T,I think it's anyones guess on the crayfish.Whats amazing is that if bass can't control them on the Woods,hard to believe they can be controlled naturally anywhere.
http://www.seagrant.umn.edu/ais/rustycrayfish_invader

F Whiz,Did you conduct the experiment in the materials cited?Results from that will be as helpful as most speculation here.After that experiment,no harm in doing more experiments on the water on your own.
There is only one true source for the answers you seek-the musky gods.Unfortunately they talk only to me and,to be honest,I haven't had any meaningful communication with them since I quit drinking.