Restoring rivers can also restore vital habitats. One of the most impressive success stories of recent years has been that of the Rhine. It was once one of Europe’s most important rivers for salmon, but fish stocks were wiped out as a result of engineering works, the discharge of wastewater, and a devastating chemical accident in the 1980s. This did not go unnoticed by the general public, and it triggered a wave of solidarity among conservationists, fishermen, and citizens. Under the auspices of the International Commission for the Protection of the Rhine, numerous coordinated measures were taken to improve water quality, prevent floods, and preserve nature. These included ladders to help salmon go up and down weirs, facilities to protect fish from turbines, restoring habitats close to riverbanks, the creation of suitable areas for spawning, and the reconstruction of habitats for young fish.
By the end of 2016, more than 8,000 salmon had migrated from the sea to the Rhine system. The actions taken to help the salmon also improved conditions for many of the region’s other fish species. For example, it was possible to reintroduce the houting, a kind of whitefish. The Rhine is now home to 63 fish species and is almost complete again – and the salmon has also returned. It has not yet reached Switzerland, but it has been observed swimming up many tributaries. It will still be a while before the Rhine’s stocks can sustain themselves without human intervention, but the results that have been achieved are encouraging. The salmon is back.
know nothing of what their fellow salmon have gone through. As they have done for millennia, this year the brightly colored fish will once again swim up the Koroc River to the place where they hatched years ago. The cycle of life will begin afresh.
David Ramler, PhD, worked as a fish ecologist at the University of Vienna and is a freelance biologist. His latest research looks at restoration projects in the Danube.