Yabbies usually grow to a max size of 350 gram. Yabbies have a life span of only 6- 7 years, their main predators are insect larvae, fish, , turtles, birds and water rats. Blue claw yabbies are genetically blue, but Yabbies can be any colour black, white, brown, red, green or any combination, whichever is most suitable for camouflage in the wild.
The yabby was recorded as early as 1831 in the north of the State by the Thomas Mitchell .In 1894, the Horn expedition to Central Australia found it was said 'to be eaten regularly by the wandering tribes of natives who know it as the yabber' and from yabber only the present name of 'yabby' came.
Basically, they are vegetarian but also scavenge decaying plant and animal matter.
Aquarium yabbies are excellent pets, and you can treat them the same as a gold fish. Fill the tank with water; yabbies breathe oxygen from the water. To keep your water fresher longer an aerator or filter in the tank can be used. Feed your yabbies vegetables or pellets. Each yabby requires a home, logs in the tank are important.
Yabbies have a hard exoskeleton, Yabbies are fast growing, in order to do so they must molt. Availability of food, shelter, density and water temperature are the main factors deciding their growth. Yabbies are cold blooded animals, Below 10 degree C yabbies dont feed, when water temperatures are between 22 to 28 degree C, best growth is seen in yabbies. Depending on the amount of With sufficient amount of time, dedication, effort and money, it is possible to grow your yabbies from 0 to 150mm ( 100 gram ) plus in 1 year.
Yabbies and freshwater crayfish can be successfully kept in an aquaponics system. Details:
Name: Yabby (Cherax destructor)
Distribution: Murray-Darling Basin
General Hardness: 80 – 300 ppm
Diet: Low protein
Growth: 1.5 years (50g)
Temperature: 15 – 25o C
pH: 6.5 – 8.5
Habitat
The smooth-shelled crayfishes occur in lakes, swamps, farm dams, irrigation canals and bore drains (mainly still, warm waters) and also in slow, muddy rivers. The common yabby is especially hardy and can survive many years of drought, later coming out during wet periods to feed, breed and migrate.
Yabbies have been occasionally blamed for the collapse of dam walls, only if the walls are less than 2 metres thick, and if water levels change frequently .
Environmental requirements
If its gills are kept moist, it can absorb oxygen from the air and survive for many days out of water, so complete immersion in water is not essential. To breed, it must be in water.Experiments have shown that growth is faster on a natural substrate such as mud, than on an artificial one such as plastic tanks.
WATER QUALITY
Dissolved oxygen
The yabby can tolerate very low dissolved oxygen (DO) ,water should preferably contain over 4 parts per million of DO.
Temperature
Can tolerate water temperatures from near freezing to above 35 degree Celsius.
Salinity
A salinity of 12 ppt- equal to about 35 per cent seawater – will not affect the yabby.
Hardness
To maintain strength in the shell, the water must be hard enough (as dissolved calcium)
Heavy metals: As yabby can concentrate Hg and Pb in its body without harm, that is why used
as biological indicator of environmental pollution.
pH: The water in most good yabby dams is alkaline i.e.,pH 7.5 to 10.5
Pesticides
The yabby is susceptible to herbicides and insecticides (organochlorines).
Reproduction
The reproductive or genital papillae of the male crayfish are short projections on the bases of the last pair of walking legs & the female has oval openings on the bases of the third-last pair of legs.
The female yabby reaches sexual maturity when about 9 to 10 centimetres long - the male when slightly smaller.
The female is responsible for the protection of the eggs carefully. Once maturity is reached, the female grows more slowly than the male, because of the greater effort devoted to spawning.
In spring when the water temperature reaches 15 to 16 degree Celsius, breeding begins.
Diet
Healthy yabby populations are usually found where manure is washed into farm dams from surrounding paddocks, or where cattle drop it directly into the water. Juveniles and young yabbies eat the same food as adults.
Growth
The yabby must periodically moult its shell (an exoskeleton) to grow; this type of growth is not continuous, and occurs in steps. Water temperature, available food and population density (that is, the degree of crowding), these are the determinants of growth. Growth usually suffers over about 28 degree Celsius but they can tolerate upto 35 degree Celsius.
Death and disease
Causes of death:
1) Old age
2) Injury
3) Predation (natural, cannibalism and fishing)
4) Starvation and disease, for example, Porcelain disease (also 'white tail' or 'white muscle' disease). In the aquarium
Finally we can conclude that, the yabby is an easy to keep and entertaining pet in the aquarium. Six to ten medium ones, would suit a 100-litre tank. Provide them rocks in which to hide when moulting, and a little lean meat. The yabby can live for months without eating at all, still feed them small amounts of vegetable scraps and chicken pellets now and then, and better to remove what is not eaten each day.
Yabbies breed readily. No special food is required for the young but there should be plenty of cover where juveniles can escape from the adults.To stop the yabby uprooting them while burrowing or searching for food; aquatic plants should be tied to large stones. It is better to keep the water level far enough below the top of the tank to prevent yabbies from climbing the air hose and crawling out.
Yabbies are used in Aquaculture also and yes yabbies are suitable for your tank in your Aquaponics system if all the above mentioned points about its growth, requirements, food, shelter, reproduction are kept in the mind.
