Trudelle Laurène, Cerchio Salvatore, Zerbini Alexandre N, Geyer Ygor, Mayer François-Xavier, Jung Jean-Luc, Hervé Maxime R, Pous Stephane, Sallée Jean-Baptiste, Rosenbaum Howard C, Adam Olivier, Charrassin Jean-Benoit
Bioacoustics Team, Institut de Neurosciences Paris-Saclay (NeuroPSI), CNRS UMR 8195, Université Paris Sud, 91405 Orsay, France; Sorbonne Universités (UPMC, Univ. Paris 06)-CNRS-IRD-MNHN, LOCEAN-IPSL, 4 place Jussieu, 75005 Paris, France; Biotope, Unité Recherche et Développement, 22 Boulevard Maréchal Foch, BP 58, 34140 Meze, France.
New England Aquarium, Central Wharf, Boston, MA, USA; Woods Hole Oceanographic Institution, 266 Woods Hole Road, Woods Hole, MA 02543, USA.
R Soc Open Sci. 2016 Dec 21;3(12):160616. doi: 10.1098/rsos.160616. eCollection 2016 Dec.
Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed 25 satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioural metrics: behavioural state of 'transiting' (consistent/directional) versus 'localized' (variable/non-directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behaviour in deep waters (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males' active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviours in shallow waters and favoured high chlorophyll- concentrations. Active swimming speed accounts for a large proportion of observed movement speed; however, breeding humpback whales probably exploit prevailing ocean currents to maximize displacement. This study provides evidence that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expand the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.
评估座头鲸繁殖期的运动模式和关键栖息地特征，是对这种具有恋巢性的物种进行保护管理的前提条件。为了研究马达加斯加海域座头鲸的运动与环境条件之间的相互作用，我们在马达加斯加的东北和西南海岸部署了25个卫星标签。对于每个记录的位置，我们整理了环境变量的估计值，并计算了两个行为指标：“过境”（一致/定向）与“局部”（可变/非定向）的行为状态，以及主动游泳速度（即相对于水流的速度）。在沿海栖息地（即水深<200米及相邻区域），雌性在深水中（191±20米）且离海岸较远（14±0.6公里）时表现出局部行为，这表明它们的繁殖栖息地超出了靠近海岸线的最浅水域。雄性的主动游泳速度在浅水中降低，但环境参数并未影响它们表现出局部运动的可能性，这可能主要由社会因素主导。在海洋栖息地，雄性和雌性在浅水中均表现出局部行为，且偏好高叶绿素浓度区域。主动游泳速度占观测到的运动速度的很大比例；然而，繁殖期的座头鲸可能利用盛行的洋流来实现最大位移。这项研究提供了证据，表明通常承受巨大人类压力的沿海地区，仍然是马达加斯加海域座头鲸的核心栖息地。我们的研究结果扩展了对座头鲸在海洋栖息地的栖息地利用情况，以及对诸如洋流和叶绿素水平等环境因素变化的响应的认识。
