When I think of fall and the leaves start to turn, I think salmon fishing. September often marks the beginning of the fall pacific salmon migration in the Great Lakes. Depending on where you are, there are three species available — king or chinook, coho, and in some places, pink. These fish have spent the majority of their lives out in the big lakes feeding, and are now returning to rivers and streams for reproduction. Males and females migrate into the rivers and look for ideal gravelly areas to spawn. Once they spawn, their life cycle is complete and they die.
The Miraculous Nature of Salmon
Alaska Salmon Viewing | Best Locations To See Spawning… | udimonteverde.org
Pacific salmon start returning to Alaska during green-up in May and continue to show in some rivers well after leaves have turned in the fall. At the climax of a run, salmon might be arrayed bank-to-bank, like an armada of blushing torpedoes. Further upstream, watching lone fish reach the end of their epic journey can also be awe-inspiring but in a profound and elegiac way. Pairs of decaying spawners swirl and wiggle in crystal water, as females deposit eggs and the males fertilize. From river mouth to feeder stream, the spawning spectacle is always engrossing. See the action of salmon swimming upriver from the salmon viewing deck at the Eagle River Nature Center.
The salmon run is the time when salmon , which have migrated from the ocean , swim to the upper reaches of rivers where they spawn on gravel beds. After spawning, all Pacific salmon and most Atlantic salmon  die, and the salmon life cycle starts over again. The annual run can be a major event for grizzly bears , bald eagles and sport fishermen. Most salmon species migrate during the fall September through November.
All Pacific salmon are anadromous. In the rich ocean environment salmon can grow rapidly, gaining more than a pound a month. These salmon mature and return to freshwater within 2 - 8 years.