Yabby ()

The Lyrebird

This wide spread crustacean looks a lot like a smaller version of the more well known lobster.  It can be found in dams, rivers, steams and swamps throughout Victoria and New South Wales.  It is known as the destructor because of it's habit of digging holes of up to 2 meters, (6.5 feet), deep in dams and causing a lot of damage. This crayfish can live in incredible conditions.  It can handle water between 1 and 35 degrees Celsius, (34 to 95 degrees Fahrenheit).  Its comfort range is situated between 20 and 25 degrees Celsius, (68 to 77 degrees Fahrenheit), though so anything lower will make it fall into a state of hibernation and anything higher will ultimately lead to its death.  The color of their shells varies a lot depending on the color of the water they live in.  Muddier water will produce darker olive colored Yabbies and clearer water will have beautiful blue colored Yabbies. 

Spawning season depends a lot on the temperature of the water they are in so normally starts in the spring when the water reaches 15 c.  Fertilized eggs are green in colour and measure about 2 millimeters, (0.08 inches), in length.  The female Yabby will carry the 100 to 1000 eggs depending on her size in a little compartment she makes by curving her tail under herself.  She waits for the babies to hatch before releasing them. This usually takes between 19 and 40 days depending on the temperature of the water. 

The Yabby will moult as it grows.  Babies will moult every few days and adults maybe  twice a year.  When they lose a layer of shell, the underneath layer is soft at first.  The Yabby will take in water to make itself bigger so that when the shell hardens and it releases the water it will have room to grow.  To produce a new shell they need calcium so it is not uncommon that they will eat their old shell to use that calcium for the new shell.  The color of the new shell can be different than the last if the water they are in has changed.

Just like us, Yabbies are omnivorous. They will normally eat rotting plants but will also eat some meat off dead fish.  Since they are very territorial they will fight if they feel crammed and will even eat each other to survive.

Further Information on the Yabby:

Bibliography:

Http://www.growfish.com.au/Grow/Files/fn082.pdf
http://australian-animals.net/yabby.htm
http://www.nativefish.asn.au/yabby.html
http://www.abc.net.au/creaturefeatures/facts/yabby.htm