Jellyfish reproduction involves several different stages. In the adult, or medusa, stage of a jellyfish, they can reproduce sexually by releasing sperm and eggs into the water, forming a planula. In this larval stage of jellyfish life, the planula hooks on to the bottom of a smooth rock or other structure and grows into another stage of jellyfish life, the polyp—which resembles a miniature sea anemone (pictured above). During this stage, which can last for several months or years, asexual reproduction occurs. The polyps clone themselves and bud, or strobilate, into another stage of jellyfish life, called ephyra. It is this form that grows into the adult medusa jellyfish.
Written by: Ian Hiler