Crayfish Kingzett lake/ the quarry

Hello everyone, I was wondering if anyone knows the status of crayfish in the quarry and are they editable. I use to stop there everyday I could after work for a swim, I could finesse my street bike around the gate saving on the walk, anyway. The water was so clear you could see fish swim by and watching a Utube vid, kids were catching crayfish by the bucket although, one poster here mentioned because the water didn't move or recirc, so their was contamination and he wouldn't swim in it; I do remember they had fish pens there quite some time ago so perhaps that made for issues. It looked like their was plenty of crayfish and seemed inviting to try it out, if a person can eat them, any thoughts or info appreciated, regards