Alaska is renowned for its amazing salmon runs. Some river systems also receive good late summer runs of steelhead trout (rainbows that spend most of their life feeding in saltwater but return to freshwater to spawn late in the autumn). Chinook, chum, pink and coho (silver) salmon start to arrive in early summer and continue through the short summer months. Seasons in the far northwest of the US can be extreme. The ideal time to visit, fish, tour and explore is July through into early September.
For further information on Alaska:
https://anglersworld.tv/game-fishing/alaskainformation/