Poutargue in Montreal?
There is a source in Montreal that I've tried. It involved going to some tenement in CDN, and meeting a guy in a ripped tank top and sweats who handed over a waxy package.
It's not Italian bottarga, I think they use Gulf of Mexico mullet roe.
Here's the connex:
For US and Canada orders, click: http://boutargue.org/english/boutargue_order.html
Alternately, for the Sardinian stuff, though not sure they ship to Canada
I second the request! It is also known as Bottarga...
I would suspect it is to be found in some sort of Mediterranean deli kind of place. Northern Mediterranean to be more specific, since I have seen recipes for it from Spain, France, Italy, and Turkey (of course, I may have just never seen the recipes from other places...that's not to say they don't exist).
Another option is to make your own, but finding fish roe that is fresh enough that you would want to eat it uncooked may be even harder than finding the bottarga itself.