Shell Beach
Interesting facts
- Shell Beach is one of very few beaches in the world made almost entirely of shells rather than sand.
- Each Shark Bay cockle grows to only about 14 millimetres long, yet live populations can reach some 4,000 animals per square metre.
- The cockle lives only about a year and spawns once annually, so each generation is a single age group.
- Like giant clams, the Shark Bay cockle hosts photosynthetic algae in its tissues that feed it with sugars alongside the plankton it filters.
- The water of L'Haridon Bight can hold up to twice as much dissolved salt as the open ocean, which keeps most of the cockle's predators away.
- The cockle lives in shallow water down to about 6.5 metres and ranges along Western Australia from the Dampier Archipelago to the Houtman Abrolhos Islands.
Why it is worth it
Where the sand should be, there is none: along the shore of L'Haridon Bight in Shark Bay, the white strip between the red scrubland and the turquoise water is made almost entirely of tiny shells. They belong to a single species, the Shark Bay cockle, Fragum erugatum, a small burrowing mollusc found only in Western Australia, and they lie heaped along some 60 kilometres of coast. In places the shell bank reaches seven to ten metres in depth, and it crunches underfoot rather than giving like sand.
The reason for such abundance lies in the water itself. Shark Bay is hot and dry, evaporation far outstrips rainfall, and dense seagrass meadows slow the tidal exchange with the open ocean, so the shallow bays become hypersaline, roughly one and a half to two times saltier than normal seawater. Few of the cockle's predators tolerate those conditions, while the cockle thrives, and over thousands of years its empty shells have washed up and accumulated along the eastern side of the Taillefer Isthmus. The same salty water a little further south-east, in Hamelin Pool, shelters some of the world's most diverse living marine stromatolites.
Deeper in the deposit the shells have compacted and cemented into a soft limestone known as coquina. In the early 1900s it was cut into blocks and used as building stone, and several historic buildings in the nearby town of Denham, among them St Andrew's Church and the Old Pearler, were built from it. Today cutting is tightly controlled and permitted only to repair existing shell-block buildings. The beach lies within Shell Beach Conservation Park and within the Shark Bay World Heritage Area, inscribed by UNESCO in 1991 and the first such site in Western Australia.
Getting there
Shell Beach lies about 45 km south-east of Denham, the administrative town of Shark Bay, on the road that links Denham with the North West Coastal Highway at the Overlander Roadhouse. The nearest larger city is Geraldton, about 300 km to the south. Shark Bay Airport (MJK) at Denham is about 40 km away.
On these lists
-26.21500, 113.77361per Wikidata