British Columbia, Canada. At the end of every summer, an impressive natural spectacle takes place here which has been witnessed for as long as anyone can remember – the migration of the salmon. Many thousands of these large salmon, of which no less than five species can be recognised here, return to the upper reaches of the rivers in which they were born some years before.
Change of scene. The river Wupper in the Bergisch Land region of central Germany. The salmon caught here by State approved fishermen in the autumn may not be very plentiful – but they are a clear sign that there is a new population which is being encouraged to see the Wupper as its home.
A couple of centuries ago, this river was a typical salmon-bearing river, teeming with many different species.
However, 175 years ago, as the industrialisation process took hold here and water power was needed, the salmon left the area and took with them the sea trout, a close relation.
Since the beginning of the 1980s, the quality of the water in the Wupper has improved dramatically. As a result, the Government of North Rhine-Westphalia, the local governments and a number of associations have joined forces - successfully - to reintroduce these migrating fish to the river.
Norwegian researchers are even attaching transmitters to young salmon to enable them to be tracked by radio telemetrics and satellite navigation as they migrate.
