We consider species below the species level. We can look at subspecies or at genetically distinct populations.
For example, the fish in Atlantic Canada are bound to be genetically distinct, or they may well be genetically distinct, from ones in the Great Lakes. In that case, we would look at those two “subspecies”, we could call them, albeit we actually call them “designatable units”, and assess each of those separately. It's possible for one of them to then be listed for protection under the Species At Risk Act and the other one could be deemed not to be at risk.