The population size structure, vertical distribution, gonad maturation, individual fecundity and embryonic development of the chaetognath Eukrohnia hamata were studied in the northernmost part of its distribution area, the Arctic Ocean. Analysis was based on stratified zooplankton samples collected in the Canada Basin during July 2005 that covered the depth range from the surface down to the bottom (or 3000 m). E. hamata abundance averaged 1087 ind. m^-2 (0.8% of zooplankton community), while their biomass averaged 379 mg DW m^-2 (10% of community biomass). Individual length of E. hamata ranged from 2 to 41 mm. Younger juvenile specimens <10 mm comprised ~80% of the population, while specimens >20 mm contributed only 5%. Size of the mature specimens, carrying 2 ovoid egg-sacs within a marsupium, varied between 24 and 38 mm. E. hamata was encountered down to 1000 m depth, but was absent from deeper layers. Specimens with eggs or developing embryos in the marsupium, as well as the smallest young specimens of 2–3 mm, were found predominately between 300 and 750 m depths. Juveniles 4–6 mm and 7–12 mm long showed a clear preference for the depth layer between 100-500 m and 50–500 m, respectively, suggesting an upward ontogenetic migration of the growing specimens to the strata with richer prey densities. The peak of fully mature male, female and specimens with ruptured marsupial sacs within the lowermost portion of the species vertical range (500–750 m) indicates that the ascent of growing individuals is followed by the downward migration of mature ones for reproduction. The number of eggs and embryos in marsupial egg sacs of 63 mature specimens collected on six expeditions to the deep Arctic Ocean (1993–2016) averaged to 153 with a maximum of 266 ind^-1. For the first time, embryonic development of E. hamata from the egg until young hatching from marsupial sacs is documented. Our data provide novel insights into E. hamata ecology and distribution in the deep Arctic Ocean.

在北冰洋分布区域的最北端，研究了白蜡木Eukrohnia hamata的种群大小结构，垂直分布，性腺成熟，个体繁殖力和胚胎发育。分析基于2005年7月在加拿大盆地中收集的分层浮游动物样本，覆盖了从地表到底部（或3000 m）的深度范围。E. hamata的平均数量为1087 ind。m ^-2（浮游动物群落的0.8％），而它们的生物量平均为379 mg DW m ^-2（群落生物量的10％）。hamata的个体长度范围从2到41毫米。年龄小于10毫米的年轻标本约占总人口的80％，而直径大于20毫米的标本仅占5％。成熟的标本的大小在一个有袋动物中携带2个卵形卵囊，大小在24到38毫米之间。滨ata遇到了低至1000 m的深度，但在更深的层中却没有。在蛋壳中有卵或正在发育的胚胎的标本，以及最小的2–3 mm的年轻标本，主要发现在300至750 m的深度之间。幼体4–6 mm和7–12 mm分别显示出对100-500 m和50-500 m之间深度层的明显偏好，这表明生长中的标本向上迁移到具有更丰富猎物密度的地层。在物种垂直范围的最下部分（500-750 m）内，完全成熟的雄性，雌性和有袋囊破裂的标本的峰值表明，随着个体的成长，成年个体向下迁移以繁殖。^-1。有史以来第一次，有文献记载了从鸡蛋中分离出的大肠埃希菌（E. hamata），直到有袋囊的年轻孵化。我们的数据提供了关于北冰洋深层中哈姆埃特氏菌生态学和分布的新颖见解。