Sharks are viviparous, oviparous and also ovoviviparous.
[..] There are over 500 species of shark living in waters around the world and the majority give birth to live young. The remainder are oviparous, meaning they lay eggs. [..]
[..]Whale sharks (Rhincodon typus) are the largest species of shark. Although these animals produce eggs, they don't lay them. Instead, the young hatch while still in the female's body and are born as miniature adults. This is known as ovoviviparity.[..] In some species, the female will produce unfertilised eggs, which are eaten by embryos. This is known as oophagy ('egg eating') and occurs in species including the shortfin mako (Isurus oxyrinchus) and bigeye thresher sharks (Alopias superciliosus).
Embryos of other sharks survive by feeding on their smaller siblings. This is called intrauterine cannibalism or sometimes as embryophagy ('embryo eating'). This is known to occur in sand tiger sharks (Carcharias taurus).
Placental viviparity occurs in some species of shark - once the yolk sac has been depleted, it attaches to the uterine wall, acting as a pseudoplacenta.[..]
Addendum to previous comment: I am reminded of Leviathans of Jupiter by Ben Bova(we lost him to covid pneumonia and stroke on 29 nov 2020)
The Leviathans..city sized sentient whale like creatures that replicate by splitting themselves ..a process called ‘budding’. A very enjoyable read. This thread made me look it up to read again. If you like good old fashioned sci-fi, I recommend it. It’s part of Ben Bova’s Grand Tour series.
[..] There are over 500 species of shark living in waters around the world and the majority give birth to live young. The remainder are oviparous, meaning they lay eggs. [..]
[..]Whale sharks (Rhincodon typus) are the largest species of shark. Although these animals produce eggs, they don't lay them. Instead, the young hatch while still in the female's body and are born as miniature adults. This is known as ovoviviparity.[..] In some species, the female will produce unfertilised eggs, which are eaten by embryos. This is known as oophagy ('egg eating') and occurs in species including the shortfin mako (Isurus oxyrinchus) and bigeye thresher sharks (Alopias superciliosus).
Embryos of other sharks survive by feeding on their smaller siblings. This is called intrauterine cannibalism or sometimes as embryophagy ('embryo eating'). This is known to occur in sand tiger sharks (Carcharias taurus).
Placental viviparity occurs in some species of shark - once the yolk sac has been depleted, it attaches to the uterine wall, acting as a pseudoplacenta.[..]
https://www.nhm.ac.uk/discover/do-sharks-lay-eggs.html