Reproduction and growth of the Arctic hyperiid amphipod Themisto libellula Mandt
Reproduction and growth of the Arctic hyperiid amphipod Themisto libellula Mandt
复制标题
北极超类片脚类 Themisto libellula Mandt 的繁殖和生长
作者：
J. A. Percy
摘要超甲片脚类动物 Themisto libellula 在北冰洋中大量存在，是鱼类、鸟类和哺乳动物的重要猎物。由于缺乏冬季系列，对其生命周期的描述受到了阻碍。在这项研究中，连续五年在冬季、春季和夏季对居住在弗罗比舍湾水柱上部 30 m 的那部分超级鱼类种群进行了定期采样。在一年的冬季和春季采集中，出现了大量的产卵雌性。这些样本提供了有关北极 T. libellula 的繁殖时间、成熟大小、繁殖力、胚胎发育、孵化、释放和生长速度的新信息。产卵雌性的平均长度为23.3毫米。这和夏季约6毫米/月的生长速度表明它们一岁时就可以繁殖。卵在二月初之前产下，虽然一些幼崽最早可能在三月中旬从有袋动物中释放出来，但大多数在四月和五月期间释放。繁殖力与雌性身长显着相关，平均长 23 毫米的个体有 275 个胚胎。特定大小的繁殖力与温带和亚热带水域的金丝桃类相似。
SummaryThe hyperiid amphipod, Themisto libellula, is abundant in Arctic seas and is an important prey for fish, birds and mammals. Characterization of its life cycle has been hampered by the lack of winter collections. In this study, that portion of the hyperiid population inhabiting the upper 30 m of the water column in Frobisher Bay was sampled periodically in winter, spring and summer during five consecutive years. In one year the winter and spring collections included large numbers of ovigerous females. These samples provide new information about timing of reproduction, size at maturity, fecundity, embryonic development, hatching, release and rate of growth of T. libellula in the Arctic. The average length of the ovigerous females was 23.3 mm. This and the summer growth rate of about 6 mm/month indicates that they can reproduce when one year old. Eggs are laid prior to early February, and although some young may be released from the marsupium as early as mid-March, most are liberated during April and May. The fecundity is significantly correlated with female length and an average 23 mm long individual had 275 embryos. The size-specific fecundity is similar to that of hyperiids from temperate and subtropical waters.