Peak mating and breeding period of the humpback whale - (Megaptera novaeangliae) in Okinawa Island, Japan.
Peak mating and breeding period of the humpback whale - (Megaptera novaeangliae) in Okinawa Island, Japan.
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DOI：
10.4236/ojas.2016.63022
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发表时间：
2016-01-01
期刊：
影响因子：
--
通讯作者：
Uchida, S.
中科院分区：
文献类型：
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作者：
Kobayashi, N.;Okabe, H.;Uchida, S.
虽然在繁殖区制定有效和可持续的观鲸计划需要详细的座头鲸繁殖生态知识，但对该物种的繁殖生态仍知之甚少。因此，我们研究了座头鲸在冲绳的迁徙时间，冲绳是座头鲸的繁殖地之一，通过区分繁殖状态(雄性、雌性或雌性有一只幼鲸)、群体组成(单胞胎、双胞胎或三头以上的鲸鱼)和群体类型(歌唱者或竞争群体)来评估繁殖活动的高峰期。从1991年到2012年，总共进行了1192天的照片识别调查，在调查期间总共发现了7366头座头鲸。其中，性别决定鲸1284头(雄性848头，雌性147头，雌性289头)，观察到1138头独生鲸，1416对和710群3头以上的鲸鱼。雌性无小牛一般发生在1月下旬至2月下旬，这是繁殖季节的开始，在这一时期观察到雄性和雌性配对最频繁。在此期间，也观察到了由雌性和雄性组成的与交配相关的行为群体--竞争性群体的出现高峰期。这些结果表明，冲绳座头鲸的交配高峰期出现在1月下旬至2月下旬。有小牛的雌性从2月中旬到繁殖季节结束时趋于增加，在3月下旬保持了较高的单位努力视力(SPUE)值。因此，我们认为，冲绳的那个时期可能是分娩和新生儿护理的高峰期。这些发现扩大了我们对冲绳水域座头鲸繁殖生态的认识。
Although detailed knowledge on breeding ecology of humpback whales is required for developing effective and sustainable whale watching programs in breeding areas, the breeding ecology of this species is still poorly understood. Hence, we examine the migratory timing of humpback whales in Okinawa that is one of their breeding ground, distinguishing the reproductive status (male, female, or female with a calf), group compositions (singleton, pair, or whales more than three) and group types (singer or competitive group) in order to assess the peak period of breeding activities. A total of 1192 days of photo-identification surveys were conducted from 1991 to 2012 and a total of 7366 humpback whales were sighted during the surveys. Among them, 1284 whales were sex-determined (848 males, 147 females and 289 females with a calf), 1138 singletons, 1416 pairs and 710 groups of more than three whales were observed. Females without calves tended to occur from late January to late February, which was the beginning of the breeding season and male-female pairs were observed most frequently during this period. The peak occurrence of competitive group which was considered a mating-related behavior group, formed by females and males, was also observed during this period. These results indicated that humpback whales peak mating period in Okinawa occurred between late January and late February. Females with a calf tended to increase from mid-February toward the end of the breeding season maintaining a high sighting per unit effort (SPUE) value in late March. We, therefore, suggested that the peak time of birthing and newborn care was probably that period in Okinawa. These findings extended our knowledge on the reproductive ecology of humpback whales in Okinawan waters.