WAVES volunteer – Trina, age 13 continues her series on sea life with this interesting article on Shark Eggs. Divers familiar with diving off the southern California have most likely seen these odd little objects underwater.
There are about 400 different species of shark, and 40% of them lay eggs. They are called oviparity. The eggs are in a protective egg case. When the eggs of the bamboo sharks (Hemiscylliidae), the zebra sharks (Stegostomatidae), catsharks (Scyliorhinidae) and horn sharks (Heterodontus francisci) lay eggs they are called mermaid purses. The egg case has tendrils that help it stay on coral, seaweed or the ocean floor. The horn shark eggs are pushed into the floor or into cracks between or under rocks.
In oviparous shark species, the young get their food from a yolk sac. They may take several months or even years to hatch depending on water temperature. In some species, the eggs stay inside the female for a period of time before they are laid, so that the young have a chance to develop more fully and spend less time in the egg cases before they hatch.
“Shark species that lay eggs include: Bamboo sharks, Wobbegong sharks, Carpet sharks, Horn (bullhead) sharks, Swell sharks, many Catsharks”