Autumn Migration Route Inspection Underway Every autumn the Foundation's habitat team undertakes an inspection of both Wye and Usk catchments. This is to ensure that migration routes are clear for Atlantic salmon and brown trout to reach their spawning grounds. The countless pipe bridges, weirs and other man-made structures throughout the catchments can pose potential problems for fish migration. After each flood (and there have been a few recently!) a build-up of trees, branches and other debris can block or limit upstream passage. This prevents the fish from utilising the good habitat and spawning gravels above such structures. This inspection is vital for salmon and trout populations, as is the removal of any potential blockages. If passage is restricted or prevented, fish can be forced to spawn in a more condensed area below the blockage. Each section of river can only hold a certain number of juveniles, so overall numbers can be decreased as a result. Read more about our work to restore access for migrating fish.