Kosi, have you actually been lucky enough to see your villagers catch the crabs? It took me a while, but I have seen them. I think it depends on the skill of the farmer as to whether they catch crabs or not, and also noticed that onec they started catching the crabs, they do so quite rapidly.

I don't know the stats of catching them with the game on and off though, sorry.....anyway, I wouldn;t complain about the number caught...they bring in a stack of food