Humpback whales Megaptera novaeangliae that breed in the western North Pacific (WNP) are listed as endangered under the US Endangered Species Act. Previous research in the WNP concluded that the full extent of humpback whale breeding areas is unknown. Recovering this endangered population requires identifying all associated breeding grounds and potential threats in those locations. Prior to 2015, humpback whales were known to occur in the Mariana Archipelago (within the WNP), but their population identity and habitat use there were unknown. To determine the population identity of humpback whales in the Mariana Archipelago and whether the area serves as a breeding ground for these whales, small-boat photo-identification and biopsy sampling surveys were conducted in the southern portion of the archipelago during February and March 2015−2018. A total of 14 mother−calf pairs and 27 other non-calf whales were encountered. Seven non-calves were re-sighted in multiple years, including 4 females associated with calves in one or more years. Competitive behavior was observed in multiple years. Comparisons with other North Pacific humpback whale catalogs resulted in matches to breeding (Japan and Philippines) and feeding (Russia) grounds in the WNP. DNA profiling of 28 biopsy samples identified 24 individuals (14 females, 10 males) representing 7 mitochondrial DNA haplotypes. The haplotype frequencies from the Mariana Archipelago showed the greatest identity with the Ogasawara breeding ground and Commander Islands feeding ground in the WNP. This study establishes the Mariana Archipelago as a breeding area for endangered WNP humpback whales, which should be considered in ongoing research and conservation efforts.

中文翻译：

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发现：马里亚纳群岛濒临灭绝的北太平洋西部座头鲸失踪的繁殖地

根据美国濒危物种法案，在北太平洋西部 (WNP) 繁殖的座头鲸 Megaptera novaeangliae 被列为濒危物种。WNP先前的研究得出结论，座头鲸繁殖区的全部范围尚不清楚。恢复这种濒危种群需要确定这些地点的所有相关繁殖地和潜在威胁。在 2015 年之前，已知座头鲸出现在马里亚纳群岛（WNP 内），但它们的种群特征和栖息地用途尚不清楚。为了确定马里亚纳群岛座头鲸的种群特征以及该地区是否是这些鲸鱼的繁殖地，2015 年 2 月和 3 月期间，在该群岛南部进行了小船照片识别和活检抽样调查- 2018 年。总共遇到了 14 对母小鲸鱼和 27 其他非小鲸鱼。在多年内重新观察了七只非小牛，其中包括 4 名在一年或多年内与小牛相关的女性。多年观察到竞争行为。与其他北太平洋座头鲸目录的比较结果与 WNP 的繁殖（日本和菲律宾）和饲养（俄罗斯）地相匹配。28 个活检样本的 DNA 分析确定了 24 个个体（14 名女性，10 名男性），代表 7 种线粒体 DNA 单倍型。马里亚纳群岛的单倍型频率显示出与 WNP 中小笠原繁殖地和指挥官群岛觅食地的最大同一性。这项研究将马里亚纳群岛确定为濒临灭绝的 WNP 座头鲸的繁殖区，