There are different kinds of crabs… and in this article we are going to discuss a few of those crustaceans found along our local shoreline and estuaries.
Mud crabs are mainly known for their table manners and are found in mangrove estuaries, tidal flats and sheltered creeks. Their diet consists of barnacles and mollusc and they also eat other crabs? Yes…they are cannibals.
Their large claws are used for crushing shellfish (and I guess other crabs), while the smaller claws are for cutting and biting. Their hindlegs are flattened for using in swimming.
Mud crabs are nocturnal feeders and usually remain in their protective burrow at night.
Eurimbula Creek, north of Round Hill Creek at Seventeen Seventy, and all adjoining waterways are closed to the harvesting of mud crabs. It is a mud crab sanctuary. For further information see the link below…
Soldier crabs as their name suggests, march in massive numbers in their blue uniforms at the low tide across the tidal mudflats at Seventeen Seventy.
Their small round blue bodies are held up high by the long jointed purple striped legs. As the army of soldiers move along, they sort through the moist sand for organic matter to feed on and then leave behind round pellets of discarded sand.
They emerge to the surface for a few hours just before low tide and burrow back into the sand using a corkscrew motion. They differ from other crabs as they walk forward instead of sideways.
Sand bubbler crabs are found in vertical burrows near the high water mark on our sheltered sandy beaches around Agnes Water and are coloured similar to the surrounding sand.
Little balls of sand radiate from their burrow as part of the crabs housekeeping duties… clearing out the sand from the burrow. The crabs have flattened broad patches on their legs which absorb oxygen from the air.
Sand bubbler crabs feed on organic matter which is sifted out from the sand pellets by using their mouthparts.
Fiddle crabs are found in muddy estuaries, mangroves and on river banks around our coast and in Gladstone.
They feed on surface organic matter on rocks and mud. It is only the male fiddle crab that has the large claw which he uses to distinguish himself from females and for courting, and also for territorial aggression with other males.
Each fiddler crab species has its own distinct wave, and a female will only mate with a crab of her own species. A male fiddler crab, on the other hand (or claw), will attempt to mate with any crab passing by including males who have lost their large claw.
Claw loss is rare as fighting is more for show and they rarely get into actual physical contact.
When it comes to telling the tide just ask a fiddler… they change colour with the tide.
Take a walk on the Wild Side
by Denise Wild