FAD阵列（毛里求斯，瓦胡岛，夏威夷和马尔代夫），根据相邻FAD之间的距离而不同。考虑到一组指标（FAD的停留时间和FAD两次访问之间的缺勤（旅行）时间）及其趋势，研究了增加FAD之间距离的影响。当FAD之间的距离减小时，金枪鱼会访问更多的FAD（FAD之间的连接性更高），花在FAD之间的时间更少，而花的时间也更多。观察到的不存在（旅行）时间的趋势似乎与金枪鱼运动行为中的随机搜索成分兼容。相反，FAD的停留时间显示出相反的趋势，这可能是社交行为和/或猎物可用性的结果。我们的研究结果提供了金枪鱼联想行为改变以增加FAD密度的第一个证据。更普遍地说，它们强调需要在异类生境中比较动物的运动，以增进对人为生境的改变对野生动物生态学影响的理解。我们的研究结果提供了金枪鱼联想行为改变以增加FAD密度的第一个证据。更普遍地说，它们强调需要在异类生境中比较动物的运动，以增进对人为生境的改变对野生动物生态学影响的理解。我们的研究结果提供了金枪鱼联想行为改变以增加FAD密度的第一个证据。更普遍地说，它们强调需要在异类生境中比较动物的运动，以增进对人为生境的改变对野生动物生态学影响的理解。