|Low tide terrace of Yorkeys Knob Beach is prime swash fauna habitat, even for mole crabs|
Each beach has its own wave and sand characteristics and the fauna present vary greatly. In North Queensland, there is a spectrum of beaches from steep beaches with coarse sand and almost flat beaches with fine sand. The best beaches for fauna are the beaches between the two extremes. Most of the swash fauna migrate up and down the beach with the tides, probably to escape predation. When a beach is very flat, the distances between high and low tide swash zones becomes very far and the swash becomes so slow and gentle that it does not liquefy the sand. Most of the migrating swash fauna also need the sand to be mobilised or liquefied by waves so that they can burrow into it. Burrowing into hard packed sand is very difficult for many creatures. At the other end of the spectrum are steep beaches with coarse sand where waves crash down hard on bare sand. Very little fauna can be found in these beaches. Beaches that do not have swash such as beaches within river mouths also do not have much fauna.
|Swash zone fauna do not like waves that crash down on the beach|
|Pipi (Cuneate Wedge Shell, with foot and siphons exposed|
Much rarer than pipi are mole crabs. I have only ever caught one. They are neither common or easy to find. Mole crabs filter feed with their antennae.
|A mole crab - Albunea-symmysta|
|The entire undersurface of Albunea is dedicated to digging implements|
|Feeding Albunea poke their antennae into the retreating swash|
|Head and palps of filter feeding worms, click to enlarge as they are hard to see|
|The filter feeding worms are quite small|
|However the spionid? worms cover the beach|
|Common Moon Crab - Matuta victor|
When the tide retreats, the swash zone also provides food for ghost crabs and pied oystercatcher.
|Pied Oystercatcher feeding on Wedge Shells|
|Baby horn-eyed ghost crab|
|Shrimp dug up in swash zone|
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