Jellyfish do not give birth in the normal sense. The process of
releasing jellyfish ephyra into the marine column is called
strobilation.
Early in the life cycle of a jellyfish, it takes the form of a
tiny stalk attached to the seafloor, and at that point it is called
a polyp. The unattached end of this stalk forms a disk shaped bud,
that is eventually shed by a process of fission. This process
continues until dozens more of these little disks (ephyras) are
released.
This type of reproduction is obviously asexual, since each
ephyra is a clone of the others, yet a jellyfish is also sexually
reproduced, when, near the end of the adult medusa stage of life, a
jellyfish releases gametes into the water column to randomly join
another gamete from another individual jellyfish.
