Splish Splosh Splash Rocky Shores

The inter-tidal zone is home to one of the richest marine habitats teeming with life and activity

Hear all about it!

Rocky shores are one of the richest marine habitats. Lots of organisms live in the inter-tidal zone. This is the area above water at low tide and under water at high tide. As the tide moves out tide pools are left which are then covered again when the tide moves in.

Organisms that live in this harsh environment have to be well-adapted to survive in the impact zone of the waves where they are also exposed to seawater and air. Many anchor themselves to the shore. For barnacles and mussels, this anchorage is their permanent home. Others such as limpets, sea urchins, starfish and sea anemones, can move short distances. Bryozoans and hydroids (plant-like animals with a crown of tentacles for filter feeding) have adapted flexible bodies which move with the waves from a secure anchor point. Some creatures wedge themselves tightly into rock cracks, gullies and crevices.

Rocky shores support lots of types of molluscs. The Blue Littorina Periwinkle can be found high up on the rocks where only the sea spray reaches. Black sea snails and false limpets are found on the lower, wetter rock face. Further down, bivalve mussels (molluscs with a hinged double shell) are found in clumps. Roe’s Abalone lives at the site of the greatest wave action. Its broad foot holds it firmly onto the rocks. Abalone feed by scraping off the algae covering the rocks and by reaching up to catch drifting seaweed. The Serpent’s Head Cowry Shell lives in small dips in the rock surface. The shells of cowries are kept shiny by a mantle of flesh that which extends up to cover the shell. The beautiful Ridged Abalone or Ear Shell lives on underside of rocky ledges.

Conservation Status

The waters around Rottnest Island are a designated Marine Reserve. Also, some parts of Rottnest’ rocky shores are included the Marine Sanctuary Zones shown in the Rottnest Island Marine Management Strategy (2007).
  • Extinct
  • Extinct in Wild
  • Critically Endangered
  • Endangered
  • Vulnerable
  • Near Threatened
  • Least Concerned

Protect this sensitive habitat and preserve the Island’s ecosystem by:

  • Do Not Collect coral or shells
  • Do use water wisely on the island
  • Do dispose of your litter correctly
  • Do snorkel and enjoy the marine environment