Set netting is a type of subsistence fishing. You set a net on either side of a "fish highway" (like stringing a net from one side of the road to the other to catch any cars going down the road). You catch all the fish that are passing through. Only with the net there, they get stuck. Usually, they get stuck around the gills (which also kills them) and you have to wrench them out of the net (picking the net).
Once they're caught, you pick the net. You take your boat and keep working up and down the line of the net, pulling all the fish out that are stuck. We went with our friend when he set net for red salmon. We hauled in more than 75 fish in one day. It is a lot of work. Whew! But really good eating -- yum!
See pictures of set netting for red salmon.