Distribution and Local Movement of Humpback Whales in Okinawan Waters Depend on Sex and Reproductive Status
Distribution and Local Movement of Humpback Whales in Okinawan Waters Depend on Sex and Reproductive Status
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DOI：
10.2108/zs160012
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发表时间：
2017-02-01
影响因子：
0.9
通讯作者：
Uchida, Senzo
中科院分区：
文献类型：
--
作者：
Kobayashi, Nozomi;Okabe, Haruna;Uchida, Senzo
采用样线法和照片识别法对日本西南部冲绳岛西海岸海域座头鲸的分布和局部运动模式进行了调查。2011 - 2014年进行样线调查，2006 - 2012年进行照片识别调查。在调查期间，座头鲸聚集在伊伊岛和卡拉马岛周围地区，当它们在这两个地方之间移动时，往往沿着冲绳岛的近岸海岸移动。共有496只已知性别的座头鲸被拍照确认（322只雄性，75只雌性和99只带着幼崽的雌性）。其中，24.8%被证实在同一季节内在伊岛和卡拉马群岛的地点之间本地移动。公鼠、母鼠和育仔母鼠的局部运动频率分别为41.9%、25.0%和15.1%；雄性的局部运动频率显著高于雌性和有小牛的雌性。这些结果表明，与雌性和有幼崽的雌性相比，雄性座头鲸倾向于在当地繁殖地之间更积极地移动。我们推测，雄性会寻找更多的交配机会，而有了幼崽的雌性则倾向于留在同一个地方照顾它们的幼崽。这些发现扩展了我们对冲绳水域座头鲸的栖息地利用和生殖生态的了解，这方面的了解仍然很少。
The distribution and local movement patterns of humpback whales in waters off the west coast of Okinawa Island, southwest Japan, were investigated using line transect and photo-identification methodologies. Line transect surveys were conducted from 2011 to 2014 and photo-identification survey from 2006 to 2012. During the surveys, humpback whales aggregated in the areas around Ie and Kerama Islands, and tended to travel along the inshore coast of Okinawa Island when they move locally between those two sites. A total of 496 humpback whales of the known sex were photo-identified (322 males, 75 females and 99 females with a calf). Of these, 24.8% were confirmed moving locally between the sites of Ie and Kerama Islands within the same season. Frequency rates of the local movement for males, females and females with a calf were 41.9, 25.0, and 15.1%, respectively; the frequency of local movement for males was significantly higher than that for females and females with a calf. These results indicate that male humpback whales tend to move more actively between the local breeding sites as compared to females and females with a calf. We speculate that the males search for more opportunities to mate, whereas females with a calf tend to remain in the same areas to nurse their calves. These findings extend our knowledge of the habitat use and reproductive ecology of humpback whales in Okinawan waters, which remain poorly understood.