A slough is a channel where water is usually stagnant. They are usually found at backwaters of a large river system or where a small stream connects with a larger river system.
When fishing in British Columbia, sloughs and streams share the same fishing regulations. A good example of a slough is Nicomen Slough in the Fraser Valley, between Mission and Agassiz.
Fishing can be excellent for both salmon and trout in a slough. Because the current is minimal, spincasting lures and bottom fishing with bait are the best techniques.