Transport Canada is looking for public comments regarding potential mandatory lifejacket laws for recreational watercraft. The included research doc has some very interesting data, such as the observed finding that kayakers have a higher lifejacket wear rate (78% of kayakers) than canoers (41%).
Lifejacket use is already mandatory for all commercially guided watercraft trips. This is well known (and I would argue practiced) by whitewater and sea kayak guides. Guided flatwater canoe trips likely is not as compliant, and as for guided fishing... good luck finding any pfd's in sight on fishing outfitters websites. I believe my fly fishing guide service (Algonquin Fly Fishing) and only one other in Southern Ontario require pfd use (my insurance requires it as well).
For mandatory recreational lifejacket use there is bound to be lots of push back. There is a bill before the Ontario legislature requiring kids 12 and under to wear one, however that age group makes only a small portion of boating fatalities (7%), so obviously adults make up the remaining 93%. Unmentioned in the lifejacket conversation is the presence of alcohol in boating fatalities (40% of fatalities, according to one boating safety course).
You can see the supporting TC docs and take part in the survey here.