From the
WI DNR Spearing and Netting Regulations 2011-2012
"Crayfish
Season: Wisconsin/Minnesota Boundary Waters - May 1 to the following March 1 Remainder of State - Continuous open season.
No person may possess live crayfish and angling equipment simultaneously on any water except the Mississippi River, Lake Superior, Lake Michigan, Green Bay, Sturgeon Bay, Sawyer’s Harbor, and the Fox River from its mouth up to De Pere Dam.
Must possess a valid fishing license or small game license, except persons under the age of 16 do not need a license.
Crayfish traps placed in trout streams shall conform to the dimensions of minnow traps. See Nets and Traps for Minnows (page 14)
Crayfish scoops may be used in the Wisconsin/Minnesota boundary waters provided the scoops do not exceed 4 feet in length, 3 feet in width and 18 inches in depth attached to a handle not to exceed 4 feet in length.
Crayfish may be taken in all waters by the following means only: By hand, by use of minnow seines and minnow dip nets, where the same are permitted for the taking of minnows, and by crayfish traps (other than in trout streams) with the entrance to the trap not to exceed 2-1/2 inches at the greatest diagonal measurement. Traps must bear the name and address
of the owner and must be raised and emptied at least once each day following the day set.
Parts of fish and fish by-products including fish meal or prepared parts of such fish may not be used for bait unless: the fish were caught from the water being trapped, were obtained from a bait dealer, or were used with written authorization from the WDNR. Other meats (e.g., chicken and beef livers) may be used for bait for crayfish.
Floats or markers used to locate traps 1) may not exceed 5 inches in size, 2) may not extend more than 4 inches above the water surface, 3) must clearly display the name and address (in the English language) of the owner or operator, and 4) must not be orange or any other fluorescent color."
Also; there are crayfish (crawfish if you will) that are on the endangered species list. Know what you are catching or face a big fine.