The 'pleasure craft license' is one of the items, the other is the boat registration. The boat registration is linked the number on the side of your hull. The pleasure craft licence is different. You need the licence to operate a boat.
Below are quotes from Transport Canada's website
http://www.tc.gc.ca/eng/marinesafety/debs-obs-paperwork-paperwork_operator-360.htm
"A pleasure craft licence is a document with a unique licence number for a pleasure craft. The number allows Search and Rescue personnel to access important information in an emergency.
The law requires all pleasure craft powered by 10 horsepower (7.5 kW) or more engine, to have a pleasure craft licence, unless they have a vessel registration. There is a $250 fine if you are found operating a vessel without a licence. You must carry a copy of your Pleasure Craft Licence on board at all times and display the pleasure craft licence number on the bow of your boat above the waterline on both sides in block characters that:
•are at least 7.5 centimetres (3 inches) high; and
•in a colour that contrasts with the colour of the bow.
Cost: Pleasure craft licences are free and are valid for 10 years. "
"The Competency of Operators of Pleasure Craft Regulations require all operators of pleasure craft fitted with any type of motor and used for recreational purposes to carry proof of competency on board.*
Proof of competency indicates the boater has a basic level of boating safety knowledge required for safe recreational boating. In the past, anyone of any age could operate a recreational boat without any minimum boating safety knowledge, experience or training. These requirements were introduced in 1999 in response to boating deaths and injuries, with the goal of improving safety on Canadian waterways through education and training.
Proof of competency can be any of the following:
•A Pleasure Craft Operator Card - this is the most common proof, obtained after passing an accredited boating safety test
•Proof of having passed a boating safety course in Canada before April 1, 1999
•A specified marine certificate from the List of Certificates of Competency, Training Certificates and other Equivalencies accepted as Proof of Competency when Operating a Pleasure Craft
•A completed rental-boat safety checklist – good only for the rental period
•For Foreign Visitors, an operator card or equivalent which meets the requirements of their own state or country. "