It’s not just about salmon and sea trout — all fish, including resident brown trout, need to be able to move up and downstream to complete their lifecycles. Whilst some barriers in rivers occur naturally, we humans have added a staggering 40,000 artificial barriers (check out this blog post from the AMBER project) with inevitable consequences on our fish populations.
This blog post by Peter Jones describes the results of research into small barriers on fish communities.
You can read the full paper in the Journal of Applied Ecology.
For more information about rivers and barriers, visit our Rivers Resource Hub on this website, and specifically this page on weirs, culverts and hydropower.