Nurturing Secrets of Six-Rayed Sea Stars

Aug 23, 2024

Secret Life of the Six-Rayed Sea Star

Introduction

  • A six-rayed sea star has a secret: she is nurturing her embryos and larvae beneath her body.

Life Cycle of the Sea Star

  • Embryos and Larvae:
    • Chubby embryos are hidden away.
    • Hatched larvae look different from the adult form initially.
    • Over a couple of months, the larvae will resemble their mother more closely.

Characteristics of the Sea Star

  • Physical Traits:
    • Has six arms (one more than typical sea stars).
    • Size comparable to a bottle cap.
  • Habitat:
    • Found in Northern California's intertidal zone.

Parenting Behavior

  • Brooding:
    • Unique behavior among sea stars, where the mother protects her babies under her body.
    • Unlike most sea stars that are broadcast spawners (release many eggs and sperm into the water), six-rayed sea star mothers have fewer babies and are more involved.
    • They actively clean and care for their brood, sacrificing their own feeding for approximately three months.

Development of Larvae

  • Temporary Limbs:
    • Babies initially cling to the mother using brachiola arms (stubby limbs).
  • Growth:
    • After a month, they develop new arms and tube feet, reabsorbing their temporary limbs.
  • Independence:
    • Once matured, the young sea stars venture out to find food.

Feeding

  • Adult Diet:
    • Adult sea stars consume shellfish like barnacles and snails.
  • Baby Diet:
    • Young sea stars eat smaller versions of shellfish, using their arms to capture prey and digesting them alive.

Conclusion

  • The attentive nurturing gives the six-rayed sea stars a higher chance of survival into adulthood.
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