The CFIA's regulations actually don't have a specific definition for “sustainability” in terms of it being on a package. That's one of the issues we have identified when companies are making these claims on packages without any evidence to back them up.
We would define “sustainability”, in terms of it being on the package, as having those three or four key pieces of information, providing information on where it was caught, how, and what species it is, as a way to then use that information to look up its sustainability status. That could be using, for example, the Monterey Bay Aquarium Seafood Watch ranking system to look at those pieces of information and say whether that product was harvested or farmed in a sustainable way.
I'm sure my colleague Kurtis can also touch on the sustainability piece from a certification perspective.