Abstract
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.
Highlights
The Greenland shark (Somniosus microcephalus, Squaliformes: Somniosidae) is a long-lived and migratory top predator [1,2,3]
We provide the first statistical analyses of body length-at-maturity, quantitative descriptions of reproductive parameters as well as estimate fecundity, body length-at-birth and elucidate the reproductive cycle of the Greenland shark
That body length-at-first maturity for males is 2.7 m TL and TL50 2.86 m, which is less than that suggested by Yano et al [8]
Summary
The Greenland shark (Somniosus microcephalus, Squaliformes: Somniosidae) is a long-lived and migratory top predator [1,2,3]. Considering the high historical and modern fishing pressures on Greenland sharks [4, 5], pertinent questions arise concerning population size and proper conservation actions across its main distribution area throughout the Arctic [6]. When evaluating the reproductive biology of live-bearing sharks, and in particular the reproductive output of a Squaliform shark, it is important to differentiate between ovarian fecundity and uterine fecundity. Ovarian fecundity refers to the number of unfertilized, ripe ova in the ovaries, whereas uterine fecundity is the number of fertilized ova/developing pups in the uterus. Beside the study by Yano et al [8], where body length-at-maturity was estimated
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
