The story of the Atlantic Salmon (Salmo salar) is one worthy of Tolkien. It is a tale of there and back again, taking the salmon from fresh water high upstream to thousands of miles out into the Atlantic Ocean. Then, with a swish of the tail, it turns back home to the very same river where it was born. With a journey of such epic proportions, the salmon has much to tell us about the health of our rivers and seas. The adventure has become increasingly perilous and reflects humanity’s impact on the natural world, both at home and out on the high seas.

As a result of our actions, the Atlantic Salmon population has declined by 70% in the last 25 years. Some have even dubbed the species the canary in the coal mine when it comes to the climate and ecological emergency. However, this dramatic loss has not gone unnoticed. Many heroes in the form of volunteers, land managers and ecologists are working hard to bring this indicator species back from the brink and, through greater understanding of what exactly has gone wrong, we can find solutions. Though this once plentiful fish is now classed as endangered in the UK, rewilding our rivers and seas offers a story of hope.

The Urban Myth

The salmon has long been celebrated here in the UK, from the Picts who carved its image into stone to the incredible footage of a salmon leaping in the BBC’s Wild Isles documentary. It was of particular note for those who lived alongside the rivers and estuaries. For these communities, their seasons would be marked by the behaviour of this migratory fish. Festivals and parades marked the salmon’s return and it can be found in many family crests. There were even riots in Stirling when the local Abbey commandeered salmon stocks for export. 

It’s been said that salmon were once so plentiful in our rivers that servants and apprentices built clauses into their contract so that they would not be fed it every day. This was dismissed as an urban myth in the 1890s by Thomas Nadauld Brushfield who could find no record of any such clause, despite painstaking research. However the endemic nature of the story points to its believability. Perhaps the memories of such plentiful fish populations would have chimed with the words of parents and grandparents who bemoaned their decline. Today, the notion that the Tweed or the Thames would be bursting with so many fish is far more unbelievable. There have been generations of forgetting.  

Marine biologist Daniel Pauly spoke of how we too often measure nature depletion with reference to living memory. He coined the phrase ‘Shifting Baseline Syndrome’ to describe the phenomenon of how our understanding of norms in nature gradually shift. It is an issue which those in rewilding have experienced time and time again and not just with fish. People too often have a lost sense of what our land and sea should be like – what it could be like. When we look at our environment with an historical perspective we instead understand that our fields are lacking so many flowers, our skies hold too few insects, and, in our waters, salmon which should be there have disappeared. This September, research found that salmon numbers in England have hit their lowest level on record and in Scotland, the threat of declining numbers has led to the formulation of a Scottish wild salmon strategy. But, like in some hair-raising B-movie, our salmon are not just disappearing; they are also shrinking. 

The Canary in the Coal Mine

Given the salmon’s transitory nature, the reason for the shrinking and the disappearance of the salmon is complex. Some have blamed issues within the rivers; others point to problems within the seas. The truth of the matter is that the salmon faces threat at every stage on its migratory journey, contributed to by both habitat loss and climate change. 

Within the rivers salmon need cool clean waters with a mixture of calm gravel beds in which to spawn and develop and fast flowing waters to help them along their way down to the sea to feed. The natural course of a river will provide all these elements as it bends and falls along the valleys, shaded by riparian woodland. Unfortunately, in so many areas of the UK, such river ideals were lost in the name of progress. Trees were felled for fuel and building materials and rivers were straightened in an effort to reclaim land or to control the flow. Even as forests were replanted, the chosen crop of conifer plantations contrasted to the dappled light of native broadleaf trees preventing much needed vegetation alongside the rivers. Not only this, but the needles increased the acidity of the water. However, with climatic change, a lack of any shade presents a further problem. Thermal maps produced by Marine Scotland Science have highlighted that even rivers in the Scottish Highlands are reaching temperatures that are inhospitable for salmon.

Salmon have also been hit by the problem of pollutants in our rivers. Initially this was from the sewage of overpopulated cities and the chemical pollution and acid rains of the industrial revolution. Then, as agriculture intensified, our rivers met with fertiliser and slurry run-off. This increases nutrients in the water and leads to an imbalance in decaying vegetable matter and a fall in oxygen levels. Degraded peatlands also harm water quality and oxygen levels whereas healthy peatlands can benefit salmon by regulating peak flow. Though efforts have been made at times to address river pollution, we are sadly, once again facing the presence of sewage in our rivers. 

Pollution also comes at the estuaries and coastlines from another source. Although populations of wild salmon have decreased, our appetite for salmon has not. Salmon farms have sprung up to address the deficit and, with thousands of fish in each pen, make for a far easier catch. These commercial farms are often set up such that clean water flows in but waste and chemical treatments flow out, affecting the ecology of the surrounding area. With so many fish in close proximity, these farms also become a breeding ground for salmon lice (Lepeophtheirus salmonis) which escape to infect and feed on their wilder cousins, leading to their death.

Conditions in the rivers and estuaries test salmon’s resilience, but out at sea there is little relief. As technology in fishing improved, fleets began to venture further from the coastlines and became increasingly effective in catching fish of all sizes. Throughout their journey of thousands of miles to reach remote feeding grounds in the Atlantic, they are under threat from fishing nets and trawlers. The smaller fish upon which they feed are likewise depleted, affecting the salmon’s ability to grow and to thrive.  Rising temperatures at sea have also affected the abundance of another food source, plankton.  Researchers found that the average weight of salmon returning to the River Esk in Scotland had fallen by 29% for the salmon which stay at sea for just one year (grilse) and the shrinkage was even higher for salmon who had stayed at sea for two winters.

For those fish who successfully make it back to their natal rivers there are further barriers to their survival. The charity Wildfish reports that 97% of UK rivers are no longer connected. Man-made barriers such as weirs and dams prevent the fish from making their way back up to their spawning ground to complete their migratory journey or may trap them on their way out to sea. Salmon are athletic enough to leap waterfalls and beaver dams when water levels are seasonally high. However, the modification of waterways for industry and the lower water levels caused by drought are holding them back.

The Hope in Rewilding

This all paints a bleak picture for the salmon. It also shines a light on the effect that we are having on our natural environment. Some of the problems raised sit at the heart of modern debate on the Anthropocene. We are not going to tackle climate change overnight and we are already committed to further warming, but the impacts are already demonstrating the need for urgent action. In the meantime, we can address other challenges the salmon face to give them the best possible chance of survival.

Action starts high up at the river’s source. By rewilding our uplands through drain-blocking and promoting the growth of sphagnum moss, we can improve the water quality and regulate its flow. Such restoration work also helps the land to store carbon to add to our efforts to address climate change.

Then we can begin to cool the rivers by returning the river woodlands which once ran along the banks of salmon rivers to shade them and provide food for the fish.  Even the King is rewilding rivers on his Balmoral Estate to address the dramatic fall in salmon numbers on the Muick. The work of the estate, alongside other landowners, is part of the Riverwoods Initiative which has been beautifully covered in a film from Scotland: The Big Picture.

Another success story for the salmon lies in the rewiggling of rivers. A partnership project between the RSPB, Haweswater landowner United Utilities, the Environment Agency and Natural England saw the natural curve of Swindale Beck restored after 150 years. This led to a slowing of the river and the formation of gravel beds in which salmon could lay their eggs. As the RSPB wrote ‘If you bend it, they will come’

Campaigners such as WIldfish are also coordinating a public call for the barriers which fragment our rivers to be removed.  Where this has already happened, the results have been striking. High up in the Pennines, where industrialisation had led to a long series of weirs and locks. The removal of many of these, and the installation of salmon passes where this was not possible, led to the recording of the first Atlantic Salmon in West Yorkshire for 250 years.

Meanwhile, around our coastlines, seawilding to bring back our lost kelp forests creates habitats which shelter salmon and provide them with food. This positive step can also be balanced with better regulation of the fisheries to prevent trawling, overfishing and the negative impacts of farmed salmon. 

The King of Fish

All of these actions are well worth doing. They don’t just help endangered salmon populations but also other species within our rivers and seas. They provide a food source for otters, birds of prey, seals, tuna and dolphins. They themselves prey on smaller species such as herring, crustaceans and sand eels whilst out at sea and insects whilst they themselves are young. Occupying this middle spot, as both predator and prey, they help to create balance. As such they are not just an indicator species but also a keystone species.

They are also ecologically significant in the connection they provide. Through their migratory life-cycle they transfer nutrients derived from the ocean to far up in freshwater catchments. Their bodies, which have become large in the feeding grounds of the Atlantic, decompose back to the soils around spawning streams and enrich them with carbon, nitrogen and phosphorus to feed the riparian woodlands which shade them and feed their young.

Salmon have been respected by generations for many reasons. Their great size has earned them the title ‘King of Fish’; their ability to leap up to 3 metres earned them the name ‘the leaper’ (reflected in their Latin name ‘salar’). But it is their less visible attributes in terms of balance and connectivity which should be respected above all else. It is our knowledge and understanding of these two things that might inspire us to protect them.

The Salmon of Knowledge

In folklore, the Atlantic Salmon has long been associated with knowledge. The Irish hero Fionn mac Cumhaill gained the wisdom of the whole world from the salmon of knowledge. In Scandinavia too the salmon of northern rivers were believed to hold such wisdom. Whilst in Ireland the salmon had eaten hazelnuts that fell from the tree above the Well of Wisdom, in Scandinavia they had instead eaten the leaves of the world tree Yggdrasil as they fell into the river. Meanwhile, in Wales, King Arthur’s cousin Culhwch is directed to the salmon, the wisest of all creatures, to help him solve a challenge. It may have been wonder at the species’ skill in finding its way back home after years out at sea that led to this accolade. Scientists have now found this to be based on their ability to smell out the rivers of their birth, but it remains no less something to be marvelled at. 

Perhaps the deep knowledge of home possessed by the salmon should inspire wisdom in us, just as it did for the Fionn, Odin and Culhwch. After all, the word ecology is itself derived from the Greek for home, oikos. By understanding the balance of the home we left in pursuit of progress, we can address the mistakes that we have made and build a more harmonious future in which both we and the salmon can flourish.