Why are salmon at risk?

Once upon a time, the proto-salmon evolved to take advantage of the abundant food of the sea and the relative safety of freshwater as a place to reproduce. Now, the value that epic migration confers is more ambiguous. The salmon is threatened at all stages of its life cycle and each threat multiplies the risk to the future of the species. Twenty out of the 23 rivers in England that still contain salmon are now judged to be ‘at risk’.

Scientists refer back to the 1960s for a benchmark against which to measure our dwindling populations of salmon. This ground zero is known as ‘pre-fishery abundance’ and dates from a time before the salmon’s feeding grounds in the sea were discovered and pillaged, when there were five times as many salmon in British rivers as there are today. In truth, the salmon has been under threat since the first millennium, or even earlier. That 1960s ‘abundance’ is itself a shadow of what once existed. Salmon would once have been present in every British river, but were almost extinct across the breadth of lowland England before the Middle Ages, shut out by mills and pollution. The priest William Harrison was able to say of the River Thames in 1586 that it was so full of “fat and sweet salmons… as no river in Europe was able to exceed it”. Yet Thames salmon were extinct by 1821, wiped out by the filth produced by the Industrial Revolution.

The impact of pollution on salmon

Today, the curse of industrial pollution for salmon has, to a large extent, receded, but other, more pernicious threats have replaced it. Diffuse pollution – fertilisers, pesticides and agricultural run-off from soil erosion – has a malignant impact on juvenile salmon in apparently pristine, rural streams. Acid rain too; specifically the reaction of acidified rainwater with pine needles from the conifer plantations that cover large parts of upland Britain, which creates spikes of lethally toxic, acidified river water.

Dams, navigations and hydro-schemes continue to shut the door on the migrating adult salmon, something that has been illegal since the 12th century, although the laws have never actually stopped anyone.

Salmon farming

We discovered the salmon’s oceanic feeding grounds in the late 1950s and, for three decades, fished the hell out of the species, drastically reducing the global population. The impact of netting has diminished in recent years largely thanks to the Herculean efforts of the late, great Orri Vigfússon, an Icelandic entrepreneur and conservationist. During the 1990s, he managed to broker moratoria with salmon fishermen of the Faroe Islands and quota and net buyouts from other fishing fleets in the region. Today, there is very little salmon netting in the North Atlantic and the fishermen have been helped to convert to more sustainable alternative activities.

In fishing’s wake has come a new minotaur: salmon farming. Smoked salmon – once a luxury comparable with caviar – is now ubiquitous and inexpensive, but at massive environmental cost. The salmon farms that dot the sea lochs and estuaries of western Scotland create pestilential plagues of sea lice that have wiped out or seriously diminished runs of wild salmon (and sea trout) in those places. Although the technology exists to do things differently, salmon are farmed in ways that would never be tolerated in other, more visible forms of agriculture.

How will climate change affect salmon populations?

As if that weren’t bad enough, one threat – a warming Atlantic – may yet undo our salmon altogether. The temperature of the ocean affects how far the salmon have to travel to find food and how much they find when they get there. When once up to 15% of the young salmon that went to sea survived to return, now that number is more like 4%, and worsening with every passing decade.

In the face of such a decline, is there anything we can do to save the species in Britain? Fortunately, the salmon inspires devotion among rod-and-line fishermen, and they make a small army of conservationists. On the English and Welsh Wye, for example, a band of salmon lovers has in the last decade driven a three-fold increase in the salmon run by knocking down dams, neutralising acidified streams with lime, plus mile after tireless mile of habitat improvements. The best we can do to counter the poor survival at sea is to send as many young fish to sea as possible, at least until mankind finds a way to save itself and the planet from suicide by carbon emissions.

As for the general public, demanding a change to the way salmon are farmed would make a big difference. We should also hold the government to account over its agricultural and fisheries policies. Less soil erosion, less diffuse pollution, better landscape management – these things will all help save the nation’s most ancient resident. Salmon have been present along the south coast of England, which has never been covered by glaciation, since their evolution as a species two million years ago. We ought to make sure they do not disappear under our watch.

Where to see salmon in the UK?

Atlantic salmon can be found in freshwater rivers in Wales, Scotland and North and South West England.

• Philiphaugh Salmon Viewing Centre, Selkirkshire, TD7 5LX
• Stainforth Force, on the River Ribble, Settle, Yorkshire Dales, BD24 9QD
• Hexham Bridge Salmon Ladder, on the River Tyne, Northumberland
• Linn of Tummel, on the River Tummel, near Pitlochry, Perthshire, PH16 5NP
• Buchanty Spout, on the River Almond, Glenalmond, Perthshire
• Cenarth Falls, on the River Teifi, Pembrokeshire, South Wales
• Falls of Shin Visitors Centre, Achany Glen, Lairg, IV27 4EE

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