I was amazed to discover a number of crayfish in the outflow between my two ponds. I never looked for them in my pond but assumed there were none. I guess I was wrong. I had intended to stock some but hadn’t gotten that far yet. So my question is how to determine whether there are a lot of crayfish in the pond or was it just a few in the discharge between ponds? And for the record the ponds were originally lined with shale so the habitat would be well suited for them. So anyway how do I figure out if there are crayfish in larger numbers ? Trapping? Any suggestions appreciated.