Follow this link https://www.youtube.com/watch?v=-rcNSnVSBLg&t=14s to watch numerous eels try to ascend a steep weir on the River Doon. With numbers of eels in serious decline across Scotland and Europe every barrier has an impact; depletion the fish of energy, giving the fish greater exposure to predators and preventing access to large tracts of habitat.

Source: Ayshire River Trust – Eel Migration on the River Doon.