It is in fact part of Citizenship and Immigration, and the reason for the decrease is a technical matter revolving around the revolving fund, so that effectively there's a surplus being run in Passport Canada; because of the 10-year passport there's a large influx in cash.
Cet organisme fait bel et bien partie de Citoyenneté et Immigration, et la diminution est attribuable à un élément technique concernant le fonds renouvelable. Il y a un excédent à Passeport Canada, car le passeport valide pour 10 ans apporte un revenu important.