Foraging movements of great frigatebirds from Aldabra Island: Relationship with environmental variables and interactions with fisheries
Foraging movements of great frigatebirds from Aldabra Island: Relationship with environmental variables and interactions with fisheries
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阿尔达布拉岛大型军舰鸟的觅食活动：与环境变量的关系以及与渔业的相互作用
DOI：
10.1016/j.pocean.2010.04.003
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发表时间：
2010
影响因子：
4.1
通讯作者：
F. Marsac
中科院分区：
文献类型：
--
作者：
H. Weimerskirch;M. Corre;Emilie Tew Kai;F. Marsac
大军舰鸟（Fregata minor）是一种大型热带海鸟，主要依靠金枪鱼或鲸目动物等水下捕食者来捕获猎物。本文研究了在印度洋最大的群体阿尔达布拉岛（9.4°S，46.4°E）上繁殖的14只军舰鸟的觅食运动。这个群体位于距离主要渔场500多公里的地方，那里是一个非常重要的以水面金枪鱼为目标的工业围网渔业。尽管军舰鸟的飞行速度很慢（16公里每小时-1），但它们在繁殖时能够在距离殖民地1000公里以上的地方觅食，在海洋沃茨上使用2500- 4750公里长的觅食圈。所有的旅行都是从岛的北部到赤道。觅食的较量，表明降低飞行速度，是罕见的，并位于整个行程。觅食点往往是更频繁的表面叶绿素浓度较高，并与一些气旋性涡旋。然而，中尺度活动是相对较弱的阿尔达布拉和赤道和叶绿素的变化主要是风混合过程中的西南季风的结果。这些结果表明，军舰鸟觅食广泛分布的资源，以北部的阿尔达布拉。最北端的觅食区位于围网渔场附近，但军舰鸟和金枪鱼船队之间没有明显的重叠。该研究的结果与欧罗巴岛（22.3°S，40.3°E）的另一个种群的结果进行了比较，那里的鸟类在可预测的特征上觅食，即莫桑比克海峡标记的气旋漩涡边缘。我们讨论的后果，人口的依赖对比海洋条件觅食策略和生活史的演变，这些长寿的动物在不断变化的气候，以及过度捕捞对军舰鸟种群的可能影响。
Great Frigatebirds (Fregata minor) are large tropical seabirds that rely primarily on sub-surface predators such as tunas or cetaceans to capture their prey. We studied the foraging movements of 14 Great Frigatebirds breeding on Aldabra Island (9.4°S, 46.4°E), the largest colony in the Indian Ocean. This colony is located at more than 500km from the main fishing grounds of a very important industrial purse-seine fishery targeting surface-dwelling tunas. Despite their slow flight speeds (16kmh−1), frigatebirds are able to forage at more than 1000km from the colonies when breeding, using 2500–4750km long foraging loops over oceanic waters. All trips were directed to the north of the island up to the equator. Foraging bouts, indicated by reduced flight speeds, were rare and located throughout the trips. Foraging spots tended to be more frequent on higher surface chlorophyll concentration and in association with some cyclonic vortices. However, mesoscale activity is relatively weak between Aldabra and the equator and the chlorophyll variability is mostly the result of wind-mixing processes during the southwest monsoon. These results suggest that frigatebirds forage for widely distributed resources to the north of Aldabra. The northernmost foraging bouts were located in the vicinity of the purse-seine fishing grounds, but without a significant overlap between frigatebirds and tuna fleets. The results of the study are compared with those from another population at Europa Island (22.3°S, 40.3°E) where birds were foraging on predictable features, the edge of cyclonic eddies that are marked in the Mozambique Channel. We discuss the consequences of the reliance of populations on contrasted oceanographic conditions on foraging strategies and on the evolution of life histories in these long-lived animals in a changing climate, as well as the possible effects of overfishing on frigatebird populations.