Fish are a relatively easy way to get your hands on protein and nutrition in a survival setting, without expending a whole lot of energy.
Two methods of fishing while expending little energy are to run trot and jug lines.
A trotline is a long line of cordage with baited hooks suspended off of it at periodic intervals that soak overnight that you retrieve (hopefully with a harvest) the next day.
Jug lines are lines with baited hooks attached to a jug and allowed to float freely in a body of water overnight that is also retrieved (hopefully with more fish attached) the next day.
The concept is easy to grasp, but practical application, particularly of the trotline can be tricky.
The video on the next page walks through the steps so you can see how to lay out the trot line and bring it back in as well as how jug lines work.