Some ponds used to be populated by the crayfish are now probably depleted because of newly alien fish predation on larvae. Do you advise cage shelter to protect them? Any recommendations (material, shape, size)? Vegetation is not abundant under the waterhole and natural burrows are scarce.
Fish removal is currently impossible.
Thanks for your experiences!
Hi, you may want to consider video observations by sheltering juveniles in perforated transparent 500mL bottles illuminated with infrared light for night time observations. Worked very well for measuring relative predation on Australasian spiny lobsters Jasus edwardsii. Best wishes
Article Lobster in a bottle: a novel technique for observing the pre...
You could perhaps introduce more refugia by using sections of plastic pipe fixed together and weighted in a 'pan pipe' kind of arrangement with one end closed off. People use these as artificial refuge traps because crayfish shelter in them during the day so they can be sampled by simply retrieving the trap. Pipe diameter can be selected depending on the size of target crayfish and the fish you want to exclude. Attached file has some more info. Cages could work too, but more expensive and difficult to deploy and maintain, and you would need to keep crayfish stocking densities very low in cages to avoid cannibalism. Good luck.
It is always better and advisable to provide shelter to avoid predation.
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