OK, the three year conservation licence is new, I think. Here are the current options, straight from the Ontario Government's mouth:

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So if you're planning four or fewer Ontario fishing trips over the next three years, it's cheaper to buy the 8-day licences as you need them in the one-trip years, and a one-year licence in the years in which you will be taking two or more trips. If you will be taking five or more trips over the next three years, it's cheaper to buy the three-year licence.

Unless prices go up. Who knew fishing was so much work?