I heard a funny quip about how some guys in northern Wisconsin were dealing with the Indians and walleyes. Apparently these fellas got sick of the Indians taking all the fish, so they made some cement " fish" and painted them fluorescent so they reflect at night. Apparently the Indians frequently shine them at night and then spear them. These guys claimed to have harvested a good number of Indian spears/tridents based on what they found on the banks. Sorry about your luck.