How AI Is Reclaiming Norway's Rivers from an Invasive Species

2023 is a big year for Norway’s system of 500 rivers.

From early June into September, a flood of salmon will swarm upstream in the Scandinavian nation’s river system to seek spawning grounds.

With a 24-month breeding cycle, the arrival of Pacific salmon – also known as humpback salmon – peaks in odd years. While 2021 saw a record-breaking 111,700 Pacific salmon enter Norway’s rivers, 2023 is set to be a pivotal year, with its breeding cycle underway and numbers set to skyrocket – perhaps doubling.

However, this is far from good news. The Pacific salmon is an invasive species, one that is threatening the extinction of Norway’s wild Atlantic salmon.

Arriving from the Russian White Sea in the 1950s and quickly spreading throughout Norway’s river system, the invader quickly began disrupting food chains, reducing the overall life that rivers can support, introducing disease, and outcompeting Norway’s wild Atlantic salmon for food and spawning grounds.

Since the 1980s, the population of wild Atlantic salmon has halved. Conversely, the number of Pacific salmon that arrives from the ocean for their biennial spawning season is increasing exponentially.

Given the importance of wild Atlantic salmon to Norway’s culture and economy, this alarming trend frequently makes local headlines and an urgent solution is required.

Fishing for a smart solution

To help develop a tech-based answer under the guidance of local environmental protection agencies, Huawei teamed up with local angling and hunting association Berlevag JFF (BJFF) under Huawei’s TECH4ALL initiative to figure out how to identify and filter out the invasive species.

The traditional manual method – people standing in the river and sorting fish by hand – is as impractical as it is ineffective.

In 2021, a solution was born and deployed in Storelva River in the northern fishing town of Berlevåg. With underwater cameras providing a continuous video stream, AI algorithms were trained to accurately identify Atlantic salmon, setting the stage for a filtering system. In 2022, we deployed a gate system that opens to let wild Atlantic salmon and other fish pass upstream to spawn, but filters the invasive Pacific salmon into a holding tank for removal.   

This year, the efficacy of the solution was put to the test with the biennial arrival of Pacific salmon. And so far, it has indeed proven effective, capturing around 5,500 Pacific salmon to date, with an accuracy rate of 100%!

And in an article posted this week by the Norwegian media outlet VG covering the invasive species problem, Eirik Frøiland from Norway’s Environment Agency told VG:

“In Berlevåg, for example, the hunting and fishing association has used AI to let through Atlantic salmon and stop pink salmon. That’s not our project. But the Environmental Administration thinks this idea is so good that a competition has been announced with support from the Research Council of Norway to develop such traps by 2027.

As the project has progressed and been deployed, one thing I’ve learned from people in Berlevåg is that everyone is aware of the solution and hopes are high that it will be as effective as we believe it will be. Many local businesses, like restaurants and hotels, depend on the river’s appeal as an angling destination, an appeal that would be lost if the ability of the river to support marine life is compromised.

It’s also worth pointing out that in Berlevåg, people are as helpful as they are friendly. When an unexpected problem occurs onsite, everyone is prepared to pitch in and help out. For example, a local resident overheard us saying we needed a path to access the area where the gate and timer was installed so we could maintain it easily. He told us to wait and, 20 minutes later, returned with wood, a hammer, and nails. Then in two hours, we had our path.

What we’ve learned so far about the solution’s efficacy

Since the peak arrival of the invasive species in June, we’ve made several observations.

Underwater camera showing the solution in action

1. A few Atlantic salmon swim into the filtering system with the Pacific salmon and enter the holding tank at the same time. They can be retrieved from the holding tank and placed back into the river by manual sorting.
2. Some Atlantic salmon hang back farther down the river, potentially waiting for days until the flood of Pacific salmon has passed before proceeding through the gate.
3. Most Atlantic salmon wait below the fence at the entrance to the system until the Pacific salmon have passed through the tunnel and been filtered into the holding tank. The Atlantic salmon then swim through the tunnel and proceed upstream.

As the above observations indicate, a secondary benefit of the solution can reveal patterns of migratory behavior, monitor different types of fish populations, provide information for further research, and help prevent overfishing.

This early success gives hope that the solution can be applied in other rivers in Norway that face the threat of this invasive species.

Read more about the background to this project: Saving Norway’s Endangered Atlantic Salmon

Disclaimer: Any views and/or opinions expressed in this post by individual authors or contributors are their personal views and/or opinions and do not necessarily reflect the views and/or opinions of Huawei Technologies.