The gestation period of the spiny dogfish lasts up to 2 years. Spiny dogfish are ovoviviparous, meaning that the embryos develop inside eggs inside the female, and are nourished by yolk-filled sacs. Finally, the female gives birth to 1-20 pups, each one measuring around 20 to 33 centimeters. The spiny dogfish lives to the age of 20–75 years.