Backyard Aquaponics
A place to discuss aquaponics

Hi all, can anyone here please help me identify these crayfish species, Thanks.

Redclaw.

Thanks Charlie, are all 3 of them redclaw? Mind sharing on how to tell them apart? Thanks once again.

Yep, all 3 are redclaw.

Redclaw only have 4 ridges on top of the head, two longitudinal ridges extending backwards from the rostrum and two ridges extending behind the eye. Males have the red band on the claw (middle pic) but females and juveniles dont (top and bottom pic).

Marron have 5 ridges on top of the head. They have two raised longitudinal ridges extending backwards from behind the eyes, two raised ridges extending backwards from each edge of the rostrum and one raised ridge in the middle of the two raised rostral ridges like in this image below..




Yabbies only have 2 ridges and really short rostrums and no spines or spikes like the others do. They also generally have larger claws.

Thanks, very informative. One more question, where is the location of said spines/spikes? (PS. I leave in Malaysia so am not too sure what is the common species found here and the pet-store owner was not much of help. I hope there are none other species that might be mixed up.)

Thanks again, cheers.

Redclaw have been in malaysia for some time now, Im pretty sure they are farming them there somewhere. Not sure how they were introduced though sorry. Ill do some reading. The spikes are on the rostrum, keel and telson. Basically, forehead, under eyes and tail centre.

thanks Charlie, very informative, I sometimes stuggle to identify some of the yabbies in my pond. especially the younger ones.

The Charax destructors i use for bait (Ocasionally turn one onto a nice fish)

The Cherax quadricarinatus/ Red Claw i leave to reproduce for future use in an aquaponic salad.

No probs guys. I do love my crustaceans

Got any pics Freddie? You know the rules mate

Hi Charlie, it is a bit off topic but do you know where to get info on how to start a small aquaponics system? Seeing your system is thriving. For example, what is the ratio of fish to plants for the system to be effective? Or the depth of the grow bed. Thanks in advance.

You can find all the basics within the forum.

A good place to start is the IBC of aquaponics http://ibcofaquaponics.com/

Thanks, very informative although the IBC system is a bit larger then what my place can accommodate for now, might be able to divide the recommended quantity and come to a satisfactory number for me. By the way does the number of fish equates to crayfish? Seeing that the crays is smaller in size.

Yea the basic guide can be transfered to any size system, the basics remain the same... ie stock to filtration capacity etc etc.

Crayfish are a little different in the respect that you need to stock to your floor space and provide an adequate and complex habitat. Crustaceans dont grow well in an overstocked situation so theres a few guidlines that need to be followed to grow them out well and fast. Luckily you have temp on your side in your location.

I talked a bit about how I do things with yabbies over on the backyard farming site here http://backyardfarming.com.au/phpbb3/vi ... f=14&t=634


here is a cut and paste of my recommendations from the above link..


Firstly a couple of points to keep in mind.. yabbie growth rates rely heavily on temp, 20-28deg being optimal and below 16deg and they enter a state of reduced metobolic activity, basically hibernation. Obviously aeration at higher temps will improve DO levels and water quality.

Also make sure your PH levels dont become to acidic, this will soften the exoskeleton and promote disease therefore reducing activity. Try keep it above 7 - 7.5.

Although nutritional requirements of yabbies is relatively unknown, I like to stick to high protein diets like aquaculture pellets, potatoe and lupins. A few worms and snails now and then are also a good addition. Just keep an eye on left over food as you would already know. I think farmers feed at around 3% per body wieght per day but I wouldnt fuss on that number for what you are doing.

Ok, in relation to grading, there are a few ways to go about it. I wont go into them all but the system I use is relatively simple. For this you require 3 tanks. A juvenile tank, a breeding tank and a grow out tank.

The juvenile tank is the most important. It will be home to the babies and berried females. Females are removed about 2-3 weeks after brood. This needs a complex habitat, I use lots of hides with pipe cut offs (its a good idea to close one end) and a massive bunched up length of shade cloth.

The breeding tank is home to 1 male per 3 females at a stock density of around 8-12 yabbies per 1m2 of floor space. Once again, hides are crucial. There will be carnage in this tank, its impossible to avoid. Move the males to the grow out tank regularly and eat the females after a couple of broods and replenish with young from the juvenile tank. Young females are good to go at around 20-30g.

The grow out tank is all male occupied, I stock this at around 30 per 1m2 of floor space. Also a haven for carnage but thats the way it goes... usually when they mault. Yabbies will grow faster in an all male situation and in fact research into mono-sexing and hybrid species is likely to intensify and increase production substantially over the next decade within the farming world.

Ive read some really good articles by an australian marine biologist Dr Craig Lawrence who bred a Cherax albidus with a Cherax rotundus which produced only male offspring, quite possibly might become the future of aussie yabbie farming.

There is slight variations to that method as redclaw are a bit different but I hope that gives you an idea of what to expect.

Thanks Charlie, I read that red claws are less aggressive, does that change the stocking amount? As i am limited to space i feel that i might not be able to stock enough to get it to workout, although i have an idea for a solution that i would like to run by you. Does shelving the tank work? We will have more "floor" space in that sense.

Yes redclaw and marron are less destructive and evasive compared to yabbies so you could probably stock higher. I have no experience with redclaw so I cant offer much assistance there sorry but I have tried marron a few times and Ive found them quite difficult to grow out.

A shelving style system may help with redclaw but not much defference for yabbies. With yabbies its at night time when the carnage begins... they all go looking for food and it gets ugly. You may have to bite the bullet and give it a go. Make sure you start up a thread and document your progress as we all get something from it.

Yeah i guess so, currently am on the drawing board trying to come up with a working concept while reading more on how and where to begin. By the way Charlie, was wondering if you might be able to give a clearer picture on the basics as well as in "Cycling". In the cycling process should i do it without any plants and fish? What are the results/trends i am looking for? Thanks again.