Genetic connectivity provides a basis for evaluating the resilience of animal communities by elucidating gene flow and serves as a proxy for realized dispersal through planktonic larval dispersal, settlement, and reproductive success. Gandalfus yunohana (Takeda, Hashimoto & Ohta, 2000) is a brachyuran crab endemic to deep-sea hydrothermal vents in the northwestern Pacific. Although an iconic and often dominant species, the connectivity among its populations is yet to be examined. We obtained barcoding sequences of the mitochondrial COI gene of G. yunohana from four vent fields including two on the Izu Arc, one on the northern Mariana Arc, and one in the Okinawa Trough. Genetic diversity of populations on the Izu and northern Mariana arcs were similar and shared the dominant haplotypes, showing no genetic subdivision regardless of the habitat depth. The Okinawa Trough population, for which only one specimen was available, was not genetically different from specimens from the Izu/Mariana arc populations. Estimation of the number of immigrants among populations suggests that the migration from north to south is higher than in the reverse direction. Our results resonate with previous laboratory-culture experiments, suggesting a high dispersal capability for G. yunohana. Visual observations and sampling, however, suggest that G. yunohana is exceedingly rare in the Okinawa Trough. This perhaps results from a lack of sufficient larval supply from the Izu-Bonin-Mariana Arc vents, and there may not be a reproductive population in the Okinawa Trough.

中文翻译：

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西北太平洋深海热液喷口的蟹Gandalfus yunohana（Takeda，Hashimoto＆Ohta，2000）（十足目：Brachyura：Bythograeidae）的种群连通性

遗传连通性通过阐明基因流为评估动物群落的复原力提供了基础，并通过浮游幼虫的散布，定居和繁殖成功实现了有效的散布。Gandalfus yunohana（竹田，桥本和大田，2000年）是特产于西北太平洋深海热液喷口的短臂蟹。尽管是标志性物种，通常是优势物种，但其种群之间的连通性尚待检验。我们获得了G. yunohana的线粒体COI基因的条形码序列。来自四个喷口区，其中两个在伊豆弧线上，一个在马里亚纳弧北部，另一个在冲绳海槽中。伊豆弧段和北马里亚纳弧上种群的遗传多样性相似，并具有优势单倍型，无论生境深度如何，均无遗传细分。冲绳海槽种群只有一个样本可用，在遗传上与伊豆/马里亚纳弧种群的样本没有遗传差异。对人口中移民数量的估计表明，从北向南的移民比反方向的移民高。我们的结果与以前的实验室培养实验产生了共鸣，表明云南假单胞菌具有很高的分散能力。肉眼观察和取样表明，G。yunohana在冲绳海槽中极为罕见。这可能是由于伊豆-波宁-马里亚纳弧喷口缺乏足够的幼体供应，并且冲绳海槽可能没有繁殖种群。