Some Negril establishments will accept payment in Canadian dollars. Do not for a minute think that someone will take $100 Cdn for payment, if you owe them $100US. They may accept the equivalent amount in Canadian dollars. These days the equivalent amount of $100US is approximately $132 Cdn.
jamaicarob, if Fun Holiday quotes you a rate in Cdn. dollars, I have to think they base that rate quote on an equivalent amount of US dollars. Say for example a one night stay is $75 US (they would quote around $100 Cdn per night).