Issue 6, 2019

Dossier of Discovery: A Seashell Smorgasbord

article by Anne Renaud , photo At Shell Beach by Bryn Pinzgauer

If you’re searching for seashells—try saying that 10 times fast—you may want to head over to Shell Beach in Western Australia’s Shark Bay, where there are billions, if not trillions, to be found!

In fact, Shell Beach is among the few beaches in the world made up entirely of seashells. No sand, just tiny shells, up to 10 metres deep in some areas.
The animal whose shell can be found in such abundance is called the Shark Bay cockle.

It is a burrowing mollusc that makes its home in a tiny bivalve shell that is less than 14 millimetres long.  These cockles can only be found in Western Australia and they burrow into the sea floor in relatively shallow areas of Shark Bay.

Shark Bay has a salinity level twice that of the ocean. This hypersalinity creates a favourable environment for the survival of some marine animals—such as cockles—as well as an unfavourable environment for its predators.

Because the Shark Bay cockle has no predators, and because it has existed in such huge numbers for thousands of years, its shells have washed ashore to create a snow-white beach that stretches nearly 70 kilometres.

Several buildings in nearby Denham and surrounding areas were built from blocks of the compacted shells. The shells are also mined for the production of calcium for poultry feed and exotic mulch for gardens and plants.