The are probably one of the shyest and hard to catch crabs. I have taken out rocks that I know are full of several, and can't find a single one when I look in the holes. They don't go for he usual bait, so I can't say for sure. You can try a hyposalinity dip, but I hate that kind of treatment. Somebody on here got quite a bit of stuff out by shooting hot water into the holes, but again... I would just take out rocks and set them in a bucket with a heater and airstone and check every so often to see if any are on the bottom. Good luck.