The Arctic polychaete, Oligobrachia haakonmosbiensis (Family Siboglinidae), is the most abundant symbiotic species inhabiting the Haakon Mosby Mud Volcano (Norwegian Sea, depth 1250 m). Different aspects of gametogenesis, fecundity, embryogenesis, and larval development were studied using biometric measurements, classical histology, and scanning electron microscopy on specimens (n = 15) collected in July 2009 at two sites (72° 00.28′ N, 14° 43.36′ E; 72° 00.33 ′N, 14° 43.22′ E). Several cohorts of oocytes, from oogonia to mature oocytes were observed in brooding females. Embryos with 16–64 cell divisions, trochophore and metatrochophore larvae, were found, in sequence, in female tubes, from just above the tentacles to the anterior end of the tube. Trochophores had both a prototroch and a telotroch; metatrochophores had an additional ciliary band, the neurotroch, but lacked a down-stream feeding system. All female reproductive stages, oocytes, embryos, and larvae, were recovered in a single specimen suggesting the release of different batches of oocytes at least on the date of collection, which coincided with the boreal summer. Only one brooding female contained exclusively germ cells in the gonad suggesting a pause in reproduction. Fecundity was low: a maximum of 60 mature oocytes per female was counted, and if all the different stages of oocytes, embryos, and larvae were combined, a total fecundity of ~ 250–300 propagules was found in each female. This study advances knowledge of the reproductive biology of O. haakonmosbiensis and has particular significance for understanding the distribution of this ecologically important deep-sea chemosymbiotic species in the Arctic region. The new data on life-history traits are critical for modeling, and predicting dispersal potential and connectivity among cold seeps in the Arctic, which is an essential component of marine spatial management.

中文翻译：

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北极冷泉多毛纲 Oligobrachia haakonmosbiensis 的育雏策略

北极多毛类 Oligobrachia haakonmosbiensis（Siboglinidae 科）是栖息在 Haakon Mosby 泥火山（挪威海，深度 1250 m）中最丰富的共生物种。使用生物特征测量、经典组织学和扫描电子显微镜对 2009 年 7 月在两个地点（北纬 72° 00.28'、北纬 14° 43.36'）收集的标本（n = 15）进行了配子发生、繁殖力、胚胎发生和幼虫发育的不同方面的研究。 E；72° 00.33 'N，14° 43.22' E)。在育雏雌性中观察到几组卵母细胞，从卵原细胞到成熟卵母细胞。在雌性管中，从触手上方到管前端，依次发现了具有 16-64 个细胞分裂的胚胎，即滋养体和后体细胞幼虫。Trochophores 有一个 prototroch 和一个 telotroch。metatrochophores 有一个额外的睫状带，神经营养器，但缺乏下游喂养系统。所有雌性生殖阶段、卵母细胞、胚胎和幼虫都在一个标本中回收，这表明至少在收集之日释放了不同批次的卵母细胞，这与北方夏季相吻合。只有一只育雏雌性的性腺中只含有生殖细胞，这表明生殖暂停。繁殖力低：每只雌性最多计数 60 个成熟卵母细胞，如果将所有不同阶段的卵母细胞、胚胎和幼虫结合起来，每只雌性的总繁殖力约为 250-300 个繁殖体。这项研究增进了对 O. haakonmosbiensis 生殖生物学的认识，对于了解这种具有重要生态意义的深海化学共生物种在北极地区的分布具有特殊意义。