Those might just be the taxes for the route.
Pricing up a random cash one-way on ITA I get:
Code:
Fare 1: Carrier AA L21N4 YVR to SEA (rules)
Passenger type ADT, one-way fare, booking code L
Canadian Goods and Services Tax (XG)
CA$9.24
USDA APHIS Fee (XA)
CA$5.20
US Immigration Fee (XY)
CA$9.20
US Customs Fee (YC)
CA$7.20
Vancouver Airport Improvement Fee (SQ)
CA$20.00
US International Arrival Tax (US)
CA$23.40
Canadian Air Travelers Security Charge (CA)
CA$12.10
Taxes per passenger (36.15%)
CA$86.34
You might avoid the GST on an award ticket but the rest of them I imagine you'd need to pay.