The Marine Mammal Interpretation Centre is the best indoor stop before or after a whale trip. It explains why the meeting of the Saguenay and St. Lawrence is so rich in marine life, and covers the whales, seals, and porpoises seen in the area.
Use it to put names and habits to what you may see from the boat. It is especially useful on a grey day, when the river is impressive but not always easy to read.