Data from: Population differentiation of 2 forms of Bryde’s whales in the Indian and Pacific Oceans

Accurate identification of units for conservation is particularly challenging for marine species as obvious barriers to gene flow are generally lacking. Bryde’s whales (Balaenoptera spp.) are subject to multiple human-mediated stressors, including fisheries bycatch, ship strikes, and scientific whaling by Japan. For effective management, a clear understanding of how populations of each Bryde’s whale species/subspecies are genetically structured across their range is required. We conducted a population-level analysis of mtDNA control region sequences with 56 new samples from Oman, Maldives, and Bangladesh, plus published sequences from off Java and the Northwest Pacific. Nine diagnostic characters in the mitochondrial control region and a maximum parsimony phylogenetic analysis identified 2 genetically recognized subspecies of Bryde’s whale: the larger, offshore form, B. edeni brydei, and the smaller, coastal form, B. e. edeni. Genetic diversity and differentiation indices, combined with a reconstructed maximum parsimony haplotype network, indicate strong differences in the genetic diversity and population structure within each subspecies. Discrete population units are identified for B. e. brydei in the Maldives, Java, and the Northwest Pacific, and for B. e. edeni between the Northern Indian Ocean (Oman and Bangladesh) and the coastal waters of Japan.

准确划定海洋物种的保护单元极具挑战性，因为这类物种普遍缺乏明显的基因交流障碍。布氏鲸（Balaenoptera spp.）受到多种人为胁迫因素的影响，包括渔业兼捕、船舶撞击以及日本的科学捕鲸活动。为实现有效管理，需要清晰了解每个布氏鲸物种/亚种的种群在其分布范围内的遗传结构。本研究针对线粒体DNA控制区（mtDNA control region）序列开展种群水平分析，所用数据包括来自阿曼、马尔代夫和孟加拉国的56份新增样本，以及爪哇外海和西北太平洋的已发表序列。通过线粒体控制区的9个诊断性特征以及最大简约法系统发育分析，本研究确认了布氏鲸的2个遗传认定亚种：体型更大的远洋型亚种B. edeni brydei，以及体型更小的近岸型亚种B. e. edeni。遗传多样性与分化指数，结合重构的最大简约法单倍型网络，结果显示两个亚种内部的遗传多样性及种群结构均存在显著差异。本研究确定了分布于马尔代夫、爪哇及西北太平洋的B. e. brydei种群单元，以及北印度洋（阿曼与孟加拉国）和日本近岸海域的B. e. edeni种群单元。