Below is right out of the Ontario Fishing Regulations (2007) – the current regs.
Possession or Use of Bait
28. No person shall release live bait or live baitfish, or empty the contents of a bucket or other moveable container used to hold bait or baitfish into any waters or within 30 m of any waters.
28.1 No person, other than the holder of a commercial baitfishing licence or any other licence that authorizes the culture of baitfish, shall catch and retain in any one day, or possess, more than 120 baitfish.
29. (1) No person shall use as bait, or possess for use as bait, an invasive fish or live fish that is not a species of baitfish.
– It is interesting to note that it is illegal to empty the contents (I think that means water too) of any bucket or bag of minnows within 30 meters (30 giant steps or about 100 feet) of the lake. Good to know when transferring minnows into the minnow bucket and really good to know about what you shouldn’t be doing with left over minnows after your trip is over.
– Did you realize that an individual is only allowed 120 baitfish (bought or otherwise) in one day.
– And the third point, the key is “live fish that is not a species of baitfish” which answers the old question as to whether it is legal to use a walleye gullet for bait. They do work well and they are legal. A further reading of what defines a fish for purpose of a limit makes it sound like the gullet by itself might be construed as a “fish” so watch how you count!