Historic Changes in Tweed Salmon Runs

The video describes how the run times of the types of Tweed Salmon have changed over the centuries. The information comes from a long term study that was made by the Tweed Foundation using historic Tweed Salmon catches, mostly from the netting stations. It shows that the kind of changes that we are currently seeing in Salmon runs have occurred in the past and postulates that they may be part of a very long term, periodic cycle. The talk was first given to the River Tweed Commission by Dr Ronald Campbell on 5th December 2016.
The video was recorded live and contains one small contradictory error made in the verbal delivery, at 3:16m, describing the period from 1990 when there were more Grilse than Salmon: the slide is correct.