Depending on species, sea anemones reproduce either sexually or asexually. During sexual reproduction, eggs and sperm are released through the mouth. Asexual reproduction occurs through longitudinal fission, binary fission or pedal laceration. Sea anemones do not have a free-swimming larval form, but instead develop an egg that once fertilized becomes first a planula and then a sedentary polyp.
In sea anemones that reproduce sexually, some species have separate sexes while others are protandric hermaphrodites, which are males that later change into females. Sexually reproducing anemones often breed during the summer, coinciding with warm surface water temperatures. Warm waters cause males’ gonads to enlarge on their internal mesenteries. When the gametes mature, males stimulate females to release eggs. The fertilized egg grows into a planula, settles on an object and forms a polyp, the nw anemone.
Sea anemones that reproduce asexually through longitudinal or binary fission split in half along their length to make two fully-formed individuals. When sea anemones reproduce through pedal laceration, pieces of their pedal disc, their central support, break off, settle and grow into new anemones. Because sea anemones are mostly sedentary, parents and offspring grow near each other, forming colonies that sometimes live and grow for decades.