Fishing has greatly affected all of the Great Lakes and the St. Lawrence, whether people are sport fishing or fishing for a living; all contribute to keeping the populations of fish down.
Boating, cottaging and other water sports and recreation are also very common in the Great Lakes and the St. Lawrence lowlands due to the high concentration of large lakes
Mining, construction, energy production, manufacturing and farming are also prevalent in the Great Lakes and the St. Lawrence lowlands due to the fact that it is the most populous area in Canada and the fact that the resources in the general area are used in that kind of thing.