How do echinoderm parents protect their young in Antarctic and deep-sea habitats?

In Antarctic and deep-sea habitats, echinoderms often utilize direct development, a process where large, yolk-rich eggs transform directly into juveniles without passing through a free-swimming larval stage. Because these young do not disperse via the plankton, they are typically reared by the female parent through various forms of brood protection.1

Parents protect their young by keeping them in close physical proximity, which serves as a vital survival strategy in these challenging environments. Specific methods of brood protection include:1

• External retention: Young may be held on the underside of the parent’s body or clustered around the mouth, a behavior observed in some species of starfishes and sea cucumbers.1
• Specialized pouches: Some sea urchins, sea cucumbers, and asteroids possess dedicated pouches on the upper surface of their bodies where the developing young are safely housed.1

This parental care ensures that the offspring remain protected until they are sufficiently developed to survive as juveniles on the seafloor.1