Answer
Atlantic salmon spawn in the fall -- October through November. This is the time when oceangoing salmon can be seen moving upstream in great numbers. They color up and change in appearance, they generally get beat to hell, and they do whatever it takes to get to the place where they were born. At some point during the spawn cycle they stop eating and after they've spawned they die of exhaustion/starvation. Trout spawn, too, though it's much less dramatic than a salmon run. Most trout live through spawning, though it is stressful and requires a lot of energy and the right conditions. Rainbow and cutthroat trout spawn in late winter. Brown trout spawn in late fall or early winter. If you know what to look for, you can find spawning redds and catch big numbers of spawning trout (though in some states fishing for spawning fish is restricted or off limits). Landlocked salmon -- those with no connection to the ocean -- may also spawn but they are more like trout under those conditions. They spawn annually and can return to their birth places for many years. In New York State you probably have lots of different species of salmon and trout, some of which are native, some of which are stocked, and some wild nonnatives. Sort of depends on stream conditions, ocean connectivity, and species as to what they do during spawning runs. Here in the west we have kokonee salmon (landlocked sockeye salmon). They act and spawn just like large, schooling trout -- they color up, get super feisty and hungry, and move from lakes and reservoirs into streams and tributaries. Fishing them is a blast. In the spring and early summer, oceangoing salmon will smolt -- they'll move out of their freshwater birth streams and into the ocean. At this time they are moving downstream and usually they do not migrate in the great numbers as those moving upstream to spawn.