River restoration and salmon migration in Ätran

Ätran is a classic west coast salmon river in Sweden, and the Herting project is a key part of its recent restoration history. The project improved fish passage past Herting hydropower plant, recreated several hundred metres of old riverbed as stream habitat and made migration easier to follow through the fish counter at Hertingforsen.

For anglers, Herting is useful because it adds context. It does not predict catches, but it helps show how fish move through the lower river and why Ätran is now a well-documented Swedish example of salmon river restoration and improved fish passage.

• Herting is a key lower-river migration point on Ätran.
• The project improved upstream and downstream fish passage.
• Several hundred metres of old riverbed were recreated as stream habitat suitable for salmon and sea trout.
• The Herting fish counter provides useful movement data, but not a catch forecast.
• For anglers, Herting data should be read as context, not as a standalone answer.

Herting is located on the lower Ätran in Falkenberg, close to the part of the river that matters most for fish entering from the sea. For migratory species such as Atlantic salmon and sea trout, a barrier in the lower river can affect access to spawning and nursery areas farther upstream.

The Herting project was created to solve that problem. Its aim was to restore free upstream and downstream passage for fish past Herting hydropower plant while keeping part of the power production in place.

For anglers and river managers, Herting is one of the best-documented places for understanding salmon migration in the lower Ätran today. Fish passage, restored habitat and live counting data all meet in one lower-river location.

The Herting project ran between 2002 and 2015. The main work focused on improving fish passage around Herting hydropower plant and rebuilding part of the river environment. Construction work began in 2013, and the new fishway opened in spring 2014.

The project changed three things at once:

• Fish passage: salmon, sea trout and other migratory species gained improved passage past Herting.
• River habitat: several hundred metres of old riverbed were recreated as flowing stream habitat.
• Migration monitoring: fish moving through Hertingforsen could be followed with a modern fish counter.

This matters because restoration is not only about making a river look more natural. In a salmon river, open passage and usable habitat decide whether fish can reach the right parts of the system and use them for spawning and juvenile growth.

Salmon migration depends on access. If fish reach a lower-river obstacle and cannot pass it efficiently, the effect can be felt far upstream. Good spawning and nursery areas lose value if returning fish struggle to reach them.

The Herting project was built around this basic issue. It restored passage in both directions: upstream for adult fish returning from the sea, and downstream for fish moving back through the system.

To understand why this matters, it helps to think of salmon migration as a chain. If one lower-river link does not work, the whole system can be affected.

After the restoration, positive changes were already visible in the wider Ätran system. The Länsstyrelsen report notes that in 2017 more than 1,000 salmon were lifted into Högvadsån at Nydala kvarn, higher up in the catchment, and that fish reached Nydala much faster than before the project.

That does not mean every change in the salmon population can be explained by Herting alone. Rivers are affected by flow, temperature, marine survival, fishing pressure and many other factors. Herting should be seen as one of the clearest documented restoration points in Ätran’s recent salmon history.

The current fish counter at Hertingforsen was put into operation in March 2014. According to Fiskdata, it is placed in the new open dam at the top of Hertingforsen and registers fish making a full passage through the counter, both upstream and downstream. Fish are also measured, filmed and published online.

For anglers, the counter is useful because it provides movement data from a key point in the lower river. It can show whether fish are moving through Herting, whether activity is increasing and how movement changes during the season.

But the counter should not be read as a direct fishing forecast. Fiskdata states that the live data is unreviewed and uninterpreted, and that figures may contain errors. That makes it valuable as live context, but not as a complete answer on its own.

Herting data should be read together with current water, temperature, local reports, permits and rules. Migration data tells you that fish are moving. It does not tell you exactly where to stand, which pool to fish or whether conditions are right for your method.

For anglers, the Herting project matters because it changed the lower Ätran from a migration bottleneck into a restored and monitored passage point. That gives the river a clearer modern salmon profile than many rivers where migration is harder to follow.

The practical value is context. If fish are passing Herting, you know that salmon or sea trout are moving through a lower-river point. If the numbers change after rain, flow shifts or temperature changes, that can help you understand the rhythm of the river.

Still, Herting should be treated as one part of the decision. A salmon angler planning Ätran should not rely only on counter data. The stronger approach is to combine migration with conditions, reports and local rules.

In simple terms:

• Fish counter data shows movement.
• Water data shows whether the river is in a fishable state.
• Catch reports show recent fishing outcomes.
• Rules and permits decide where and how you can fish.

For a trip decision, these signals work best together. Counter data shows movement, but conditions and rules decide whether the river is actually worth fishing on a given day.

The Herting project was also analysed in economic terms. The 2018 Länsstyrelsen report estimated its net present value at about 65.3–65.4 million SEK over 50 years, using a 3% discount rate.

In the report’s cost-benefit analysis, the main monetised benefits came from recreation, sport fishing and the existence value of a genetically unique salmon stock. The main costs were linked to construction work, new fish passage infrastructure and a permanent loss of about 40% of the power plant’s production capacity.

For anglers, the important point is not the calculation itself, but what it shows. Salmon restoration can create value beyond biology: through sport fishing, tourism, recreation and the long-term identity of a salmon river.

For Ätran, that matters because salmon are not just a species in the river. They are part of the river’s fishing value, local identity and long-term role as a west coast salmon destination.

For Ätran, Herting is best understood as both a migration signal and a restoration landmark. It helps explain how fish move through the lower river today, but a good fishing decision still depends on current water, temperature, reports, permits and local rules.