Rocks and boulders provide a hard substrate upon which marine organisms can colonise and grow, additionally when the tide is out they act as refugees by providing shade and shelter.
|  | 
| Common limpets (Pattella vulgata) congregate in the shade of boulder overhangs 
 
 | 
Look beneath boulder overhangs, in crevices and on the undersides of small boulders to observe the under-boulder communities comprised of fishes, molluscs, crustaceans, cnidarians, sponges, bryozoans and polychaetes worms.
|  | 
| Under-boulder community | 
|  | 
| Green shore crab (Carcinus maenas) found under a boulder | 
|  | 
| Blenny (Lipophyrys pholis) found under a boulder |