For the Environment

Wild Atlantic salmon are what is known as a ‘Keystone’ species – a species which is critical to the overall structure and functioning of an ecosystem. With their incredible lifecycle, in which they begin life in freshwater, migrate out to the ocean to reach adulthood, and then return to their home rivers to spawn (often dying afterwards), their bodies are a unique transportation vessel for marine-derived nutrients to be delivered far up into our freshwater catchments.

The importance of this nutrient transfer is well-known in the Pacific where many runs of wild salmon are still abundant, but is not largely considered as important in the Atlantic, probably due to the long-term decline of the species and this important ecological function being lost in time. It is estimated for example that the Rhine river system alone once saw runs of 10 million returning adult wild Atlantic salmon each year, five times the now estimated total number of 2 million adult wild Atlantic salmon remaining across the entire North Atlantic. In the past, before industrialisation across Europe and the proliferation of stream-blocking water mills, hydropower dams, the canalisation and modification of river channels, and large-scale urbanisation and agriculture, wild Atlantic salmon runs may well have been as spectacular as the Pacific salmon runs we still see in some places, with rivers quite literally full of fish, sustaining large predators like bears, wolves and lynx, as well as smaller animals such as otters and birds. The nutrient transfer from wild Atlantic salmon populations of this historic magnitude is now lost from our environment, but the benefits to biodiversity and our landscapes which would come from rebuilding this function, would be incredible.

Wild Atlantic salmon are also known as an ‘Indicator’ species. This means that, due to their requirements for an environment that provides cold, clean water both in freshwater, around our coasts, and at sea, they act as messengers, reporting back to us about the health and condition of these environments. The dramatic decline in wild Atlantic salmon is signaling that we have significant problems in these ecosystems, and the loss of this indicator species would represent the loss of a key measurement metric that holds immense value to us, and nature more generally, when it comes to tackling the climate and biodiversity crises. We cannot afford to lose them.

There are also symbiotic relationships in which wild Atlantic salmon are essential to the survival of other species, for example the freshwater pearl mussel whose larvae can only survive by clinging to the gills of juvenile wild Atlantic salmon. Without salmon, the pearl mussels die, and the loss of these two species together has a knock-on impact on the species which rely on them for prey.