Nunavut's public sport fishing guide makes the exemption structure clear. Beneficiaries of the Nunavut Agreement do not need a sport fishing licence. The guide also says Nunavut residents and Canadian residents under 16 do not need a licence, and non-residents under 16 do not need one when they are accompanied by a person who holds a sport fishing licence.
The senior rule is different. The current public guide says Nunavut residents and Canadian residents over 65 still need a licence, but there is no fee for that licence. That is easy to miss if you only look for a simple senior exemption and assume the paperwork disappears too.