Dams took a toll, of course, but so did habitat destruction, overfishing, the impact of overproduction at hatcheries and cycles of ocean productivity.
(Dams; took; a toll, of course) (so; did; habitat destruction, overfishing, the impact of overproduction at hatcheries and cycles of ocean productivity)
Dams so
took did
a toll, of course
habitat destruction, overfishing, the impact of overproduction at hatcheries and cycles of ocean productivity