Spawning starfish. Chocolate chip starfish (Protoreaster nodosus) about to spawn. These knobbled echinoderms produce either sperm or eggs on each of their five arms, depending on their sex. During the reproductive period these are released into the water, where fertilisation occurs. One female starfish can release around 2.5 million eggs every time she spawns. Each fertilised egg hatches into a larva, which later metamorphoses into a five-armed adult. Photographed off Sabah, Malaysia.