This part of the site constantly being updated - lots more info on yabbies to be crammed into here.
3. What influences the colour of yabbies?
The biggest factor in this is the colour of the water and the colour of the soil where the dam/pond is located. Smaller yabbies are clean and light coloured because they are moulting a lot more often than the large yabbies. Yabbies that haven’t moulted for a long time are usually dirty looking.
4. What do yabbies eat?
Yabbies will pretty much eat anything, dead/decaying plants/animals is their main diets in dams/ponds. Yabbies can be fed hay and lupins or special crayfish pellets in their pond.
5. How many offspring can a female produce in one spawning?
Genetic strains and size of yabby plays a big part in this. Approximately 200-1000. Usually around the 300-400 mark.
6. How many times can a female spawn in one season?
Yabbies can spawn up to 3 times in one season.
Yabbies belong to the 'Parastacidae' family of crayfish. These are crayfish from the Southern Hemisphere. The other families are 'Astacidae' (Europe) and 'Cambaridae' (USA, Mexico, Asia).
Some advantages for the aquaculture of Cherax Destructor are:
- Repeated, fast breeders
- Large numbers per brood
- Mature and grow quickly
- Tolerate big populations
- Tolerate low oxygen
- Easy to harvest
- Survive long time out of water - easy to transport
- Easy to cook, taste great
- Simple habitat requirements
- Markets for all grades/sizes
- Thrive in a big variety of climates
- In tremendous demand
This section contains some information (you guessed it) about growing yabbies. Yabbies are prolific, and in my opinion are the easiest aquaculture species to farm. Crayfresh’s yabbies are all from farm dams, mainly built for watering stock. None of the dams ever need to be stocked, and it is amazing how I have seen dams sit totally dry for a year and 6-12 months after a rain throw some traps in and pull them out all full with yabbies. Being from a rural area, I am still with the ‘old-school’ way of thinking, and that is, growing yabbies extensively. Growing yabbies extensively simply means that you use more land and more water to grow the yabbies, with minimal input. Due to our current ‘wonderful’ NSW government, for farms on the coast this is proving difficult , as it is getting harder and harder to gain approval for ponds over vast amounts of land (and not to mention the cost of land on the coast). This means a lot of these farms are having to farm their yabbies with the ‘sem-intensive’ method, which means less water, but higher densities per Ha of water. This method also requires much more input of money to reach these high densities, including daily feeding, aeration of the ponds, and erection of bird netting.
Farm dams are great for yabbies, and in certain areas can produce large amounts of yabbies. Generally, they love farm dams as there are not many predators in the farm dams eating all the yabbies. On the Eastern drainage however, eels are a major predator and will eliminate nearly all yabbies in a dam unless measures are taken to prevent this. On the Western drainage, eels aren’t a problem, but you could run into problems with carp, or turtles. Farm dams are generally used for water storage, watering stock, and sometimes for irrigation. One of the problems with farm dams is that they are so deep in the middle that not many yabbies will occupy this part of the dam bottom and will grow much slower, due to the water being a lot colder there, and not being as well oxygenated. On the other hand, as most farm dams are rain-fed, having a farm dam so deep can be of great value when going through a long drought.
Good Farm Dams
The best farm dams are the ones with low banks, so the water stays well oxygenated, that catches plenty of run-off to feed the yabbies. The most important thing a dam must have is turbidity (muddy water). Yabbies don’t like clear water, because they don’t feel as safe in it because predators can easily see and catch them. Yabbies will generally be in much lower densities in clear water dams, and will only come out to feed at night times, which means the yabbies will grow much slower and you can only trap yabbies in these dams at night time. One way to improve yabby productivity in these dams is to eliminate carp/turtles from the dam and add plenty of shelter throughout the dam. I’m currently trialling this idea in my dams, and will give an update of whether this method will substantially enhance yabby productivity in non-turbid dams. The conclusion at this stage is to stick to turbid dams.
Improving farm dam conditions for yabbies
Firstly, a problem limiting yabby productivity (mostly in older dams) is silting. This is the thick sludge on the bottom of the dam. This sludge can reduce the area on the bottom of the dam the yabbies can occupy as it can mean low oxygen and can suffocate yabbies. This is when you can take advantage of dry dams due to a drought. To remove this silt we have our 2 325 Horsepower Steiger tractors on either side of the dam, connected to a silt scoop via wire ropes. Tractor one pulls the scoop through the sludge and dumps it over the other side of the bank. Tractor 2 then pulls the scoop and tractor one back. This is a time consuming and often monotonous task, but does a pretty good job. Another option is to get an excavator in to scoop up all the silt and dump it, this can work well also. I have also heard of using a swamp dozer to clean out dams. I have no knowledge of these but it sounds fair enough. Don’t use a normal dozer to clean out a dam, as you may never see the dozer again.
Feeding yabbies in the dam can also increase yabby sizes and improve densities. Lupins or other grain such as oats or wheat can work great, but due to rules created by NSW Fisheries it is illegal to feed your yabbies with these as overfeeding can cause pollution in your dams and that water is then discharged to the environment when it rains. It is legal to line the bottom of your dams with hay.
Trapping yabbies is a way of managing stock, and regular trapping will help improve the overall value of the yabby population in your dam as most dams are generally overcrowded with yabbies, and this will stunt their growth. It is recommended you trap about every 6 weeks.
Yabbies are a great pet to keep and very interesting to watch. Just keep them in a normal fish tank and make sure it is aerated and has a filter. Your pet yabby (or yabbies) should have plenty of shelter and things to hide under, or in, in their tank. They can be fed carrots, vegetables scraps, meat, chicken pellets, or pretty much anything. Be careful not to feed them just meat, this will kill your yabby. Meat should only be fed to your yabby occasionally. Feeding pet yabbies too much food is often the cause of the yabby dying. Yabbies only need to be fed a very little amount and any uneaten food should be cleaned out of the tank the next day.