Did you put your bait in a container in the center of the trap? If you didn't it will float up to the top of the trap and they can nibble on it from the outside of the trap without having to go inside.
2011 five acre pond. LMB, SMB, HSB, SPB, BG, CNBG, HBG, RES, WM, CC, BCP, GC, FHM, GSH
| 
