Joe, this is what it says in the Ontario Regulations booklet:
Size limits refer to total length, which is a
measure from the tip of the mouth with the jaws closed to
the tip of the tail, with the tail fin lobes compressed to give
the maximum possible length. Provincial regulations are
established using the metric system. If you catch a fish in a
restricted size range, you must release it immediately. The
conversion to inches has been rounded to one decimal place
for the convenience of anglers.