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The Yabby is a freshwater crayfish, also known as a crawchie, crawdad, craybob or
even lobbie, it's dependant on where you come from. These yabbies are also know as the
western blue claw and they are a native of the Murray Darling System (west of the Great
Divide) and are basically blue in colour. Blue claw yabbies are genetically blue, but
will change colour to that which is most suitable for camouflage in the wild. Yabbies
can be any colour blue, black, white, brown, red, green or any combination.
Yabbies grow to a maximum size of 350 grams, however, the common large size is 120 –
150 grams. Yabbies have a life span of only 5 – 7 years under ideal conditions, in the
wild their life expectancy is much shorter as they are on the bottom of the food chain
and a vast amount of animals consume them. Some of their main predators are insect
larvae, fish, eels, turtles, birds, platypus and water rats.
We grow all our yabbies at Aquablue in earthen ponds filled with rainwater. They
are harvested with baited traps and the catch each day is returned to holding tanks in
our purging/packaging facility. Yabbies are sorted and graded and held in tanks for at
least 3 days prior to sale to ensure their waste line is clean and clear (purged).
Growth
Yabbies are fast growing, but to do so they must moult. Yabbies have a hard
exoskeleton which limits their size, for them to grow they must moult the old shell and
grow a new one. In good farm dam situations the majority of your population going from
newborn to over 100mm (50 grams) in one year is normal. However, there is an extreme
variation in growth rates of individuals from the same brood. Some may reach this size
in six months, whereas others may take longer than two years. Growth is dependant on
the availability of food, shelter, density and water temperature. Yabbies are cold
blooded animals, the warmer the water the faster their metabolism goes and the faster
they grow, etc. Below 10°C yabbies don’t feed. From 10–14°C they feed but no
noticeable growth; above 14°C noticeable growth. Best growth occurs when water
temperatures are between 22–28°C. Depending on the amount of time, effort and
money available, it is possible to grow your yabbies from 0 to 150 mm (100 grams) plus
in twelve months.
Density
Yabbies survive extremely well in high density situations. Good farm dams can easily
produce 1,000kgs per hectare per year, and specifically designed and cared for yabby
ponds may reach up to 3,000kgs per hectare per year. A density 3-4 yabbies per square
metre is ideal with the smaller the density the faster and easier they grow. We do not
recommend a density of more than 10 per square metre. A 100mm (4") yabby weighs
approximately 40-50 grams. Yabbies are cannibalistic and death due to larger yabbies
eating smaller ones is extremely common.
Breeding
Yabbies are highly prolific, place a pair together and they will breed if conditions
are right. Whether in a fish pond or dam, with good conditions allow an average of 2 -
3 breedings per season and 1,000 young per female per year. Conditions for best
breeding: long hours of daylight and warm water.
Aquariums
Aquarium yabbies make excellent pets, basically treat them the same as a gold fish.
Fill the tank completely with water, yabbies breathe oxygen from the water the same as
fish. An aerator or filter in the tank will keep your water fresher longer. Usually
you don't have to change the water until it becomes smelly. Water quality is directly
related to the amount of food placed into the water. Don't feed yabbies chunks of meat,
feed your yabbies pellets or vegetables and the occasional garden worm. Shelter is
important, each yabby requires a home of its own, rocks or logs in the tank are
essential.
Dams
Yabbies thrive in farm dams. Best dams are those without large numbers of predators
in them, i.e. fish, eels, turtles, etc. Also best results will be in very turbid
(muddy) dams, yabbies don’t like clear water. Average farm dams produce 50-100 kgs of
yabbies per year without any effort. To stock your dam use dam stock breeders 50-100mm
head to tail, these are yabbies large enough to look after themselves, too large for
most predators to eat and ready to breed. Minimum required to start a population is
100, maximum is 1,000. The more you put in the greater your chances of successfully
starting a viable population. No feeding required, yabbies eat grass, leaves, seeds,
whatever blows or washes into the dam plus whatever grows in the dam - weeds, algae,
insects, etc. Yabbies also actively hunt for their food and will catch and eat worms,
beetles, bugs and fish if available. You can capture then via meat on a string or get
a commercial yabby trap to capture large numbers. Traps are available from the
Aquablue website.
Stocking
Farm dams can be stocked at very low rates if Dam Stock Breeders are used. Breeders
70 – 100 mm head to tail are the ideal size. Larger animals over 100mm tend to wander
from the dam, smaller animals are vulnerable to predation and need time before ready to
breed. Dam Stock Breeders are ready to breed right away and too large for most animals
to eat. Technically you only need two to start a population, one male and on female,
however the chances of something happening to one is high. Plus the chance of that boy
finding that girl in the dam again is astronomical. Best results are achieved by
stocking with a minimum of 100 yabbies. Larger dams over 1000 square metres surface
area will need 200 or more. Commercial farmers stock at a rate of one dam stock breeder
per square metre. The higher the stocking the sooner a harvest.
Aquarium Pets
Yabbies make excellent aquarium pets, but before you have one as a pet, listen to
what this yabby has to say.
Hi, I’m a yabby and I want to be your pet. I’m an easy pet to look after, all I
need is a home to call my own, food to eat and oxygen to breathe.
Most people keep me in a fish tank, just like a Goldfish. If I am small and the tank
is large, then no aeration is required, but I would be happiest with a small aquarium
aerator going all the time. Aerators are very good for me as they not only place oxygen
in the water for me to breathe, but also circulate the water and reduce the risk of
pollution occurring in my tank.
In my tank I also like sand or gravel on the bottom, so when I get bored I can pretend
to be a bulldozer and dig holes and make mountains with the gravel. Also, a rock or
log that I can climb over and make a home under would be wonderful.
As a climber none can compare, so in my tank please beware air hoses, rocks and logs I
will climb, so keep a lid on my tank all the time.
I don’t eat much and most people kill my friends with kindness by over feeding them.
Please don’t overfeed me! I only eat a little food and if you place more than I can eat
into my tank then the extra food just sits on the bottom and rots. Rotting food will
pollute my water and polluted water will kill me. Please be careful I’m too young to
die.
I’m not a very fussy eater. In fact I will eat almost anything if it is fresh, I don’t
like rotten food. Most people feed me vegetable matter, this is better than meat as
meat pollutes my water very rapidly.
Specially formulated, water stabilized yabby pellets are great, also sinking fish food,
budgie seed, potato peels, spinach, peas, circles of carrot and most fruits are some of
my favorite foods. All aquatic plants are also excellent food, especially if you are
going on holidays for a week or two. Just go down to your local creek, collect a few
handfuls of water weeds and drop them into my tank. The weeds will live and grow in the
tank without polluting my water, so I can eat whenever I like. If you want to feed me
meat, then garden worms are best, they can live for extended periods in my tank until I
get around to eating them.
I’m a prolific breeder and hundreds of young ones are the norm. If I’m a female I’ll
lay eggs under my tail which take 6–8 weeks to hatch into tiny baby yabbies that are
miniature adults. When all my babies are running around the bottom of the tank I can be
taken away from them, otherwise I may eat them. Other adults will also eat babies so if
left in the tank then lots of shelter is required as the more hiding places the greater
the survival.
As a baby I’m cute and friendly and I’ll eat the same food as mum and dad, but I
quickly become bored if fed the same food day after day, so please give me a
variety.
I’m easy to look after – if you follow these rules – you cant go wrong, but be warned!
I’m a yabby and very strong, so be extra careful – or I’ll nip on!
Many people in the course of keeping yabbies for pets have the need to add extra
yabbies to a tank with existing yabbies in it. This can be a problem. The ones in the
tank are in their own territory, when you add extras they are invaders and a massive
fight will occur with death or injury the result. To alleviate this problem, simply
remove existing yabbies from the tank and rearrange it. For example move your rocks
from one side to the other, mound the sand up in a corner etc. Once the tank has been
rearranged, drop them all in together, old and new yabbies are all in new territory
together and they will all settle in harmony with little fuss.
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