The Ugly Duckling - Denmark's Skjern

Terkel Broe Christensen

Jul 3, 2019
A Skjern Atlantic salmon about to be released to continue its migration to spawning grounds upstream. Courtesy of the House of Salmon
In September 1981, biologists Niels Wegner and Søren Larsen were on the upper reaches of the River Skjern on Denmark’s Jutland Peninsula.

They were electrofishing to see what was living in the river, counting and identifying fish before letting them go. In one stretch they came across what they assumed to be six juvenile trout from the easily recognizable dark fingerlike marks along the sides of the fish.

On closer examination, however, they noticed unusually large pectoral fins and tiny red dots lined up perfectly in a row along their midline. They stared in amazement because this species was thought to have vanished from the Skjern. But, here was proof—Atlantic salmon had returned.

The story of the River Skjern, which cuts through the middle of the Danish mainland before emptying into the North Sea is like a true to life fairy tale. Of course, we Danes are no strangers to mythical fables. Denmark is the home of Hans Christian Andersen, a prolific writer best remembered for stories like the Emperor’s Clothes, The Princess and the Pea, The Little Mermaid and Thumbelina.
Anglers reap the benefits of an incredibly successful restoration effort in this river flowing across Denmark's Jutland. Photos courtesy of Kenny Frost, The House of Salmon
The Skjern’s own fairy tale begins when it was still famous for big multi-sea-winter salmon. Up into the middle of the 20th century, the River Skjern was a healthy, lowland river. Anglers routinely caught salmon greater than 40 pounds. In 1954, one fisher caught a salmon that weighed a little over 58 pounds, a Danish record that still stands.

Like the Restigouche in Canada, a higher percentage of Skjern salmon remain in the ocean for two years or more before returning to spawn. It’s an evolutionary strategy developed over millennia, a behavior that explains the river’s reputation for big salmon.

The Skjern itself is the largest river system in Denmark, draining around 10 percent of the country. It flows from groundwater sources in Tennet Krat, a region of oak forests, heaths and springs. Unlike many salmon rivers which plunge down from mountains and highlands, the River Skjern is a lowland river and rises only 68 meters from the sea to its source.

A beautiful river, running though the Danish countryside, what could go wrong? But like any good Hans Christian Andersen tale, there is always a villain. In Thumbelina it’s the evil toad, in the Little Mermaid, it’s a sea witch. Sadly for the Skjern, mankind is the villain.
The finding of wild Atlantic salmon parr in the Skjern in 1981 has led to an amazing recovery of a river's salmon run. Marek Rybar © Shutterstock
During the early part of the 20th century, farmers constructed dams to provide water for farming and weirs were built to feed fish farming operations. The effect on upstream and downstream salmon migration was obvious. The head ponds formed by the dams flooded spawning areas, while the runoff from the intensification of agriculture and the waste from fish farms raised pollution levels.

The final blow to the river and its salmon population came in the 1960s when a megaproject remade the lower 26 kilometres of the river. In order to control flooding and drain low-lying land, meanders were removed and tributaries turned into straight ditches flushing water badly polluted with fertilizer, herbicides and pesticides directly into the main stem. Some referred to this process of channelization as the river being “put into chains.” The lower reaches of the Skjern became a 19-kilometre-long lifeless canal.

To add insult to injury, in the process of dredging and digging, much of the fine spawning gravel habitat was removed or smothered by sand and mud.

Not surprisingly, the river’s salmon population plummeted. Rod catches dwindled from hundreds to fewer than ten salmon a season. By the time Wegner and Larsen had made their remarkable discovery, biologists for the local Ringkøbing County had estimated numbers of wild salmon returning to be as low as 25 fish. They predicted the total extinction of the Skjern salmon run within a few years.
Considering the damage done, it was a natural question whether the salmon parr found while electrofishing were from the original River Skjern strain. Wild Atlantic salmon are known to occasionally stray and enter a different river from where they were born. Perhaps Wegner and Larsen had chanced upon such “strays.” Using new gene technology and DNA material in archived scale samples, scientists were able to prove that the parr were descendants of the original River Skjern salmon.

Yet even the most optimistic conservationists understood that the population teetered on the brink of extinction. Such a scarce population, just a few dozen individuals, would be extremely vulnerable to any type of poaching, and prone to inbreeding.

Still, the discovery of wild salmon parr sent shockwaves through the local angler associations. Volunteers offered to scour the river looking for adults. Finding scarce salmon in a river more than 90-kilometers long was like looking for a needle in a haystack, but eventually, a sufficiently large number of spawners were caught. They were brought to the Danish Center for Wild Salmon where eggs and milt were carefully stripped and the resulting fry released back to the river.

Of course, none of this work would have any hope of jumpstarting the Skjern salmon run if the river remained in its present state. Nitrogen rich fertilizer runoff choked the lower river and polluted Ringkøbing Fjord. With its channel mechanically straightened and adjacent wetlands filled in, the river had lost much of its natural filtering properties.

The canal building project 25 years earlier came under increased scrutiny and criticism. Outrage at the state of the coastal waters, which was linked to the channeling of the river, combined with a general change in attitude toward the environment in Denmark.
The Skjern River before and after restoration efforts. Courtesy of the House of Salmon
The government now moved to remedy some of the environmental sins of the past. As a result, a national project to reduce nutrients contaminating the fjord was undertaken. Planners took aim at the “river in chains” and decided that freeing the Skjern to flow through its former course would help bring back its ability to clean itself.

Based on old aerial photos, the former meanders were mapped out and recreated. Dams and weirs were removed and the government began purchasing the many fishpond style aquaculture operations and shutting them down. By installing deflectors, recreating riffles and rapids, and re­pla­cing lost gravel, the river slowly regained its original form.

The Skjern restoration project was the largest of its kind in Northern Europe. Ironically, by the time the Skjern had become a river again, the cost of the work equalled the amount of money that had been spent to turn it into a canal.

As the Skjern regained its natural form, the flow slowed around deep meanders and water was oxygenated in riffles, and purified by reformed marshy areas. Like Hans Christian Andersen’s magical fable, The Ugly Duckling, the Skjern turned from a lifeless canal into a lovely, natural flowing river. The salmon responded in kind.

In 2003, Denmark’s Prince Joachim held an inauguration ceremony to celebrate the restored Skjern and that year anglers caught 150 salmon in the river. By 2010, seven years after the restoration was completed, a stunning 1,149 salmon were caught—an 800 percent improvement in less than a decade.
“Today, the River Skjern has become by far the best salmon river in Denmark,” explains Kenny Frost, who runs “The House of the Salmon”, a local angling information centre.

Frost is a passionate salmon angler himself and has been fishing the river since the 1980s. Back then, he says, there was a saying among the locals that anglers had to wear out at least two pairs of hip waders—and a car—before they could even dream of hooking up with one of the rivers big salmon, called “storlaks” in Danish.

But that’s all ancient history now, explains Frost.

“The last couple of years have been mind-blowing and the 2017 season beat all records with no less than 141 ‘storlaks’ taken.”

The most recent estimate puts the number of returning adults at around 5,500 salmon.

The drive to improve water quality and habitat has spread to other Danish regions and rivers, where both salmon and trout are also rebounding.

“River Skjern can now compete with the big boys in the class,” Kenny Frost exclaims proudly. As an example, he cites the world-famous Lakselv in northern Norway. In 2017, anglers there caught around 1,206 salmon. In the River Skjern, 1,684 salmon were landed.

Of course many threats remain. The cormorant population has grown, and like salmon from rivers around the North Atlantic, their ocean migration has become increasingly deadly.

Like “The Ugly Duckling,” the Skjern has blossomed into a beautiful river, but its rebirth isn’t over yet.

“If we continue to improve and enhance salmon habitat, then 12,000-15,000 River Skjern salmon is not out of the question,” says Kenny Frost smiling like a child wrapped up in a Hans Christian Andersen fairy tale.

Terkel Broe Christensen
is a Danish biologist and freelance writer. He spends as much time as possible on the Skjern River, sometimes catching and releasing a “laks ,” but always marvelling at the river’s rebirth.

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