However, some options you could use are:
* School - This is the most common collective noun for fish, so it works for salmon as well.
* Run - This term is often used to refer to a large group of salmon migrating upstream to spawn.
* Shoal - Similar to a school, but often used for larger gatherings of fish.
* Cast - This is a more poetic term, potentially used to describe a group of salmon leaping upstream.
Ultimately, the best collective noun depends on the specific context and the image you want to evoke.