Starfish, or sea stars, can reproduce sexually or asexually. During sexual reproduction, the male and female release sperm and eggs into the environment, resulting in fertilized free-swimming embryos. During asexual reproduction, a part of the arm and central disk detach from the parent and develop into an individual sea star.
The microscopic larvae resulting from sexual reproduction begin to grow and, within several months, look like adult sea stars. The swimming embryos are animals that eventually metamorphose, settle to the floor of an ocean area and develop into adults. Some species of sea stars that inhabit the polar oceans sit on their eggs or use specialized brooding baskets. Sea stars can regenerate their limbs by housing most or all of their vital organs in their arms. Some sea star species cannot regenerate without the central disk intact, but a few species can grow a new individual sea star from just a portion of a severed arm. The process of regeneration may take as long as a year.
The most well-known species of sea stars, the crown-of-thorns starfish, decimated large populations of corals in the Great Barrier Reef. Early attempts to control the population of sea stars involved chopping the sea stars into pieces.