A trotline. Notice how the line is weighted with rocks.

You can improvise a 'seine' using a shirt and two sticks. Push it in front of you as you approach a bank or small cove on the edge of the water. This can often yield more food than

A basic trap for
fish in a stream.

Two basic snares.

Above, animals often seek
shelter in hollowed out logs.

Below, animals use log bridges regularly, and snares can take advantage of this habit.

A wide assortment of traps and snares are possible,
and a good outdoor-survival book with plenty
of illustrations is highly recommended.