The Fence Post

Easy Counting

A counting fence is a live trap fence used in rivers to capture salmon and trout. This results in an accurate count of the number of fish present. Sometimes V-shaped, it extends across the river's entire width. As the fish swim up or down the river they are caught in a box-like trap structure where they can be easily counted.

The following video shows a counting fence on Morrison Creek the day after heavy rains. The fence has been dislocated somewhat by the higher water level. It gives you an idea of how this fence works.

River Counting Fence The counting fence is a live trap fence which is composed of rebar and is v-shaped. It extends across the entire length of the river with a box-like/trap structure in the centre. It's function is to trap and count adult salmon and trout that return to the river to spawn

Old and New 

On the Babine River in British Columbia, a counting fence has been in place since 1946. In early July, 4' x 7' aluminum panels that make the fence are installed along the 330' permanent frame. 6' x 8½' trap boxes are installed next. Then the count begins.

A newer design is a floating fence. When leaves, branches, or logs float downstream, the fence submerges so that the debris slides over the fence rather than getting caught and clogging the fence causing a blowout. The fence is removed when not in use.

While we're on the subject of counting fish, here's some great info on tracking Pacific Northwest salmon. 

Have you ever seen a counting fence in use?