Aquaponics - Marron stocking density

I'd like to grow some marron but they eat each other.

One of the issues with things that use their claws to catch and kill things, is they tend to use them on each other, or their young.

Marron, for those who don't know fall into the "things with claws that walk on the ground under water" category. They also fall into the "delicious" category.

The problem is that, because they eat each other, you cant keep many in an aquaponics system. Given a choice, marron would like to be left alone and hangout and eat. The problems arise when they go looking for food, or a mate, or when the just go out for a stroll and bump into another marron also out for a stroll.

One solution is to give them plenty of hides in the form of hundreds of short lengths of PVC tubing. Which sounds like a good idea because I seem to love using PVC tubing, but I'm not sure if it solves the bumping into each other problem.

Another is to only populate one marron in each half square metre of fish tank bottom space. That would only allow 2 or 3 in a 1000 litre system, but allows each marron to back away from more aggressive marron they meet strolling around. I'm hoping for stocking densities that might allow 30 or 40 marron in my new fish tank rather than 2 or 3.

Yet another solution I have seen, was to create high rise housing that float around in a fish tank where each crustacean (yabby in this case) has its own space to stop them killing each other.  The yabby spaces where stacked on top of each other so that in a one metre deep fish tank, there might have been ten stacked on each other. These yabby buildings floated around in the current. The problem I see with this approach is that unless there is a great deal of turbulence in the water, the feed might never meet the yabbies. In the system I have seen video of, there seemed to be a great deal of wasted food that simply got filtered out of the system, and dumped.

Other than the feed issue, the marron high rise seems like the best idea. I think I'm leaning in that direction, but perhaps with a way of feeding each "building" via a tube that runs down through each marron's house, so that each marron gets a share of the food, and nobody misses out.

I'm off to buy a fish tank or two tomorrow, so I want to design a system that includes marron before I start building my new bigger aquaponics system.

My research continues.