Dulau Violaine, Pinet Patrick, Geyer Ygor, Fayan Jacques, Mongin Philippe, Cottarel Guillaume, Zerbini Alexandre, Cerchio Salvatore
GLOBICE, Saint Pierre, 97410 Réunion.
Parc National de la Reunion, Plaine des Palmistes, 97431 Réunion.
Mov Ecol. 2017 May 1;5:11. doi: 10.1186/s40462-017-0101-5. eCollection 2017.
Humpback whales are known to undertake long-distance migration between feeding and breeding sites, but their movement behavior within their breeding range is still poorly known. Satellite telemetry was used to investigate movement of humpback whales during the breeding season and provide further understanding of the breeding ecology and sub-population connectivity within the southwest Indian Ocean (SWIO). Implantable Argos satellite tags were deployed on 15 whales (7 males and 6 females) during the peak of the breeding season in Reunion Island. A switching-state-space model was applied to the telemetry data, in order to discriminate between "transiting" and "localized" movements, the latter of which relates to meandering behavior within putative breeding habitats, and a kernel density analysis was used to assess the spatial scale of the main putative breeding sites.
Whales were tracked for up to 71 days from 31/07/2013 to 16/10/2013. The mean transmission duration was 25.7 days and the mean distance travelled was 2125.8 km. The tracks showed consistent movement of whales from Reunion to Madagascar, demonstrating a high level of connectivity between the two sub-regions, and the use of yet unknown breeding sites such as underwater seamounts (La Perouse) and banks (Mascarene Plateau). A localized movement pattern occurred in distinct bouts along the tracks, suggesting that whales were involved in breeding activity for 4.3 consecutive days on average, after which they resume transiting for an average of 6.6 days. Males visited several breeding sites within the SWIO, suggesting for the first time a movement strategy at a basin scale to maximize mating. Unexpectedly, females with calf also showed extensive transiting movement, while they engaged in localized behavior mainly off Reunion and Sainte-Marie (East Madagascar).
The results indicated that whales from Reunion do not represent a discrete population. Discrete breeding sites were identified, thereby highlighting priority areas for conservation. The study is a first attempt to quantify movement of humpback whales within the southwestern Indian Ocean breeding range. We demonstrate a wandering behavior with stopovers at areas that likely represent key breeding habitat, a strategy which may enhance likelihood of individual reproductive success.
座头鲸已知会在觅食地和繁殖地之间进行长途迁徙，但其在繁殖范围内的移动行为仍鲜为人知。利用卫星遥测技术研究座头鲸在繁殖季节的移动情况，以进一步了解西南印度洋（SWIO）内的繁殖生态和亚种群连通性。在留尼汪岛繁殖季节高峰期，对15头鲸鱼（7头雄性和6头雌性）部署了可植入的Argos卫星标签。将切换状态空间模型应用于遥测数据，以区分“过境”和“本地化”移动，后者与假定繁殖栖息地内的蜿蜒行为有关，并使用核密度分析来评估主要假定繁殖地的空间尺度。
从2013年7月31日至2013年10月16日，对鲸鱼进行了长达71天的跟踪。平均传输持续时间为25.7天，平均移动距离为2125.8公里。跟踪结果显示鲸鱼从留尼汪岛持续移动到马达加斯加，表明这两个次区域之间具有高度连通性，并且鲸鱼会利用诸如水下海山（拉佩鲁斯）和海堤（马斯卡林高原）等未知的繁殖地。在跟踪路线上出现了明显的局部移动模式，这表明鲸鱼平均连续4.3天参与繁殖活动，之后它们平均恢复过境移动6.6天。雄性鲸鱼访问了西南印度洋内的多个繁殖地，首次表明了一种在盆地尺度上的移动策略，以最大化交配机会。出乎意料的是，带幼崽的雌性鲸鱼也表现出广泛的过境移动，而它们主要在留尼汪岛和圣玛丽岛（马达加斯加东部）附近进行局部行为。
结果表明，来自留尼汪岛的鲸鱼并不代表一个离散的种群。确定了离散的繁殖地，从而突出了保护的优先区域。该研究首次尝试量化座头鲸在西南印度洋繁殖范围内的移动情况。我们展示了一种在可能代表关键繁殖栖息地的区域中途停留的游荡行为，这种策略可能会提高个体繁殖成功的可能性。
