Greenland Institute of Natural Resources, Nuuk, Greenland.
Faculty of Biosciences, Fisheries and Economics, UiT The Arctic University of Norway, Tromsø, Norway.
PLoS One. 2020 Oct 7;15(10):e0238986. doi: 10.1371/journal.pone.0238986. eCollection 2020.
The Greenland shark (Somniosus microcephalus, Squaliformes: Somniosidae) is a long-lived Arctic top predator, which in combination with the high historical and modern fishing pressures, has made it subject to increased scientific focus in recent years. Key aspects of reproduction are not well known as exemplified by sparse and contradictory information e.g. on birth size and number of pups per pregnancy. This study represents the first comprehensive work on Greenland shark reproductive biology based on data from 312 specimens collected over the past 60 years. We provide guidelines quantifying reproductive parameters to assess specific maturation stages, as well as calculate body length-at-maturity (TL50) which was 2.84±0.06 m for males and 4.19±0.04 m for females. From the available information on the ovarian fecundity of Greenland sharks as well as a meta-analysis of Squaliform reproductive parameters, we estimate up to 200-324 pups per pregnancy (depending on maternal size) with a body length-at-birth of 35-45 cm. These estimates remain to be verified by future observations from gravid Greenland sharks.
格陵兰睡鲨（Somniosus microcephalus，角鲨目：睡鲨科）是一种长寿的北极顶级掠食者，由于历史上和现代捕捞压力较高，近年来成为了更多科学研究的对象。其繁殖关键方面的知识并不为人所知，例如关于产仔大小和每胎产仔数量的信息很少且相互矛盾。本研究基于过去 60 年收集的 312 个标本，首次全面研究了格陵兰睡鲨的繁殖生物学。我们提供了量化繁殖参数的指南，以评估特定的成熟阶段，并计算体长成熟度（TL50），雄性为 2.84±0.06 米，雌性为 4.19±0.04 米。根据现有的关于格陵兰睡鲨卵巢中卵子数量的信息，以及对角鲨目繁殖参数的荟萃分析，我们估计每胎怀孕的幼仔数量可达 200-324 只（取决于母体大小），出生时体长为 35-45 厘米。这些估计数有待未来对怀有身孕的格陵兰睡鲨的观察来验证。
