I am assuming you are going to be declaring and bringing the rod in yourself. If you have it brought in by UPS for instance you will be subject to their brokerage fees and whatever duty and taxes are applicable. I would not go that option because it could cost you a few bucks once it is said and done.
The best way is to go on a holiday and then you are allowed to bring in on a sliding scale certain amounts duty free. For instance, if you are on holiday in the U.S. for more than one week, you would not have pay any duty or taxes on your rod. Now if you go on a day trip, you will have to pay duty and taxes on the rod. It will be based on the GST, provincial tax, and whatever applicable duty once they look it up on the schedule. Depending on who does the calculation you can get quite a bit of latitude, but I would think you would not have to pay more than fifty to eighty dollars to bring your new rod into Canada.