How do star fish mate?

Sea stars, commonly called starfish, exhibit diverse reproductive strategies, including both sexual and asexual reproduction. Here's a general overview of sea star reproduction:

Sexual Reproduction:

1. Spawning: During certain times of the year, usually in spring or summer, mature sea stars release their gametes, which include sperm and eggs, into the water. This process is called spawning.

2. Sperm and Eggs: Sea stars are dioecious, meaning that they have separate male and female individuals. Each individual releases either sperm or eggs into the water.

3. External Fertilization: The released sperm and eggs mix externally in the water. When the sperm encounters an egg, fertilization occurs.

4. Zygote and Development: The fertilized egg, now known as a zygote, undergoes multiple cell divisions and eventually develops into a planktonic larva. The specific type of larva varies among sea star species.

Asexual Reproduction:

1. Regeneration: Some sea stars have the ability to regenerate lost arms. Under favorable conditions, a lost arm can regrow into a new individual, resulting in asexual reproduction.

2. Fission: Certain species of sea stars, like the common starfish (*Asterias rubens*), can undergo asexual reproduction through fission. During fission, an individual sea star splits into two or more fragments. Each fragment develops into a complete new individual, thus propagating the species.

It's important to note that the specific reproductive strategies may vary among different sea star species. For some species, reproductive behavior and development can be quite complex.